Chapter 4 - Risk Assessment

Chapter 4 - Risk Assessment

4 R

ISK

A

SSESSMENT

Requirement §201.6(c)(2): [The plan shall include] A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards.

Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards.

As defined by the Federal Emergency Management Agency (FEMA), risk is a combination of hazard, vulnerability, and exposure. It is the impact that a hazard would have on people, services, facilities, and structures in a community and refers to the likelihood of a hazard event resulting in an adverse condition that causes injury or damage.

The risk assessment process identifies and profiles relevant hazards and assesses the exposure of lives, property, and infrastructure to these hazards. The process allows for a better understanding of a jurisdiction‘s potential risk to natural hazards and provides a framework for developing and prioritizing mitigation actions to reduce risk from future hazard events.

This risk assessment followed the methodology described in the FEMA publication

Understanding Your Risks—Identifying Hazards and Estimating Losses (FEMA 386-2, 2002), which breaks the assessment down to a four-step process:

1) Identify Hazards;

2) Profile Hazard Events;

3) Inventory Assets; and

4) Estimate Losses.

Data collected through this process has been incorporated into the following sections of this

chapter: Section 4.1: Hazard Identification: Natural Hazards identifies the natural hazards that

threaten the planning area and describes why some hazards have been omitted from further

consideration. Section 4.2: Hazard Profiles discusses the threat to the planning area and

describes previous occurrences of hazard events and the likelihood of future occurrences.

Section 4.3: Vulnerability Assessment assesses the planning areas‘ exposure to natural hazards;

considering assets at risk, critical facilities, and future development trends. Section 4.4:

Capability Assessment inventories existing mitigation activities and policies, regulations, and plans that pertain to mitigation and can affect net vulnerability.

This risk assessment covers the entire geographical extent of the Butte County Planning Area

(planning area), including the incorporated communities and other participating jurisdictions.

Since this plan is a multi-jurisdictional plan, the Hazard Mitigation Planning Committee

(HMPC) is required to evaluate how the hazards and risks vary from jurisdiction to jurisdiction.

While these differences are noted in this chapter, they are expanded upon in the annexes of the participating jurisdictions. If no additional data is provided in an annex, it should be assumed

Butte County

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4.1

that the risk and potential impacts to the affected jurisdiction are similar to those described here for the entire Butte County Planning Area.

This Local Hazard Mitigation Plan (LHMP) update involved a comprehensive review and update of each section of the 2007 risk assessment. As part of the risk assessment update, new data was used, where available, and new analyses were conducted. Refinements, changes, and new methodologies used in the development of this risk assessment update are summarized in

Chapter 2 What‘s New and detailed in this Risk Assessment portion of the plan.

4.1 Hazard Identification: Natural Hazards

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type…of all natural hazards that can affect the jurisdiction.

The Butte County HMPC conducted a hazard identification study to determine the hazards that threaten the planning area. This section details the methodology and results of this effort.

4.1.1 Methodology and Results

Using existing natural hazards data and input gained through planning meetings, the HMPC agreed upon a list of natural hazards that could affect Butte County. Hazards data from the

California Emergency Management Agency (CAL EMA), FEMA, the National Oceanic and

Atmospheric Administration (NOAA), and many other sources were examined to assess the significance of these hazards to the planning area. Significance of each identified hazard was measured in general terms and focused on key criteria such as frequency and resulting damage, which includes deaths and injuries, as well as property and economic damage. The natural hazards evaluated as part of this plan include those that have occurred historically or have the potential to cause significant human and/or monetary losses in the future.

The following hazards in Table 4.1, listed alphabetically were identified and investigated for this

plan update. As a starting point, the updated California State Hazard Mitigation Plan was consulted to evaluate the applicability of new hazards of concern to the State to the planning area. Building upon this effort, hazards from the past plan were also identified, and comments explain how hazards were updated from the previous plan. Most hazards from the 2007 plan were profiled in this plan, with the exception of the naturally occurring biological threats and the domestic security threat of terrorism, which has been eliminated from further consideration in this natural hazards plan, as they have been addressed in other state, regional, and County planning mechanisms.

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4.2

Table 4.1. Hazard Identification and Comparison

2013 Hazards

Dam Failure

Drought & Water Shortage

Earthquakes

Earth Movements: Landslide

Earth Movements: Erosion

Floods: 100/500 year

Floods: Localized Stormwater

Hazardous Materials Incidents:

Transportation

Invasive Species: Pests/Plants

2007 Hazards

Dam Failure

Extreme Weather (drought/heavy rain/hailstorm/windstorm/tornado

Earthquake

Comment

Performed dam inundation analysis in both map and tabular form.

Added water shortage discussion

Landslide

Floods*

Hazardous Materials Incidents

Insect Infestation

Added liquefaction analysis and discussion.

Similar analysis was performed

New hazard

Performed greater analysis on 100 year flood. Added analysis on 500 year flood.

New hazard

A greater focus on transportation routes was given. Analysis was performed on populations in the hazardous materials routes in the County.

Added invasive plant species discussion

Levee Failure

Marine Invasive Species

Severe Weather: Extreme Heat

Severe Weather & Storms:

Heavy rain, hailstorm, lightning

Severe Weather: Tornado

Severe Weather: Windstorms

Extreme Weather (drought/heavy rain/hailstorm/windstorm/tornado)

Extreme Weather (drought/heavy rain/hailstorm/windstorm/tornado)

Extreme Weather (drought/heavy rain/hailstorm/windstorm/tornado

New hazard

New hazard

New hazard (though mentioned in the 2007 plan drought profile)

Similar analysis was performed.

Similar analysis was performed.

Similar analysis was performed.

New hazard Severe Weather: Winter Storm/

Freeze

Volcanoes

Wildfires

Wildfires

Naturally Occurring Biological

Threats

Terrorism (CBRNE), Chemical,

Biological, Radiological, Nuclear,

Explosive

New hazard

Greater analysis was performed.

This has been eliminated from this plan.

They have been kept for reference purposes in Appendix H.

These have been eliminated from this plan, and will be included in County Response

Planning. They have been kept for reference purposes in Appendix H.

The worksheet below was completed by the HMPC to identify, profile, and rate the significance of identified hazards. Only the more significant (or priority) hazards have a more detailed hazard

profile and are analyzed further in Section 4.3 Vulnerability Assessment. Table 4.29 in Section

4.2.19 Natural Hazards Summary provides an overview of these significant hazards.

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4.3

Table 4.2. Butte County Hazard Identification Worksheet

Hazard

Geographic

Extent

Dam Failure

Drought & Water shortage

Significant

Extensive

Earthquakes Extensive

Earth Movements: Landslide Limited

Earth Movements: Erosion

Hazardous Materials

Incidents: Transportation

Limited

Floods: 100/200/500 year Significant

Floods: Localized Stormwater Extensive

Significant

Invasive Species: Pests/Plants Significant

Levee Failure Significant

Marine Invasive Species

Severe Weather: Extreme

Heat

Limited

Significant

Severe Weather: Freeze and

Winter Storm

Severe Weather: Heavy rain, hailstorm, lightning

Significant

Significant

Probability of

Future

Occurrences

Unlikely

Occasional

Occasional

Likely

Highly Likely

Occasional

Highly Likely

Likely

Highly Likely

Occasional

Occasional

Highly Likely

Highly Likely

Highly Likely

Magnitude/Severity

Critical

Critical

Critical

Negligible

Significant

Critical

Critical

Critical

Limited

Limited

Limited

Critical

Critical

Critical

Significance

Medium

Medium

Medium

Low

Medium

High

Medium

Medium

Low

High

Low

Low

Medium

Medium

Severe Weather: Tornado Limited

Severe Weather: Windstorms Extensive

Volcanoes

Wildfires

Significant

Significant

Likely

Highly Likely

Unlikely

Highly Likely

Limited

Critical

Critical

Critical

Low

Medium

Low

High

Geographic Extent

Limited: Less than 10% of planning area

Significant: 10-50% of planning area

Extensive: 50-100% of planning area

Probability of Future Occurrences

Highly Likely: Near 100% chance of occurrence in next year, or happens every year.

Likely: Between 10 and 100% chance of occurrence in next year, or has a recurrence interval of 10 years or less.

Occasional: Between 1 and 10% chance of occurrence in the next year, or has a recurrence interval of 11 to 100 years.

Unlikely: Less than 1% chance of occurrence in next 100 years, or has a recurrence interval of greater than every 100 years.

Magnitude/Severity

Catastrophic

—More than 50 percent of property severely damaged; shutdown of facilities for more than 30 days; and/or multiple deaths

Critical

—25-50 percent of property severely damaged; shutdown of facilities for at least two weeks; and/or injuries and/or illnesses result in permanent disability

Limited

—10-25 percent of property severely damaged; shutdown of facilities for more than a week; and/or injuries/illnesses treatable do not result in permanent disability

Negligible

—Less than 10 percent of property severely damaged, shutdown of facilities and services for less than 24 hours; and/or injuries/illnesses treatable with first aid

Significance

Low: minimal potential impact

Medium: moderate potential impact

High: widespread potential impact

Source: AMEC Data Collection Guide

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4.1.2 Disaster Declaration History

One method to identify hazards based upon past occurrence is to look at what events triggered federal and/or state disaster declarations within the planning area. Disaster declarations are granted when the severity and magnitude of the event‘s impact surpass the ability of the local government to respond and recover. Disaster assistance is supplemental and sequential. When the local government‘s capacity has been surpassed, a state disaster declaration may be issued, following the local agency‘s declaration, allowing for the provision of state assistance. Should the disaster be so severe that both the local and state government‘s capacity is exceeded, a federal disaster declaration may be issued allowing for the provision of federal disaster assistance.

Butte County has experience 18 federal and 21 state declarations since 1950. 12 of the federal declarations and 12 of the state declarations were associated with flood events. Of the 6 remaining federal declarations, two were related to fire, one was related to drought, one to freezes, one to earthquake, and one due to Hurricane Katrina evacuations in 2005. Of the 9 remaining state disasters, 1 was related to drought, 2 were related to freeze, and 6 were related to wildfire. There have been 2 recent USDA Secretarial Disaster Designations in Butte County related to agricultural losses from natural hazards. The County FSA office was not able to provide historical USDA disaster declarations. A summation of federal and state disaster

declarations is shown in Table 4.3.

Table 4.3. Butte County Federal and State Disaster Declaration History

Year Disaster Name

2008 -

Disaster

Type

Agricultural

2008 - Agricultural

2008

2008

2008

2008

2005/

2006

2005

Mid-year fires Fire

Humboldt Fire Fire

Ophir Fire

2008 January

Storms

2005/06 Winter

Storms

Hurricane

Katrina

Evacuations

Fire

Flood

Flood

Economic

2004 Oregon Fire

1999 1999 August

Fires

1998 1998 El Nino

Floods

Fire

Fire

Flood

Disaster

Fire

Fire

Cause

Drought

Storms

Disaster #

S2708

Freezing

Temperatures

S3109

Fire EM-3287

-

-

State

Declaration

FM 2771

FM 2770

6/28/2008

6/11/2008

6/10/2008

GP 2008-01 1/15/2008

Federal

Declaration

9/16/2008

6/30/2008

-

-

-

-

Storms

Hurricane

Fire

Fire

Storms

DR

‐1628

-

EM

‐3248 2005 -

FM-2545

EM-3140

DR

‐1203

-

8/26/1999

Proclaimed

2/3/2006

9/13/2005

8/11/2004

9/1/1999

2/19/1998

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4.5

Year Disaster Name

1997 1997 January

Floods

Disaster

Type

Flood

Flood 1995 1995 Severe

Winter Storms

1995 1995 Severe

Winter Storms

1990 1990 Freeze

Flood

Freeze

1990

1987

1986

1982

1976

1975

1990 Severe

Storms

1987 Wildland

Fires

Flood

Fire

1986 Storms Flood

Winter Storms Flood

1976Drought Drought

Storms

Flood

-

Disaster

Cause

Storms

Storms

Storms

Freeze

Storms

Fire

Disaster #

DR

‐1155

State

Declaration

Federal

Declaration

1/2/97

‐1/31/97

1/4/1997

DR-1046

DR

‐1044

DR-894

GP 989-06

GP

DR

DR

‐758

‐677

EM-3023

1/6/95

1/6/95

12/19/1990 -

1/18/1991

2/22/1990

9/10/87

2/18

‐3/14/95

3/12/1995

‐3/14/95 1/13/1995

2/11/1991

-

-

‐86-3/12/86 2/18/1986

12/8/82

‐3/21/83 2/9/1983

2/9/76,

2/13,76,

2/24/76,

3/26/76,

7/6/76

-

1/20/1977

8/1/1975

1973

1970

1969

1964

1962

Butte

Earthquake

1973 Freeze

1970 Northern

California

Flooding

Earthquake Earthquake DC 75-03

Freeze

Flood

Freeze

Flood

-

DR-283

1969 Storms

1964 Late

Winter Storms

1962 Floods and Rain

Flood

Flood

Flood

Fire

Storms

Storms

Storms

Fire

DR

DR-183

DR-138

-

‐253

2/28/1973

1/27/1970,

2/3/1970,

2/10/1970,

3/2/1970

1/23/69-3/12/69 1/26/1969

-

10/17/62,

10/25/62,

10/30/62, &

11/4/62

9/18/1961

-

2/16/1970

12/24/1964

10/24/1962

- 1961 1961

Widespread

Fires

1958 1958 April

Storms and

Floods

Source: Cal EMA, PERI

Flood Storms DR-82 4/5/1958 4/4/1958

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Local Hazard Mitigation Plan Update

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4.6

4.2 Hazard Profiles

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the…location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

The hazards identified in Section 4.1 Hazard Identification Natural Hazards, are profiled

individually in this section. In general, information provided by planning team members is integrated into this section with information from other data sources. These profiles set the stage

for Section 4.3 Vulnerability Assessment, where the vulnerability is quantified, as data allows,

for each of the priority hazards.

Each hazard is profiled in the following format:

Hazard/Problem Description—This section gives a description of the hazard and associated issues followed by details on the hazard specific to the Butte County Planning Area. Where known, this includes information on the hazard extent, seasonal patterns, speed of onset/duration, and magnitude and/or any secondary effects.

Past Occurrences—This section contains information on historical incidents, including impacts where known. The extent or location of the hazard within or near the Butte County

Planning Area is also included here. Historical incident worksheets were used to capture information from participating jurisdictions on past occurrences.

Frequency/Likelihood of Future Occurrence—The frequency of past events is used in this section to gauge the likelihood of future occurrences. Where possible, frequency was calculated based on existing data. It was determined by dividing the number of events observed by the number of years on record and multiplying by 100. This gives the percent chance of the event happening in any given year (e.g., three droughts over a 30-year period equates to a 10 percent chance of a experiencing a drought in any given year). The likelihood of future occurrences is categorized into one of the following classifications:

Highly Likely—Near 100 percent chance of occurrence in next year or happens every year

Likely—Between 10 and 100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less

Occasional—Between 1 and 10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years

Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.

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4.7

Section 4.2.19 Natural Hazards Summary provides an initial assessment of the profiles and

assigns a level of significance or priority to each hazard. Those hazards determined to be of medium or high significance were characterized as priority hazards that required further

evaluation in Section 4.3 Vulnerability Assessment. Those hazards that occur infrequently or

have little or no impact on the planning area were determined to be of low significance and not considered a priority hazard. Significance was determined based on the hazard profile, focusing on key criteria such as frequency and resulting damage, including deaths/injuries and property, crop, and economic damage. This assessment was used by the HMPC to prioritize those hazards of greatest significance to the planning area, enabling the County to focus resources where they are most needed.

The following sections provide profiles of the natural hazards that the HMPC identified in

Section 4.1 Hazard Identification. Given that most disasters that affect the planning area are

directly or indirectly related to severe weather events, severe weather hazards begins this section, and the individual hazard profiles following alphabetically.

4.2.1 Severe Weather: General

Severe weather is generally any destructive weather event, but usually occurs in the Butte

County Planning Area as localized storms that bring heavy rain, hail, lightning, and strong winds.

The National Oceanic and Atmospheric Administration‘s National Climatic Data Center

(NCDC) has been tracking severe weather since 1950. Their Storm Events Database contains data on the following: all weather events from 1993 to current (except from 6/1993-7/1993); and additional data from the Storm Prediction Center, which includes tornadoes (1950-1992), thunderstorm winds (1955-1992), and hail (1955-1992). This database contains 50 severe weather events that occurred in Butte County between January 1, 1950, and August 31, 2011.

Table 4.4 summarizes these events.

Table 4.4. NCDC Severe Weather Reports for Butte County, 1950 to August 31, 2011*

Type

Dam Break

Flash Flood

Funnel Cloud

Hail

Heavy Rain

High Wind

Lightning

Thunderstorm Winds

Tornado

Wildfire

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Local Hazard Mitigation Plan Update

May 2013

# of Events Deaths Injuries Property Damage Crop Damage

1 0 0 $0 $0

6

1

0

0

0

0

$50,000

$0

$0

$0

8

6

1

3

0

0

0

0

0

0

0

0

$0

$0

$50,000

$5,090,000

$0

$0

$0

$0

5

14

4

0

0

0

0

6

5

$0

$8,232,000

$2,380,000

$0

$0

$0

4.8

Winter Storm

Type # of Events Deaths Injuries Property Damage Crop Damage

1

Totals

Source: NCDC

*Note: Losses reflect totals for all impacted areas

50

0

0

0

11

$0

$15,802,000

$0

$0

The HMPC supplemented NCDC data with data from SHELDUS (Spatial Hazard Events and

Losses Database for the United States). SHELDUS is a county-level data set for the United

States that tracks 18 types of natural hazard events along with associated property and crop losses, injuries, and fatalities for the period 1960-2010. Produced by the Hazards Research Lab at the University of South Carolina, this database combines information from several sources

(including the NCDC). The database includes every loss causing and/or deadly event between

1960 through 1979 and from 1995 onward. Between 1980 and 1995, SHELDUS reflects only events that caused at least one fatality or more than $50,000 in property or crop damages. For events that covered multiple counties, the dollar losses, deaths, and injuries were equally divided among the affected counties (e.g., if four counties were affected, then a quarter of the dollar losses, injuries, and deaths were attributed to each county). From 1995 to 2010 all events that were reported by the NCDC with a specific dollar amount are included in SHELDUS.

SHELDUS contains information of 104 severe weather events that occurred in Butte County

between 1960 and 2010. These events are shown and summarized in Table 4.5.

Table 4.5. SHELDUS Severe Weather Report for Butte County 1960-2010

Type

Earthquake

Flooding

Flooding - Severe Storm/Thunder Storm

Flooding - Severe Storm/Thunder Storm - Wind

Flooding - Winter Weather

Hail

Hail - Lightning

Hail - Severe Storm/Thunder Storm - Wind -

Winter Weather

Heat

Lightning

Lightning - Severe Storm/Thunder Storm

Lightning - Wind - Winter Weather

Severe Storm/Thunder Storm

Severe Storm/Thunder Storm

– Wind

Severe Storm/Thunder Storm - Wind - Winter

Weather

Severe Storm/Thunder Storm - Winter Weather

# of

Events

1

8

Injuries Deaths

0

14.54

0

Property

Damage

$6,000,000

Crop Damage

$0

3.22 $11,608,888.90 $1,013,472.23

2

1

2

1

0.00

0

0.00

0.00

0.00

0

0.00

0.00

$86,206.90

0

$20,718.82

$0.00

$35,714.29

$11,241,379.31

$0.00

$25,000.00

1

1

0.00

0.02

0.00

0.03

$500.00

$86.21

$0.00

$0.00

1

8

1

1

8

11

3

2

1.03

7.29

0.00

0.07

0.30

3.77

0.00

0.00

0.00 $0.00

1.57 $4,162,678.58

0.00

0.00

0.80

1.18

0.03

0.00

$178.57

$3,571.43

$885,717.11

$561,909.95

$23,768.47

$3,821.43

$0.00

$0.00

$178.57

$357.14

$18,189.66

$90,081.76

$8,620.69

$0.00

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Tornado

Wildfire

Wind

Type

Wind - Winter Weather

# of

Events

8

4

23

2

Injuries Deaths

4.00

7.00

2.04

0.31

0.00

0.00

0.35

0.00

Property

Damage

$591,000.00

$2,594,285.71

$1,261,286.64

$33,881.58

Crop Damage

$5,000.00

$0.00

$10,254.27

$31,250.00

Winter Weather 15 2.51 0.29 $488,224.84 $8,890,071.26

Totals 104 42.88 7.47 $28,326,725.14 $21,369,569.18

Source: SHELDUS

*Events may have occurred over multiple counties, so damage may represent only a fraction of the total event damage and may be not specific to Butte County

The NCDC and SHELDUS tables above summarize severe weather events that occurred in Butte

County. Only a few of the events actually resulted in state and federal disaster declarations. It is further interesting to note that different data sources capture different events during the same time period, and often display different information specific to the same events. While the

HMPC recognizes these inconsistencies, they see the value this data provides in depicting the

County‘s big picture hazard environment.

As previously mentioned, most all of Butte County‘s state and federal disaster declarations have been a result of severe weather and related flooding. For this plan, severe weather is discussed in the following subsections:

Extreme Heat

Heavy rain, hailstorm, lightning

Tornado

Windstorm

Winter Storm and Freeze

Due to size of the County and changes in elevation (i.e., from approximately 60 feet to more than

7,000 feet above mean sea level (msl)) and climate, weather conditions can vary greatly across the County. For purposes of this hazard profile, the County will be divided into two distinct sections, as applicable: western Butte County, which is predominantly below an elevation of

2,000 feet above msl, is generally below the snowfall line, and includes the land to the west

(including all incorporated cities and towns); and eastern Butte County, which is generally above

2,000 feet above msl and receives snowfall. The profiles that follow provide information, where possible, from two weather stations located in these two different parts of the County: Oroville

(elevation: 160 feet above msl) in west Butte County and De Sabla (elevation: 2,720 feet above msl), in east Butte County.

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4.2.2 Severe Weather: Extreme Heat

Hazard/Problem Description

According to information provided by FEMA, extreme heat is defined as temperatures that hover

10 degrees or more above the average high temperature for the region and last for several weeks.

Heat kills by taxing the human body beyond its abilities. In a normal year, about 175 Americans succumb to the demands of summer heat. According to the National Weather Service (NWS), among natural hazards, only the cold of winter—not lightning, hurricanes, tornados, floods, or earthquakes—takes a greater toll. In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat. In the heat wave of 1980, more than 1,250 people died.

Heat disorders generally have to do with a reduction or collapse of the body‘s ability to shed heat by circulatory changes and sweating or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body‘s inner core begins to rise and heat-related illness may develop. Elderly persons, small children, chronic invalids, those on certain medications or drugs, and persons with weight and alcohol problems are particularly susceptible to heat reactions, especially during heat waves in areas where moderate climate usually prevails.

Heat emergencies are often slower to develop, taking several days of continuous, oppressive heat before a significant or quantifiable impact is seen. Heat waves do not strike victims immediately, but rather their cumulative effects slowly take the lives of vulnerable populations.

Heat waves do not cause damage or elicit the immediate response of floods, fires, earthquakes, or other more ―typical‖ disaster scenarios. While heat waves are obviously less dramatic, they are potentially more deadly. According to the 2010 California State Hazard Mitigation Plan, the worst single heat wave event in California occurred in Southern California in 1955, when an eight-day heat wave resulted in 946 deaths. Severe heat in California often causes rolling blackouts. These blackouts have occurred in the past (namely 2001 and 2002) and can increase the risk of injury or death.

Figure 4.1 and Figure 4.2 show the Heat Index (HI) as a function of heat and relative humidity.

The Heat Index describes how hot the heat

‐humidity combination makes it feel. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration. As the HI rises, so do health risks.

When the HI is 90°F, heat exhaustion is possible with prolonged exposure and/or physical activity.

When it is 90°

‐105°F, heat exhaustion is probable with the possibility of sunstroke or heat cramps with prolonged exposure and/or physical activity.

When it is 105°

‐129°F, sunstroke, heat cramps or heat exhaustion is likely, and heatstroke is

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4.11

possible with prolonged exposure and/or physical activity.

When it is 130°F and higher, heatstroke and sunstroke are extremely likely with continued exposure. Physical activity and prolonged exposure to the heat increase the risks.

Figure 4.1. Heat Index

Source: National Weather Service

Note: Since HI values were devised for shady, light wind conditions, exposure to full sunshine can increase HI values by up to

15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

Figure 4.2. Possible Heat Disorders by Heat Index Level

Source: National Weather Service

The NWS has in place a system to initiate alert procedures (advisories or warnings) when the

Heat Index is expected to have a significant impact on public safety. The expected severity of the heat determines whether advisories or warnings are issued. A common guideline for the

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4.12

issuance of excessive heat alerts is when the maximum daytime high is expected to equal or exceed 105°F and a nighttime minimum high of 80°F or above is expected for two or more consecutive days. The NWS office in Sacramento can issue the following heat-related advisory as conditions warrant.

Excessive Heat Outlook: are issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to Heat Index forecast map for the contiguous United States those who need considerable lead time to prepare for the event, such as public utilities, emergency management and public health officials.

Excessive Heat Watch: is issued when conditions are favorable for an excessive heat event in the next 12 to 48 hours. A Watch is used when the risk of a heat wave has increased, but its occurrence and timing is still uncertain. A Watch provides enough lead time so those who need to prepare can do so, such as cities that have excessive heat event mitigation plans.

Excessive Heat Warning/Advisory: are issued when an excessive heat event is expected in the next 36 hours. These products are issued when an excessive heat event is occurring, is imminent, or has a very high probability of occurring. The warning is used for conditions posing a threat to life or property. An advisory is for less serious conditions that cause significant discomfort or inconvenience and, if caution is not taken, could lead to a threat to life and/or property.

Information from the two representative weather stations introduced in Section 4.2.1 is

summarized below and in Figures 4.3 and 4.4.

Eastern Butte County

– De Sabla Weather Station, Period of Record 1906 to 2012

In the eastern portion of Butte County, monthly average maximum temperatures in the warmest months (May through October) range from the low 60s to the high 80s. Monthly average minimum temperatures from November through April range from the low to upper 30s. The highest recorded daily extreme was 112°F on August 14, 1933. The lowest recorded daily extreme was -2°F on January 20, 1937. In a typical year, maximum temperatures exceed 90°F on 51.2 days with 0.4 days falling below 32°F, and minimum temperatures fall below 32°F on

74.9 days with 0 days falling below 0°F.

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Figure 4.3. Eastern Butte County Extreme Temperatures 1906 to 2012

Source: Western Regional Climate Center

Western Butte County

– Oroville Weather Station, Period of Record 1953 to 2012

In the western portion of Butte County, monthly average maximum temperatures in the warmest months (May through October) range from the mid 70s to the low 90s. Monthly average minimum temperatures from November through April range from the upper 30s to the mid 50s.

The highest recorded daily extreme was 115°F on June 16, 1961. The lowest recorded daily extreme was 12°F on January 22, 1990. In a typical year, maximum temperatures exceed 90°F on 93.3 days with no days falling below 32°F, and minimum temperatures fall below 32°F on

21.8 days with no days falling below 0°F.

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Figure 4.4. Western Butte County Extreme Temperatures, 1953 to 2012

Source: Western Regional Climate Center

Past Occurrences

The NCDC data shows no extreme heat incidents for Butte County since 1993, while SHELDUS reports just one, an August 13 to 20, 1992 event that caused one case of heat stroke in Butte

County. These databases may not give a full and accurate depiction of extreme heat in Butte

County. While extreme heat may not be an issue in the eastern portions of the County, given the increases in altitude, the western areas have seen temperatures in excess of 115°F.

The County Agricultural Commissioner reported that from March 12-15, 2004, the prune crop was damaged by a period of high temperatures and low humidity during the blossoming period.

Estimated losses to the prune crop were in excess of $11.7 million.

Likelihood of Future Occurrences

Highly Likely—Although only one past event was recorded in national databases, data from the

Western Regional Climate Center indicates that high temperatures will continue to occur in the planning area on an annual basis; thus the likelihood of future occurrence is highly likely.

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Climate Change and Extreme Heat

The California Climate Adaptation Strategy (CAS), citing a California Energy Commission study, states that ―over the past 15 years, heat waves have claimed more lives in California than all other declared disaster events combined.‖ 1

This study shows that California is getting warmer, leading to an increased frequency, magnitude, and duration of heat waves. These

factors may lead to increased mortality from excessive heat. This is shown in Figure 4.5.

Figure 4.5. California Historical and Projected Temperature Increases - 1961 to 2099

Source: Dan Cayan; California Climate Adaptation Strategy

As temperatures increase, California and Butte County will face increased risk of death from dehydration, heat stroke, heat exhaustion, heart attack, stroke and respiratory distress caused by extreme heat. According to the CAS report and the 2010 State of California Hazard Mitigation

Plan, by 2100, hotter temperatures are expected throughout the state, with projected increases of

3-5.5°F (under a lower emissions scenario) to 8-10.5°F (under a higher emissions scenario)

1

California Climate Adaptation Strategy, California Natural Resources Agency, December 2009, p. 32; Messner,

Steven, Sandra C. Miranda, Karen Green, Charles Phillips, Joseph Dudley, Dan Cayan, Emily Young (2009).

Climate Change Related Impacts in the San Diego Region by 2050. PIER Research Report, CEC

‐500‐2009‐027‐D,

Sacramento, CA: California Energy Commission.

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4.2.3 Severe Weather: Freeze and Winter Storm

Hazard/Problem Description

Winter Storm

Winter snow storms can include heavy snow, ice, and blizzard conditions. Heavy snow can immobilize a region, stranding commuters, stopping the flow of supplies, and disrupting emergency and medical services. Accumulations of snow can collapse roofs and knock down trees and power lines. In rural areas, homes and farms may be isolated for days, and unprotected livestock may be lost. The cost of snow removal, damage repair, and business losses can have a tremendous impact on cities and towns.

Heavy accumulations of ice can bring down trees, electrical wires, telephone poles and lines, and communication towers. Communications and power can be disrupted for days until the damage can be repaired. Power outages can have a significant impact on communities, especially critical facilities such as public utilities. Even small accumulations of ice may cause extreme hazards to motorists and pedestrians.

Some winter storms are accompanied by strong winds, creating blizzard conditions with blinding wind-driven snow, severe drifting, and dangerous wind chills. Strong winds accompanying these intense storms and cold fronts can knock down trees, utility poles, and power lines. Blowing snow can reduce visibility to only a few feet in areas where there are no trees or buildings.

Serious vehicle accidents with injuries and deaths can result.

In Butte County, snow falls in and above the Town of Paradise. Between the period from 1957 to 2012, the annual average snowfall in the Town of Paradise was 2.2 inches of snow. The highest annual snowfall on record for the Town of Paradise was 21.3 inches occurring in 1972 -

1973. 18.8 inches of snow fell in December of 1972. Figure 4.6 illustrates the daily snowfall

average and extreme for the Paradise Weather Station.

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Figure 4.6. Town o Paradise Daily Average and Extreme Snowfall

Source: Western Regional Climate Center

Freeze

Extreme cold often accompanies a winter storm or is left in its wake. It is most likely to occur in the winter months of December, January, and February. Prolonged exposure to the cold can cause frostbite or hypothermia and can become life-threatening. Infants and the elderly are most susceptible. Pipes may freeze and burst in homes or buildings that are poorly insulated or without heat. Extreme cold can disrupt or impair communications facilities. Extreme cold can also affect the crops grown in Butte County.

In 2001, the NWS implemented an updated Wind Chill Temperature index, which is reproduced below. This index was developed to describe the relative discomfort/danger resulting from the combination of wind and temperature. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature.

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Figure 4.7. Wind Chill Temperature Chart

Source: National Weather Service

Information from the two representative weather stations introduced in Section 4.2.2 is

summarized below.

Past Occurrences

The NCDC data shows no extreme cold incidents for Butte County since 1993. SHELDUS

contains 12 events as shown in Table 4.6.

Table 4.6. Winter Storm Events in Butte County 1960-2010

Hazard

Begin

1/20/1962

1/27/1981

10/27/1981

12/22/1982

2/5/1992

Hazard

End

Hazard

Type

1/21/1962 Winter

Weather

1/29/1981 Winter

Weather

10/28/1981 Winter

Weather

12/22/1982 Winter

Weather

2/16/1992 Winter

Weather

Injuries

0.86

0.00

0.00

1.00

0.22

Fatalities

0.12

Property

Damage

$8,620.69

Crop

Damage Remarks

$0.00 Winter Storm

0.00

0.00

0.00

0.05

$1,041.67

$3,571.43

$2,941.18

$0.00

$0.00 Winter Storm

$0.00 Winter Storm

$0.00 Snow

$0.00 Winter Storm

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Hazard

Begin

2/9/1992

1/13/1993

12/11/1993

2/16/1994

Hazard

End

Hazard

Type

2/11/1992 Winter

Weather

1/14/1993 Winter

Weather

12/11/1993 Winter

Weather

2/21/1994 Winter

Weather

12/20/1996

12/5/1998

12/20/1996 Winter

Weather

12/6/1998 Winter

Weather

4/8/2005

Total

4/10/2005 Winter

Weather

Source: SHELDUS

Injuries

0.00

0.29

0.00

0.00

0.14

0.00

0.00

2.51

Fatalities

0.00

Property

Damage

$892.86

Crop

Damage Remarks

$0.00 Winter Storm

0.00

0.00

0.00

0.07

0.00

0.00

0.24

$357,142.86

$3,448.28

$1,282.05

$0.00

$20,000.00

$3,076.92

$402,017.94

$0.00 Winter Storm

$0.00 Winter Storm

$0.00 Winter Storm

$0.00 Heavy Snow

$0.00 Winter Storm

$0.00 Winter Storm

$0.00

The NCDC data shows no extreme cold incidents for Butte County since 1993. SHELDUS

contains 3 events as shown in Table 4.7.

Table 4.7. Extreme Cold Events in Butte County, 1960-2010

Hazard

Begin Hazard End

Hazard

Type

2/5/1989 2/5/1989 Winter

Weather

12/20/1990 12/25/1990 Winter

Weather

12/19/1998 12/29/1998 Winter

Weather

Total

Source: SHELDUS

Injuries

0.00

0.00

0.00

0.0

Fatalities

0.00

0.05

0.00

0.05

Property

Damage

$0.00

Crop

Damage Remarks

$128,205.13 Record Cold

$86,206.90 $8,620,689.66 Cold Wave

$0.00 $141,176.47 Extreme

Cold

$86,206.90 $8,890,071.26

In addition, the HMPC noted the following freeze events:

In 1993, a severe winter storm in the spring caused damages to crops in Butte County.

Almonds, kiwi, peaches, pistachios, prunes, and walnuts were affected. In excess of $8.8 million ($20 million in 2012 dollars) in damages were reported.

In March of 1995, a severe winter storm affected crops in Butte County. Almonds and prune crops were affected. Damages to these crops exceeded $50 million. In addition, many orchards were flooded, leading to an additional $50 million in damages to irrigation systems, ditches, levees, pumps, roads, and buildings.

In March of 1998, a severe winter storm affected crops in Butte County. Prunes, kiwi, walnuts, peaches, almonds, wheat, rice, barley, and alfalfa were affected. Damages to these crops exceeded $29 million.

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On April 8 and 9 of 2001, freeze damage affected crops in Butte County. Prunes, kiwi, walnuts, peaches, and almonds were affected. Damages to these crops exceeded $24 million.

Although freezes are infrequent, a freeze can severely affect agriculture in Butte County. Figure

4.8 shows disaster declarations due to freeze in the County. The greatest concentrations are in

the Central Valley. The disaster declarations for Butte County were issued in 1990, 2001, and

2002.

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Figure 4.8. State and Federal Declared Freeze Disasters from 1950 to 2009

Source: Cal EMA

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Likelihood of Future Occurrences

Likely—18 winter storm and freeze events occurred in Butte County over 51 years (1960-2010) of record keeping which equates to one event every 2.8 years, on average, and a 35.3 percent chance of winter storm or extreme cold occurring in any given year.

Temperature extremes are likely to continue to occur annually in the Butte County planning area.

Figures 4.9 and 4.10 indicate the likelihood of freezing temperatures for the eastern County in

the fall and the spring. Figures 4.11 and 4.12 indicate the likelihood of freezing temperatures for

the western County in the fall and the spring.

Figure 4.9. Eastern Butte County Fall Freeze Probability

Source: Western Regional Climate Center

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Figure 4.10. Eastern Butte County Region Spring Freeze Probability

Source: Western Regional Climate Center

Figure 4.11. Western Butte County Fall Freeze Probability

Source: Western Regional Climate Center

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Figure 4.12. Western Butte County Spring Freeze Probability

Source: Western Regional Climate Center

Climate Change and Freeze

Freezing spells are likely to become less frequent in California as climate temperatures increase; if emissions increase, freezing events could occur only once per decade in large portion of the state by the second half of the 21 st

century. According to a California Natural Resources Report in 2009, it was determined that while fewer freezing spells would decrease cold related health effects, too few freezes could lead to increased incidence of disease as vectors and pathogens do not die off.

4.2.4 Severe Weather: Heavy Rain, Hailstorm, Lightning

Hazard/Problem Description

Storms in the Butte County planning area are generally characterized by heavy rain often accompanied by strong winds and sometimes lightning and hail. Approximately 10 percent of the thunderstorms that occur each year in the United States are classified as severe. A thunderstorm is classified as severe when it contains one or more of the following phenomena: hail that is three-quarters of an inch or greater, winds in excess of 50 knots (57.5 mph), or a tornado. Heavy precipitation in the Butte County area falls mainly in the fall, winter, and spring months.

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Hail is formed when water droplets freeze and thaw as they are thrown high into the upper atmosphere by the violent internal forces of thunderstorms. Hail is sometimes associated with severe storms within the Butte County planning area. Hailstones are usually less than two inches in diameter and can fall at speeds of 120 miles per hour (mph). Severe hailstorms can be quite destructive, causing damage to roofs, buildings, automobiles, vegetation, and crops.

Lightning is defined as any and all of the various forms of visible electrical discharge caused by thunderstorms. Thunderstorms and lightning are usually (but not always) accompanied by rain.

Cloud-to-ground lightning can kill or injure people by direct or indirect means. Objects can be struck directly, which may result in an explosion, burn, or total destruction. Or, damage may be indirect, when the current passes through or near an object, which generally results in less damage.

High winds, often accompanying severe thunderstorms, can cause significant property and crop damage, threaten public safety, and have adverse economic impacts from business closures and power loss.

Tornadoes (see Section 4.2.5 Tornado) and funnel clouds can also occur during these types of

storms.

Past Occurrences

Heavy rains and severe storms occur in the planning area primarily during the late fall, winter, and spring (i.e., November through April). Damaging winds often accompany winter storm systems moving through the area.

According to the HMPC, short-term, heavy storms can cause both widespread flooding as well as extensive localized drainage issues. With the increased growth of the area, the lack of adequate drainage systems has become an increasingly important issue. In addition to the flooding that often occurs during these storms, strong winds, when combined with saturated ground conditions, can down very mature trees.

Information from the two representative weather stations introduced in Section 4.2.1 Severe

Weather: General is summarized below and in Figures 4.13-4.16.

Eastern Butte County

– De Sabla Weather Station, Period of Record 1906 to 2012

Average annual precipitation in eastern Butte County is 64.06 inches per year. The highest recorded annual precipitation is 121.24 inches in 1983. The lowest recorded annual precipitation was 22.66 inches in 1976.

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Figure 4.13. Eastern Butte County Monthly Average Total Precipitation

Source: Western Regional Climate Center

Figure 4.14. Eastern Butte County Daily Precipitation Average and Extremes

Source: Western Regional Climate Center

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Western Butte County

– Oroville Weather Station, Period of Record 1953 to 2012

Average annual precipitation in western Butte County is 28.69 inches per year. The highest recorded annual precipitation is 59.98 inches in 1983. The lowest recorded annual precipitation was 15.46 inches in 1976.

Figure 4.15. Western Butte County Monthly Average Total Precipitation

Source: Western Regional Climate Center

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Figure 4.16. Western Butte County Daily Precipitation Average and Extremes

Source: Western Regional Climate Center

Thunderstorms, lightning, and hail in Butte County are few in number and usually occur in the late fall or in the spring. 23 specific events were detailed by HMPC members or the NCDC

database (see Table 4.8).

Table 4.8. Incidences of Hail, Heavy Rain, Lightning, and Thunderstorm Winds in

Butte County from 1978 – August 31, 2011

Location Date

Butte

Butte

06/15/1978

09/25/1986

Type

Thunderstorm Winds

Hail, Magnitude .75 inches

Death/Injuries Reported Property Damage/Description

0

0

None Reported

None Reported

Butte None Reported

Butte

Butte

Butte

02/28/1988 Thunderstorm Winds,

Magnitude 52 kts.

04/23/1989 Thunderstorm Winds,

Hail, Magnitude .75 inches

0

0

09/26/1991 Thunderstorm Winds 0

11/11/1993 Lightning 0

None Reported

Oroville 02/10/1994 Funnel Clouds 0

None Reported

$5 Million. Lightening struck a department store during an evening thunderstorm. The fire smoldered for several hours before it was reported. Substantial damage was done to the store.

A Fire Chief heading to the site of a tornado observed three funnel clouds.

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Location

Biggs

Date

01/1995

Type

Heavy Rain, High

Winds

Palermo 03/04/1996 Thunderstorm Winds,

Magnitude 50 kts.

Countywide 01/12/1998 Heavy Rain 0

Death/Injuries Reported Property Damage/Description

Rainfall totaling 3 - 4 inches accumulated in just 24 hours. Flooding was generally limited to public streets. Many trees were damaged or destroyed by high winds, numerous power outages both within the City and with the electrical transmission lines.

0 None Reported

Countywide 01/18/1998

Bush Creek 01/22/2000

Heavy Rain

Heavy Rain

0

0

0

Heavy rains from a strong Pacific storm caused widespread but minor flooding.

Heavy rains from a Pacific storm brought brief but heavy rain to the area. Power outages and numerous traffic accidents occurred.

Rainfall totaling 4.91 inches accumulated in just over 48 hours.

One inch of hail was reported in Oroville. Oroville

Chico

02/22/2001 Hail, Magnitude 1.00 inches

02/22/2001 Hail, Magnitude 1.00 inches

Town of

Paradise

Brush

Creek

02/22/2001 Hail, Magnitude 1.00 inches

02/22/2001 Hail, Magnitude 1.00 inches

0 1/07/2005 Heavy Rain Oroville

Durham 06/10/2005 Hail, Magnitude .75 inches

Countywide 12/22/2005 Heavy Rain

Chico

Airport

6/5/2007 Lightning

0

0

0

0

0

0

0

0

One inch of hail was reported in Chico.

One inch of hail was reported in Magalia, a few miles north of the Town of Paradise.

One inch of hail was reported in Brush Creek.

None Reported

None Reported

A series of powerful but warm winter storms brought heavy rainfall to Northern California during a five day period. It brought 13.02 inches of rain to Brush Creek and 4.65 inches of rain to Oroville.

Lightning struck a deodora cedar tree, causing an explosion which sent debris up to

300 feet away. Pieces of flying wood damaged an apartment awning, the roof of a home, and several vehicles. Another lightning strike on a transformer left many residents without power.

No damages reported. Richvale

Airport

3/2/2009 Heavy Rain

Paradise 3/3/2009 Lightning

Stirling City 10/13/2009 Heavy Rain

0

0

Chico 2011

Source: NCDC

Hail

$10,000 in property damage was reported.

The remnants of Super Typhoon Melor from the western Pacific Ocean combined with a

Canadian upper level low pressure system to form a strong storm over Northern California.

Numerous trees and large branches were knocked down, causing damage to cars and homes.

No details were reported.

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Likelihood of Future Occurrences

Highly Likely – Based on NCDC data and HMPC input, 23 hail, heavy rain, lightning, and thunderstorm wind incidents over a 35-year period (1978-2012) equates to a severe storm event every 1.5 years and a 65 percent chance of a severe storm in any given year. This database doesn‘t report all hail, heavy rain, and lightning events. Severe weather, including heavy rain, thunderstorms, hail, lightning, and wind is a well-documented seasonal occurrence that will continue to occur annually in the Butte County Planning Area.

4.2.5 Severe Weather: Tornado

Hazard/Problem Description

Tornadoes are another severe weather hazard that can affect the Butte County Planning Area, primarily during the rainy season in the late fall and early spring. Tornadoes form when cool, dry air sits on top of warm, moist air. Tornadoes are rotating columns of air marked by a funnelshaped downward extension of a cumulonimbus cloud whirling at destructive speeds of up to

300 mph, usually accompanying a thunderstorm. Tornadoes are the most powerful storms that exist. They can have the same pressure differential across a path only 300 yards wide or less as

300 mile wide hurricanes. Figure 4.17 illustrates the potential impact and damage from a

tornado.

Figure 4.17. Potential Impact and Damage from a Tornado

Source: FEMA: Building Performance Assessment: Oklahoma and Kansas Tornadoes

Prior to February 1, 2007, tornado intensity was measured by the Fujita (F) scale. This scale was revised and is now the Enhanced Fujita scale. Both scales are sets of wind estimates (not measurements) based on damage. The new scale provides more damage indicators (28) and

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associated degrees of damage, allowing for more detailed analysis and better correlation between damage and wind speed. It is also more precise because it takes into account the materials

affected and the construction of structures damaged by a tornado. Table 4.9 shows the wind

speeds associated with the original Fujita scale ratings and the damage that could result at

different levels of intensity. Table 4.10 shows the wind speeds associated with the Enhanced

Fujita Scale ratings.

Table 4.9. Original Fujita Scale

Fujita (F)

F0

F1

F2

F3

Scale

Fujita Scale Wind

Estimate (mph)

< 73

73-112

113-157

158-206

Typical Damage

Light damage. Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged.

Moderate damage. Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off roads.

Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; lightobject missiles generated; cars lifted off ground.

Severe damage. Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown.

F4 207-260 Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated.

F5 261-318 Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters

(109 yards); trees debarked; incredible phenomena will occur.

Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/f-scale.html

Table 4.10. Enhanced Fujita Scale

Enhanced Fujita (EF) Scale

EF0

EF1

EF2

Enhanced Fujita Scale Wind Estimate (mph)

65-85

86-110

111-135

EF3

EF4

136-165

166-200

EF5 Over 200

Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/ef-scale.html

Tornadoes can cause damage to property and loss of life. While most tornado damage is caused by violent winds, the majority of injuries and deaths generally result from flying debris.

Property damage can include damage to buildings, fallen trees and power lines, broken gas lines, broken sewer and water mains, and the outbreak of fires. Agricultural crops and industries may also be damaged or destroyed. Access roads and streets may be blocked by debris, delaying necessary emergency response.

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According to the National Weather Service Sacramento Office, compared to the area east of the

Rocky Mountains, tornado occurrence over the western United States is much less frequent.

However, climatological studies reveal certain subregions throughout the west where there is a significant increase in tornado occurrence. Two of the regions are in California: the Los Angeles area, and the Central Valley of California comprising the Sacramento and San Joaquin Valleys.

Comparative climatological studies show that most California tornadoes are relatively weak (F0 or F1 intensity) and have relatively short path lengths, with median values 0.62 miles (1.0 km) long and 43 yards (39.3 m) wide compared to 4 miles (6.4 km) long and 170 yards (155.4 m) for

Iowa tornadoes. Also, the vast majority of California tornadoes occur during the cool season and primarily between 1 PM and 3 PM local time.

Past Occurrences

Figure 4.18 shows the location of recorded touchdowns and tornado paths in Butte County using

NOAA data from 1950 to 2010.

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Figure 4.18. Butte County Tornado Touchdowns and Paths

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During the rainy season, the Butte County planning area is prone to relatively strong thunderstorms, sometimes accompanied by funnel clouds and tornadoes. While tornadoes do occur occasionally, most often they are of F0 or F1 intensity. Documented incidents of tornadoes in the Butte County planning area from the NCDC Storm Events Database are listed in

Table 4.11 and explained in further detail in the text below the table.

Table 4.11. Butte County Tornado Events from 1950 to August 31, 2011

Type

Unknown

F0

F1

F2

Total

Source: NCDC

# of Events

2

6

4

2

14

Property Loss

$28,000,000

$514,000.00

$2,570,000.00

$5,120,000.00

$36,204,000.00

Crop Loss

0

0

0

0

0

Deaths

0

0

0

0

0

Injuries

0

0

4

2

9

June 28, 1970 – An F1 tornado touched down in the County. No injuries or deaths were reported. No property damages were reported.

March 4, 1978 – A tornado touched down in the County. Its magnitude on the F Scale was unknown. No injuries or deaths were reported. $3,000 in property damages was reported.

March 23, 1978 – A tornado touched down in the County. Its magnitude on the F Scale was unknown. No injuries or deaths were reported. $25,000 in property damages was reported.

January 22, 1981 – An F0 tornado touched down in the County. No injuries or deaths were reported. $3,000 in property damages was reported.

December 17, 1992 – An F1 tornado touched down in the County. 4 injuries and 0 deaths were reported. $2,500,000 in property damages was reported.

January 7, 1993 – An F1 tornado touched down in the County near Biggs. A barn roof was tossed 75 feet and 2 vehicles were damaged by the tornado. No injuries or deaths were reported.

$50,000 in property damages was reported.

April 17, 1993 – An F0 tornado touched down in the County in Chico. A tornado touched down in the center of Chico near Fourth Street and Chico State University. The brief touchdown resulted in damage to a number of trees, and was observed by local authorities. No injuries or deaths were reported. $10,000 in property damages was reported.

February 10, 1994 – An F2 tornado touched down in the County near Oroville. A tornado formed behind a cold front and traveled through a housing subdivision in Oroville. A total of 47 homes were damaged. One home was destroyed while 25 others suffered major damage. 2 injuries and 0 deaths were reported. $5,000,000 in property damages was reported.

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March 10, 1994 – An F0 tornado touched down in the County near Oroville. A resident saw the tornado illuminated by a lightning strike as it uprooted trees in his neighborhood. The falling trees damaged houses, and knocked out power lines. No injuries or deaths were reported.

$500,000 in property damages was reported.

April 25, 1994 – An F0 tornado touched down in the County near Honcut. Fire department officials spotted the tornado as it briefly touched down in southern Butte County. No injuries or deaths were reported. No property damages were reported.

May 16, 1998 – An F0 tornado touched down in the County near Richvale. No injuries or deaths were reported. No property damages were reported.

January 8, 2005 – An F1 tornado touched down in the County near Oroville. Brief touchdown reported south of Oroville damaging two structures. No injuries or deaths were reported.

$20,000 in property damages was reported.

April 8, 2005 – An F0 tornado touched down in the County near Durham. Minor damage was done to a residence and nearby trees. No injuries or deaths were reported. $10,000 in property damages was reported.

May 25, 2011 – An F2 tornado touched down in the County near Thermalito. Three tornadoes moved through Glenn and Butte Counties the evening of May 25, 2011. Significant damage was caused to several structures and thousands of almond trees were destroyed. No injuries or deaths were reported. $120,000 in property damages was reported.

Likelihood of Future Occurrences

Likely—14 tornadoes occurred in Butte County over 63 years (1950-2012) of record keeping which equates to one tornado every 4.5 years, on average, and a 22.2 percent chance of a tornado occurring in any given year. But of these, only two were greater than an EF1. Historical tornado activity within the planning area indicates that the area can occasionally experience the formation of funnel clouds and low intensity tornadoes during adverse weather conditions, especially during the winter months. The actual risk and vulnerability to the County is dependent on the nature and location of any given tornado.

4.2.6 Severe Weather: Windstorm

Hazard/Problem Description

The planning area is subject to significant, non-tornadic (straight-line), winds. High winds, as defined by the NWS glossary, are sustained wind speeds of 40 mph or greater lasting for 1 hour or longer, or winds of 58 mph or greater for any duration. These winds may occur as part of a seasonal climate pattern or in relation to other severe weather events such as thunderstorms.

Straight-line winds may also exacerbate existing weather conditions, as in blizzards, by

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increasing the affect on temperature and decreasing visibility due to the movement of particulate matters through the air, as in dust and snow storms. The winds may also exacerbate fire conditions by drying out the ground cover, propelling fuel around the region, and increasing the ferocity of exiting fires. These winds may damage crops, push automobiles off roads, damage roofs and structures, and cause secondary damage due to flying debris.

Figure 4.19 depicts wind zones for the United States. The map denotes that Butte County falls

into Zone I, which is characterized by high winds of up to 160 mph.

Figure 4.19. Wind Zones in the United States

Source: Federal Emergency Management Agency

Past Occurrences

Table 4.12 depicts the total number of high wind events reported and recorded by SHELDUS in

the planning region. A total of 23 events have been recorded since 1960.

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Table 4.12. Wind Occurrences in Butte County 1960 to 2010

Date

10/9/1960

11/3/1960

3/16/1961

9/2/1961

10/7/1961

4/18/1972

12/15/1982

12/22/1982

1/26/1984

3/4/1987

12/5/1987

2/17/1988

2/19/1993

2/7/1998

6/16/1998

11/7/1998

2/6/1999

2/9/1999

4/3/1999

2/11/2000

10/21/2000

2/7/2001

1/4/2008

Total

Source: SHELDUS

Likelihood of Future Occurrences

Injuries Fatalities

0.02 0.03

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.38

0.21

0.13

1.00

0.00

0.03

0.00

0.13

0.06

0.07

0.00

0.00

0.00

0.30

0.00

0.00

0.00

0.00

0.00

0.03

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

2.04

0.00

0.00

0.00

0.00

0.00

0.00

0.35

Highly Likely –High winds are an annual occurrence in the County.

4.2.7 Dam Failure

Property Damage

$86.21

Crop

Damage

$0.00

$500.00

$862.09

$3,571.43

$862.07

$0.00

$0.00

$357.14

$0.00

$500.00

$62,500.00

$1,041,666.67

$3,333.33

$4,545.45

$50.00

$6.25

$104.17

$333.33

$4,545.45

$3,571.43

$8,620.69

$50,000.00

$17,647.06

$1,000.00

$41,176.47

$3,846.15

$7,000.00

$1,333.33

$555.56

$1,739.13

$0.00

$2,600.00

$2,222.22

$0.00

$1,500.00 $0.00

$4,869.57 $0.00

$1,261,286.64 $10,254.27

$35.71

$0.00

$0.00

$0.00

$0.00

$0.00

$0.00

Hazard/Problem Description

Dams are manmade structures built for a variety of uses including flood protection, power generation, agriculture, water supply, and recreation. When dams are constructed for flood protection, they are usually engineered to withstand a flood with a computed risk of occurrence.

For example, a dam may be designed to contain a flood at a location on a stream that has a certain probability of occurring in any one year. If prolonged periods of rainfall and flooding

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occur that exceed the design requirements, that structure may be overtopped and fail.

Overtopping is the primary cause of earthen dam failure in the United States.

Dam failures can also result from any one or a combination of the following causes:

Earthquake;

Inadequate spillway capacity resulting in excess overtopping flows;

Internal erosion caused by embankment or foundation leakage, or piping or rodent activity;

Improper design;

Improper maintenance;

Negligent operation; and/or

Failure of upstream dams on the same waterway.

Water released by a failed dam generates tremendous energy and can cause a flood that is catastrophic to life and property. A catastrophic dam failure could challenge local response capabilities and require evacuations to save lives. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Major loss of life could result as well as potentially catastrophic effects to roads, bridges, and homes. Electric generating facilities and transmission lines could also be damaged and affect life support systems in communities outside the immediate hazard area. Associated water supply, water quality and health concerns could also be an issue. Factors that influence the potential severity of a full or partial dam failure are the amount of water impounded; the density, type, and value of development and infrastructure located downstream; and the speed of failure.

In general, there are three types of dams: concrete arch or hydraulic fill, earth and rockfill, and concrete gravity. Each type of dam has different failure characteristics. A concrete arch or hydraulic fill dam can fail almost instantaneously; the flood wave builds up rapidly to a peak then gradually declines. An earth-rockfill dam fails gradually due to erosion of the breach; a flood wave will build gradually to a peak and then decline until the reservoir is empty. And, a concrete gravity dam can fail instantaneously or gradually with a corresponding buildup and decline of the flood wave.

Dams and reservoirs have been built throughout California to supply water for agriculture and domestic use, to allow for flood control, as a source of hydroelectric power, and to serve as recreational facilities. The storage capacities of these reservoirs range from a few thousand acre feet to five million acre-feet. The water from these reservoirs eventually makes its way to the

Pacific Ocean by way of several river systems.

The California Department of Water Resources Division of Safety of Dams assigns hazard ratings to large dams within the State. The following two factors are considered when assigning hazard ratings: existing land use and land use controls (zoning) downstream of the dam. Dams are classified in three categories that identify the potential hazard to life and property:

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High hazard indicates that a failure would most probably result in the loss of life

Significant hazard indicates that a failure could result in appreciable property damage

Low hazard indicates that failure would result in only minimal property damage and loss of life is unlikely

According to data provided by Division of Safety of Dams, there are 35 dams in Butte County constructed for flood control, storage, electrical generation, and recreational purposes. Of the 35 dams located inside the County, 16 are rated as high hazard, 5 as significant hazard, and 4 as low

hazard. 10 dams in the County have an unknown hazard class. Table 4.13 identifies the 30 dams

located in the Butte County Planning Area. Figure 4.20 illustrates the locations of identified

dams.

Table 4.13. Butte County Dam Inventory

Name of

Dam

Hazard

Class Stream

A. L. Chaffin L

Apple

Tree**

Bidwell Bar

Canyon

Saddle

H

Butte Creek

Head**

Tributary of

Cottonwood

Creek

Nearest City

Distance

Population at Risk Type

Capacity

(acrefeet*)

ERTH 450 None

-

1-10

None

-

> 1000

  

Dam

Height

Year

Built

65 1957

3,540,000 47

Unknown Non-

1968 jurisdictional dam - data not verified

Feather River Oroville

5 miles

-

-

-

> 1000

  

Status

State certified dam since

4/22/1966

California

Park

Cannon

Ranch

H

H

Dead Horse

Slough

Tributary of

Oregon Gulch

Chico

0 miles

> 1000

House

0.2 miles

1 - 10

ERTH 335

ERTH 176

23

18

Unknown Nonjurisdictional dam - data not verified

1986

1870

State certified dam since

1/7/1987

State certified dam since

3/6/1967

Concow H VARA 6,370 94 1925

DeSalba

Forebay

Feather

River

Hatchery**

H

L

Forbestown

Diversion

L

Concow Creek Oroville

4 miles

10 - 100

Middle Butte Cr De Sabla

1 mile

100 - 1000

Feather River Oroville

0 miles

10-100

South Fork of

Feather River

Oroville

7 miles

0

ERTH 280

GRAV 580

VARA 358

53

63

99

1903

1964

1962

State certified dam since

9/16/1966

State certified dam since

6/13/1966

State certified dam since

8/11/1966

State certified dam since

8/5/1966

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Name of

Dam

Grizzly

Creek

Hazard

Class Stream

S

Nearest City

Distance

Population at Risk Type

Grizzly Creek Clipper Mills

-

0

Capacity

(acrefeet*)

ERTH 76

Grub Flat**

Tributary of

Feather River

-

-

> 1000

ERTH 49

Dam

Height

50

18

Year

Built

1964

1863

Hendricks

Head

Intake**

Kunkle

Lake

Madrone

Lake

Wyandotte

Littlefield

Lost Creek

Magalia

Miners

Ranch

Morgan

Olive

Products**

S

H

H

H

H

H

W Branch

Feather River

North Fork of

Feather River

-

-

> 1000

-

-

> 1000

Tributary W Br

Feather R

-

-

1 - 10

Berry Creek

North Honcut

Creek

Tributary of

Feather River

Lost Creek

Little Butte

Creek

Tributary of

North Honcut

Creek

-

-

Berry Creek

1 mile

10

– 100

Honcut

18 miles

10 - 100

> 1000

Oroville

12 miles

1 - 10

Kelly Ridge

1 mile

> 1000

-

-

> 1000

-

-

> 1000

ERRK 130

ERTH 253

ERTH 200

ERTH 313

ERTH

VARA 5,680

Pines Community <

100 yards

> 10000;

Butte Creek Canyon

7 miles;

<1000;

Durham

12 miles;

> 1000

HYDF 2,900

ERRK 895

15

54

35

46

18

122

103

55

1907

Unknown Nonjurisdictional dam - data not verified

1907 State certified dam since

3/17/1972

1931

1924

State certified dam since

9/16/1966

State certified dam since

3/5/1997

1863

Status

State certified dam since

8/22/1966

Nonjurisdictional dam - data not verified

Nonjurisdictional dam - data not verified

1924

1918

1962

Nonjurisdictional dam - data not verified

State certified dam since

1/16/2004

State certified dam since

11/3/1997

State certified dam since

8/5/1966

Unknown Nonjurisdictional dam - data not verified

Unknown Nonjurisdictional dam - data not verified

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Name of

Dam

Oroville

Paradise

Parish

Camp

Saddle Dam

Philbrook S

Hazard

Class Stream

H

Nearest City

Distance

Population at Risk Type

Feather River Oroville

3 miles

> 1000

Capacity

(acrefeet*)

Dam

Height

ERTH 3,537,577 742

Year

Built

1968

H Little Butte

Creek

Pines Community

< 100 yards

> 10000;

Butte Creek Canyon

10 miles

<1000;

Durham

15 miles;

> 1000

ERTH 11,500

  

175

1957

Philbrook

Creek

ERTH 5,180 85 1926

Poe

Ponderosa

Diversion

S

L

North Fork of

Feather River

South Fork of

Feather River

Oroville

30 miles

10

– 100

Pulga

1 mile

10 - 100

Oroville

1 mile

0

GRAV 1,150

ERTH 4,750

62

157

1959

1962

Round

Valley

Sly Creek

Sutter Butte

Div**

S

H

West Tributary of Feather

River

Oroville

32 miles

10 -100

Lost Creek

Oroville

13 miles

10 - 100

-

-

> 1000

ERTH 1,147

ERTH 65,050

 

30

271

Thermalito

Afterbay

H Tributary of

Feather River

Richvale/Biggs

1 mile

10 - 100

ERTH 57,041

Thermalito

Diversion

H Feather River Oroville

2 miles

100

– 1000

GRAV 13,328

Thermalito

Forebay

H Tributary of

Cottonwood

Creek

Oroville

1 mile

> 1000

ERTH 11,768

Source: California Department of Water Resources Division of Safety of Dams

*One Acre Foot=326,000 gallons

**Unmapped dam

38

128

75

Status

State certified dam since

10/31/1968

State certified dam since

5/25/1977

State certified dam since

2/20/1968

State certified dam since

1/11/1974

State certified dam since

1/16/2004

1877

1961

1967

State certified dam since

7/20/1966

State certified dam since

6/12/1990

Unknown Nonjurisdictional dam - data not verified

1967 State certified dam since

2/10/1988

1967 State certified dam since

11/17/1967

State certified dam since

11/17/1967

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Figure 4.20. Location of High and Significant Hazard Dams in Butte County

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In addition to these dams, there are other dams outside the County with the potential to affect people and property in Butte County. These dams are:

Shasta (Shasta County)

Little Grass Valley Lake (Plumas County)

Lake Almanor (Plumas County)

Cal EMA provides local jurisdictions with hazard information based on data from the U.S.

Bureau of Reclamation and the Department of Water Resources. Included in this information is a series of dam inundation maps for Butte County.

Division personnel inspect the Department of Water Resources Division of Safety Dams (DSD) each year. The DSD has also evaluated the seismic safety of the dams at Lake Wyandotte, Lost

Creek, and Round Valley. As a result of the study done for Lake Wyandotte, the spillway has been lowered to contain the reservoir in the event of dam lowering in an earthquake. Lost Creek dam personnel submitted their study and are in the process of studying several faults of special concern. Round Valley has also submitted a study which found the dam in compliance with earthquake standards. The main focus of this study was correcting seepage. According to the area engineer for the Division of Dam Safety, this problem has been corrected.

Magalia Dam (which threatens the Town of Paradise) has been identified by the DSD as at risk to failure in the event of significant seismic activity. In the event of such failure floodwater would cause significant damages in the Little Butte Creek and Butte Creek Canyons and the town of Durham, and exceed the capacity of the downstream Butte Creek levees. The Town of

Paradise would be affected since the water treatment plant and the 42-inch supply line that provides drinking water for the residents in the community could be severely damaged since it is located at the downstream toe of the dam. The primary access road to the Pines Community would be eliminated and impact 10,000 residents. Reconstruction of the damaged facilities would be difficult, cause a significant water outage, take many months to restore, and the repair costs would be very high.

In a 1992 study of Magalia Dam it was concluded that the upstream slope of the dam was found to have inadequate stability under seismic loading conditions. In 1997 in response to this concern, the DSD required the water storage in the reservoir to be decreased to 800 acre-feet. If stabilized, the capacity of Magalia Reservoir could be restored to 2,570 acre-feet. The change in water level elevation from 2,225 feet when full, was lowered to the current restricted operating level of 2,199 feet, or a reduction of 26 feet. Each year the DSD conducts a dam inspection and the District prepares a ―Surveillance Report‖, with assistance from the URS Corporation.

In 2004, the Paradise Irrigation District constructed a diversion structure above Magalia

Reservoir and a pipeline to the water treatment plant. This improvement will supply water to the treatment plant during any reconstruction of Magalia Dam, or the widening of Skyway across

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Magalia Dam. The Paradise Irrigation District is working on extending its water rights permits, which must be secured before further work is contemplated on Magalia Dam.

The County is doing preliminary engineering on a project to widen the Skyway across Magalia

Dam. The Paradise Irrigation District‘s preferred alternative for the widening project involves stabilizing the dam and would permit the restoration of the design water level behind Magalia

Dam.

The DSD also identified an additional safety hazard at the Lake Madrone dam. The spillway is below the minimum design standard. It has been certified as safe for a 500-year flood, whereas the normal minimum level is for a 1,000 year flood event. However, minimum levels differ in various locations and depend on construction type, terrain, seismic features in the area, and habitat (human and otherwise) in the downstream flood zone. This facility is under court order to increase dam spillway capacity. Of the remaining dams, Kunkle is typical of several dams whose use has been restricted to a particular storage level. The DSD believes these dams are safe at a particular fill level and has restricted their use to that level or lower.

Past Occurrences

The National Performance of Dams data shows four dam incidents for Butte County since 1932.

However, these incidents were quite limited in scope and since the incidents occurred, improvements to the dam system have been made.

1932 – An incident occurred at the De Sabla Forebay dam which is owned by PG&E. It is unclear if the dam breached. There was a piping incident in the fill at the downstream toe.

There was also cavitation in the upstream slope.

May 1938 – The Slate Creek dam was overtopped and breached near the outlet. A section of dam washed out. Cause of failure: no spillway provision. Dam was not rebuilt.

1965 - Since the mid-1960's the porous concrete of the Lost Creek dam had spalled and cracked.

This contributed to further deterioration of the downstream face of the dam due to freeze-thaw.

The dam did not fail, and was repaired. In 1997, a geomembrane was installed to stop leakage through the dam.

July 5, 1997 - A gate failure on Cresta Dam sent a surge of water (measured as 14.5 feet high at the nearest downstream gage) through the north fork of the Feather River. Several people trapped by the sudden surge had to be rescued by helicopter. The release contributed to a four inch rise in the level of Lake Oroville.

Likelihood of Future Occurrences

Unlikely—Although four dam incidents occurred from the early 1930s to the mid 1960s, numerous improvements have been made and future catastrophic failure is considered unlikely.

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However, the DSD is concerned that if the epicenter of an earthquake of significant magnitude were to occur nearby a dam, the likelihood of failure is high. Local dams vulnerable to earthquake damage are hydraulic-filled embankment dams built with sluicing materials from an adjacent area and depositing the slurry into the embankment, such as the Magalia Dam. The dam incident in 1997 was not a dam failure event, but a gate failure. It should be noted that the gate failure on the Cresta dam was contained by another flood control structure, the Oroville dam, downstream. Further, based on input from the HMPC, it is unlikely that major dam failure event will occur in Butte County. It should be noted that a dam failure of the Oroville Dam would have far ranging affects on both Butte County and communities downstream.

4.2.8 Drought and Water Shortage

Hazard/Problem Description

Drought is a gradual phenomenon. Although droughts are sometimes characterized as emergencies, they differ from typical emergency events. Most natural disasters, such as floods or forest fires, occur relatively rapidly and afford little time for preparing for disaster response.

Droughts occur slowly, over a multi-year period, and it is often not obvious or easy to quantify when a drought begins and ends. Water Districts normally require at least a 10 year planning horizon to implement a multiagency improvement project to mitigate the effects of a drought and water supply shortage.

Drought is a complex issue involving (see Figure 4.21) many factors—it occurs when a normal

amount of precipitation and snow is not available to satisfy an area‘s usual water-consuming activities. Drought can often be defined regionally based on its effects:

Meteorological drought is usually defined by a period of below average water supply.

Agricultural drought occurs when there is an inadequate water supply to meet the needs of the state‘s crops and other agricultural operations such as livestock.

Hydrological drought is defined as deficiencies in surface and subsurface water supplies. It is generally measured as streamflow, snowpack, and as lake, reservoir, and groundwater levels.

Socioeconomic drought occurs when a drought impacts health, well-being, and quality of life, or when a drought starts to have an adverse economic impact on a region.

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Figure 4.21. Causes and Impact of Drought

Source: National Drought Mitigation Center

Drought in the United States is monitored by the National Integrated Drought Information

System (NIDIS). A major component of this portal is the U.S. Drought Monitor. The Drought

Monitor concept was developed jointly by the NOAA‘s Climate Prediction Center, the NDMC, and the USDA‘s Joint Agricultural Weather Facility in the late 1990s as a process that synthesizes multiple indices, outlooks and local impacts, into an assessment that best represents current drought conditions. The final outcome of each Drought Monitor is a consensus of federal, state, and academic scientists who are intimately familiar with the conditions in their respective regions. A snapshot of the drought conditions in California and the planning area can

be found in Figure 4.22.

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Figure 4.22. Current Drought Status in Butte County

Source: US Drought Monitor

The California Department of Water Resources (DWR) says the following about drought:

One dry year does not normally constitute a drought in California. California‘s extensive system of water supply infrastructure—its reservoirs, groundwater basins, and inter-regional conveyance facilities—mitigates the effect of short-term dry periods for most water users. Defining when a drought begins is a function of drought impacts to water users. Hydrologic conditions constituting a drought for water users in one location may not constitute a drought for water users elsewhere, or for water users having a different water supply. Individual water suppliers may use criteria such as rainfall/runoff, amount of water in storage, or expected supply from a water wholesaler to define their water supply conditions.

The drought issue in California is further compounded by water rights. Water is a commodity possessed under a variety of legal doctrines. The prioritization of water rights between farming and federally protected fish habitats in California is part of this issue. For instance the Paradise

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Irrigation District is required to release 0.5 CFS from the Magalia Dam to enhance the riparian environment.

Drought is not initially recognized as a problem because it normally originates in what is considered good weather, which typically includes a dry late spring and summer in

Mediterranean climates, such as in California. This is particularly true in Northern California where drought impacts are delayed for most of the population by the wealth of stored surface and ground water. The drought complications normally appear more than a year after a drought begins. In most areas of California, ranchers that rely on rainfall to support forage for their livestock are the earliest and most affected by drought. Even below normal water years could affect ranchers depending on the timing and duration of precipitation events. In fact, the earliest indicator of drought in Butte County has been a ―State of Emergency‖ declared for economic impact on livestock industries. It is difficult to quantitatively assess drought impacts to Butte

County because not many county-specific studies have been conducted. Some factors to consider include the impacts of fallowed agricultural land, habitat loss and associated effects on wildlife, and the drawdown of the groundwater table. The most direct and likely most difficult drought impact to quantify is to local economies, especially agricultural economies. The State has conducted some empirical studies on the economic effects of fallowed lands with regard to water purchased by the State‘s Water Bank; but these studies do not quantitatively address the situation in Butte County. It can be assumed, however, that the loss of production in one sector of the economy would affect other sectors.

The drawdown of the groundwater table is one factor that has been recognized to occur during repeated dry years. Lowering of groundwater levels results in the need to deepen wells, which subsequently lead to increased pumping costs. These costs are a major consideration for residents relying on domestic wells and agricultural producers that irrigate with groundwater and/or use it for frost protection. Some communities in higher elevations with shallow bedrock do not have a significant source of groundwater.

Drought impacts are wide-reaching and may be economic, environmental, and/or societal. The most significant impacts associated with drought in the planning area are those related to water intensive activities such as agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. Also, during a drought, allocations go down and water costs increase, which results in reduced water availability. Voluntary conservation measures are a normal and ongoing part of system operations and actively implemented during extended droughts. A reduction of electric power generation and water quality deterioration are also potential problems. Drought conditions can also cause soil to compact and not absorb water well, potentially making an area more susceptible to flooding and erosion.

Water Shortage

Northern Sacramento Valley counties, including Butte County, generally have sufficient groundwater and surface water supplies to mitigate even the severest droughts of the past

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century, except for some of the mountainous regions of the County Many other areas of the

State, however, also place demands on these water resources during severe drought. For example, Northern California agencies, including those from Butte County, were major participants in the Governor‘s Drought Water Bank of 1991, 1992 and 1994.

Past Occurrences

Many people consider drought and associated water shortages to be are and random events; however, it is a normal, recurrent, and insidious climatic event. Although it has many different definitions, a drought usually originates from a cumulative deficiency of precipitation over a season or more. Drought is not solely a physical phenomenon; it affects society‘s water supply and water demand associated with agricultural, urban, and environmental uses.

Drought conditions in Butte County have reoccurred numerous times throughout history. Table

4.14 summarizes the time and duration of droughts in Butte County since the twentieth century.

Table 4.14. Northern California Recent Drought Years

Drought Years

1912-1913

1918-1920

1923-1924

1929-1934

1947-1950

1959-1961

1976-1977

1987-1992

1993-1994

2007-2010

Source: Butte County

Duration (years)

1

2

1

5

3

3

1

5

1

4

Droughts exceeding three years occurred three times since the 1900s. Figure 4.23 presents

hydrologic year types from 1960 through 2011 based on the Sacramento 40-40-30 Water Supply

Index. Severe droughts in Butte County occurred during periods of extended dry and critical years.

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Figure 4.23. Sacramento Valley Water Year Index

Sacramento Valley Water Year Index

20

15

Wet

Above

Normal

Below

Normal

Dry

Critcial

10

5

0

Water Year

Source: Butte County

The HMPC provided data from the De Sabla Forebay reservoir. This is shown in Figure 4.24.

In Butte County, the worst drought since 1900 occurred in the 1920s.

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Figure 4.24. Precipitation at De Sabla Forebay 1900-2000

Source: Butte County

Because of the minimal data available for hydrologic conditions prior to 1900, it is difficult to determine prior drought occurrences. However, scientists have used various other methods to document severe droughts in early California history. Scientific evidence shows the reoccurrence of drought throughout history and confirms the possibility for a future drought. For example, trees appear to have grown 6000 years ago in areas now submerged under Lake Tahoe,

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suggesting a drier climate. Other tree ring dating studies suggest a sustained drought during the mid-1500s. Another early drought indicator is the presence and disappearance of civilization. For example, the Anasazi civilization flourished (in what is called the Medieval Warm Period from

900-1300) when monsoonal rains supported its irrigations systems. In contrast, the Anasazi culture declined and disappeared during the Little Ice Age (1300-1800), which is attributed in part to drought conditions that made irrigated agriculture infeasible. Given the limited knowledge of the fairly recent past, it is difficult to understand the full ramifications of drought conditions.

According to the State of California Hazard Mitigation Plan, Butte County has experienced one

drought that resulted in a state disaster declaration in 1976/1977. This can be seen in Table 4.3

and Figure 4.25.

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Figure 4.25. Declared Drought Disasters in Butte County

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Likelihood of Future Occurrences

Occasional—Historical drought data for the Butte County Planning Area and region indicate there have been 4 significant droughts in the last 84 years. This equates to a drought every 21 years on average or a 4.8 percent chance of a drought in any given year. Based on this data, droughts will occasionally affect the planning area. Water shortages occur during these times of drought, although to varying degrees, making water shortages occasional.

4.2.9 Earthquake

Hazard/Problem Description

An earthquake is caused by a sudden slip on a fault. Stresses in the earth‘s outer layer push the sides of the fault together. Stress builds up, and the rocks slip suddenly, releasing energy in waves that travel through the earth‘s crust and cause the shaking that is felt during an earthquake.

The amount of energy released during an earthquake is usually expressed as a magnitude and is measured directly from the earthquake as recorded on seismographs. An earthquake‘s magnitude is expressed in whole numbers and decimals (e.g., 6.8). Seismologists have developed several magnitude scales. One of the first was the Richter Scale, developed in 1932 by the late Dr. Charles F. Richter of the California Institute of Technology. The Richter

Magnitude Scale is used to quantify the magnitude or strength of the seismic energy released by an earthquake. Another measure of earthquake severity is intensity. Intensity is an expression of

the amount of shaking at any given location on the ground surface (see Table 4.15). Seismic

shaking is typically the greatest cause of losses to structures during earthquakes.

Table 4.15. Modified Mercalli Intensity (MMI) Scale

MMI

I

II

III

IV

V

VI

VII

VIII

IX

X

Felt Intensity

Not felt except by a very few people under special conditions. Detected mostly by instruments.

Felt by a few people, especially those on upper floors of buildings. Suspended objects may swing.

Felt noticeably indoors. Standing automobiles may rock slightly.

Felt by many people indoors; by a few outdoors. At night, some people are awakened. Dishes, windows, and doors rattle.

Felt by nearly everyone. Many people are awakened. Some dishes and windows are broken. Unstable objects are overturned.

Felt by everyone. Many people become frightened and run outdoors. Some heavy furniture is moved.

Some plaster falls.

Most people are alarmed and run outside. Damage is negligible in buildings of good construction, considerable in buildings of poor construction.

Damage is slight in specially designed structures, considerable in ordinary buildings, and great in poorly built structures. Heavy furniture is overturned.

Damage is considerable in specially designed buildings. Buildings shift from their foundations and partly collapse. Underground pipes are broken.

Some well-built wooden structures are destroyed. Most masonry structures are destroyed. The ground is badly cracked. Considerable landslides occur on steep slopes.

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MMI

XI

Felt Intensity

Few, if any, masonry structures remain standing. Rails are bent. Broad fissures appear in the ground.

XII Virtually total destruction. Waves are seen on the ground surface. Objects are thrown in the air.

Source: Multi-Hazard Identification and Risk Assessment, FEMA 1997

California is seismically active because it sits on the boundary between two of the earth‘s tectonic plates. Most of the state

‐ everything east of the San Andreas Fault ‐ is on the North

American Plate. The cities of Monterey, Santa Barbara, Los Angeles, and San Diego are on the

Pacific Plate, which is constantly moving northwest past the North American Plate. The relative rate of movement is about two inches per year. The San Andreas Fault is considered the boundary between the two plates, although some of the motion is taken up on faults as far away as central Utah.

Earthquakes can cause structural damage, injury, and loss of life, as well as damage to infrastructure networks, such as water, power, gas, communication, and transportation.

Earthquakes may also cause collateral emergencies including dam and levee failures, seiches, hazmat incidents, fires, avalanches, and landslides. The degree of damage depends on many interrelated factors. Among these are: the magnitude, focal depth, distance from the causative fault, source mechanism, duration of shaking, high rock accelerations, type of surface deposits or bedrock, degree of consolidation of surface deposits, presence of high groundwater, topography, and the design, type, and quality of building construction. This section briefly discusses issues related to types of seismic hazards.

Ground Shaking

Groundshaking is motion that occurs as a result of energy released during faulting. The damage or collapse of buildings and other structures caused by groundshaking is among the most serious seismic hazards. Damage to structures from this vibration, or groundshaking, is caused by the transmission of earthquake vibrations from the ground to the structure. The intensity of shaking and its potential impact on buildings is determined by the physical characteristics of the underlying soil and rock, building materials and workmanship, earthquake magnitude and location of epicenter, and the character and duration of ground motion. Much of the County is located on alluvium which increases the amplitude of the earthquake wave. Ground motion lasts longer and waves are amplified on loose, water-saturated materials than on solid rock. As a result, structures located on alluvium typically suffer greater damage than those located on solid rock. Conservatively, ground motions as strong as those observed during the 1975 Oroville earthquake (Modified Mercalli Intensity VIII) can be expected anywhere in Butte County.

Seismic Structural Safety

Older buildings constructed before building codes were established, and even newer buildings constructed before earthquake-resistance provisions were included in the codes, are the most likely to be damaged during an earthquake. Buildings one or two stories high of wood-frame construction are considered to be the most structurally resistant to earthquake damage. Older

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masonry buildings without seismic reinforcement (unreinforced masonry) are the most susceptible to the type of structural failure that causes injury or death.

The susceptibility of a structure to damage from ground shaking is also related to the underlying foundation material. A foundation of rock or very firm material can intensify short-period motions which affect low-rise buildings more than tall, flexible ones. A deep layer of waterlogged soft alluvium can cushion low-rise buildings, but it can also accentuate the motion in tall buildings. The amplified motion resulting from softer alluvial soils can also severely damage older masonry buildings.

Other potentially dangerous conditions include, but are not limited to: building architectural features that are not firmly anchored, such as parapets and cornices; roadways, including column and pile bents and abutments for bridges and overcrossings; and above-ground storage tanks and their mounting devices. Such features could be damaged or destroyed during strong or sustained ground shaking.

As mentioned in the Dam Failure hazard section of this plan, the DSD is concerned that if the epicenter of an earthquake of significant magnitude were to occur nearby a dam, the likelihood of a structural failure is high. Local dams vulnerable to earthquake damage are hydraulic-filled embankment dams built with sluicing materials from an adjacent area and depositing the slurry into the embankment, such as the Magalia and De Salba Dams.

Liquefaction Potential

Liquefaction is a process whereby soil is temporarily transformed to a fluid form during intense and prolonged ground shaking. Liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. This water exerts a pressure on the soil particles that influence how tightly the particles themselves are pressed together.

Prior to an earthquake, the water pressure is relatively low. However, earthquake shaking can cause the water pressure to increase to the point where the soil particles can readily move with each other. When liquefaction occurs, the strength of the soil decreases and the ability of soil to support foundations for buildings is reduced. Mapping developed by Butte County for its 2006

Flood Mitigation Plan indicates that much of the west and southwestern part of the County is considered to have a moderate to high potential for liquefaction. A map of vulnerability to

liquefaction in the County is shown in Figure 4.70 in the vulnerability assessment.

Settlement

Settlement can occur in poorly consolidated soils during ground shaking. During settlement, the soil materials are physically rearranged by the shaking to result in a less stable alignment of the individual minerals. Settlement of sufficient magnitude to cause significant structural damage is normally associated with rapidly deposited alluvial soils or improperly founded or poorly compacted fill. These areas are known to undergo extensive settling with the addition of irrigation water, but evidence due to ground shaking is not available.

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Other Hazards

Earthquakes can also cause seiches, landslides, and dam failures. A seiche is a periodic oscillation of a body of water resulting from seismic shaking or other factors that could cause flooding. Seiches have not been recorded in any of the reservoirs in Butte County that are within the jurisdiction of the California Division of Dam Safety. However, the potential for seiches does exist in Butte County, either from landslides or from stronger earthquakes that have been experienced in historical times. Earthquakes may cause landslides, particularly during the wet season, in areas of high water or saturated soils. Landslide is discussed in greater detail in

Section 4.2.10. Finally, earthquakes can cause dams to fail (see Section 4.2.7 Dam Failure).

Faults

A fault is defined as ―a fracture or fracture zone in the earth‘s crust along which there has been displacement of the sides relative to one another.‖ For the purpose of planning there are two types of faults, active and inactive. Active faults have experienced displacement in historic time, suggesting that future displacement may be expected. Inactive faults show no evidence of movement in recent geologic time, suggesting that these faults are dormant.

Two types of fault movement represent possible hazards to structures in the immediate vicinity of the fault: fault creep and sudden fault displacement. Fault creep, a slow movement of one side of a fault relative to the other, can cause cracking and buckling of sidewalks and foundations even without perceptible ground shaking. Sudden fault displacement occurs during an earthquake event and may result in the collapse of buildings or other structures that are found along the fault zone when fault displacement exceeds an inch or two. The only protection against damage caused directly by fault displacement is to prohibit construction in the fault zone.

There are a number of faults within Butte County and a large number of relatively nearby faults that could be considered potentially active, based either on the fairly restrictive criteria developed by the California Mining and Geology Board. Following is a description of the active faults in or near Butte County and the potential affect they have on the County. These faults are

detailed below and shown in Figure 4.26.

Cleveland Hills Fault. As of 2003 there is only one identified active fault located within Butte

County - the Cleveland Hills fault. The State Geologist has mapped and studied it since 1977. It is subject to the Alquist-Priolo Act and is identified pursuant to AB6x as an earthquake fault zone. This fault was responsible for the 1975 Oroville earthquake of Richter magnitude 5.7, an event that produced surface displacement along about 2.2 miles of the fault. Ground motions corresponding to MMI VIII were experienced at Gridley and Oroville. Significant structural damage occurred to unreinforced masonry buildings in Oroville. Geologic studies indicate that the total length of the Cleveland Hills fault is probably 11 to 15 miles. The maximum credible earthquake on this fault is probably about magnitude 6.5 to 6.7. An event of this magnitude would cause substantially more damage than the 1975 event.

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Big Bend Fault. Some geologists consider the Big Bend fault zone potentially active. This fault could produce a magnitude 7.0 earthquake with MMI of IX or X in Butte County. Intensities this high would result in major damage.

Foothills Shear Zone. The Foothills shear zone extends into southern Butte County. A possible magnitude 7.0 earthquake in this zone would result in intensities as high as IX in Butte County.

Magalia Fault. The Magalia Fault is located near the northern end of the Foothill Fault System, a system of northwest trending east dipping normal fault formed along the margin of the Great

Valley and the Sierra Nevada provinces. The DSD, based on Fault Activity Guidelines in 2001 recalssified the Magalia Fault as conditionally active. The Paradise Irrigation District commissioned a study by Holdrege & Kull, dated January 2007 to evaluate the Magalia Fault.

Chico Monocline Fault. The Chico Monocline fault which extends northwesterly from Chico was considered potentially active in an unpublished 1988 report by the California Geological

Survey. Based on its length, this fault could produce at least a magnitude 7.0 earthquake which would cause major damage in Chico and elsewhere in Butte County.

Willows Fault. West of Butte County is the 40-mile long Willows fault which could produce a

Magnitude 7 earthquake and could yield a MMI as high as VIII in Butte County (comparable to the intensity experienced during the 1975 Oroville earthquake).

Coast Ranges Thrust Zone. The Coast Ranges Thrust Zone is approximately 35 miles west of

Butte County. This fault zone could potentially produce a magnitude 8.0 earthquake which could be experienced in Butte County as MMI IX or X. An event of this magnitude would cause major damage to Butte County.

San Andreas Fault System. The San Andreas fault, along with related faults such as the

Hayward and Calaveras faults, is one of the most active faults in California. Total displacement along this fault has been at least 450 miles and could possibly be as much as 750 miles. This fault system was responsible for the magnitude 8.0 San Francisco earthquake of 1906 as well as numerous other damaging earthquakes, including the 1989 Loma Prieta earthquake. At its nearest point, the San Andreas fault is about 95 miles west of Butte County. The 1906 earthquake was strongly felt in Butte County, at approximately MMI V and VI in western Butte

County and IV to V in eastern Butte County, but there was little damage.

Hayward-Calaveras Fault. The Hayward-Calaveras fault complex is considered to be a branch of the San Andreas fault. An 1868 earthquake is reported to have caused strong fluctuations in the water level in the Sacramento River near Sacramento and in a slough near Stockton.

Midland-Sweitzer Fault. The 80-long Midland-Sweitzer fault lies approximately 40 miles southwest of Butte County. Historically, earthquakes of Richter magnitudes between 6.0 and 6.9 have occurred on or near this fault, including two strong earthquakes in 1892. Based on the fault

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length and the historic activity, this fault is capable of producing a magnitude 7.0 earthquake which would be experienced in Butte County with MMI as high as VIII or IX.

Eastern Sierra Faults/Russell Valley Fault. The Eastern Sierra contain a number of active faults including the Russell Valley fault, which produced the 1966 Truckee earthquake of magnitude approximately 6.0, and several faults in the Last Chance and Honey Lake fault zones, which have produced several magnitude 5.0 to 5.9 earthquakes. These fault zones are approximately 50 miles east of Butte County. Earthquakes on these faults could be experienced in Butte County with MMI as high as VII or VIII.

Last Chance-Honey Lake Fault Zones. The Last Chance-Honey Lake fault zones are approximately 100 miles long and trend north-northwest along the California-Nevada border.

These faults are active and have resulted in earthquakes ranging between 5 and 5.9 Richter.

Other Potentially Active Faults. Other potentially active faults which could result in significant ground motion in Butte County include the Sutter Butte faults, Dunnigan fault,

Camel's Peak fault, Melones-Dogwood Peak faults and the Hawkins Valley fault. All of these faults should be considered potentially active due to geologic, historic, or seismic data. Other potentially active faults may also exist within the County.

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Figure 4.26. Faults in the Vicinity of Butte County

Source: Butte County General Plan 2030 Health and Safety Element

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Maps indicating the maximum expectable intensity of groundshaking for the County are

available through several sources. Figure 4.27, prepared by the California Division of Mines and

Geology, shows the expected relative intensity of ground shaking and damage in California from anticipated future earthquakes. The shaking potential is calculated as the level of ground motion that has a 2% chance of being exceeded in 50 years, which is the same as the level of groundshaking with about a 2500 year average repeat time. Although the greatest hazard is in areas of highest intensity as shown on the map, no region is immune from potential earthquake damage.

Figure 4.27. Maximum Expectable Earthquake Intensity

Source: California Division of Mines and Geology

Past Occurrences

Seismic risk in Butte County results from earthquake faults within the County, as well as from faults outside the County whose seismic activity would cause potentially damaging ground motion in the County. The Sierra foothills contain literally hundreds of mapped faults, dozens of which are located within Butte County. Most of these faults are not now considered active.

However, most of these faults are very short and thus are probably not capable of producing severely damaging earthquakes.

The greatest amount of groundshaking experienced in the County occurred on August 1, 1975, when an earthquake, known as the Oroville quake, shook Butte County. Structural damage, consisting mainly of cracks in chimneys and walls, broken windows and plaster, and loosened light fixtures, occurred at several schools, hospitals, and houses in the Oroville-Thermalito area.

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Many chimneys toppled or had to be taken down in Oroville and Palermo. Property damage was estimated at $2.5 million.

This earthquake was associated with the first recorded surface faulting in the western foothills of the Sierra Nevada. New fractures in the ground were observed in a 3.8-km-long north- to northnorthwest-trending zone. The earthquake was felt over a large area of northern California and western Nevada. The Oroville earthquake resulted in a state disaster declaration (DC 75-03) for

the area in and around Butte County. This is shown in Figure 4.28.

Figure 4.29 shows major historical earthquakes in California.

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Figure 4.28. State and Federal Declared Earthquake Disasters

Source: Cal EMA

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Figure 4.29. Historic Earthquakes Near Butte County

Source: State of California 2010 Hazard Mitigation Plan

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In addition, the USGS Earthquake database contains data on earthquakes in the Butte County

area. Table 4.16 shows the approximate distances earthquakes can be felt away from the

epicenter. According to the table, a magnitude 5.0 earthquake could be felt up to 90 miles away.

The USGS database was searched for magnitude 5.0 or greater on the Richter Scale within 90

miles of Butte County. These results are shown in Table 4.17.

Table 4.16. Approximate Relationships between Earthquake Magnitude and Intensity

Richter Scale Magnitude Maximum Expected Intensity (MM)* Distance Felt (miles)

2.0 - 2.9

3.0 - 3.9

4.0 - 4.9

5.0 - 5.9

I

– II

II

– III

IV

– V

VI

– VII

0

10

50

90

6.0 - 6.9

7.0 - 7.9

VII

– VIII

IX

– X

135

240

8.0 - 8.9 XI

– XII

365

*Modified Mercalli Intensity Scale.

Source: United State Geologic Survey, Earthquake Intensity Zonation and Quaternary Deposits, Miscellaneous Field Studies

Map 9093, 1977.

Table 4.17. Magnitude 5.0 Earthquakes within 90 Miles of Butte County*

Date

8/1/1975

8/2/1975

8/2/1975

2/22/1979

11/28/1980

11/26/1998

9/3/2000

8/10/2001

4/26/2008

Source: USGS

*Search dates 1973- May 25, 2012

Likelihood of Future Occurrences

Magnitude

5.8

5.1

5.1

5.2

5.2

5.4

5.0

5.2

5.0

Distance from Butte County

Inside County

Inside County

Inside County

85 miles

61 miles

86 miles

87 miles

51 miles

85 miles

Occasional – Butte County‘s Safety Element notes that there is potential that the area will be subject to at least moderate earthquake shaking one or more times over the next century. As discussed above, Butte County could be affected by earthquake activity from several local and regional fault systems. In 2008, the United States Geological Survey (USGS) and the California

Geological Survey (CGS) released the time

‐dependent version of the Uniform California

Earthquake Rupture Forecast (UCERF II) model. These were the first statewide peer reviewed forecasts and Next Generation Attenuation (NGA) ground motion prediction efforts undertaken.

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The UCERF II results have helped to reduce the uncertainty in estimated 30

‐year probabilities of

strong ground motions in California. The UCERF map is shown in Figure 4.30 and indicates

that Butte County has a low to moderate risk of earthquake occurrence, which coincides with the likelihood of future occurrence rating of occasional.

Figure 4.30. Probability of Earthquake Magnitudes Occurring in 30 Year Time Frame

Source: United States Geological Survey Open File Report 2007

‐1437

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4.2.10 Earth Movement: Landslide

Hazard/Problem Description

Landslides refer to a wide variety of processes that result in the perceptible downward and outward movement of soil, rock, and vegetation under gravitational influence. Common names for landslide types include slump, rockslide, debris slide, lateral spreading, debris avalanche, earth flow, and soil creep. Landslides may be triggered by both natural and human-induced changes in the environment that result in slope instability.

A landslide is the breaking away and gravity

‐driven downward movement of hill slope materials, which can travel at speeds ranging from fractions of an inch per year to tens of miles per hour depending on the slope steepness and water content of the rock/soil mass. Landslides range from the size of an automobile to a mile or more in length and width and, due to their sheer weight and speed, can cause serious damage and loss of life. Their secondary effects can be far

‐reaching; such as catastrophic flooding due to the sudden release of river water impounded by landslide debris or slope failure of an earthen dam.

Landslide problems can be caused by land mismanagement, particularly in mountain, canyon, and coastal regions. In areas burned by forest and brush fires, a lower threshold of precipitation may initiate landslides. Land-use zoning, professional inspections, and proper design can minimize many landslide, mudflow, and debris flow problems.

The susceptibility of an area to landslides depends on many variables including steepness of slope, type of slope material, structure and physical properties of materials, water content, amount of vegetation, and proximity to areas undergoing rapid erosion or changes caused by human activities. These activities include mining, construction, and changes to surface drainage areas.

Landslides often accompany other natural hazard events, such as floods, wildfires, or earthquakes. Landslides can occur slowly or very suddenly and can damage and destroy structures, roads, utilities, and forested areas, and can cause injuries and death.

Landslides directly damage buildings in two general ways: 1) disruption of structural foundations caused by differential movement and deformation of the ground upon which the structure sits; and 2) physical impact of debris moving down slope against structures located in the travel path.

In addition to buildings, other types of engineered structures are vulnerable to the impact and ground deformation caused by slope failures, particularly utilities and transportation structures.

These belong to a category of structures called lifelines. Transmission lines such as telephone lines, electric power, gas, water, sewage, roadways, etc., are necessary for today‘s functioning society. They present a particular vulnerability because of their geographic extent and susceptibility to physical distress. Lifelines are generally linear structures that, because of their geographic extent, have a greater opportunity for impact by ground failure.

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According to the Butte County General Plan Environmental Impact Report, the eastern portion of

Butte County includes rolling foothills, mountainous peaks and deep stream-cut valleys. The steep slopes associated with this terrain can become saturated and lose strength, causing slope instability and landslides. Other natural causes of landslides include weak rock, inclined planes of weakness, undercutting by streams and waves, intense rainfall, vegetation removal by fire, and earthquakes. Slope instability can be exacerbated through human activities such as improper road and/or building design, excavation of the top of a slope or excess loading of the top of a slope, vegetation removal, mining, and human-introduced water sources, such as lawn watering, leachfields, leaking stormdrains, and water lines. Landslide potential for different areas of Butte

County is shown in Figure 4.31.

Areas of greatest slope instability include excessively steep slopes, locations of past landslides, hillsides where clay and silt-rich soils or weathered rock absorb water, and areas of weak or stratified rock with bedding or foliation parallel to surface slopes. In addition, slope failure may occur where faults have fractured rock and along the base of slopes or cliffs where supporting material has been removed by stream erosion, flowing water, or human activities.

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Figure 4.31. Butte County Landslide Risk

Source: Butte County General Plan 2030 Health and Safety Element

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Most landslides in Butte County occur on slopes greater than 15 percent, and most new landslides occur in areas that have experienced previous landslides. The areas of highest landslide potential are in the mountainous central area of the County where well-developed soils overly impervious bedrock on steep slopes which at times undergo heavy rainfall. The slopes around flat uplands, such as Table Mountain, are also highly susceptible to landslides.

Most of the rest of Butte County has moderate to low landslide potential. The areas of lowest landslide potential are the flat lands of the Sacramento Valley. There may, however, be some landslide hazard due to possible liquefaction of soils bordering the Sacramento River and its tributaries.

Past Occurrences

Butte County has a history of landslides and has experienced several landslides in the past.

May 22, 1990 - A huge boulder loosened by weekend rains careened onto a road in eastern

Butte County and crushed a car, killing two people and seriously injuring two others, authorities said. The Ford Bronco was driving at 5 m.p.h. when a rockslide tumbled down the mountainside and hit the vehicle on a country road about 20 miles northeast of Oroville,

California.

October 31, 2008 –The California Highway Patrol reported multiple locations of rock and mud debris on Highway 70 near Yankee Rd and the town of Concow. A wildfire had burned this area earlier in the year, making it susceptible to debris slides.

March 28, 2009 – Severe winter weather caused two landslides that closed Oro Quincy highway from French Creek Road to Bald Rock Road. The road was closed until November of 2011. The Federal Highways Administration oversaw the work that repaired damage done from a slide above the road and another slide on the downhill side of the road. About

$900,000 was spent on the repairs.

Likelihood of Future Occurrences

Likely – Most landslides in Butte County occur on slopes greater than 15 percent, and most new landslides occur in areas that have experienced previous landslides. The areas of highest landslide potential are in the mountainous central area of the County where well-developed soils overly impervious bedrock on steep slopes which at times undergo heavy rainfall. The slopes around flat uplands, such as Table Mountain, are also highly susceptible to landslides. These portions of the County, coupled with the amount of previous occurrences, equates to a likelihood of future occurrence of likely.

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4.2.11 Earth Movement: Erosion

Hazard/Problem Description

Erosion is a two-step process by which soils and rocks are broken down or fragmented and then transported. Aside from natural causes of erosion, including flooding and fire, human activities such as mining, logging and cattle ranching can also facilitate erosion.

Erosion from Wind and Heavy Rain

A dust storm occurs when fine particles of soil are driven by strong winds into the air. Dust storms are often a result of wind, severe drought and poor soil conservation practices. A dust storm usually arrives suddenly in the form of an advancing wall of dust and debris that can be several miles long and thousands of feet high. Besides contributing to transportation problems dust storms are a health and safety hazard to persons and animals, and can foul machinery,

HVAC systems, and electronic equipment. Water ditches filled with soil can impact water quality and water carrying capacity. Dust storms can be economically damaging to the agricultural industry, since the most fertile part of the soil is removed during events, reducing productivity and threatening the long term stability of the land. Specific wind erosion areas in

Butte County and the United States as a whole are shown in Figure 4.32.

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Figure 4.32. Wind Erosion Areas of the United States

Source: USDA, http://soils.usda.gov/use/worldsoils/mapindex/eroswind.html

Erosion hazard potential in Butte County, which is displayed in Figure 4.33, is dependent on the

underlying geology and the amount of rainfall the area receives, and erosion hazard increases when protective vegetation is removed. Erosion hazard potential is highest in the mountainous central area of the county where well-developed soils overlay impervious bedrock on steep slopes, which at times undergo heavy rainfall.

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Figure 4.33. Butte County Erosion Map

Source: Butte County General Plan 2030 Health and Safety Element

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Erosion and debris flows can also occur in California in the months and years following large hot fires. Wildfires greatly reduce the amount of vegetation, which in turn reduces the amount of rainwater absorption, allowing excessive water runoff that often includes large amounts of debris, dirt, and other sediments. Erosion in areas of steep slope can lead to landslides and rockfall.

River/Stream/Creek Bank Erosion

Any flowing body of water (brook, creek, stream, river) is a stream. Stream flow is expressed as volume per unit time, usually cubic meters per second, cubic feet per second, sometimes cubic kilometers per second, or acre-feet per second or day. Stream flow varies tremendously with time. Short term controls include rainfall, snowmelt, and evaporation conditions. Long term controls include land use, soil, groundwater state, and rock type.

Streams erode by a combination of direct stream processes, like down cutting and lateral erosion, and indirect processes, like mass-wasting accompanied by transportation. Water tends to move

downstream in slugs that extend all the way across a channel as shown in Figure 4.34. When the

channel bends, water on the outside of the bend (the cut-bank) flows faster and water on the inside of the bend (the point) flows slower. This distribution of velocity results in erosion occurring on the outside of the bend (cut) and deposition occurring on the inside of the bend.

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Figure 4.34. Meanders and Stream flows

Stream bank erosion is a natural process, but acceleration of this natural process leads to a disproportionate sediment supply, stream channel instability, land loss, habitat loss and other adverse effects. Stream bank erosion processes, although complex, are driven by two major components: stream bank characteristics (erodibility) and hydraulic/gravitational forces. Many land use activities can affect both of these components and lead to accelerated bank erosion. The vegetation rooting characteristics can protect banks from fluvial entrainment and collapse, and also provide internal bank strength. When riparian vegetation is changed from woody species to annual grasses and/or forbs, the internal strength is weakened, causing acceleration of mass wasting processes. Stream bank aggradation or degradation is often a response to stream channel instability. Since bank erosion is often a symptom of a larger, more complex problem, the long-

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term solutions often involve much more than just bank stabilization. Numerous studies have demonstrated that stream bank erosion contributes a large portion of the annual sediment yield.

Determining the cause of accelerated streambank erosion is the first step in solving the problem.

When a stream is straightened or widened, streambank erosion increases. Accelerated streambank erosion is part of the process as the stream seeks to re-establish a stable size and pattern. Damaging or removing streamside vegetation to the point where it no longer provides for bank stability can cause a dramatic increase in bank erosion. A degrading streambed results in higher and often unstable, eroding banks. When land use changes occur in a watershed, such as clearing land for agriculture or development, runoff increases. With this increase in runoff the stream channel will adjust to accommodate the additional flow, increasing streambank erosion.

Addressing the problem of streambank erosion requires an understanding of both stream dynamics and the management of streamside vegetation.

As farmers settled the valleys, the Gold Rush drew prospectors to the hills. As mining in the

Sierra Nevada turned to the more ―efficient‖ methods of hydraulic mining, the use of environmentally destructive high-pressure water jets washed entire mountainsides into local streams and rivers. Hydraulic gold mining in the northern Sierra Nevada foothills produced 1.1 billion cubic meters of sediment. Approximately 38% of the total hydraulic-mining sediment produced was stored in piedmont deposits of the Yuba and Bear Rivers and the lower Feather

River. As a result, the enormous amounts of silt deposited in the riverbeds of the Central Valley increased flood risk. These low-lying, unconsolidated deposits reside below all dams and reservoirs and are largely between modern levees. As a remedy to these rising riverbeds, levees were built very close to the river channels to keep water velocity high and thereby scour away the sediment. However, the design of these narrow channels has been too successful. While the

Gold Rush silt is long gone, the erosive force of the constrained river continues to eat away at the levee system.

Since the construction of the Oroville Dam and Thermalito Afterbay, sediment loads from waters discharged from the dams into the Feather River have decreased significantly. This lack of suspended sediment in the river has caused the river to become more erosive in the northern portion of the alignment, transporting the mining debris and older alluvium downstream. Data from a 1978 study on the affects of Oroville Dam on sediment transport indicated sediment yield increased between Gridley and Marysville, which was attributed to channel erosion accelerated by the clear-water dam releases and to change in frequency and magnitude of flow rates.

Erosion and deposition are occurring continually at varying rates over the planning area. Swiftly moving floodwaters cause rapid local erosion as the water carries away earth materials. This is especially problematic in leveed areas. Severe erosion removes the earth from beneath bridges, roads and foundations of structures adjacent to streams. By undercutting it can lead to increased rockfall and landslide hazard. The deposition of material can block culverts, aggravate flooding, destroy crops and lawns by burying them, and reduce the capacity of water reservoirs as the deposited materials displace water.

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Streambank erosion increases the sediment that a stream must carry, results in the loss of fertile bottomland and causes a decline in the quality of habitat on land and in the stream.

Past Occurrences

Erosion from Wind and Heavy Rains

Erosion from wind and heavy rains occurs on an annual basis in the County. No database tracks this information, and the HMPC could provide no specific information on past occurrences.

River/Stream/Creek Bank Erosion

In 2006, after the City of New Orleans was flooded, concern was raised for the threat of flooding to the Sacramento Valley. In February 2006, the governor of California declared a state of emergency for the Central Valley levees. Soon after, all the sites that were defined as ―critical‖ in the 2005 inventory were repaired. Repairs have continued every year since and over 100 sites have been repaired since the declaration through the combined efforts of the US Army Corps of

Engineers and the California Department of Water Resources.

While sites are currently being repaired, more sites enter the erosion inventory every year. The number of erosion sites within the system is large and even with repairs being completed every year, the number of stream bank erosion sites shows little decline year over year. With the large number of sites, a ranking system was developed to help determine which sites should be considered the highest priority for repair. Based on a 2007 field investigation, the total number

of erosion sites within Butte County was 4 sites. These are shown in Figure 4.35.

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Figure 4.35. Levee Erosion Repair Sites in Butte County

Source: California Department of Water Resources

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At the Sycamore Creek diversion near Marigold Avenue, the channel and its banks show signs of severe erosion which provides the sediment source for deposition in the downstream reaches that have milder slopes and slower velocities, such as the Cohasset Road Bridge.

Figure 4.36. Evidence of Erosion in South Sycamore Creek

Source: 2006 Butte County Flood Mitigation Plan

The Sacramento River has cut away approximately 65 feet of bank along the stretch of River

Road between West Sacramento Avenue and Big Chico Creek. River Road is only approximately four feet away from the Sacramento River. The Butte County Department of

Public Works has placed a temporary concrete barrier along the roadway; however a more permanent solution is necessary to protect the people and the road.

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Figure 4.37. Erosion along River Road

Source: 2006 Butte County Flood Mitigation Plan

Past channel erosion in the County has also happened in the tributaries of Dry Creek in the developed areas of the City of Oroville.

Likelihood of Future Occurrences

Erosion from Wind and Heavy Rain

Highly Likely – Normal erosion processes are occurring all the time at various points in the

County.

River/Stream/Creek bank Erosion

Highly Likely – Due to the high number of linear feet of levees and creek banks, the likelihood of future occurrences of streambank erosion in Butte County is highly likely.

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4.2.12 Flood: 100/500-year and Localized Flooding

Hazard/Problem Description

Flooding is the rising and overflowing of a body of water onto normally dry land. History clearly highlights floods as the most frequent natural hazard impacting Butte County. Floods are among the most costly natural disasters in terms of human hardship and economic loss nationwide. Floods can cause substantial damage to structures, landscapes, and utilities as well as life safety issues. Floods can be extremely dangerous, and even six inches of moving water can knock over a person given a strong current. A car will float in less than two feet of moving water and can be swept downstream into deeper waters. This is one reason floods kill more people trapped in vehicles than anywhere else. During a flood, people can also suffer heart attacks or electrocution due to electrical equipment short outs. Floodwaters can transport large objects downstream which can damage or remove stationary structures, such as dam spillways.

Ground saturation can result in instability, collapse, or other damage. Objects can also be buried or destroyed through sediment deposition. Floodwaters can also break utilities lines and interrupt services. Standing water can cause damage to crops, road, foundations, and electrical circuits. Direct impacts, such as drowning, can be limited with adequate warning and public education about what to do during floods. Where flooding occurs in populated areas, warning and evacuation will be of critical importance to reduce life and safety impacts from any type of flooding. Additional information on evacuation and post-disaster mitigation policies and

procedures can be found in Section 4.4 of this Risk Assessment.

Certain health hazards are also common to flood events. While such problems are often not reported, three general types of health hazards accompany floods. The first comes from the water itself. Floodwaters carry anything that was on the ground that the upstream runoff picked up, including dirt, oil, animal waste, and lawn, farm and industrial chemicals. Pastures and areas where cattle and hogs are kept or their wastes are stored can contribute polluted waters to the receiving streams.

Floodwaters also saturate the ground, which leads to infiltration into sanitary sewer lines. When wastewater treatment plants are flooded, there is nowhere for the sewage to flow. Infiltration and lack of treatment can lead to overloaded sewer lines that can back up into low-lying areas and homes. Even when it is diluted by flood waters, raw sewage can be a breeding ground for bacteria such as e. coli and other disease causing agents.

The second type of health problem arises after most of the water has gone. Stagnant pools can become breeding grounds for mosquitoes, and wet areas of a building that have not been properly cleaned breed mold and mildew. A building that is not thoroughly cleaned becomes a health hazard, especially for small children and the elderly.

Another health hazard occurs when heating ducts in a forced air system are not properly cleaned after inundation. When the furnace or air conditioner is turned on, the sediments left in the ducts

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are circulated throughout the building and breathed in by the occupants. If a city or county water system loses pressure, a boil order may be issued to protect people and animals from contaminated water.

The third problem is the long-term psychological impact of having been through a flood and seeing one‘s home damaged and irreplaceable keepsakes destroyed. The cost and labor needed to repair a flood-damaged home puts a severe strain on people, especially the unprepared and uninsured. There is also a long-term problem for those who know that their homes can be flooded again. The resulting stress on floodplain residents takes its toll in the form of aggravated physical and mental health problems.

Flooding and Floodplains

The areas adjacent to stream channels are considered the floodplain. Floodplains are illustrated on inundation maps, which show areas of potential flooding and water depths. In its common usage, the floodplain most often refers to that area that is inundated by the 100-year flood, the flood that has a one percent chance in any given year of being equaled or exceeded in any given year. The 100-year flood is the national minimum standard to which communities regulate their floodplains through the National Flood Insurance Program (NFIP). The 500-year flood is the flood that has a 0.2 percent chance of being equaled or exceeded in any given year. The potential for flooding can change and increase through various land use changes and changes to land surface, which result in a change to the floodplain. A change in environment can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity.

In addition to those 100- and 500-year floodplains regulated under the NFIP, recent California legislation resulting from Senate Bill 5 (2007) requires cities and counties within the

Sacramento-San-Joaquin Valley to address new flood protection standards of the 1-in 200 year

(0.5 percent chance of being equaled or exceeded in any given year) flood when considering new development in Urban or Urbanizing Areas. Urban Areas are developed areas in which there are

10,000 residents or more (California Government Code Section 650007(j)). Urbanizing Areas are developed areas or areas outside a developed area that is planned or anticipated to have

10,000 residents or more within the next 10 years (California Govenment Code Section

650007(k)). These standards are under development and will become effective over the next several years as ongoing technical studies are performed.

Cloudburst storms, sometimes lasting as long as three hours, occur over Butte County anytime from late spring to early fall, and they may occur as an extremely severe sequence within a general winter rainstorm. Cloudbursts are high-intensity storms that can produce peak flow equal to or somewhat greater than those of general rainstorms in portions of the study area.

Flooding from cloudbursts is characterized by high peak flow, short duration of floodflow, and small volume of runoff. Flooding is more severe when antecedent rainfall has resulted in saturated ground conditions.

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The Butte County Planning Area is susceptible to various types of flood events: riverine, flash, and localized stormwater flooding. The area is also at risk to flooding resulting from levee failures and dam failures. Levee and Dam failure flooding are discussed separately in Sections

4.2.7 and 4.2.15 of this document. Regardless of the type of flood, the cause is often the result of

severe weather and excessive rainfall, either in the flood area or upstream reach.

Riverine flooding – Riverine flooding, defined as when a watercourse exceeds its ―bankfull‖ capacity, generally occurs as a result of prolonged rainfall, or rainfall that is combined with snowmelt and/or already saturated soils from previous rain events. This type of flood occurs in river systems whose tributaries may drain large geographic areas and include one or more independent river basins. The onset and duration of riverine floods may vary from a few hours to many days and is often characterized by high peak flows combined with a large volume of runoff. Factors that directly affect the amount of flood runoff include precipitation amount, intensity and distribution, the amount of soil moisture, seasonal variation in vegetation, snow depth, and water-resistance of the surface due to urbanization.

In the Butte County Planning Area, riverine flooding can occur anytime from November through April and is largely caused by heavy and continued rains, sometimes combined with snowmelt, increased outflows from upstream dams, and heavy flow from tributary streams.

These intense storms can overwhelm the local waterways as well as the integrity of flood control structures. Flooding is more severe when antecedent rainfall has resulted in saturated ground conditions. The warning time associated with slow rise riverine floods assists in life and property protection.

Flash flooding – Flash flooding describes localized floods of great volume and short duration. This type of flood usually results from a heavy rainfall on a relatively small drainage area. Precipitation of this sort usually occurs in the winter and spring. Flash floods often require immediate evacuation within the hour.

Localized flooding – Localized, stormwater flooding problems are often caused by flash flooding, severe weather, or an unusual amount of rainfall. Flooding from these intense weather events usually occurs in areas experiencing an increase in runoff from impervious surfaces associated with development and urbanization as well as inadequate storm drainage systems.

The Butte County Waterway System and Major Sources of Flooding

The watersheds of Butte County include numerous watersheds contained within the County as well as several watersheds that drain into Butte County from surrounding counties. For the purposes of the this plan, the watershed delineation set forth in the 2006 Butte County Floodplain

Management Plan (FMP) by the Butte County Department of Water and Resource Conservation is used, which includes:

Big Chico Creek Watershed

Butte Creek Watershed

Dry Creek/Cherokee Canal Watershed

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Feather River/Lower Honcut Creek Watershed

Lake Oroville/Upper Feather River Watershed

Little Chico Creek Watershed

Pine Creek Watershed

This LHMP planning effort is updating the 2006 FMP with additional information for Butte

County. The following section, taken primarily from the 2006 Flood Mitigation Plan and the

2011 Flood Insurance Study, discusses the stream systems and flood hazards by watershed.

Figure 4.38 illustrates the watersheds of Butte County. Table 4.18 and Figure 4.39 detail the

watersheds in Butte County.

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Figure 4.38. Butte County Watersheds

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Table 4.18. Watersheds in Butte County

Watershed Name

Big Chico Creek

Butte Creek

Dry Creek/Cherokee Canal

Feather River/Lower Honcut Creek

Source: Butte County GIS

Area (acres) Watershed Name

107,949 Lake Oroville/Upper Feather River

162,199 Little Chico Creek

167,053 Pine Creek

178,925

Area (acres)

340,669

87,137

29,938

Figure 4.39. Watershed Acreage in Butte County

Source: 2006 Butte County Flood Mitigation Plan

In Butte County, there are three main rivers, the Sacramento River, the Feather River, and Butte

Creek. All surface water originating in or passing through Butte County discharges to the ocean via the Sacramento and San Joaquin Rivers, which join at the head of Suisun Bay, the easternmost arm of San Francisco Bay. With a combined tributary drainage area of approximately 60,000 square miles, these rivers provide most of the freshwater inflow to San

Francisco Bay.

High water levels along the Sacramento and Feather Rivers are a common occurrence in the winter and early spring months due to increased flow from storm runoff and snowmelt. An extensive system of dams, levees, overflow weirs, drainage pumping plants, and flood control bypass channels strategically located on the Feather River has been established to protect the area from flooding. These facilities control floodwaters by regulating the amount of water passing through a particular reach of the river. The amount of water flowing through the levee system can be controlled by Oroville Dam on the Feather River. However, flood problems in

Butte County are still quite a concern. Numerous areas of the County are still subject to flooding

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by the overtopping of rivers and creeks, levee failures, and the failure of urban drainage systems that cannot accommodate large volumes of water during severe rainstorms.

Big Chico Creek Watershed

Big Chico Creek originates from a series of springs that flow off of the Sierra Mountains to form a main channel at Butte Meadows. Big Chico Creek flows a distance of 45 miles from its origin, crossing portions of Butte and Tehama counties, to its confluence with the Sacramento River.

The Big Chico Creek watershed also encompasses three smaller drainages to the north:

Sycamore, Mud, and Rock Creeks. Closest to Big Chico Creek is Sycamore Creek, which originates at approximately 1,600 feet and is a tributary to Mud Creek. Mud and Rock Creek, further north, originate between 3,600-3,800 feet. Mud Creek drains off of Cohasset Ridge to the south, flowing 26 miles to its confluence with Big Chico Creek. Rock Creek drains the north side of Cohasset Ridge and flows 28.5 miles before it joins Mud Creek (Big Chico Creek Watershed

Alliance, 2004). Flooding hazards within the Big Chico Creek watershed is attributed to potential high flows from Lindo Channel, Sycamore Creek, Rock Creek, Keefer Slough, and Big

Chico Creek. The flooding hazards in the Big Chico Creek Watershed are summarized below:

Lindo Channel: At the Lindo Channel diversion, located at Five-Mile Park levee erosion, lack of freeboard, and the accumulation of large, woody debris at the entrance to the

Sycamore Creek Diversion Structure has historically resulted in flooding in the area during high flow events. This also contributes to high flows into Lindo Channel. Lindo Channel does not have constructed flood control levees and thus can easily exceed its channel capacity during high flows. The majority of Lindo Channel flows through the City of Chico.

Sycamore Creek: At the Sycamore Creek Diversion Structure there has accumulated a significant amount of sediment and debris both upstream and downstream of the structure.

This sediment and debris can force higher than normal flows to flow down Lindo Channel.

At the end of the Sycamore Creek diversion channel near Marigold Avenue, the channel and its banks show signs of severe erosion which provides the sediment source for deposition in the downstream reaches of Sycamore and Mud Creek that have milder slopes and slower velocities, such as the Cohasset Road Bridge. In addition to sediment deposits, large woody debris has plugged the bridge and the levees in this area have been overtopped during high flow events in the past.

Keefer Slough: At the split of Rock Creek and Keefer Slough just upstream of Hagenridge

Road increased accumulationof sediment and debris on the Rock Creek side of the fork have forced a majority of the upstream flow of Rock Creek down the Keefer Slough side in high flow events. This causes damages to areas adjacent to Keefer Slough because it does not have capacity to carry this additional amount of flow (see the discussion below on localized

flooding and Figures 4.40 and 4.41). Keefer Slough crosses State Route 99 (SR99) just north

of the City of Chico and during these high flow events the slough has inundated SR99 causing CalTrans to close the highway. Once Keefer Slough crosses SR99 it can leave its defined channel and spread out through the agricultural areas west of SR99 and north of

Nord Highway flooding the orchards and fields. The flows than join other waters near the

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community of Nord and cause flooding in Nord and the surrounding area. There are no formal flood control facilities along Keefer Slough and the slough runs on private property for its entire length.

Confluence of Big Chico Creek and Lindo Channel: At the confluence of Big Chico Creek and Lindo Channel, a private levee near Meridian Road and Grape Way broke during a recent high flow event, leaving the residents vulnerable to flooding.

Rock Creek: From its split with Keefer Slough Rock Creek flows in a well-defined but somewhat narrow channel west toward SR99. The channel in much of this stretch of the creek is chocked with sediment and debris which reduces the channel capacity of the creek.

The creek does not have any certified levees but does have embankments that retain the flow within the channel on this stretch of the creek. West of SR99 Rock Creek flows in a wider well-defined channel with more substantial levees until it intersects the UPRR tracks just north of the community of Nord. These levees were built by local farmers and not to any design standard and are thus not recognized as a certified flood control facility. The lower reaches of this section of Rock Creek periodically inundate the agricultural areas north of

Nord and leave it vulnerable to flooding. South of the UPRR tracks Rock Creek flows in a wide well-defined channel until it empties into the lower end of the Mud/Sycamore Creek

Flood Control system just south of West Sacramento Ave. west of the City of Chico. This stretch of the creek has no formal levees except in areas where a farmer may have pushed up material to keep the creek flows from flooding his fields. Where this portion of the creek crosses West Sacramento Ave. it has flooded the road especially when drbris is washed up against the bridge..

Sacramento River: The Sacramento River has cut away approximately 65 feet of bank along the stretch of River Road between West Sacramento Avenue and Big Chico Creek. River

Road is only approximately four feet away from the Sacramento River. The Butte County

Department of Public Works has placed a temporary concrete barrier along the roadway; however a more permanent solution is necessary to protect the people and the road.

Butte Creek Watershed

Butte Creek originates in the Lassen National Forest at over 7,000 feet. Butte Creek travels through canyons through the northwestern region of Butte County and through the valley, entering the floor near Chico. The northern Sierra and southern Cascade mountain ranges divide the valley section from the mountainous section of the Butte Creek watershed in Butte County.

Once Butte Creek enters the valley section of the watershed near Chico, it travels approximately

45 miles before it enters the Sacramento River (Butte Creek Existing Conditions Report, 2000).

Levees were constructed along Butte Creek in the 1950s by the Corps of Engineers. These levees extend for over 14 miles along the Butte Creek channel. The primary flooding hazards are summarized below:

Butte Creek Levees: According to the FEMA FIS and DFIRMs, the water surface elevations under a 100-year and 500-year storm event would encroach on the levee freeboard and overtop parts of the levees along Butte Creek. The BFE ranges between approximately 104

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ft to 230 ft as indicated on the FEMA DFIRM dated January 6, 2011. The Butte Creek levees were constructed in the 1950s and the condition of the levees at this time, with respect to US Army Corps of Engineers levee certification criteria, is not known. Butte Creek contained a flow greater than the 100-year event, as published in the FEMA FIS, in 1997, confirming that the floodplain provided in the FEMA FIRMs from Butte Creek is largely due to theoretical levee failure. This method of floodplain determination near levees is adopted by FEMA for levees that are not certified.

Dry Creek/Cherokee Canal Watershed

Cherokee Canal, which was originally constructed to protect agricultural land from mining debris, now serves as an irrigation drainage canal. Dry Creek becomes Cherokee Canal northeast of Richvale, and Gold Run and Cottonwood Creek join the Cherokee Canal upstream of the

Richvale Road crossing. Cherokee Canal eventually enters Butte Creek near the southwestern corner of Butte County, south of Highway 162 in an area called the ―Butte Sink.‖ The primary flooding hazards within the Cherokee Watershed is caused by sedimentation and structures located within the FEMA SFHA.

Cherokee Canal: According to a 1970 report by DWR entitled, ―Debris Deposition in the

Cherokee Canal Flood Control Project,‖ Cherokee Canal experiences flooding due to heavy rains and valley flooding. After several historical attempts to rectify the sediment and debris loading of the channel and in response to the Sacramento River Major and Minor Tributaries

Flood Control Act of 1944, the USACOE developed the ―Review of Interim Flood Control

Survey Report on Sacramento River and Tributaries, Cherokee Canal and Butte Creek, 15

June 1948.‖ The report recommended building a levee and channel flood control project and the present Cherokee Canal was constructed in 1960 based upon the recommendations in the report.

According to a recent study of the hydrologic, hydraulic, and sediment yield/transport in the Dry Creek and Cherokee Canal (U.S. Army Corps of Engineers, 2003), Dry Creek contributes the most sediment to Cherokee Canal. According to the report, it is estimated that 103,000 tons of sediment would be delivered to Cherokee Canal in a 100-year event.

An example of the affects of sedimentation and debris on constricting the channel was seen clearly at the bridge crossing at Nelson-Shippee Road during an April 2005 field visit.

Chemical Facilities Storage in the FEMA SFHA: Structures that store fertilizers and chemicals for the Butte County Rice Growers Association (BCRGA) are located in the

FEMA-designated SFHA along Cherokee Canal. The U.S. Department of Agriculture

(USDA) rice storage warehouses are also located in the Cherokee Canal FEMA designated 100-year SFHA. The consequences of flooding in these storage warehouses would be extensive, as floodwater would mix with the chemicals stored in these facilities and potentially release chemicals into surface water, groundwater, and surrounding areas.

Public health would also be a major concern.

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Feather River/Lower Honcut Creek Watershed

After the Feather River flows through the Oroville Dam it enters the City of Oroville, and continues south, joining with the Yuba River at Marysville and Yuba City, and eventually the

Sacramento River. The Feather River/Lower Honcut Creek watershed also contains a Dry Creek, unrelated to the Dry Creek in the Cherokee Watershed. This Dry Creek is located within the City of Oroville and contains three tributaries that join together and the main channel ends within the

City of Oroville. Wyman Ravine, which originates south of the City of Oroville, drains the southern portion of the watershed and flows into Honcut Creek. Flooding in the Feather

River/Lower Honcut Creek watershed has been attributed to several sources: Dry Creek and its tributaries, stormwater drainage in the City of Oroville, the Feather River, and Wyman Ravine.

The three major forks of Dry Creek originate and join within the City of Oroville urban area. The flood hazards witnessed in this watershed include:

Dry Creek: During high flow events, the northernmost fork of Dry Creek exceeds channel capacity and inundates the Oroville urban area. There are seven detention basins on the three forks. One of these detention basins is the Argonaut basin, located on the middle fork of Dry

Creek, which fills up before all others in the system. Channel erosion in the tributaries of Dry

Creek was evident through the developed areas in the City of Oroville.

Dry Creek Tributaries Confluence: Heavy development and excessive erosion near the confluence of the three main forks of Dry Creek in the City of Oroville urban area exposes nearby residents to potential flooding.

City of Oroville Stormwater Drainage: The limited capacity of the urban stormwater drainage pipes in the downtown area restrict the volume of water that can be conveyed to the Feather

River, leading to local flooding at different locations in the City.

Feather River: During high flows in the Feather River water rises through the gravel deposits in the industrial area near Feather River Boulevard on the west side of the City of Oroville.

The severity of this problem is proportional to the water surface elevation in the Feather

River, which is contained by levees above the adjacent ground, through the industrial area. A boil in the Feather River concrete levee near 4th Street and Safford Street creates a leak during high flow events. This levee is maintained and operated by the City of Oroville.

Wyman Ravine: Wyman Ravine, which is located south of the City of Oroville and runs northeast to southwest, floods nearby houses and a number of County roads including

Railroad Avenue, Cox Lane, Central House Road, Middle Honcut Road and Lower Honcut

Road in the lower reachs before it spills into North Honcut Creek.

Wyandotte Creek: Wyandotte Creek, which is located south of the unincorporated community of Palermo and runs northeast to southwest, can flood nearby houses and a number of County roads including Cox Lane, Central House Road, Middle Honcut Road and

Lower Honcut Road before it spills into North Honcut Creek.

North Honcut Creek: North Honcut Creek, which is located south of the unincorporated community of Honcut runs east to west, it can flood nearby houses and Lower Honcut Road before it merges with South Honcut Cree before spilling into the Feather River.

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Lake Oroville/Upper Feather River Watershed

The North Fork of the Feather River originates in northern California in the Lassen Volcanic

National Park. It flows south into Lake Oroville, where it joins the south and middle forks of the

Feather River. Oroville Dam, constructed in 1968, houses six power generation units and four additional units in the Thermalito Power Plant. The Thermalito Forebay and Afterbay are holding reservoirs, located downstream of Lake Oroville, that allow water released from Lake

Oroville to generate power during established peak periods and to be pumped back into the lake during off-peak periods. Other smaller creeks in the watershed flow into Lake Oroville, including Cirby and Concow creeks, which initially join to flow into the Concow Reservoir upstream of Lake Oroville. Flooding hazards occur primarily upstream of the Concow Reservoir at several road crossings at Concow Creek and at Cirby Creek.

Concow Creek: The region near the Concow Reservoir, north of Lake Oroville, has experienced periodic inundation and several crossings are severely deteriorated. In particular, the Hoffman Road Bridge at Concow Creek has limited capacity and is inundated during annual storms. The bridge has severely deteriorated and cannot handle heavy traffic that would be expected during rescue and evacuation. The culverts underneath the bridge are severely damaged and large sections of concrete have fallen into the creek and show signs of continuing erosion. The Hoffman Road Bridge serves as the only route out of the area for the close to thirty residents who live on the right bank of Concow Creek.

Cirby Creek: The Camelot Subdivision, just upstream of the Hoffman Road Bridge, contains many privately owned bridges, such as the Cirby Creek Road crossing at Cirby Creek that have limited capacity to convey heavy flows and suffer debris blockage in high flow events.

Many of the bridges cannot handle the heavy traffic that would be needed for rescue and evacuation purposes.

Little Chico Creek Watershed

Little Chico Creek originates on the northwestern boundary of the Butte Creek watershed and flows through canyons before reaching the City of Chico. Before Little Chico Creek enters the

City of Chico urban area, it passes a diversion structure constructed in the 1960

‟s, which is intended to divert high flow from Little Chico Creek into Butte Creek. Little Chico Creek flows through the City of Chico before entering the valley, at which point it disperses through numerous waterways within the region (Butte Creek Watershed Existing Conditions Report,

2000).

Flooding in Little Chico Creek has largely affected residents within the City of Chico urban area; however during high flow events the lower section of the watershed has experienced substantial damage. Flooding hazards are primarily excessive vegetation in the Little Chico Creek channel, flooding from Dead Horse Slough, flooding in the lower reaches of Little Chico Creek, and the levees along the Little Chico Creek-Butte Creek Diversion channel.

Vegetation in Little Chico Creek: Excessive invasive vegetation has reduced the channel

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capacity and accumulating storm drainage from Dead Horse Slough and the Chico urban area has reduced the capacity of the channel. Recent hydraulic analysis of the Little Chico Creek channel that was done as part of the Butte Creek Watershed Floodplain Management Plan, showed that the current channel capacity of Little Chico Creek is approximately 1,800 cfs, compared to the estimated 2,350 cfs used to map the SFHA in the FEMA FIS. Due to the limited channel capacity of Little Chico Creek, the 100-year SFHA along the Chico urban area, as determined by FEMA in the early 1990s, would actually be larger if remapped today.

Dead Horse Slough: The Dead Horse Slough crossing at El Monte Avenue experiences periodic inundation and nearby structures have inundated as recently as 1997. In the lower reaches of Little Chico Creek, the Little Chico Creek crossing at Alberton Avenue and at

Taffee Avenue has experienced levee overtopping, sheet flow flooding, and levee seepage.

Drainage in Little Chico Creek: Inadequate Storm Drainage System in the City of Chico results in excessive drainage and pollution into Little Chico Creek.

Uncertified Levee: The levees along the Little Chico Creek-Butte Creek Diversion channel were constructed in 1957. The condition of the levees and its foundation are not known and are not certified by the USACOE, thus the floodplain shown on the FEMA FIRM reflects an inadequate levee in relation to the out-of-bank flooding that can occur from Butte Creek upstream.

Pine Creek Watershed

The Pine Creek watershed is located in the northeastern section of Butte County. Pine Creek, as well as Rock Creek and Keefer Slough (which are located in the Big Chico Creek watershed), drain part of the northern region of the Big Chico Creek watershed and eventually drain into the

Sacramento River. Flooding in the Pine Creek watershed has been attributed to limited channel capacities due to excessive vegetation and sediment deposits, which occur in both Pine Creek and its main tributary, Singer Creek. Some County roads in the area can experience flooding where they cross Pine Creek and its main tributary, Singer Creek. Those road include Wilson

Landing Road, Nord Gianella Road, and Bennett Road.

Other Flood--Related Hazards: Bridges

Bridge damage and collapse due to high velocity flow and excess debris pose a risk to life and can cause damage to property and structures. According to Flood Damage Survey Reports (DSR) conducted by Natural Resource and Conservation Service (NRCS) and Butte County for FEMA, the flood event in 1997 caused:

Embankment failure to the Oroville-Chico Highway, 1.1 miles east of Midway Road. The eroded material was replaced with rock fill to the original profile, resulting in $21,000 in repairs.

The Butte Creek Bridge on Nelson Road, eight miles west of Highway 99, had extensive damage to the support columns and embankment, resulting in $68,000 in repairs.

Erosion of the piers and the bank on the north side of the Honey Run Covered Bridge had to

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be repaired to its original condition, costing $16,000.

Damage to the Butte Creek Bridge at Humboldt road due to excessive rock, trees, and debris carried by floodwaters resulted in over $25,000 in repairs.

The bridge at Humbert Road and Colby Creek sustained damage to the bridge abutment and guardrail and cost over $12,000 in repairs.

The Sycamore Valley Road junction with Cohasset Road at Cohasset Bridge sustained damages behind the bridge wingwall, where floodwaters overtopped the roadway, washing out behind the bridge wingwall and cost over $6,000 in repairs.

The Meridian Road Bridge was overtopped causing pavement deterioration and washout of the riprap, resulting in a portion of a $7,000 repair.

The Pine Creek Bridge on Nord Gianella Road sustained debris damage resulting in almost

$6,000 in repairs.

The Skyway Bridge at Butte Creek sustained damages that cost almost $4,000 in repairs.

Localized Flooding

Localized, stormwater flooding also occurs throughout the County. Urban storm drainpipes and pump station have a finite capacity. When rainfall exceeds this capacity, or the system is clogged, water accumulates in the street until it reaches a level of overland release. This type of flooding may occur when intense storms occur over areas of development.

According to Butte County, numerous parcels and roads throughout the County not included in the FEMA 100- and 500-year floodplains are subject to flooding in heavy rains. Several issues cause drainage problems that lead to flooding in the watershed. Ditches and storm water systems are needed to convey storm water away from developed areas; however, in some areas the topography prevents surface water from draining quickly to a ditch, stream, or storm drain during an intense rainfall event.

Typically, storm water systems are designed to handle storm runoff for events smaller than the

100-year event, such as a 10-year event. Older storm water systems were typically designed to convey the 10-year storm or less. These systems became inadequate as additional watershed development and associated runoff increases occurred in these developed areas. In recent years the County has implemented a requirement that new development must not increase the peak flows from the development and must retain the peak runoff within the development projects site. Storm water systems, ditches, and other waterways can also be blocked by debris, resulting in ponding storm water prior to the storm water system clearing. Many roads not in the FEMAdesignated floodplains have experienced damage in the past due to this type of localized flooding.

Although there are not any FEMA SFHAs in the Town of Paradise, inadequacies in the storm drainage facilities have resulted in areas of recurrent flooding. To solve this issue, the Town of

Paradise has developed an ―Interim Policy‖ to comply with FEMA policies and objectives. The

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areas that have repeatedly inundated during storm events are delineated as ―Special Permit

Zones.‖

Any development in these Special Permit Zones requires a certified elevation certificate based on the determination of the 100-year base flood elevation per FEMA guidelines. This policy has proven effective for the residents in the Town of Paradise; however, it has not changed the repeated flooding during storm events.

The 1991 City of Oroville Drainage Master Plan identifies inadequacies in the existing storm drainage system and recommends improvements to upgrade existing facilities to rectify the inadequacies and to accommodate future land uses. In conformance with the Drainage Master

Plan, the City of Oroville installed detention basins along Dry Creek to accommodate additional flow from storm water runoff. After the development of the Drainage Master Plan and the installation of the detention basins, FEMA mapped the area and determined the 100-year SFHA without determining the base flood elevations or taking into account the affect of the detention basins on downstream flooding. As a result of ongoing commercial building in the areas subject to FEMA regulations, the City of Oroville developed the ―Basin Hydrology and Floodplain

Analysis‖ to determine the base flood elevations in these areas and the affect of the detention basins on downstream flooding.

Due to increased drainage from the City of Chico urban area and Dead Horse Slough and excessive vegetation, the capacity of Little Chico Creek to accept stormwater drainage in addition to high flows in a storm event is limited. The City of Chico Storm Drainage Master

Plan has not been updated with criteria to accept these excess flows.

The community of Nord is located in a FEMA A Zone. The HMPC noted that there has been extensive localized flooding in the community of Nord. This happens when Keefer Slough and

Rock Creek flood due to inadequate carrying capacity of those drainages. When that happens, it sends a sheet of water over Highway 99 north of Chico that keeps flowing west toward the

Sacramento River. The moving lake advances over orchard land and right into the Nord area.

An example of recent flooding in the Nord community can be seen in Figures 4.40 and 4.41.

High water marks are easily seen roughly two feet up on each of the structures.

4.95 Butte County

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Figure 4.40. Nord Localized Flooding

Source: Butte County

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Figure 4.41. Nord Localized Flooding

Source: Butte County

Flood Maps

As part of the County‘s ongoing efforts to identify and manage their flood prone areas, Butte

County relies on a variety of different mapping efforts. What follows is a brief description of

FEMA and DWR mapping efforts covering the Butte County planning area.

FEMA Floodplain Mapping

FEMA established standards for floodplain mapping studies as part of the National Flood

Insurance Program (NFIP). The NFIP makes flood insurance available to property owners in participating communities adopting FEMA-approved local floodplain studies, maps, and regulations. Floodplain studies that may be approved by FEMA include federally funded studies; studies developed by state, city, and regional public agencies; and technical studies generated by private interests as part of property annexation and land development efforts. Such studies may include entire stream reaches or limited stream sections depending on the nature and scope of the study. A general overview of floodplain mapping and associated products is

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provided in the following paragraphs. Details on the NFIP and mapping specific to participating

jurisdictions are in Section 4.3 Vulnerability Assessment and in the jurisdictional annexes.

Flood Insurance Study (FIS)

The FIS develops flood-risk data for various areas of the community that will be used to establish flood insurance rates and to assist the community in its efforts to promote sound floodplain management. The current Butte County FISs are dated January 6, 2011. This study covers both the unincorporated County and the incorporated jurisdictions.

Flood Insurance Rate Map (FIRM)

The FIRM is designed for flood insurance and floodplain management applications. For flood insurance, the FIRM designates flood insurance rate zones to assign premium rates for flood insurance policies. For floodplain management, the FIRM delineates 100- and 500-year floodplains, floodways, and the locations of selected cross sections used in the hydraulic analysis and local floodplain regulations. The County FIRMs were replaced by new digital flood insurance rate maps (DFIRMs) as part of FEMA‘s Map Modernization program, which is discussed further below. These new DRIMS became available on January 6, 2011.

Digital Flood Insurance Rate Maps (DFIRM)

As part of its Map Modernization program, FEMA is converting paper FIRMS to digital FIRMs,

DFIRMS. These digital maps:

Incorporate the latest updates (LOMRs and LOMAs);

Utilize community supplied data;

Verify the currency of the floodplains and refit them to community supplied basemaps;

Upgrade the FIRMs to a GIS database format to set the stage for future updates and to enable support for GIS analyses and other digital applications; and

Solicit community participation.

DFIRMs, in conjunction with the paper FIRMs, both dated January 2011 for Butte County were used for this plan‘s flood hazard analysis.

Letter of Map Revision (LOMR) and Map Amendment (LOMA)

LOMRs and LOMAs represent separate floodplain studies dealing with individual properties or limited stream segments that update the FIS and FIRM data between periodic FEMA publications of the FIS and FIRM.

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Mapping of Levees

Also as part of FEMA‘s Map Modernization program, FEMA is mapping levees within communities, with a primary focus on levees determined to provide a 100-year level of flood protection.

In August of 2005, FEMA Headquarters‘ issued Memo 34 Interim Guidance for Studies

Including Levees. This memo recognizes the risk and vulnerability of communities with levees.

The memo mandates the inclusion of levee evaluations for those communities that are undergoing map changes such as the conversion to DFIRMs. No maps can become effective without an evaluation of all levees within a community against the criteria set forth in 44 CFR

65.10 Mapping of Areas Protected by Levee Systems. Generally, these levee certification requirements include evaluations of freeboard, geotechnical stability and seepage, bank erosion potential due to currents and waves, closure structures, operations and maintenance, and wind wet and wave run-up. In short, these guidelines require certification of levees before crediting any levee with providing protection from the 1 percent annual event (e.g., the 100-year flood).

In Butte County, similar to other locations in California, levees and flood control facilities have been built and are maintained variously by both public and private entities, including water, irrigation and flood control districts, other state and local agencies, and private interests. Some of these facilities were constructed with flood control as secondary or incidental to their primary purpose, so are not considered as providing protection from the 100-year or greater flood. As part of the efforts to convert the Butte County Planning Area to DFIRMS, an inventory of levees was undertaken within the planning area.

The current DFIRMs identified levees that are Provisionally Accredited Levees (PAL). To best address the issue of levees in the DFIRM process, FEMA provided guidance for the issuance of

PAL agreements that would allow for identified levees to be provisionally accredited for purposes of mapping while communities/levee owners are compiling and submitted data and documentation necessary for full accreditation that will establish these as providing protection from the 100-year flood. Since the issuance of the 2011 DFIRM, some of the PAL areas have been converted into fully accredited status.

Fully accredited and PAL designate levees are identified on the levee map and table provided in

Section 4.3.3 of this document. According to the County, all PAL agreements in the planning

area have expired, with the exception of one area protecting the greater Chico area that has been fully accredited. These are the Sycamore-Mud Creek Levees.

Private levees in the County are discussed in more detail in Section 4.2.15.

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Department of Water Resource (DWR) Floodplain Mapping

Also to be considered when evaluating the flood risks in Butte County are various floodplain maps developed by the California Department of Water Resources (DWR) for areas throughout

California, including the Butte County planning area.

DWR Best Available Maps

The Best Available Maps were developed pursuant to Senate Bill 5 which requires DWR to develop preliminary maps for the 100- and 200-year floodplains located within the Sacramento-

San Joaquin Valley watershed. These maps were developed by DWR to better reflect the most accurate information about the flooding potential in a community and were designed to provide a better understanding of the true risk of flooding to public safety and property. SB 5 requires that these preliminary maps be provided as best available information on flood protection to cities and counties in the watershed for: 1) areas protected by State-Federal project levees, and 2) areas outside the protection of project levees.

The new maps, compiled using information from state, local and federal agencies, have no current regulatory status for floodplain development and are for information only. They do not replace existing FEMA regulatory floodplain maps (i.e., FIRMs and DFIRMs) and therefore do not make any changes in federal flood insurance requirements for homes and businesses.

However, city and county governments will be able to use the maps to identify areas that warrant further study and to help make informed floodplain management and land use decisions. The floodplains shown on these maps delineate areas with potential exposure to flooding for two different storm events: one with storm flows that have a 1 percent chance of being equaled or exceeded in any year (100-year) and one with storm flows that have a 0.5 percent chance of being equaled or exceeded in any year (200-year).

These advisory maps will help communities begin early planning activities to meet SB 5 requirements calling for a minimum of 200-year protection for new development in urban and urbanizing areas. These ―best available‖ floodplain maps can be accessed online at: http://www.water.ca.gov/floodmgmt/lrafmo/fmb/fes/best_available_maps.

DWR Awareness Floodplain Maps

The Flood Awareness Maps, developed under the Flood Awareness Mapping Project, are designed to identify all pertinent flood hazard areas by 2015 for areas that are not mapped under the FEMA NFIP and to provide the community and residents an additional tool in understanding potential flood hazards currently not mapped as a regulated floodplain. The awareness maps identify the 100-year flood hazard areas using approximate assessment procedures. The floodplains are shown on these maps simply as flood prone areas without specific depths and other flood hazard data.

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The Flood Awareness Maps can be accessed online at: http://www.water.ca.gov/ floodmgmt/lrafmo/fmb/fes/awareness_floodplain_maps/butte/.

Levee Flood Protection Zones (LFPZ) Maps

LFPZ maps represent floodplain areas protected by Central Valley State-Federal Project Levees.

Under Water Code Section 9110(b), ―LFPZ‖ means the area, as determined by the Central

Valley Flood Protection Board or DWR, that is protected by a project levee. These maps were developed based on the best available information as required by Assembly Bill 156. This Bill requires DWR to prepare LFPZ maps to identify the areas where flood levels would be more than three feet deep if a project levee were to fail. DWR delineated the LFPZs by estimating the maximum area that may be flooded if a project levee fails with flows at maximum capacity that may reasonably be conveyed. DWR is using information from several sources, including FEMA floodplain maps, FEMA Q3 data, USACE‘s 2002 Sacramento and San Joaquin River Basins

Comprehensive Study, and local project levee studies. Using this data, DWR is implementing a multi-year program to evaluate and delineate detailed floodplains for areas protected by project levees. This effort includes new topography, hydrology, hydraulic models, and floodplain maps.

This information will be used to update the initial LFPZ maps. LPFZ maps can be accessed at: http://www.water.ca.gov/floodmgmt/lrafmo/fmb/fes/levee_protection_zones/LFPZ_maps.cfm.

Figure 4.76 in Section 4.3.10 is the most recent LFPZ map for the Butte County planning area.

Central Valley Floodplain Evaluation and Delineation Maps (CVFED)

CVFED maps, required by Senate Bill 5, represent 100- and 200- year floodplains for urban and urbanizing areas within the Sacramento-San Joaquin Valley watershed. These maps are being developed based on more detailed hydrologic and hydraulic information, topographic data, and levee evaluations. CVFED maps are still in the development stage.

Past Occurrences

The latest Flood Insurance Study for Butte County was released on January 6, 2011. In the study, past occurrences were broken up by stream groups in the County. The following discussion is sourced from this discussion.

Butte Creek

Floods of record in Butte Creek occurred in December 1937, December 1955, December 1964, and February 1986. The recurrence intervals for these flows are approximately 20 years (1937),

30 years (1955), 50 years (1964), and 50 years (1986), respectively.

Keefer Slough

Flooding along Keefer Slough is primarily due to water being diverted into Keefer Slough from

Rock Creek. The frequency of flooding has historically been dependent on the debris and vegetation in Rock Creek between State Highway 99 and its confluence with Keefer Slough.

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Farmers in the vicinity have periodically cleared Rock Creek to reduce spills into Keefer Slough.

During periods when Rock Creek has not been cleared, Keefer Slough has spilled its banks. The most notable recent flood occurred in March 1983 when Keefer Slough flooded homes in the vicinity of Keefer Road and the area southwest of State Highway 99. State Highway 99 was overtopped for 11.5 hours. These floodflows continued southwest, affecting much of the area between State Highway 99 and the Union Pacific Railroad, including the community of Nord and its vicinity.

Little Chico Creek

Flows of record measured in Little Chico Creek occurred in December 1964, March 1978, and

March 1974. The recurrence intervals for these three storms are approximately 10 years, 15 years, and 30 years, respectively. Ruddy Creek and Ruddy Creek Tributary Areas of flooding along Ruddy Creek have been at the crossings of Nelson, Tehama, and Biggs Avenues. Minor flood damage was reported after the February 1986 storm. The March 1983 storm caused the most recent widespread flooding.

Wyman Ravine and Tributaries

As Wyman Ravine flows out of the steep foothills, its bed slope flattens, downstream of Lincoln

Boulevard. Sheetflow and shallow flooding occur every few years in the orchards west of the

Western Pacific Railroad. Floodflows over Palermo Road have extended east of Wyman Ravine almost as far as Occidental Avenue. With few exceptions, the reach of Wyman Ravine between

Stimpson Lane and Lone Tree Road experiences annual flooding. The storm of February 1986 produced flow over Lone Tree Road, extending 500 feet north and 1,000 feet south of the creek.

The area to the south of Wyman Ravine Tributary 1, between the Western Pacific Railway embankment and Melvina Avenue, experiences chronic flooding, flow historically crosses over

Melina Avenue south of Wyman Ravine Tributary 1 and continues west and southwest across the farm fields. Additional flow spills to the south between the Western Pacific Railway embankment and Railroad Avenue.

Palermo Tributary floods during the 10-percent-annual-chance flood and greater discharges.

Sheetflow across roads and between homes occurs between approximately once in five years.

NCDC and SHELDUS

Both the NCDC and SHELDUS databases include a flood history for the Butte County Planning

area. These are noted in Table 4.19 and Table 4.20.

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Table 4.19. NCDC Flood History 1993 to August 31, 2011

Date

08-Feb-93

22-Jan-97

22-Jan-97

22-Jan-97

03-Oct-08

31-Oct-08

Source: NCDC

Location Fatalities Injuries

Property

Damage

Crop

Damage Remarks

0 0 $50,000

Palermo 0 0 $0

$0 Moderate to heavy rainfall on saturated ground caused water to flow into ten homes and four businesses in Palermo and three homes in Gridley.

$0 Heavy rains brought two small creeks in the town above their banks, damaging

10 homes.

Butte Creek

Canyon

Chico

0

0

0

0

$0

$0

Pulga

Big Bend

0

0

0

0

$0

$0

$0 Flooding from Butte Creek damaged 20 homes and buildings.

$0 Flooding damaged 20 homes as heavy rains overflowed in more urbanized areas and along the city's creeks.

$0 Cal Fire reported numerous debris flows on Highway 70 due to heavy rain over adjacent areas burned earlier in the year. Several of the flows were located between their fire station and the Pulga

Bridge. Cleanup was finished at 10 pm

$0 The California Highway Patrol reported multiple locations of rock and mud debris on Highway 70 near Yankee Rd and the town of Concow. A wildfire had burned this area earlier in the year, making it susceptible to debris slides.

Table 4.20. SHELDUS Flood History for the Butte County Planning Area

Date Hazard Type

12/18/1964 Flooding

1/26/1983 Flooding

3/1/1983 Flooding

2/18/1986 Flooding

3/3/1991 Flooding

1/13/1993 Flooding

12/29/1996 Flooding

2/2/1998

1/8/1973

Flooding

Flooding - Severe

Storm/Thunder Storm

1/16/1973 Flooding - Severe

Storm/Thunder Storm

3/1/1995 Flooding - Severe

Storm/Thunder Storm -

Wind

2/11/1992 Flooding - Winter

Weather

Injuries Fatalities Property Damage Crop Damage Remarks

1.96

1.33

0.64

1.33

$1,785,714.29

$1,666,666.67

$178.57 Floods

$16,666.67 Flood

1.25

10.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.25

0.00

1.00

0.00

0.00

0.00

0.00

0.00

0.00

$125,000.00

$5,000,000.00

$1,666.67

$55,555.56

$2,857.14

$0.00

$12,500.00 Flood

$0.00 Flash Flooding

$0.00 Flood

$55,555.56 Flash Flood

$0.00 Floods

$2,971,428.57 $928,571.43 Flood

$35,714.29 Heavy Rains,

Floods

$86,206.90 $0.00 Heavy Rains,

Floods

$0.00 $11,241,379.31 Flood, Rain,

Winds

0.00 0.00 $11,627.91 $0.00 Winter Storm,

Flash Flood

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Date Hazard Type

2/14/1992 Flooding - Winter

Weather

Source; SHELDUS

Injuries Fatalities Property Damage Crop Damage Remarks

0.00 0.00 $9,090.91 $0.00 Winter Storm,

Flash Flood

Likelihood of Future Occurrences

100-Year Flood

Occasional—The term ―100-year flood‖ is misleading. It is not the flood that will occur once every 100 years. Rather, it is the flood elevation (or depth) that has a 1- percent chance of being equaled or exceeded in any given year. Thus, the 100-year flood could occur more than once in a relatively short period of time.

500-Year Flood

Unlikely—The 500 year flood is the flood elevation or depth that has a 0.2 percent chance of being equaled or exceeded in any given year.

<100-Year Flood/Localized Flooding

Highly Likely—Based on historical data, flooding events less severe than a 100-year flood and those outside of the 100-year floodplain occur frequently during periods of heavy rains.

4.2.13 Hazardous Materials Incidents: Transportation

Hazard/Problem Description

A hazardous material is any item or agent (biological, chemical, physical) which has the potential to cause harm to humans, animals, or the environment, either by itself or through interaction with other factors. Hazardous materials can be present in any form; gas, solid, or liquid. Environmental or atmospheric conditions can influence hazardous materials if they are uncontained.

The U.S. Occupational Safety and Health Administration‘s (OSHA) definition of hazardous material includes any substance or chemical which is a ―health hazard‖ or ―physical hazard,‖ including: chemicals which are carcinogens, toxic agents, irritants, corrosives, sensitizers; agents which act on the hematopoietic system; agents which damage the lungs, skin, eyes, or mucous membranes; chemicals which are combustible, explosive, flammable, oxidizers, pyrophorics, unstable-reactive or water-reactive; and chemicals which in the course of normal handling, use, or storage may produce or release dusts, gases, fumes, vapors, mists or smoke which may have any of the previously mentioned characteristics.

The Environmental Protection Agency (EPA) incorporates the OSHA definition, and adds any item or chemical which can cause harm to people, plants, or animals when released by spilling,

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leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping or disposing into the environment. The EPA maintains a list of 366 chemicals that are considered extremely hazardous substances (EHS). This list was developed under the Superfund

Amendments and Reauthorization Act. The presence of EHSs in amounts in excess of a threshold planning quantity requires that certain emergency planning activities be conducted.

A release or spill of bulk hazardous materials could result in fire, explosion, toxic cloud or direct contamination of water, people, and property. The effects may involve a local site or many square miles. Health problems may be immediate, such as corrosive effects on skin and lungs, or be gradual, such as the development of cancer from a carcinogen. Damage to property could range from immediate destruction by explosion to permanent contamination by a persistent hazardous material.

Accidents involving the transportation of hazardous materials could be just as catastrophic as accidents involving stored chemicals, possibly more so, since the location of a transportation accident is not predictable. The U.S. Department of Transportation divides hazardous materials into nine major hazard classes. A hazard class is a group of materials that share a common major hazardous property, i.e., radioactivity, flammability, etc. These hazard classes include:

Class 1—Explosives

Class 2—Compressed Gases

Class 3—Flammable Liquids

Class 4—Flammable Solids; Spontaneously Combustible Materials; Dangers When Wet

Materials/Water-Reactive Substances

Class 5—Oxidizing Substances and Organic Peroxides

Class 6—Toxic Substances and Infectious Substances

Class 7—Radioactive Materials

Class 8—Corrosives

Class 9—Miscellaneous Hazardous Materials/Products, Substances, or Organisms

Much of the hazardous materials transported through Butte County are carried by truck on the

State Highway or railway systems. Figure 4.42 shows the County roads and city streets that are

used to transport locally generated wastes from the source to the regional highway system. The

County has not quantified the amount of hazardous materials that are transported through it en route to adjoining counties or states.

Some of the hazardous materials transported through the County may bypass hazardous materials routes. Chemicals supporting local industries, such as agriculture operations and agriculture support operations, may transport hazardous materials to and from the facilities and fields.

These are not shown on Figure 4.42.

Two Union Pacific rail lines serve Butte County. The first connects Chico, Biggs, and Gridley north to Oregon and south to Sacramento. The second runs through Oroville, up the Feather

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River Canyon toward Idaho, and south to Sacramento. The locations of lines are shown in

Figure 4.42.

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Figure 4.42. Hazardous Materials Routes in Butte County

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Past Occurrences

The United States Department of Transportation Pipeline and Hazardous Materials Safety

Administration‘s (PHMSA) Office of Hazardous Materials Safety performs a range of functions to support the safe transport of hazardous material. One of these functions is the tracking of hazardous materials incidents in the United States. Rail incidents since 1970 in the Butte County

Planning Area are shown in Table 4.21.

Table 4.21. Railroad Hazardous Materials Releases in Butte County 1970-2012

Date of

Incident/

Location

2/2/1992

Soda

Springs

Quantity

Released

200

Gallons

Commodity

Long Name/

Class

Ferric

Chloride

Solution

Failure Cause

Description Description of Events

Loose Closure Cap on frangible disc assy loose - 3 bolts loose - 1

Component or

Device; bolt missing nut.

8/24/1992

Oroville

200 pounds

Ammonium

Nitrate

Fertilizers

Mixtures Of

Ammonium

Nitrate With

Added Matter

Which Is

Inorganic And

Chemically

Inert Towards

Ammonium

Nitrate With

Not

Than

Less

90

Percent

Ammonium

Nitrate Etc.

Derailment;

Vehicular

Crash

Accident

Damage; or

Special agent/hazardous materials (SA/HM) J. Jara was notified that hopper car NAHX 55364 had derailed at the Oroville freight yard. SA/HM jara responded and met with Oroville Battalion Chief R. E.

Zollner on the scene. The yard operations had been shut down and sa/hm Jara inspected the car. NAHX

55364 was a three compartment hopper car and compartment number three had 50-75 lbs of product on the ground. Traynham trucking was contacted to transload product into trucks so car coul be railed. A slow order (20 mph) was placed through the yard until the cleanup was completed. Problems were encountered due to highwinds causing movement of product (dust particles) during the vacuum process.

Traynham trucking unloaded one compartment before operation was shut down. The remaining two compartments were plugged for car to be railed.

Industrial cleaning notified and vacuumed commodity up. Car was rerailed and moved to the west end of the yard. Remaining product was transloaded by fleet transport. Chemtrec Oroville Fire Department and Ca

State O.E.S. were notified of the incident.

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Date of

Incident/

Location

4/25/1993

Richvale

Quantity

Released

19,771 gallons

Commodity

Long Name/

Class

Carbon

Dioxide

Refrigerated

Liquid

(Cryogenic

Liquid)

Failure Cause

Description Description of Events

Water Damage D.W. Alm, manager CTS, was notified at by UPRR dispatcher Duane Lee that tank car gatx 15824 in

Oroville, Ca was venting. A high pitched scream was coming from the car as well as white vapor. While enroute Mgr. Alm contacted all appropriate agencies and requested a representative from liquid air product meet him at the railyard to examine the tank car of carbon dioxide. Upon arrival the car was examined and it was determined that the 440 psi rupture disk was blown. Decision was made that the 440 psi rupture disk was blown. Decision was made that to stop the venting would be dangerous, therefore the tank was allowed to vent. Tank moved to the east side of the yard and it remained there until it stopped venting at 0230 hrs 4/2/93. Cal Oro security company was enlisted by liquid air and monitored tank car until system depleted.

12/13/1999

Richvale

100,000 pounds

Ammonium

Nitrate

Fertilizers

Derailment;

Rollover

Accident;

Mgr snow notified by rmcc of derailment in Richvale

Ca. Hopper car MP 722959 load of ammonium nitrate fertilizer was overturned and spilled on to the ground.

After investigation it was determined to have spilled about 100 000 lbs on the ground. Car was uprighted and moved to consignee. Product on the ground was picked up and taken to consignee by the environmental contractor ac industrial.

Source: PHMSA Incident Search: https://hazmatonline.phmsa.dot.gov/IncidentReportsSearch/

Table 4.22. Highway Hazardous Materials Releases in Butte County 1970-2012

Date of

Incident

Location

4/6/1998

Chico(In

Plant)

Duckback

Products 2

Transportation

Phase

Unloading

Commodity

Long Name

Combustible liquid n.o.s.

Quantity

Released

5 gallons

Failure

Cause

Description Description of Events

During unloading process, one of the delivery hoses developed a bubble in it's covering. Driver shut down the process and went to get assistance from customer personnel. One of the workers was attempting to drain the hose into a bucket but miscalculated the trajectory of the pouring liquid.

Liquid missed the bucket and spilled onto ground. There were no injuries and the product did not reach any waterways. Cleanup was performed by customer employees.

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Date of

Incident

Location

2/2/2003

Chico

Midway

And

Speedway

Transportation

Phase

In transit

Commodity

Long Name

Quantity

Released

Petroleum gases liquefied

9,145 gallons

10/30/2003

Chico

14300 St

Hwy

99/Meridian

Rd

3/23/2004

Richvale

Hwy 162

Westbound

Nearest

Cros

In transit

In transit

Gasoline

Ammonia anhydrous liquefied or ammonia solutions relative density less than

0.880 at 15 degrees c in water with more than 50 percent ammonia

1,500 gallons

0

Failure

Cause

Description Description of Events

Overpressurized;

Rollover

Accident;

Vehicular

Crash or

Accident

Damage

Driver made a wrong turn on way to Coast Gas Chico and entered a commercial business parking lot to turn around. When he turned he jackknifed the trailer and tipped it over. The front of the trailer struck the frame rail on the rear of the truck puncturing it. The resulting explosion burned the trailer and the cab of the truck. The truck tank did not burst but vented.

When the trailer's contents burned out the fire was totally extinguished. Three hundred fifty gallons of propane were recovered from the truck tank. When the incident occurred the dispatcher in

Shafter was notified by phone and

Jerry Lees was given the call. I called general manager Don

Pedigo and assistant manager

Gary Reed both trained and experienced in hazmat response.

They proceeded immediately to the scene. Local authorities had already called in emergency response personnel.

Vehicular

Crash or

Accident

Damage

Our driver was driving north on highway 99 when a vehicle driver by Margaret Janty stopped at a stop sign & proceeded to enter the highway to go south on 99. Our driver tried to avoid hitting Mrs.

Janty but the impact with her car pushed our tractor into the southbound lane where the tank was ruptured by an oncoming service truck. Mrs. Janty was the causing party.

Due to Hwy 162 being shut down for investigation punposed button trans corp is filing this report. (1) no incident on package failure was noted. (2) no leak and releases were found. (3) no police report or citation were issued. (4) unable to obtain local fire response dept.

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Date of

Incident

Location

4/29/2005

Richvale

Rural farming field Hwy

162

Transportation

Phase

Unloading

Commodity

Long Name

Quantity

Released

Ammonia solutions relative density between

0.880 and 0.957 at 15 degrees C in water with more than 10 percent but not more than 35 percent ammonia

3 gallons

11/23/2005

Chico

311

Otterson

Drive Ste

60

Unloading Acetone 5 gallons

Failure

Cause

Description Description of Events

Broken

Component or

Device

At approximately 5:30pm on

4/29/05 the driver was at the remote delivery site unloaded. The driver had already unloaded the pull un it into the customer’s tank and was in the process of moving the liquid hose from rear pull tank to front tank. As the driver was moving the liquid hose from the rear pull tank to the front tank the auxiliary pump motor stopped and the backflow device was nonoperational causing approximately the spillage of three gallons Aqua

Ammonia. Upon the accidental release the driver immediately shut down the delivery pump valve closing the source of release.

The pump was immediately taken out of service and repaired with a new rubber back flow devise. The rest of the product was safely unloaded.

Human Error On 11-23-05 while offloading a tanker truck of acetone. The

Chemcraft offloader switched on ball valve on the in-house storage tank closed to divert the flow of acetone to another compartment.

The ball valve didn't get closed completely and acetone overfilled a storage tank. 5 gallons of acetone was spilled onto concrete in a area of secondary containment. And was promptly cleaned up by Chemcraft personnel. There were no injuries or exposures and acetone didn't reach soil or water. No follow-up needed. This did not involve a package failure of any kind.

Human error caused this spill.

The point of spill was at a stationary on-site storage tank.

4.111 Butte County

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Date of

Incident

Location

Transportation

Phase

Commodity

Long Name

Gasoline 9/18/2006

Chico

State Hwy

32 @ Butte

Meadows

In transit

9/18/2006

Chico State

Hwy 32 @

Butte

Meadows

In transit Diesel fuel

Quantity

Released

Failure

Cause

Description

700 gallons Rollover

Accident

Description of Events

Truck tractor & semi trailer was i/b on State Hwy 32 e/of Chico, Ca.

Vehicle traveling approx 45 mph in the dark at 4:30am. Vehicle drift off right shoulder while rounding a curve drove up an embankment and overturned tank on trailer ruptured and most of the fuel ran off roadway onto dirt shoulders.

Driver was insured and transported to hospital. Driver was released from hospital 3 days later. A hazmat clean up company called Ben's out of Red Bluff Ca was called out and cleaned up all contaminated soil. Butte County

Environmental Health supervised the clean-up operation. Removal of all contaminated soil was completed on 9/26/2006 with the approval of the appropriate agencies.

6,027 gallons

Rollover

Accident

Truck tractor & semi trailer was i/b on State Hwy 32 e/of Chico Ca.

Vehicle traveling approx 45 mph in the dark at 4:30am. Vehicle drift off right shoulder while rounding a curve drove up an embankment and overturned tank on trailer ruptured and most of the fuel ran off roadway onto dirt shoulders.

Driver was insured and transported to hospital. Driver was released from hospital 3 days later. A hazmat clean up company called ben's out of Red Bluff Ca was called out and cleaned up all contaminated soil. Butte County

Environmental Health supervised the clean-up operation. Removal of all contaminated soil was completed on 9/26/2006 with the approval of the appropriate agencies.

4.112 Butte County

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Date of

Incident

Location

Transportation

Phase

5/5/2010

Chico

1000 Ft.

North Of 99

But 44.320

In Transit

Commodity

Long Name

Gasoline

Quantity

Released

4,000 gallons

Failure

Cause

Description Description of Events

Rollover

Accident; Fire

Temperature or Heat

On 5-5-2010 a 19 year old female tried passing several cars on a rural two lane highway and apparently did not see us coming the opposite direction. According to several witnesses she had room to pull back into her lane but for reasons unknown she did not. Our driver who was fully loaded moved over as far off the road as possible to avoid a collision but the other driver made no attempt to move back over. The left front of our truck collided with the left front of the car and forced our truck to swerve hard left which caused the trailer to roll over and catch on fire.

The truck went out into a field and was completely consumed by fire along with the fuel it was carrying.

The other driver died of her injuries from the collision.

9/14/2011

Unicorp

Oroville

Sb 70 EB

But 42.080

In transit Gasoline 1800 gallons Vehicular

Crash or

Accident

Damage

Transport driver Danny Vaught was traveling eastbound on hwy

70. Danny had a lot of cars behind him so he used the turn out at

Pulga Flats to let cars pass him. At that time a Caltrans plow pulled out their gate into the turn out lane his plow hit the front tire of the pull trailer then the plow blade hit the piping under the trailer tearing it open and pulled the cable to the internal valve open allowing 1 compartment containing 1800 gallons of gasoline to spill out on the shoulder of the highway.

Danny tried the emergency shut off but the cable was wrapped up in the damaged piping and he could not release it. It took about 5 mins to empty the compartment through the hole in the pipe. The skin or shell was not damaged just the discharge pipe. Danny got his spill kit out and directed the spill off the roadway.

Source: PHMSA Incident Search: https://hazmatonline.phmsa.dot.gov/IncidentReportsSearch/

In addition to what was reported to the PHMSA, the HMPC reported the following hazardous materials transportation events:

2007

8/30/07: Truck & trailer T/C, leaked 100 gallons fuel onto roadway and shoulder

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9/19/07: Box van truck in T/C, chlorine and other acids/bases

11/6/07: Big rig fuel tank leak, 120 gallons of fuel onto state hi-way

2008

3/26/08: Gasoline tank truck T/C, set of doubles, overturned on state hi-way, fuel spill

4/3/08: Gasoline tank truck T/C, set of doubles, overturned on state hi-way, fuel spill

8/6/08: BNSF locomotive ruptured fuel tank in FR Canyon. 300 gal fuel spill

2009

9/15/09: Big rig T/C, ruptured saddle tanks, fuel leak on roadway

2010:

5/5/12: Gasoline tank truck T/C with fire and fatality, 6,000 gallons product burned/released

2011

3/21/11: UPRR derailment, LPG tank car overturned

9/14/11: Gasoline tank truck T/C and overturn in FR Canyon, fuel spill

2012

5/20/12: Tank truck T/C and overturn, released Ammonium Phosphate

Future Occurrences

Likely–There have been 4 rail related and 10 highway hazardous materials spills reported to the

PHMSA since 1970. This equates to a hazardous materials spill occurring in Butte every 3 years, or a 33.3% chance of a rail related hazardous materials spill every year. In addition, the

HMPC noted 11 events in the past 6 years, which indicates that more spills may occur in the

County than are reported to the PHMSA.

4.2.14 Invasive Species – Pests/Plants

Hazard/Problem Description

Invasive species are organisms that are introduced into an area beyond their natural range and become a pest in the new environment. This hazard addresses the issues related to invasive pests including: viruses, bacteria, fungi, insects, macro and micro invertebrate and noxious weeds that pose a significant threat to the agricultural industry and environment and are therefore a concern in the Butte County Planning Area.

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Agricultural production in Butte County is the most significant contributor to the local economy.

In addition to the $644 million in annual production value, there are hundreds of jobs directly tied to that production and thousands more that are impacted indirectly in the production, processing, transportation, and marketing of those commodities. It is estimated that there is approximately a four to one ratio for crops grown in this region, so $600 million in production value is actually a $2.6 billion impact on the local economy.

Butte County is at risk from many insects and plants that, under the right circumstances, can cause severe economic, environmental, or physical harm. Invasive pest species affecting crop production can result in economic disasters in a very short period of time. These hazards can have a major economic impact on farmers, farm workers, packers, and shippers of agricultural products.

They can also cause significant increases in food prices to the consumer due to increases in production cost and shortages. Under some conditions, pest species that have been present, and relatively harmless, can become invasive hazards. For example, severe drought conditions can weaken tree and vine crops and make them more susceptible to insect attack and disposing them to secondary microbial attack.

This hazard addresses the issues related to pests and plants that pose a concern to the Butte

County Planning Area.

Insect pests affecting crop production result in economic disasters. These hazards can have a major economic impact on farmers, farm workers, packers, and shippers of agricultural products.

They can also cause significant increases in food prices to the consumer due to shortages. Under some conditions, insects that have been present and relatively harmless can become hazardous.

For example, severe drought conditions can weaken trees and make them more susceptible to destruction from insect attacks. The major forms of insects are:

Chewing insects are defoliating insects. They generally strip plants of green matter such as leaves. Caterpillars and beetles make up the largest proportion of chewing insects. Under normal conditions, trees can usually bounce back from an attack of these defoliators, though repeat infestation will weaken a tree and can eventually kill it by starving it of energy.

Boring, or tunneling, insects cause damage by boring into the stem, roots, or twigs of a tree.

Some lay eggs which then hatch and the larvae burrow more deeply into the wood, blocking off the water-conducting tissues of the tree. Boring insects generally feed on the vascular tissues of the tree. If the infestation is serious, the upper leaves are starved of nutrients and moisture, and the tree can die. Signs of borer infestation include entry/exit holes in the bark, small mounds of sawdust at the base, and sections of the crown wilting and dying.

Sucking insects do their damage by sucking out the liquid from leaves and twigs. Many sucking insects are relatively immobile, living on the outside of a plant and forming a hard protective outer coating while they feed on the plant‘s juices. Quite often they will excrete a sweet, sticky

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substance known as honeydew which contains unprocessed plant material. Honeydew can cause sooty mold to form on leaves and can become a nuisance. Signs of infestation include scaly formations on branches, dieback of leaves, and honeydew production.

Also, while not technically an insect, it is worth noting that pathogens such as fungi can kill large stands of trees. For example, Phytopthora ramorum, the cause of Sudden Oak Death, which is devastating not only for oaks, but for many other species of trees as well, is spreading rapidly

Butte County is also at risk to noxious weeds that can affect both waterways and agricultural crops. These hazards can have major impact on farmers, farm workers, packers, and shippers of products, as well as those who use waterways for recreation or for water supply.

Butte County Agricultural Industry

Butte County contains a diverse Agricultural environment including fertile arable land, range land and timber. Total 2011 crop production value of $644,112,000 represented a 15% increase

in values/year over a 5 year average. Table 4.23 shows the total value of all agricultural products

in Butte from 2005-2011.

Table 4.23. Gross Value ($) of Agricultural Production in Butte County

Apiary

2005

$4,213,000

2006

$6,726,000

2007

$7,300,000

2008

$7,197,000

2009

$7,153,942

2010

$7,078,000

2011

$5,813,000

Field

Crops

$96,874,000 $136,697,000 $144,741,000 $266,206,000 $201,062,334 $198,690,000 $160,306,000

Fruit and

Nut Crops

$300,111,000 $252,358,000 $298,284,000 $232,981,000 $280,076,771 $371,097,000 $416,935,000

Livestock

(all)

$11,925,000 $11,815,000 $12,679,000 $11,218,000 $8,904,077 $2,604,000 $10,366,000

$11,099,000 $19,905,000 $18,832,000 $30,748,000 $26,750,760 $23,837,000 $21,728,000 Nursery

Stock

Seed

Crops

$7,256,000 $6,479,000 $8,271,000 $14,853,000 $14,861,023 $13,566,000 $18,648,000

Vegetable

Crops

Timber

$550,000 $570,000 $588,000 $720,000 $770,400 $795,000 $851,000

$7,662,000 $19,662,000 $16,558,000 $16,005,000 $4,433,950 $4,747,000 $9,465,000

Totals $439,690,000 $454,212,000 $507,253,000 $579,928,000 $544,013,257 $622,414,000 $644,112,000

Source: Butte Agricultural Commissioner

There are many harmful insect pests and plant diseases that put Butte County‘s environment and

economy at risk. Table 4.24 is a list of significant pests included in the CDFA‘s detection and

eradication programs.

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Table 4.24. CDFA Targeted Pests

Pest

Africanized

Honeybee

Description

Africanized Honeybee, Apis mellifera scutellata, are hybrids of the African honey bee that are far more aggressive than native European Species and may attack perceived threats in great numbers. Also referred to as killer bees.

Asian Citrus

Psyllid

Asian

Longhorn

Beetle

Caribbean

Fruit Fly

Asian Citrus Psyllid, Diaphorina citri, attack citrus and melons and causes

Huanglongbing disease, one of the most devastating citrus diseases in the world.

Asian longhorned beetle, Anoplophora glabripennis, tunnels through hardwoods, killing timber, nursery stock, shade trees and others.

Caribbean Fruit Fly, Anastrepha suspense, has been recorded infesting a number of cultivated and wild fruit including apple, avocado, bell pepper, carambola, citrus, date palm, guava, kumquat, loquat, mango, papaya, peach, pear, pomegranate, and tropical almond.

Diaprepes root weevil

Diaprepes root weevil, Diaprepes abbreviates, will feed on about 270 different plants from 59 plant families including citrus, guava, sugarcane, vegetables, potatoes, strawberries, sweet potatoes, papaya, mahogany, and many ornamentals. This weevil damages both the leaves and the roots of plants. In addition, the root damage makes plants susceptible to root rot disease

(Phytophthora spp.).

European

Grapevine

Moth

European Grapevine Moth, Lobesia botrana, is primarily a pest of economic importance to grapes, which is the number one agricultural plant commodity grown in California with an annual gross production value of $3.9 billion (USDA

NASS 2009)

False Codling

Moth

False Codling Moth, Thaumatotibia leucotreta, attacks grapes, peach, plum, cherry, beans, tomato, pepper, persimmon, apricot, olive, pomegranate,

English walnut, and corn. It has been reported to damage avocados, but apparently can not complete development within the fruit.

Guava Fruit

Fly

Gypsy Moth

Guava Fruit Fly, Bactrocera correcta, attacks citrus, mango, peach, guava, castor bean, castor-oil-plant, roseapple, jujube, Chinese date, fig and sapodilla.

Gypsy moth, Lymantria dispar, high populations defoliate oak, aspen and other trees; successive years of defoliation may result in tree mortality.

Japanese

Beetle

Light Brown

Apple Moth

Japanese beetle, Popillia japonica, skeletonizes leaves of 200+ plants including rose bushes, grapevines, crape myrtles; also feeds on turfgrass roots.

Light Brown Apple Moth, Epiphyas postvittana, as been associated with many plants representing 290 genera (USDA 2008). These genera contain over

2000 species of plants.

Mediterranean

Fruit Fly

Mediterranean Fruit Fly, Ceratitis capitata, has the widest host range of any pest fruit fly, and is considered the most important agricultural pest in the world.

It has been recorded infesting over 300 cultivated and wild fruits.

Melon Fruit Fly Melon Fruit Fly, Bactrocera cucurbitae, attacks over 80 different varieties of fruits.

Mexican Fruit

Fly

Oriental Fruit

Fly

Mexican Fruit Fly, Anastrepha ludens, attacks over 50 different varieties of fruits.

Oriental Fruit Fly, Bactrocera Dorsalis, attacks in excess of 230 fruits and vegetables. Fruit that has been attacked may be unfit to eat as larvae tunnel through the flesh as they feed. Decay organisms enter, leaving the interior of the fruit a rotten mass.

Detected in

Butte County*

Y

N

N

N

N

N

N

N

Y

Y

Y

Y

N

N

N

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Pest

Peach Fruit

Fly

Description

Detected in

Butte County*

N Peach Fruit Fly, Bactrocera zonata, attacks early fruit such as jujube, loquat, peach, and then moves to cucurbits, mango, citrus, guava, pomegranate and sapodilla for the rest of the year. The larvae will normally destroy the interior of the fruit as they feed on the pulp. Conspicuous, unsightly holes are made when the larvae exit for pupation. Damage to the fruit is similar to that caused by the Mediterranean fruit fly and the Melon fly. It has been reared from 33 fruits, a number of which are important commercial crops. It lowers the yield and quality of such fruits as mango, guava, citrus, eggplant, tomato, apple, peach and loquat.

Red imported fire ant, Solenopsis invicta, painful stings are a threat to people, livestock, pets and wild animals; often spread with beehives.

Red Imported

Fire Ant

Y

White Striped

Fruit fly

White Striped Fruit fly, Bactrocera albistrigata, has been recorded from the fruit of guava, mango, carambola, tropical almond, Singapore almond, jackfruit, clove, watery rose-apple, rose apple, Malay-apple, water apple, and a number of Asian trees occasionally planted as ornamentals.

N

Source: CDFA, Butte County Agricultural Commissioner

* Past Occurrences in the County may not have involved outbreak, but without mitigation of the pest, and outbreak may have occurred.

The California Conservation Corp assists in mitigating the impacts of insect pests by providing human resources to assist in state and local eradication efforts, including surveying private yards and business landscapes to detect the Glassy Winged Sharpshooter, striping citrus fruit infected by the Mexican Fruitfly, and helping eradicate the Exotic Newcastle Disease by cleaning and disinfecting backyards.

Noxious Weeds

The California Invasive Plant Council tracks invasive plants in California. Of all of the noxious weeds that are either in the County or that are a threat to the County, Scotch Broom is the weed of greatest concern to the County. It is no longer allowed to be sold in the County.

The Broom species (Scotch, French, Spanish and others) are opportunistic weeds and will quickly occupy open areas. They grow and spread very rapidly in disturbed soil. They form large mono cultures that exclude other plant species. Broom species adds significantly to the forest fuel load and creates a fire prone under story and provides a fire ladder rung to the next higher canopy in forested areas. Removal and eradicating it reduces fire danger. The Butte Fire

Safe Council is working diligently on the local level to eradicate Broom. It is a difficult task as seeds can survive 30 years or more under field conditions.

At present the Broom infestations occur in fairly, easily accessible locations for truck mounted spray equipment and are in controllable quantities; however, the infestations are spreading. A timely and aggressive control project would severely retard the spread and likely achieve eradication in most locations but no funded mitigation/control projects are presently in place.

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Impact to Human Health

Disease vectoring insects can have a substantial impact on human health and endeavors. The movement of animals, agricultural commodities and other plant material always carries the possibility for introduction of new pests that may also be a vector of disease.

Vectors have the ability to transmit infectious organisms that cause human and animal disease.

These diseases can be serious and possibly fatal. In Butte County several mosquito species are capable of transmitting West Nile Virus (WNV), Western Equine Encephalomyelitis (WEE),

Malaria and canine heartworm. Other vectors, ticks for example transmit Lyme disease.

West Nile Virus

The impact to human health that insects can have on an area can be substantial. Mosquitoes transmit the potentially deadly West Nile Virus (WNV) to livestock and humans alike. WNV first struck the western hemisphere in Queens, New York, in 1999 and killed four people. Since then, the disease has spread across the United States and is well established in most states, including California. Butte County has seen WNV activity since 2004.

Most humans infected by the virus have no symptoms. A small proportion develop mild symptoms that include fever, headache, body aches, skin rash, and swollen lymph glands. Less than 1 percent of those infected develop more severe illness such as meningitis or encephalitis, symptoms of which include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Of the few people who develop encephalitis, less than 1 out of 1,000 infected die as a result.

There is no specific treatment for the infection or a vaccine to prevent it. Treatment of severe illness includes hospitalization, use of intravenous fluids and nutrition, respiratory support, prevention of secondary infections, and good nursing care. Medical care should be sought as soon as possible for persons who have symptoms suggesting severe illness. People over 50 years of age appear to be at high risk for the severe aspects of the disease.

Malaria and the Tiger Mosquito

A protist (a type of microorganism) of the genus Plasmodium is the organism that causes the disease, Malaria. It has been known to exist in Butte County since the 1800‘s. The absence of an effective vector keeps this disease from becoming a serious, wide spread health issue in northern

California. The Butte County Mosquito and Vector Control District was formed in 1948 to combat malaria by controlling the Anopheles freeborni mosquito. Treatment and successful mosquito abatement essentially eliminated malaria as a major health concern in the early 1900‘s.

However persistent Anopheline abundance and repeated importation of malaria infected immigrants and travelers pose a risk of transmission and re-establishment in our agricultural based, mosquito-friendly central valley.

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The Tiger mosquito , Aedes albopictus is characterized by its black and white (Tiger) striped legs and body. It is native to the tropical and subtropical areas of Southeast Asia; however, in the past couple of decades this species has invaded many countries throughout the world by transport of goods and increasing international travel. This mosquito (a superior vector of many disease including malaria) has become a significant pest in many communities because it closely associates with humans (rather than living in wetlands), and typically flies and feeds in the daytime in addition to dusk and dawn flight of the native species.

Isolated introductions of this mosquito were detected and eradicated in California in 1971 and

1987. In 2001, the Tiger was found in two northern and four southern counties of California.

This mosquito did not spread to California from the ongoing invasion in eastern and central U.S., but was introduced into the State in shipments of ornamental bamboo ("Lucky Bamboo") from

South China. Rapid detection of introduction and control efforts stopped the spread of this species throughout California.

Lyme Disease and the link to Invasive Weeds.

Lyme Disease; a pathogen-induced autoimmune disease, was first recognized in 1975 after researchers investigated why unusually large numbers of children were being diagnosed with juvenile rheumatoid arthritis in Lyme, Connecticut, and two neighboring towns. The researchers discovered that most of the affected children lived and played near wooded areas where black leg

(hard body) ticks are common in the brush. The tick carries the Borrelia genus of a spirochete bacterium, the invasive species and causative pathogen of Lyme disease. If not treated promptly, the disease can be lifelong and severely disabling. The first confirmed case in California was in

San Bernardino County, 1989.

The exact circumstances of the outbreak in the North America are still a controversial and contentious debate. The Plum Island Animal Disease Center was a former War Department research and biological testing facility. Tick borne disease transition research was conducted there in the 1940‘s and 50‘s. The island is located about 10 miles from the town of Lyme. Other research suggests evidence pointing to: a mutated microbe, animals from Europe released in the eastern states. Still other research suggests the organism has always been in the U.S., but deforestation suppressed its occurrence and transmission, and that is the weed connection.

When a larval tick emerges from the egg it climbs the nearest plant it can find and waits for a host. Clinging on the tips of grasses and shrubs with their back legs, their front legs outstretched ready to grab hold of the host as it passes by. They can remain in that posture for weeks.

Invasive plants (such as Broom species) are in-filling the open areas adjacent to roads and rural communities at the margin of forested areas. This provides cover for wild animals dropping their tick load. The ticks then also have the supporting brush from which to grab a human host.

Invasive weed control helps mitigates the transmission of disease vectoring ticks.

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Foreign Animal Disease (FAD):

The term "Foreign Animal Disease‖ refers to a number of biological threats to poultry, livestock and wildlife that are introduced from outside the United States, These disease present substantial risks to animals (and often human health) and the agricultural economy. A model developed by the University of California at Davis in 1999 estimates that an outbreak of Foot and Mouth

Disease (FMD) poses a 13.5 billion dollar threat to California‘s economy. CDFA, Animal

Health Branch, Emergency Disease Programs has developed a strategy in responding to an outbreak of a FAD: The FAD Response Plan.

Anthrax

Anthrax is at the top of the World Organization for Animal Health (OIE) list of the most highly contagious animal diseases. Under the Terrestrial Animal Health Code an occurrence of anthrax must be reported to the OIE. Anthrax occurs on all the continents.

Anthrax is a disease caused by a spore-forming bacteria Bacillus anthracis. The name, derived from the Greek word for coal, because of the ulcers with dark centers that develop on the skin of affected people. The bacteria produce extremely potent toxins which are responsible for the ill effects, causing a high mortality rate. While most mammals are susceptible, anthrax is typically a disease of ruminants and humans. Anthrax doesn‘t spontaneously spread from animal to animal or person to person. The bacteria produce spores on contact with oxygen. These spores are extremely resistant and survive for years in soil, on wool or hair of infected animals. Then if ingested or inhaled by an animal, or entering through injury, the spores can germinate and cause disease. Because the blood of infected animals sometimes fails to clot and may leak from body orifices, insects can spread the bacteria to other animals.

Only four naturally acquired, human, cases have been reported in the United States in the last ten years, all among persons who had contact with contaminated animal products from Africa.

On October 4, 2001, The Florida Department of Health (FDOH) Bureau of Laboratories confirmed B. anthracis in a culture of cerebrospinal fluid from a 63-year-old news paper photo editor in Boca Raton, Palm Beach County, Florida hospitalized for a severe illness that began 2 days earlier. The patient‘s condition deteriorated and he died 3 days after admission.

A senior bio-defense researcher had apparently mailed anthrax spore laced letters to news media offices and members of the U.S Congress. 22 people were confirmed infected, 5 died. Over 2000 individual were treated with preventative antibiotics. This was the first bioterrorism-related anthrax case identified in the United States.

The last confirmed case of human anthrax in California was in 1976 and the source of infection was textile yarn made of wool imported from Pakistan.

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The Animal Health Branch—Emergency Disease Programs has historical records dating from

1926 showing 34 anthrax outbreaks in 12 counties of California. During 1984, an anthrax outbreak occurred in San Luis Obispo County that affected 12 general areas, and killed 43 cattle and 135 sheep. Since 1991, there have only been 10 known cases of anthrax in California livestock.

Exotic Newcastle Disease (END), Recent Example of FAD:

Exotic Newcastle Disease is a contagious bird disease affecting many domestic and wild avian species; it is transmissible to humans. First found in Newcastle, United Kingdom in 1926, then by Burnet in 1943 in Australia in connection with laboratory infection, where the virus was isolated from an ocular discharge of a patient to show the specific antibody titre in the patient's blood, the disease was first diagnosed in California in 1950 among pheasants imported from

Hong Kong.

The 2002-03 END outbreak in California, originally confirmed in backyard poultry in Southern

California, spread to commercial poultry operations in California and backyard poultry in

Arizona, Nevada and Texas. The Governor of California and the Secretary of the United States

Department of Agriculture (USDA) declared a state of emergency, and local emergencies were declared in four Counties. A USDA and CDFA Task Force was formed that involved over 7,000 individuals rotating in and out over the course of the outbreak. Trade restrictions resulting from the disease had negative impacts on California and U.S. poultry and egg producers. The outbreak, from discovery to eradication, lasted eleven months. The outbreak response led to the depopulation (killing) of 3.16 million birds at a cost of $161 million.

Of any possible first responders, the County Agricultural Commissioner‘s offices‘ have the most agents in the field interacting daily with the local agricultural industry. Biologist from the Ag departments are the most likely to encounter a FAD event.

The Exclusion Program, which works well for invasive insects and weeds, is, at best, marginally effective as a hazard mitigation for FAD. The best mitigation is to be able to quickly identify, isolate and prevent the spread of the disease by training Staff on FAD hazard identification and having a pre-planned response, appropriate equipment and good sterile technique/ procedures.

At present Butte County has an FAD Response Plan outline, but lacks Ag department staff training and appropriate response equipment. A serious FAD event could pose as much as a 250 million dollar economic impact to Butte and the surrounding counties.

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Impacts to the Water System

Invasive Weeds and State Water Systems: Sesbania, Loosestrife and Arundo

These foreign invaders are overrunning many shorelines, drainages and vital "riparian" lands.

The ecologically diverse natural open habitats that run along the millions of miles of our state waterways are what prevents or moderates flooding.

By far the greatest threat to the dwindling riparian resources of California is caused by three alien invasive species known as: Arundo donax, Lythrum salicria and Sesbania punicea

(A.L.S). Over the last 40 years the riparian forests and waterways of northern California have become infested. A.L.S spread by flood-fragmentation and dispersal of vegetative and seed propagules. They dramatically alter the ecological/successional processes in riparian systems and ultimately degrade the riparian habitats towards pure stands of these noxious invasive species.

The drainage is systematically impeded. Unchecked, ALS fills in all open areas and banks down to the waterline exacerbating flood prone areas. Presently no funded mitigation/control projects are in place in Butte County.

Past Occurrences

Past Occurrences to Plants and Agriculture

There have been many instances of invasive species. In addition to those shown in Table 4.24,

the Butte Regional Habitat Conservation Plan separates the County by natural community, and

delineates problem species in each community. This is shown in Table 4.25.

Table 4.25. Invasive Species in Natural Communities in Butte County

Natural Community Invasive Species/Impacts

Oak Woodland and

Savanna

Numerous invasive plants that are unpalatable to native and domestic grazers may also be locally abundant in oak woodlands and savannas, particularly in areas with past or current inappropriate livestock management practices. These species may include grasses such as

Medusa-head, barbed goatgrass, cheatgrass, and invasive forbs like yellow starthistle, and several species of mustard. Cheatgrass and barbed goatgrass, in particular, have also been shown to promote shorter fire cycles in ecosystems. In a myriad of ways, invasive plants can have large-scale changes in the oak woodland and savanna community.

Grassland (including vernal pools and swales)

Numerous invasives are unpalatable to native and domestic grazers and may also be locally abundant. These species may include grasses such as Medusa-head, barbed goatgrass, cheatgrass, and invasive forbs like yellow starthistle, as well as several species of mustard.

Medusa-head in particular produces seeds and seedheads that are noxious to livestock; its palatability is low because of high levels of silicon dioxide, and its rate of decomposition is low, resulting in the build-up of thick thatch layers. As Mediterranean annual grasses dominate most upland grasslands in the plan area, they also encroach on shallow vernal pools and vernal swales and threaten native species. In longer duration vernal pools, low or waxy mannagrass can become dominant, impacting native plant species and the invertebrate community by altering the physical and chemical characteristics of the vernal pools.

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Natural Community Invasive Species/Impacts

Riparian Giant reed, considered the state’s most invasive riparian weed, can grow in dense monocultures, crowding out native species and causing changes to hydrologic regimes. Salt cedar is another invasive found in the plan area. Both of these highly invasive plants can cause channel changes and increases in fire danger. The introduced bullfrog is an important riparian invasive in the plan area. This species has been implicated as a primary driver of native ranid frog declines in Butte County. In addition, feral cats can impact many native bird species in the plan area, for example, the proposed covered species, the tricolored blackbird.

Wetlands

Aquatic

Impacts to wetlands will be discussed in the Marine Invasive Species in Section 4.2.16.

Impacts to wetlands will be discussed in the Marine Invasive Species in Section 4.2.16.

Agriculture Several agricultural invasive species found in the agricultural natural community are considered a 36 threat to surrounding native communities. The European olive has been described as invasive to 37 riparian habitats in Santa Barbara and San Diego and may pose a concern in the future in the plan area (CalEPPC 1999). Tocalote, an invasive thistle, has been identified as a threat to surrounding 1 wildlands (CalEPPC 1999). Additionally,

Bermuda buttercup and kikuyugrass were identified as 2 possible threats requiring further study

Source: Butte Regional Habitat Conservation Plan

Invasive Species Infestation and Crop Failure

1998, Temecula Valley was the first California vineyard area to be seriously impacted by the

Glassy-Winged Sharpshooter (GWSS). The pest is responsible for the spread of a bacterium,

Xylella fastidiosa, the causative agent for Pierce‘s Disease, a disease fatal to grape vines.

Pierce's Disease devastated ~3,000 acres of wine grapes growing in the Temecula region.

Experts worried that the many millions in losses there could easily translate to billions in losses to the rest of California vineyards and other crops when it began to spread northward. A repeat of Temecula could have been the fate for these areas.

With no effective control strategy in sight, the reality was that GWSS would spread throughout the agriculture-rich San Joaquin Valley, threatening nearly 800,000 acres of table, raisin and wine grapes equaling 72 percent of the state's vineyards. A state wide application of the

Detection, Eradication and Management elements of the CDFA Pest Exclusion Program eventually mitigated the catastrophe.

Glassy-winged Sharpshooter (GWSS) Butte County:

In 1999, the detection trapping program, administered by the county agricultural department intercepted GWSS in Butte County. Subsequent delimitation surveys revealed a four square mile infestation on commercial landscape plants in the City of Chico within 1.5 miles of a contiguous expanse of production orchard. This was the most northerly infestation. A timely, effective, eradication program by CDFA and the County Ag Department collapsed and eradicated the

GWSS population in 4 years and it never reached the adjacent agricultural lands. The cost of eradication was about $500 thousand to protect a $1.2 billion industry. Presently the GWSS detection program costs about $16,000/ year.

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Past Occurrences to Human Health

Butte County, California has seen WNV activity since 2004. August 12, 2011, Dr. Mark

Lundberg, Butte County Health Officer stated ―In Butte County, there has been virus detected in mosquitoes and birds, which is a significant indication that there is high risk for WNV infection

to humans.‖ Table 4.26 summarized human incidents of WNV in Butte County.

Table 4.26. Reported Incidence of West Nile Virus In Butte County

2004 2005 2006 2007

Incidents 7 24 31 16

Source: California Department of Public Health, westnile.ca.gov

Likelihood of Future Occurrences

2008

6

2009

2

2010

1

2011

3

Likely – CDFA maintains records of county pest interceptions submitted to the state laboratory for identification and conformation. In a five year period Butte County ag biologists submitted

560 organisms. Of those submitted 329 were confirmed invasive species. Due to the high number of past, recent and continuing A* and Q* pest interceptions and history of incidence of invasive pests threatening the environment, agriculture industry, and humans in the County, it is likely that future infestation of insect and other pests will occur in Butte County. Given the diversity and high value of agricultural crops in the County, and the high population in the

County, insect, weed and FAD pests can have large impacts economically and socially.

*―A‖ rated pest: A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment

*―Q‖ rated pest: An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.

In the CDFA pest rating system, A and Q -rated pests are prohibited from entering the state because, by virtue of their rating, they have been placed on the of Plant Health and Pest Prevention Services Director’s list of organisms detrimental or possibly detrimental to agriculture

4.2.15 Levee Failure

Hazard/Problem Description

A levee is a raised area that runs along the banks of a stream or canal. Levees reinforce the banks and help prevent flooding by containing higher flow events to the main stream channel.

By confining the flow to a narrower steam channel, levees can also increase the speed of the water. Levees can be natural or man-made. A natural levee is formed when sediment settles on the stream bank, raising the level of the land around the stream. To construct a man-made levee, workers place dirt or concrete along the stream banks, creating an embankment. This embankment is flat at the top, and slopes at an angle down to the water. For added strength, sandbags are sometimes placed over dirt embankments.

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Levees provide strong flood protection, but they are not failsafe. Levees are designed to protect against a specific flood level and could be overtopped during severe weather events or dam failure. Levees reduce, not eliminate, the risk to individuals and structures located behind them.

A levee system failure or overtopping can create severe flooding and high water velocities. It‘s important to remember that no levee provides protection from events for which it was not designed, and proper operation and maintenance are necessary to reduce the probability of failure.

Under-seepage refers to water flowing under the levee through the levee foundation materials, often emanating from the bottom of the landside slope and ground surface and extending landward from the landside toe of the levee. Through-seepage refers to water flowing through the levee prism directly, often emanating from the landside slope of the levee. Both conditions can lead to failure by several mechanisms, including excessive water pressures causing foundation heave and slope instabilities, slow progressing internal erosion, and piping leading to levee slumping.

Erosion can also lead to levee failure. More information on erosion can be found in Section

4.2.11. Figure 4.43 depicts the causes of levee failure.

Figure 4.43. Potential Causes of Levee Failure

Source: USACE

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Overtopping failure occurs when the flood water level rises above the crest of a levee. The representation of the failure modes and the evaluation of the probability of levee failures for each mode are discussed in the remaining sections.

Figure 4.44. Flooding from Levee Overtopping

Source: Levees In History: The Levee Challenge. Dr. Gerald E. Galloway, Jr., P.E., Ph.D., Water Policy Collaborative,

University of Maryland, Visiting Scholar, USACE, IWR. http://www.floods.org/ace-files/leveesafety/lss_levee_history_galloway.ppt

Figure 4.45 provides an inventory of the status of levees in Butte County, separated out into 3

categories at the time of the 2011 DFIRMs were finalized for the County: Accredited Levees,

Provisionally Accredited Levees (De-Accredited) and Other Levees. There is only one levee that is fully accredited and certified as providing the 100-year level of flood protection. The accreditation occurred after the 2011 DFIRMs were finalized. This certified levee segment includes the left bank of Sycamore and Mud Creeks in the Chico area. The levee segments denoted as PAL levees were under current PAL agreements at the January 6, 2011 DFIRM effective date, but all PAL agreements have sense expired. Unless, those de-accredited areas are certified prior to the next DFIRM update, areas protected by these segments will no longer be in levee protected zone and will be remapped into a Special Flood Hazard Area (SFHA). This is

explained in more detail in Section 4.3.10.

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Figure 4.45. Location and Status of Levees in Butte County

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The Sacramento River Reclamation District also brought to light the number of private unaccredited levees in the County:

The major risk hazard is flooding by floods of a frequency of 1 in 15 years or longer. The levees along the river are private levees and the Reclamation Board of the State of California, now the Central Valley Flood Protection Board, has been obstructive to efforts of the landowners to provide for riprap protection, or in some cases, raising or relocation of the levees. The landowners recognize that the area is subject to flooding and have done an excellent job of accommodating their planting of trees, location of .improvements and their handling of the soil surface in the fall so that the least damage will occur if flowing occurs.

Past Occurrences

Butte County has experienced four significant flood events since the levees were constructed.

These record flood events occurred in 1955, 1964, 1986, and 1997. Although no levee breaks occurred in Butte County, levees did fail in nearby areas. Major flooding occurred in Yuba City and Nicolaus in Sutter County due to levee breaks on December 24, 1955. Nearly 100,000 acres flooded during a series of storms, resulting in 38 deaths and 3,200 injuries (Sutter Butte Flood

Control Agency, 2009). A series of storms in 1986 caused a levee break near the town of Linda in Yuba County. In January 1997, significant rain occurred at high elevations in the Sierra

Nevada Mountains after deep accumulation of snow. This caused the Feather River to flood and a levee failure to occur south of Olivehurst in Yuba County.

In a report from Kleinfelder to the Sutter Butte Flood Control Agency (SBFCA) regarding

Feather River Levees, the following levee failures or near failures were reported:

Table 4.27. Levee Performance on Feather River Levees within SBFCA Boundaries

DWR Stations

3300+80 to 3380+44

3302+50 to 3319+00

3409+00

3425+50 to 3434+00

3432+50 to 3435+10

3445+00 to 3463+25

3455+00 to 3462+50

3482+50 to 3487+00

3487+20

3495+25

3541+60 to 3556+50

3541+75 to 3594+50

3567+75

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Observed Performance Repairs

Seepage reported during storms of 1997.

Sinkholes observed and repaired in January 1966.

Boil and piping 1955 landward half of levee.

Heavy levee saturation reported by LD 9.

Bank saturation.

Seepage 1997.

Pinboils 1997.

Heavy levee saturation reported by LD 9.

Boil and piping 1955.

Boil 1986.

Seepage noticed in 1957 by LD 9.

Seepage and sand boils.

Boil 1986.

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DWR Stations

3584+00 to 3595+00

3595+00 to 3595+10

3682+00 to 3694+00

3687+10 to 3698+80

3844+40 to 3888+00

3982+40 to 3990+10

3984+50

Observed Performance Repairs

Landside embankment distress 1997.

Landside embankment distress 1997.

Bank erosion.

Levee erosion noticed by citizens in 1991.

Waterside seepage observed during irrigation season.

Seepage and boils 1986.

Boil 1986.

4351+50 Boil 1986.

4469+60 to 4520+00 Levee breach and boils 1955.

Source: Kleinfelder 2009, Preliminary Problem Identification and Conceptual Alternatives Analysis Report Sutter Butte Flood

Control Agency Feather River West Levee Evaluation Thermalito Afterbay to Yuba City Butte and Sutter Counties, California

Not all of the levees shown on the previous table are located in Butte County, but the levees are all located on the Feather River. The value of the table is that all of the levee issues are indicative of the levee conditions in and near Butte County.

Other levee failure issues reported by the previous plan and the 2006 Flood Mitigation Plan include:

1997 - A boil in the Feather River concrete levee near 4th Street and Safford Street creates a leak during high flow events. This levee is maintained and operated by the City of Oroville.

1997, 2005, 2006 - levees in Sycamore Creek have been overtopped during high flow events.

1997 - At the confluence of Big Chico Creek and Lindo Channel, a private levee near Meridian

Road and Grape Way broke during a recent high flow event, leaving the residents vulnerable to flooding. The levee was removed by the owner to eliminate future liability.

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Figure 4.46. Levee Break near Confluence of Big Chico Creek and Lindo Channel

Source: 2006 Butte County Flood Mitigation Plan

1997 - The Dead Horse Slough crossing at El Monte Avenue experiences periodic inundation and nearby structures have inundated as recently as 1997. In the lower reaches of Little Chico

Creek, the Little Chico Creek crossing at Alberton Avenue and at Taffee Avenue has experienced levee overtopping, sheet flow flooding, and levee seepage.

Likelihood of Future Occurrences

Occasional – Due to the number of past events, eroding levees, and the volume of levees in

Butte County, future levee failures are occasional.

4.2.16 Marine Invasive Species

Hazard/Problem Description

Invasive Species are organisms that are introduced into an area beyond their natural range and become a pest in the new environment. The terms: ―Marine Invasive Species‖ and ―Non-native

Aquatic Species‖ are used interchangeably.

This hazard addresses the economic and environmental issues related to invasive pests of a marine and fresh water nature, particularly euryhaline organisms. These are species having the ability to tolerate a wide range of salinity and can transition in and out of fresh and salt water.

There are two forms: anadromous and catadromous species.

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The introduction of NAS into coastal marine estuarine and delta waters can cause significant and enduring economic and environmental impacts. One of the most widespread mechanisms by which introductions occur is through transport of ballast water in boats. Ballast water is taken on and released by a vessel during cargo loading and discharging operations to maintain the vessel‗s trim and stability. Ships ballast water obtained from some other foreign location (state, or country) can include non

‐native organisms, untreated sewage, and other contaminants. Once introduced, NAS are likely to become a permanent part of an ecosystem and may flourish, creating environmental imbalances and economic havoc.

Butte County Aquatic/ Hydraulic Resources

Water and the natural and manmade conveyances‘ and infrastructure are among Butte County‘s most important natural and industrial resources.

Aquatic/hydraulic resources refer to water and its multiple roles as a natural resource supporting the ecosystem and human endeavors; it encompasses all the possible roles for water as an essential component of the regional economy. Butte County‘s water systems are the critical component for many of the environmental and agricultural cycles both terrestrial and aquatic.

Significant hydrologic features exist within the county, including: Lake Oroville and the hydro electric dam, the Fore and After Bays, the Western Canal, the Feather River, Butte Creek, Big

Chico Creek and the Sacramento River. Seven geologically distinctive watersheds are overlaid by 13 Irrigation and Reclamation District serviced by several major water purveyors. 90 % of the

Counties water demands are in support of the agricultural industry which is the foundation of the

County economy.

Invasive Species Infestation and Hydrology Impacts

Marine invasive species can jeopardize and damage any part of the entire system ranging from human economy dependent infrastructure to natural aquatic, riparian and wetland habitat.

Entire water sheds can be affected when an aggressive NAS infests the rivers, shorelines, tributaries, drainage, irrigation and domestic delivery systems.

The Marine Invasive NAS

Invertebrates

The Zebra mussel (Dreissena polymorpha) and Quagga mussel (Dreissena bugensis), are small bivalve mollusks that are originally native to southeast Russia, named for the striped pattern of their shell, They attach to objects, surfaces, or other mussels by anchoring threads extending from underneath the shells. They disrupt the ecosystems by monotypic colonization, and damage harbors and waterways, water treatment and power plants or any water delivery conveyance structure. Water intakes bring the microscopic free-swimming larvae directly into the structure

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where the mussels attaches and builds up in number as high as 700,000/ m² eventually blocking all flow.

The first confirmed find of Zebra mussels in California occurred at San Justo Reservoir Jan. 10,

2008 and more recently San Benito County, 2012. Surveys in August 1998 found Quagga in

Lake Dixon and San Vicente Reservoir in San Diego County.

Invasive Fish Species

The number of freshwater fish species in California is increasing due to the introduction of nonnative fishes becoming established at a rate of about 1 species every 3 years. Although no introduction of a NAS has unambiguously caused the extinction of native species, evidence suggests that their introduction is contributed to the decline.

Of the native fishes, 5 species are now extinct in California. Thus, the actual number of species maintaining populations in the state is 120. Of extant native species, 15 (22%) are threatened with extinction in the near future. Only 27 native species (40%) can be regarded as having secure populations. The effects of nonnative fish on native fish are generally in the form of predation and competition for food and breeding sites

There are multiple nonnative invasive fish species in the waterways of the County. Many of these fish were introduced for sport fishing or to provide forage for sport fish.

Centrarchids, the sunfish family (sunfish, crappie, and bass) are voracious predators and are known to eat a variety of native fish species and invertebrate. Smallmouth bass have been associated with the decline in the native Hardhead minnow (Mylopharodon conocephalus) in the plan area. Introductions of multiple species of centrarchids have been associated with the extirpation of Sacramento perch (not actually a perch but the only native California sunfish) from the Sacramento River watershed, also in the plan area.

Tilapia, Mozambique and Blue: Oreochromis mossambicus, and aureus

Tilapias are true euryhalines, able to live in freshwater or marine habitats. Two populations of tilapia have been introduced to the U.S. through escapes from fish farms: the Mozambique and

Blue Tilapia, native to the Middle East and parts of Northern Africa. Tilapias are a threat to native species because of competition for food and habitat; the presence of invasive tilapia populations will lead to further declines in wild populations of native fish.

It is legal (with a permit) to have Tilapia in only 6 counties of California (San Diego, Riverside,

San Bernardino, Los Angeles, Imperial and Orange). In any other county in California, it's illegal to possess any type of Tilapia. Wild populations occur in the many different parts of the country. It will not be long before they appear in the Sacramento River and spread throughout the estuary. There is a thriving wild population of Mozambique T. in Salton Sea, in Imperial,

Riverside county California.

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Non-native Aquatic Weeds

Many varieties of non-native aquatic weeds compete for the entire water column and shoreline in

Butte County, crowding out native species and degrading the aquatic and riparian habitat.*

Water Hyacinth (Eichhornia crassipes) a floating plant native to Brazil, is among the most serious of weed problems occurring in the California Delta. If has invaded many waterways, lakes and streams. There is no known chemical free eradication method in the world for

Water Hyacinth once a water course is completely occluded. It will jam rivers and lakes streams and ponds with uncounted thousands of tons of floating plant matter. The

Sacramento-San Joaquin Delta and several of the rivers drained by this delta are heavily infested (Thomas and Anderson 1984). One known infestation in Butte County on the Gold

Run first reported 1998. Presently no funded mitigation/control projects are in place in Butte

County.

Hydrilla (Hydrilla verticillata), native to Asia, Europe, Africa, highly resistant to salinity (>1-

100000ppt) compared to many other freshwater aquatic plants. It is considered among the most serious aquatic weed problems in the world and California. It is the last remaining

―funded‖ California Department of Food and Agriculture (CDFA) weed eradication program as of 2012, conducting eradication efforts in nine counties. It can quickly take over lakes and streams, crowding out native animals and plants and blocking hydroelectric plants, impeding water flow and delivery in any conveyance. Its rapid growth and ease of spread makes it critical to detect early and eradicate. Past infestations have occurred in Butte County. All have been eradicated.

Arundo, loosestrife, Sesbania: By far the greatest threat to the dwindling riparian resources of California is caused by three alien invasive species known as: Arundo donax, Lythrum salicria and Sesbania punicea (A.L.S). Over the last 40 years the riparian forests and waterways of northern California have become infested. A.L.S spread by floodfragmentation and dispersal of vegetative and seed propagules. They dramatically alter the ecological/successional processes in riparian systems and ultimately degrade the riparian habitats towards pure stands of these noxious invasive species. The drainage is systematically impeded. Unchecked, ALS fills in all open areas and banks down to the waterline exacerbating flood prone areas. Presently no funded mitigation/control projects are in place in Butte County.

South American Spongeplant (Limnobium laevigatum): a recently established invasive aquatic plant that has been introduced into northern and central California, having all of the negative characteristics of water hyacinth.

Past Occurrences

Once introduced, invasive species are likely to become a permanent part of an ecosystem and may flourish, creating environmental imbalances and wreaking economic havoc. Some of

California‘s most serious weed problems occur in waterways, lakes and streams.

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There are also several non-fish, nonnative invasive species found in aquatic natural communities that can damage such communities. Giant reed, considered the state‘s most invasive riparian weed, and salt cedar can grow in dense monocultures along riparian areas, crowding out native species and causing changes to hydrologic regimes in aquatic communities. The introduced bullfrog is an important riparian invasive in the plan area. This species has been implicated as a primary driver of native ranid frog declines in Butte County.

In addition to waterways, marine invasive species can damage wetland natural communities.

Giant reed is found at both Gray Lodge Wildlife Area and at Llano Seco NWR, where efforts to remove the species are ongoing. Feral cats are also an important nonnative invasive that can impact many native bird species in wetland natural communities, for example the tricolored blackbird.

The Chinese Mitten Crab

The Chinese mitten crab (Eriocheir sinensis) named for the dense patches of hairs on the claws of juveniles and adults. A euryhaline, catadromous species, adults reproduce in salt water and the offspring migrate to fresh water to mature.

It is a native to the coastal rivers and estuaries of the Yellow Sea. In Asia, the crab is a delicacy and crabs have been imported alive to markets in Los Angeles and San Francisco. The most probable introduced to the San Francisco estuary was either deliberate release to establish a fishery or accidental release of vessel ballast water.

First collected in 1992 by commercial shrimp trawlers in South San Francisco Bay it has spread rapidly throughout the estuary. It was collected in San Pablo Bay in fall 1994 and the Delta in

September 1996. As of August 1998, the known distribution of the Chinese mitten crab in the

Sacramento River drainage was, east to Roseville (Cirby Creek) and eastern San Joaquin County near Calaveras County, extending north of Colusa County to Hunter's Creek (near Delevan

National Wildlife Refuge) within 5 miles of the Butte County southern boundary.

Mitten crabs are adept walkers on land, and, in their upstream migration, they readily move across banks or levees to bypass obstructions, such as dams or weirs. They were found in rice field ditches in Colusa County. Mitten crabs are omnivores, with juveniles eating mostly vegetation, but preying upon animals, especially small invertebrates, Although the mitten crab damages rice crops no control measure have been reported.

Based on the impacts of mitten crabs in their native range and Europe, they pose several possible hazards. The crab is the secondary intermediate host for the Oriental lung fluke, with mammals, including humans, as the final host. Humans become infested by eating raw or poorly cooked mitten crabs. However, neither the lung fluke nor any of the freshwater snails that serve as the primary intermediate host for the fluke in Asia have been found in the San Francisco Estuary. It has been noted that several species of freshwater snails which could possibly serve as an intermediate host are present in the estuary and watershed.

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The ecological impact of a large mitten crab population is the least understood of all the potential impacts. A large population of mitten crabs could reduce populations of native invertebrates through predation and change the biotic structure of the Estuary's fresh and brackish water benthic invertebrate communities. They burrow into soil, which can exacerbate levee, riverbank erosion and weaken and damage rice field checks and berms.

Likelihood of Future Occurrences

Likely – The rate of NAS discoveries continues to increase. As of the December 2011 the

CDFG survey, 257 invertebrates and algae have established populations in California. San

Francisco Bay is the most invaded estuary in the United State s. Only two other regions in the world, the eastern Mediterranean and the Hawaiian Islands, have comparable numbers of reported marine invasions. Butte County is directly connected to the San Francisco Bay via the

Sacramento and Feather River. Butte County‘s rice crop is the most water dependent and most at risk to impacts from non-native aquatic invasive species, with an annual harvested acreage ranging from 95,000 to 120,000 acres equating to the 2011 crop value of $141,515,000 dollars the adjusted economic impact to the County economy could be as high as $424 million dollars/ year. Due to the high number of incidents of invasive species in the Delta and Sacramento

River, it is likely that future infestation of marine pests will occur in Butte County.

4.2.17 Volcano

Hazard/Problem Description

The California State Hazard Mitigation Plan identifies volcanoes as one of the hazards that can adversely impact the State. However, there have been few losses in California from volcanic eruptions. Of the approximately 20 volcanoes in the State, only a few are active and pose a threat. Of these, Lassen Peak is the closest to Butte County. The Long Valley area is considered to be an active volcanic region of California and includes features such as the Mono-Inyo

Craters, Long Valley Caldera, and numerous active and potential faults. Figure 4.47 shows

volcanoes in or near California and the location of the Lassen Peak and the Long Valley area relative to the Butte County Planning Area.

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Figure 4.47. Active Volcanoes in California and in the Butte County Area

Source: 2010 State of California Hazard Mitigation Plan

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Steam blasts commonly produce large pits or craters. Explosive eruptions, which may create fiery flows of hot ash (pyroclastic flows), are usually followed by the pushing up of a lava dome.

Some less violent eruptions only produce lava flows.

Populations living near volcanoes are most vulnerable to volcanic eruptions and lava flows, although volcanic ash can travel and affect populations many miles away and cause problems for aviation. The USGS notes specific characteristics of volcanic ash. Volcanic ash is composed of small jagged pieces of rocks, minerals, and volcanic glass the size of sand and silt, as shown in

Figure 4.48. Very small ash particles can be less than 0.001 millimeters across. Volcanic ash is

not the product of combustion, like the soft fluffy material created by burning wood, leaves, or paper. Volcanic ash is hard, does not dissolve in water, is extremely abrasive and mildly corrosive, and conducts electricity when wet.

Figure 4.48. Ash Particle from 1980 Mt. St Helens Eruption Magnified 200 Times

Source: US Geological Survey: Volcanic Ash: Effect & Mitigation Strategies. http://volcanoes.usgs.gov/ash/properties.html.

Volcanic ash is formed during explosive volcanic eruptions. Explosive eruptions occur when gases dissolved in molten rock (magma) expand and escape violently into the air, and also when water is heated by magma and abruptly flashes into steam. The force of the escaping gas violently shatters solid rocks. Expanding gas also shreds magma and blasts it into the air, where it solidifies into fragments of volcanic rock and glass. Once in the air, wind can blow the tiny ash particles tens to thousands of miles away from the volcano.

Past Occurrences

The Lassen region has been volcanically active for more than 3 million years. The Lassen

―volcanic center‖ began to erupt about 600,000 years ago. From 600,000 to 400,000 years ago, eruptions built a large volcano. Later, this volcano became inactive and was mostly eroded

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away, leaving remnants that include Brokeoff Mountain, Mount Conard, Mount Diller, and

Diamond Peak. Subsequent eruptions in the Lassen volcanic center have formed more than 30 steep-sided lava domes (the Lassen dome field). The most recently active parts of the volcanic center are Lassen Peak and other young domes formed in the past 50,000 years.

The most recent eruptive activity occurred at Lassen Peak in 1914-1917. This eruptive episode began on May 30, 1914, when a small phreatic eruption occurred at a new vent near the summit of the peak. More than 150 explosions of various sizes occurred during the following year. By

mid-May 1915 (see Figure 4.49), the eruption changed in character; lava appeared in the summit

crater and subsequently flowed about 100 meters over the west and probably over the east crater walls. Disruption of the sticky lava on the upper east side of Lassen Peak on May 19 resulted in an avalanche of hot rock onto a snowfield. A lahar was generated that reached more than 18 kilometers down Lost Creek. On May 22, an explosive eruption produced a pyroclastic flow that devastated an area as far as 4 miles northeast of the summit. The eruption also generated lahars that traveled more than 12 miles down Lost Creek and floods that went down Hat Creek. A vertical eruption column resulting from the pyroclastic eruption rose to an altitude of more than 5 miles above the vent and deposited a lobe of pumiceous tephra that can be traced as far as 18 miles to the east-northeast The fall of fine ash was reported as far away as Elko Nevada, more than 300 miles east of Lassen Peak. Intermittent eruptions of variable intensity continued until about the middle of 1917.

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Figure 4.49. May 1915 Eruption of Lassen Peak

Source: USGS http://vulcan.wr.usgs.gov/Volcanoes/Lassen/Maps/map_lassen_1915.html

The Cascade Range volcanic chain has a long history of geologic activity that includes both earthquakes and volcanic eruptions. Volcanoes in the Cascade Range volcanic chain have

erupted often over the past 40,000 years. As shown in Figure 4.50, over the past 4,000 years,

small to moderate eruptions have occurred at various sites along the Cascade Range volcanic chain at intervals ranging from 20 to 1,000 years.

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Figure 4.50. Volcanic Activity in the Cascade Range Volcano Chain in the Past 4,000

Years

Source: U.S. Geological Survey,

http://vulcan.wr.usgs.gov/Volcanoes/Cascades/EruptiveHistory/cascades_eruptions_4000yrs.html

Likelihood of Future Occurrences

Unlikely—According to the U.S. Geological Survey, because geologically recent volcanic activity in an area is the best guide to forecasting future eruptions, scientists study the lava flows, ash, and other deposits from past eruptions. Volcanoes in the Lassen area tend to erupt infrequently, and may be inactive for periods lasting centuries or even millennia. The most recent eruptions in the Lassen area were the relatively small events that occurred at Lassen Peak between 1914 and 1917. The most recent large eruption produced Chaos Crags about 1,100 years ago. Such large eruptions in the Lassen area have an average recurrence interval of about

10,000 years. However, the geologic history of the Lassen area indicates that volcanism there is episodic, having periods of relatively frequent eruptions separated by long quiet intervals. For example, the last large event before Chaos Crags eruption was the one that built Lassen Peak

27,000 years.

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4.2.18 Wildfire

Hazard/Problem Description

Wildland fire is an ongoing concern for the Butte County Planning Area. Generally, the fire season extends from early spring through late fall of each year during the hotter, dryer months.

Fire conditions arise from a combination of high temperatures, low moisture content in the air and fuel, accumulation of vegetation, and high winds. Throughout California, communities are increasingly concerned about wildfire safety as increased development in the foothills and mountain areas and subsequent fire suppression practices have affected the natural cycle of the ecosystem.

The Wildland Urban Interface (WUI) defines the community development into the foothills and mountainous areas of California. The WUI describes those communities that are mixed in with grass, brush and timbered covered lands (wildland). These are areas where wildland fire once burned only vegetation but now burns homes as well. The WUI for Butte County consists of communities at risk as well as the area around the communities that pose a fire threat.

There are two types of WUI environments. The first is the true urban interface where development abruptly meets wildland. For Butte County the town of Paradise and the community of Paradise Pines are examples of high density housing meeting wildland.

The second WUI environment is referred to as the wildland urban intermix. Wildland urban intermix communities are rural, low density communities where homes are intermixed in wildland areas. For Butte County the communities of; Cohasset, Forest Ranch, Concow, Yankee

Hill, Berry Creek and Forbestown are some of these examples. Wildland urban intermix communities are difficult to defend because they are sprawling communities over a large geographical area with wild fuels throughout. This profile makes access, structure protection, and fire control difficult as fire can freely run through the community.

The WUI for Butte County is shown in Figure 4.51.

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Figure 4.51. Butte County Wildland Urban Interface

Source: CDF Butte Unit 2010 Fire Plan

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WUI fires are the most damaging. WUI fires occur where the natural and urban development intersect. Even relatively small acreage fires may result in disastrous damages. WUI fires occur where the natural forested landscape and urban

‐built environment meet or intermix. The damages are primarily reported as damage to infrastructure, built environment, loss of socio

‐economic values and injuries to people.

The pattern of increased damages is directly related to increased urban spread into historical forested areas that have wildfire as part of the natural ecosystem. Many WUI fire areas have long histories of wildland fires that burned only vegetation in the past. However, with new development, a wildland fire following a historical pattern now burns developed areas. WUI fires can occur where there is a distinct boundary between the built and natural areas or where development or infrastructure has encroached or is intermixed in the natural area. WUI fires may include fires that occur in remote areas that have critical infrastructure easements through them, including electrical transmission towers, railroads, water reservoirs, communications relay sites or other infrastructure assets. Human impact on wildland areas has made it much more difficult to protect life and property during a wildland fire. This home construction has created a new fuel load within the wildland and shifted fire fighting tactics to life safety and structure protection.

Wildland fire hazards (open space, rangeland, chaparral, and forested areas) exist in varying degrees over approximately 70% of Butte County. The foothill communities of Kelly Ridge,

Bangor, Cohasset, Forest Ranch, Paradise Pines, Concow, Yankee Hill, Berry Creek, and

Forbestown are examples of intermixed urban-wildland interface areas. The communities of

Paradise and Paradise Pines (Magalia) are more characteristic of interface communities where urban or suburban development immediately abuts the wildland. Fires that occur within the urban-wildland interface areas affect natural resources as well as life and property. This type of fire is described as ―a fire moving from a wildland environment, consuming vegetation for fuel, to an environment where structures and buildings are fueling the fire.

Wildfire and urban wildfire are an ongoing concern for Butte County. Fire conditions arise from a combination of hot weather, an accumulation of vegetation, and low moisture content in the air.

These conditions when combined with high winds and years of drought increase the potential for a wildfire to occur. Urban wildfires often occur in those areas where development has expanded into the rural areas. A fire along this urban/rural interface can result in major losses of property and structures. Generally, there are four major factors that sustain wildfires and allow for predictions of a given area‘s potential to burn. These factors include fuel, topography, weather, and human actions.

Fuel. Butte County is comprised of three general fuel types; grass, brush and timber. There are a number of factors such as fuel type and size, loading (tons/acre), arrangement (vertical & horizontal), chemical composition, and dead and live fuel moisture that contribute to the flammability characteristics of vegetation. The CAL FIRE Resource Assessment Program has

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developed a hazard ranking for wildland fuels as part of the California Fire Plan that utilizes the fuel characteristics listed above coupled with slope conditions to determine a fuel hazard rank.

The valley and lower foothills up to roughly 1,000' elevation comprise the grass fuel type. This fuel type is comprised of fine dead grasses and leaf liter which is the main carrier of fire. Fires in this fuel type react dramatically to changes in weather; particularly low relative humidity and high wind. Grassland fires can be very difficult to control when under strong wind conditions, and often spread over a large area quickly threatening life and property.

The mid foothill and lower mountain areas generally between 1,000' and 2,500' elevation are dominated by brush. Fire in this fuel type can burn readily especially later in the summer as live fuel moistures drop to critical levels. Brush fuel unlike grass fuel does not react readily to changes in relative humidity. Brush fires can be difficult to control under normal summer burning conditions when their fuel moistures reach critical levels, and become very difficult to control on steep topography and/or when subject to strong winds.

The mountainous areas above the 2,000' to 2,500' elevation make up the timber fuel type.

Timber fires burn readily especially if they occur in overstocked stands, stands with a lot of down dead material, and/or later in the summer as live fuel moistures drop. Timber fires can be difficult to control under normal summer burning conditions, but become very difficult to control on steep topography and or when subject to strong winds.

Topography – Topography is the lay of the land and includes drainages (canyons, draws, chimneys, etc.) slope, aspect, and fire barriers such as lakes, rock outcroppings and roads.

Topography, particularly drainages and steeper slopes add to the difficulty in suppressing fires.

Reasons include access problems, adverse working conditions and intense fire behavior as fire reaches preheated fuel beds within the drainages.

Butte County encompasses just over one million acres of land and is divided in half by two topographical features. First are the foothills and mountainous region in the northern Sierra

Nevada and southern Cascade Mountains in the northeast. This area is scattered with homes and communities intermixed amongst woodland fuels creating a serious wildland urban interface problem. Second is the Sacramento Valley section in the southwest which is predominately farmland.

Butte County‘s foothills and mountains are carved up by several river drainages, the largest being the Feather River watershed which culminates in Lake Oroville. The Feather River watersheds include the West Branch of the North Fork east of Paradise, the North Fork separating Yankee Hill from Berry Creek, the Middle Fork separating Berry Creek and Feather

Falls, and the south fork separating Feather Falls from Forbestown and the La Porte Road communities. The northern part of Butte County is bisected by Butte Creek west of Paradise and

Big Chico Creek watersheds which separate the Forest Ranch and Cohasset ridges.

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The topography in these drainages differs significantly from the deep and very steep, heavily timbered drainages of the Feather River Watershed to the moderately steep wide and generally brush filled Butte Creek and Chico Creek drainages. The drainages are generally oriented toward south and west aspects which lead to prolonged sun exposure and diminished fuel moisture in the wildland fuels.

Weather – The climate in Butte County is generally referred to as ―Mediterranean‖ with hot dry summers and relatively cool, moderately wet winters. Rainfall throughout the County occurs primarily between October and April, and ranges between 75+ inches per year in the foothill/mountain areas, to less than 18 inches per year in the valley areas. Because the summer months are generally hot and dry, the risk of wildfires is greatest in late summer and early fall.

Compounding the severity of fire conditions are north to northeast winds, as well as low relative humidity in the summer and fall. The community of Yankee Hill/Concow is especially affected by northeast winds, because the north fork drainage of the Feather River enhances those winds.

Similar weather-related elements have complex important effects on wildfire intensity and behavior. Wind is a primary weather factor that influences fire behavior – as wind velocity increases, the rate of fire spread, intensity and spotting potential also increase. Gusty and erratic wind conditions can cause a fire to spread irregularly, making it difficult to predict its path and effectively deploy fire suppression forces. Relative humidity is also an important fire-related weather factor. As humidity levels drop, the dry air causes vegetation moisture levels to decrease, thereby increasing the likelihood that plant material will readily ignite and burn and increasing spot fire potential.

Each year, especially in the autumn months, north wind events bring high temperatures, very low humidity and strong winds. These north wind events usually produce red flag warning conditions and provide the highest potential for extreme fire behavior. With the fuels already at their driest moisture content, north winds can create a severe fire weather situation.

Human Actions – Most wildfires are ignited by human action, the result of direct acts of arson, carelessness, or accidents. Many fires originate in populated areas along roads and around homes, and are often the result of arson or careless acts such as the disposal of cigarettes, use of equipment or debris burning. Recreation areas that are located in high fire hazard areas also result in increased human activity that can increase the potential for wildfires to occur.

Potential losses from wildfire include human life, structures and other improvements, natural and cultural resources, quality and quantity of water supplies, cropland, timber, and recreational opportunities. Economic losses could also result. Smoke and air pollution from wildfires can be a severe health hazard. In addition, catastrophic wildfire can create favorable conditions for other hazards such as flooding, landslides, and erosion during the rainy season.

Consequently, wildland fires that burn in natural settings with little or no development are part of a natural ecological cycle and may actually be beneficial to the landscape. Century old policies

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of fire exclusion and aggressive suppression have given way to better understanding of the importance fire plays in the natural cycle of certain forest types.

Past Occurrences

Wildfires are of significant concern throughout California. According to the California

Department of Forestry and Fire Protection (CAL FIRE), vegetation fires occur within their jurisdiction on a regular basis; most are controlled and contained early with limited damage. For those ignitions that are not readily contained and become wildfires, damage can be extensive.

There are many causes of wildfire, from naturally caused lightning fires to human-caused fires linked to activities such as smoking, campfires, debris burning, equipment use, and arson.

Recent studies conclude that the greater the population density in an area, the greater the chance of an ignition. With population (and ignition densities) continuing to grow throughout California and the Butte County Planning Area, combined with increased fuel loads, the risk posed by wildfire also continues to grow. Within the past years alone, there have been numerous urban

and wildland fires within Butte County and vicinity. This can be seen in Figure 4.52.

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Figure 4.52. Fires in Butte County by Ignition Type 1999 to 2009

Source: CDF Butte Unit 2010 Fire Plan

Not all of these ignitions led to major fires. However, Butte County has seen many major fires.

There have been seven disaster declaration related to fire in Butte County. See Figure 4.53 and

Table 4.28 for wildfire disaster declaration information within Butte County between 1955 and

2010.

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Table 4.28. Butte County Federal and State Fire Disaster Declaration History

Disaster

Year Disaster Name

2008 Mid-year fires Fire

Type

2008

2008

Humboldt Fire Fire

Ophir Fire Fire

Fire

Fire

2004 Oregon Fire

1999 1999 August

Fires

1987 1987 Wildland

Fires

1961 1961

Widespread

Fires

Source: Cal EMA, PERI

Fire

Fire

Fire

Fire

Disaster

Cause

Fire

Fire

Fire

Fire

Fire

Disaster #

EM-3287

FM 2771

FM 2770

FM-2545

EM-3140

State

Declaration #

6/28/2008

6/11/2008

6/10/2008

-

8/26/1999

Federal

Declaration #

-

-

-

8/11/2004

9/1/1999

GP

-

9/10/87

9/18/1961

-

-

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Figure 4.53. State and Federal Fire Disaster Declarations

Source: Cal EMA

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CAL FIRE, USDA Forest Service Region 5, BLM, NPS, Contract Counties and other agencies jointly maintain a comprehensive fire perimeter GIS layer for public and private lands throughout the state. The data covers fires back to 1878 (though the first recorded incident for the County was in 1911). For the National Park Service, Bureau of Land Management, and US

Forest Service, fires of 10 acres and greater are reported. For CAL FIRE, timber fires greater than 10 acres, brush fires greater than 50 acres, grass fires greater than 300 acres, and fires that destroy three or more residential dwellings or commercial structures are reported. CAL FIRE recognizes the various federal, state, and local agencies that have contributed to this dataset, including USDA Forest Service Region 5, BLM, National Park Service, and numerous local agencies.

Fires may be missing altogether or have missing or incorrect attribute data. Some fires may be missing because historical records were lost or damaged, fires were too small for the minimum cutoffs, documentation was inadequate, or fire perimeters have not yet been incorporated into the database. Also, agencies are at different stages of participation. For these reasons, the data should not be used for statistical or analytical purposes.

The data provides a reasonable view of the spatial distribution of past large fires in California.

Using GIS, fire perimeters that intersect Butte County were extracted and are listed in Table F.1

in Appendix F: Fire History and shown in Figure 4.54. There are 266 fires recorded in this

database for Butte County. Each of them was tracked by Cal Fire; Cal Fire last updated this database in 2010. Table F.1 in Appendix F: Fire History lists each fire‘s date, cause, name, and

calculated acreage. Figure 4.54 shows fires, colored by the size of the acreage burned.

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Figure 4.54. Butte County Fire History 1900-2010

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Recent Major Fire Summaries

In addition to the information in Appendix F, the HMPC noted major recent wildfires and their impacts.

1999 Oregon Incident

A civilian caused fire burned 200 acres, injured 5 people, and destroyed several homes and outbuildings. Damages were estimated at over $480,000.

1999 Butte Complex

In August of 1999, lightning caused a fire that burned 33,294 acres in Butte County. 3 residences and 11 outbuildings were destroyed. Damage estimates were unavailable. 1 death was reported.

Concow Fire

The Concow Fire broke out on June 19, 2000. Northwest of Pinkston Canyon Road and South of

Deadwood Creek near the community of Concow (15 miles north of Oroville). A local emergency was declared. The fire burned over 1,845 acres within 2 days, and was human caused. 9 firefighters injured fighting the blaze. 1 death was attributed to the fire. In total, 10 residences, 6 mobile homes, and 28 vehicles destroyed. 5 residences damaged and 12 outbuildings were either damaged or destroyed. Initial estimate of damage to residential buildings exceeded $1 million dollars.

Poe Fire

The Poe fire broke out on September 6, 2001. It was caused by a dry branch falling on a live

PG&E power pole near the Yankee Hill community 14 miles north of Oroville. A local disaster was declared. The fire burned 8,333 acres. Several roads were closed. 49 homes, 120 outbuildings, 4 commercial structures and 55 vehicles destroyed. 3 homes damaged. The estimated loss of burned structures, outbuildings and contents were $6.2 million. There was also a loss of over 43 private wells. No human injuries or deaths were reported, but many cattle and horses were lost.

Oregon Fire

The Oregon fire broke out on August 11, 2004 on Oregon Gulch Road at Potters Ranch Road

(West side of Lake Oroville near the Community of Cherokee). The origin of the fire was unknown. In total, 2,030 acres of vegetation burned. 1 house, 2 cabins, 1 dozer (privately owned) and 2 trailers were destroyed. Estimated damage was $98,000.

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Ophir Fire

The Ophir Fire broke out on June 10, 2008. It was a human caused fire that burned 1,600 acres.

In total, 23 residences, 55 outbuildings and 53 vehicles destroyed (estimated to be $2.3 million).

Damage to power lines, telephone lines, etc. was estimated at $270,000. Estimated impact to agriculture and rangeland, animals, and other ag related losses totaled $166,000. 1 commercial building was also destroyed. No injuries or deaths were reported.

Humboldt Fire

The Humboldt Fire broke out around noon June 11, 2008, in the vicinity of Highway 32 and

Humboldt Road. It has burned thousands of acres and forced the evacuation of thousands of people in the area of Butte Creek Canyon. On July 17th, CAL FIRE publicly announced that it was caused by arson and that they were pursuing all leads to find those responsible. A $10,000 reward for the arrest of those responsible was offered. Governor Schwarzenegger declared a state of emergency in Butte County as a result of the fire. Over 9,000 people were evacuated from their homes. The fire was contained on June 16 th

. This fire burned 23,344 acres, destroyed

87 homes, damaged 7 more, and destroyed 167 outbuildings. CAL FIRE estimated costs and damages from the fire at $20.5 million. 10 injuries were sustained by those who fought the fire.

The perimeter of the burn area is shown in Figure 4.55.

Figure 4.55. Humboldt Fire Burn Area

Source: http://www.chicowiki.org/Humboldt_Fire?action=Files&do=view&target=humboldt_fire_final_perimeter.png

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Butte Lightning Complex

The Butte Lightning Complex (also known as the BTU Lightning Complex) began after an episode of dry lightning strikes on June 21, 2008, around the Concow area. At its height, it had

27 fires, many of which are/were in remote areas. This complex threatens the communities of

Paradise, Magalia, Concow, and various communities in between. This fire caused Butte County to be declared in a state of emergency on June 11 th

by Governor Arnold Schwarzenegger, allowing more free flowing funds towards the suppression and extinguishing on the fire. In total, the fire burned for more than three weeks and consumed 59,440 acres of land. 202 residences and 11 outbuildings were destroyed. Costs of fighting the fire and damages to property exceeded

$85 million. Figure 4.56 shows the fire areas consumed by these fires.

Figure 4.56. Butte Lightning Complex Fires

Source: http://www.chicowiki.org/Butte_Lightning_Complex?action=Files&do=view&target=28_June_08_fire_map.png

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Likelihood of Future Occurrences

Highly Likely – From May to October of each year, Butte County faces a wildfire threat. Fires will continue to occur on an annual basis in the Butte County Planning Area. The threat of wildfire and potential losses constantly increase as human development and population increase in the wildland urban interface area in the County. This results in a highly likely rating of future occurrence.

4.2.19 Natural Hazards Summary

Table 4.29 summarizes the results of the hazard identification and hazard profile for the Butte

County Planning Area based on the hazard identification data and input from the HMPC. For

each hazard profiled in Section 4.2, this table includes the likelihood of future occurrence and

whether the hazard is considered a priority hazard for the Butte County Planning Area.

Table 4.29. Hazard Identification/Profile Summary and Determination of Priority

Hazard: Butte County Planning Area

Hazard

Dam Failure

Drought & Water shortage

Earthquakes

Earth Movements: Landslide

Earth Movements: Erosion

Floods: 100/200/500 year

Floods: Localized Stormwater

Hazardous Materials Incidents: Transportation

Invasive Species: Pests/Plants

Levee Failure

Marine Invasive Species

Severe Weather: Extreme Heat

Severe Weather: Freeze and Winter Storms

Severe Weather: Heavy rain, hailstorm, lightning

Severe Weather: Tornado

Severe Weather: Windstorms

Volcanoes

Wildfires

Likelihood of Future Occurrence

Unlikely

Occasional

Occasional

Likely

Highly Likely

Occasional

Highly Likely

Highly Likely

Highly Likely

Occasional

Occasional

Likely

Likely

Likely

Likely

Likely

Unlikely

Highly Likely

Priority Hazard

Medium

Medium

Medium

Low

Medium

High

Medium

Medium

Low

High

Low

Low

Medium

Medium

Low

Medium

Low

Medium

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4.3 Vulnerability Assessment

Requirement §201.6(c)(2)(ii): [The risk assessment shall include a] description of the jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section.

This description shall include an overall summary of each hazard and its impact on the community.

Requirement §201.6(c)(2)(ii)(A): The plan should describe vulnerability in terms of the types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas.

Requirement §201.6(c)(2)(ii)(B): [The plan should describe vulnerability in terms of an] estimate of the potential dollar losses to vulnerable structures identified in paragraph

(c)(2)(i)(A) of this section and a description of the methodology used to prepare the estimate.

Requirement §201.6(c)(2)(ii)(C): [The plan should describe vulnerability in terms of] providing a general description of land uses and development trends within the community so that mitigation options can be considered in future land use decisions.

With Butte County‘s hazards identified and profiled, the HMPC conducted a vulnerability assessment to describe the impact that each priority hazard would have on the County. The vulnerability assessment quantifies, to the extent feasible using best available data, assets at risk to natural hazards and estimates potential losses. This section focuses on the risks to the County as a whole. Data from the individual participating jurisdictions was also evaluated and is integrated here and in the jurisdictional annexes, and noted where the risk differs for a particular jurisdiction within the planning area.

This vulnerability assessment followed the methodology described in the FEMA publication

Understanding Your Risks—Identifying Hazards and Estimating Losses. The vulnerability assessment first describes the total vulnerability and values at risk and then discusses vulnerability by priority hazards.

Data used to support this assessment included the following:

County GIS data (hazards, base layers, and assessor‘s data);

Statewide GIS datasets compiled by the CAL EMA to support mitigation planning;

FEMA DFIRM and Levee datasets;

Existing plans and studies;

CAL FIRE GIS datasets;

Written descriptions of inventory and risks provided by participating jurisdictions; and

Personal interviews with planning team members and staff from the County and participating jurisdictions.

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4.3.1 Butte County Vulnerability and Assets at Risk

As a starting point for analyzing the planning area‘s vulnerability to identified hazards, the

HMPC used a variety of data to define a baseline against which all disaster impacts could be compared. If a catastrophic disaster was to occur, this section describes significant assets at risk in the planning area. Data used in this baseline assessment included:

Total assets/values at risk;

Critical facility inventory;

Cultural, historical, and natural resources; and

Growth and development trends.

Total Values at Risk

The following data from the Butte County Assessor‘s Office is based on the 2012 Assessor‘s data. This data should only be used as a guideline to overall values in the County, as the information has some limitations. The most significant limitation is created by Proposition 13.

Instead of adjusting property values annually, the values are not adjusted or assessed at fair market value until a property transfer occurs. As a result, overall value information is most likely low and does not reflect current market value of properties within the County. It is also important to note, in the event of a disaster, it is generally the value of the infrastructure or improvements to the land that is of concern or at risk. Generally, the land itself is not a loss.

Methodology

The parcel/assessor inventory table shows the number of structures, land value and total structure value for each parcel by occupancy type and by jurisdiction. The ‗Other Value‘ column represents additional improved values that are tied to commercial fixtures or agricultural crops.

Each parcel record was attributed with its jurisdiction name (Biggs, Chico, etc.) based on whether its geographic center fell in or out of those jurisdictional boundaries. For the purposes of tabulating data, the unincorporated county was considered a jurisdiction and is listed in the table as such.

Land Use Codes within the parcel layer were used to categorize the property types and were summarized by all codes based on resource reports provided by the County Assessor. The descriptions starting with an A for agriculture, C for commercial, I for industry, R for residential and everything else without a defined code was put into an ‗Unclassified‘ category. 2,320 parcels did not have land use codes or their descriptions were labeled ‗Not Yet Defined‘; their land use field was attributed with ‗Unclassified‘. Parcels that had a structure value >$0 were assumed to have 1 structure. 4,602 of the parcel records did not have associated assessor values, and were therefore left at $0.

Butte County has a total land value of $6,212,888,288. There are 93,279 parcels in the County with a total improved value of $10,450,556,826. The City of Chico has the most structures and

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value of the County‘s jurisdictions; there are 22,991 structures there with a total value of close to

$7 billion. Table 4.30 shows the 2012 assessor values for the entire Butte County Planning Area

(i.e., the total values at risk) by jurisdiction. The roll values for unincorporated Butte County are

provided in Table 4.31 by property type showing that residential has the most structures with

67,789 and a total value including improvement, other and land value totaling $12.3 billion.

Table 4.30. Butte County Planning Area - Total Exposure by Jurisdiction

Jurisdiction

Biggs

Chico

Gridley

Total

Parcel

Count

759

Improved

Parcel

Count

620

Improved Value

$52,122,701

Total Other

Value

$4,119,113

Total Land

Value

$19,173,412

Total Value

$75,415,226

24,931

2,451

22,991

2,120

$4,453,650,296

$226,944,392

$58,918,888 $2,321,913,100

$7,559,555 $85,056,753

$6,834,482,284

$319,560,700

Oroville

Paradise

Unincorporated

5,970

11,493

47,675

4,403

10,506

34,144

$681,847,250

$1,251,863,720

$48,523,344

$13,290,814

$260,913,147

$644,005,026

$3,784,138,467 $249,574,645 $2,881,816,850

$991,283,741

$1,909,159,560

$6,915,529,962

Total 93,279 74,784 $10,450,566,826 $381,986,359 $6,212,878,288 $17,045,431,473

Source: Butte County 2012

Assessor’s Data

Table 4.31. Unincorporated Butte County Total - Exposure by Property Type

Property

Type

Agriculture

Commercial

Industrial

Total

Parcel

Count

5,264

Improved

Parcel

Count

2,596

Improved Value

Total Other

Value

Total Land

Value Total Value

$316,018,225 $208,594,539 $829,647,895 $1,354,260,659

874

297

621

231

$187,711,070

$134,843,432

$10,618,802

$23,626,494

$90,352,622

$37,276,734

$288,682,494

$195,746,660

Residential

Unclassified

39,640

1,600

30,681

15

$3,144,438,068

$1,127,672

$6,416,193 $1,921,248,114

$318,617 $3,291,485

$5,072,102,375

$4,737,774

Total 47,675 34,144 $3,784,138,467 $249,574,645 $2,881,816,850 $6,915,529,962

Source: Butte County 2012

Assessor’s Data

Critical Facility Inventory

The Butte County OEM worked with members of the HMPC to develop a definition of critical facilities for the Butte County Planning Area. For purposes of this plan, a critical facility is defined as:

Any facility, including without limitation, a structure, infrastructure, property, equipment or service, that if adversely affected during a hazard event may result in severe consequences to public health and safety or interrupt essential services and operations for the community at any time before, during and after the hazard event.

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A critical facility is classified by the following categories: (1) Essential Services Facilities, (2)

At-risk Populations Facilities, (3) Hazardous Materials Facilities.

Essential Services Facilities include, without limitation, public safety, emergency response, emergency medical, designated emergency shelters, communications, public utility plant facilities and equipment, and government operations. Sub-Categories:

Public Safety - Police stations, fire and rescue stations, emergency operations centers

Emergency Response - Emergency vehicle and equipment storage and essential governmental work centers for continuity of government operations.

Emergency Medical - Hospitals, emergency care, urgent care, ambulance services.

Designated Emergency Shelters.

Communications - Main hubs for telephone, main broadcasting equipment for television systems, radio and other emergency warning systems.

Public Utility Plant Facilities - including equipment for treatment, generation, storage, pumping and distribution (hubs for water, wastewater, power and gas).

Essential Government Operations - Public records, courts, jails, building permitting and inspection services, government administration and management, maintenance and equipment centers, and public health.

At Risk Population Facilities include, without limitation, pre-schools, public and private primary and secondary schools, before and after school care centers with 12 or more students, daycare centers with 12 or more children, group homes, and assisted living residential or congregate care facilities with 12 or more residents.

Hazardous Materials Facilities include, without limitation, any facility that could, if adversely impacted, release hazardous material(s) in sufficient amounts during a hazard event that would create harm to people, the environment and property.

To support hazard analysis of critical facilities, Butte County GIS developed a critical facilities layer that pulled mapped critical facilities from existing GIS layers and organized them into a new critical facilities layer. Each facility was assigned one of the three different categories (each with a different symbology.) County OES and others added additional mapped facilities to this layer as appropriate. The final critical facilities layer used for this analysis included facilities located in both unincorporated and incorporated communities.

A fully detailed list of all critical facilities in the planning area can be found in Appendix E. A

summary of critical facilities in the County can be found in Table 4.32.

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Table 4.32. Butte County Planning Area - Critical Facilities Summary Table

Category

City of Biggs

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

City of Chico*

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

Type

Family Day Care Home

School

Bridge

Fire Station

Law Enforcement

Wastewater Treatment Plant

CUPA

Total City of Biggs

Adult Day Care

Adult Residential

Day Care Center

Family Day Care Home

Foster Family Agency

Foster Family Agency Sub

Group Home

Infant Center

Residential Care / Elder

School

School-Age Day Care

Transitional Housing

Airport

Bridge

Fire Station

Hospital

Law Enforcement

Wastewater Treatment Plant

CUPA

Total City of Chico

Facility Count

7

2

1

115

9

1

4

2

4

4

14

12

21

1

396

758

5

20

3

8

39

115

4

3

5

1

1

1

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Category

City of Gridley

At Risk Population Facilities

At Risk Population Facilities

Hazardous Materials Facilities

City of Oroville

At Risk Population Facilities

Essential Services Facilities

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Type

Adult Day Care

Adult Residential

Day Care Center

Family Day Care Home

Foster Family Agency

Residential Care / Elder

School

Bridge

Fire Station

Hospital

Law Enforcement

Wastewater Treatment Plant

CUPA

Total City of Gridley

Adult Day Care

Adult Residential

Day Care Center

Family Day Care Home

Foster Family Agency Sub

Infant Center

Residential Care / Elder

School

School-Age Day Care

Airport

Bridge

Building Permitting and Inspection

Court

Emergency Operations Center

Fire Station

Government Administration

Helipad

Hospital

Jail

Law Enforcement

Public Health

Public Records

Wastewater Treatment Plant

Facility Count

1

3

1

1

2

2

1

2

1

12

2

1

28

1

1

1

2

10

11

7

3

3

3

1

2

1

52

74

2

4

1

1

1

1

5

1

2

4.162

Category

Hazardous Materials Facilities

Town of Paradise**

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

Unincorporated County

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

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Type

CUPA

Total City of Oroville

Adult Day Care

Adult Residential

Day Care Center

Family Day Care Home

Foster Family Agency

Foster Family Agency Sub

Group Home

Infant Center

Residential Care / Elder

School

School-Age Day Care

Transitional Housing

Bridge

Fire Station

Hospital

Law Enforcement

CUPA

Total Town of Paradise

Adult Residential

Day Care Center

Family Day Care Home

Group Home

Infant Center

Residential Care / Elder

School

School-Age Day Care

Small Family Home

Agriculture

Airport

Bridge

Fire Station

Helipad

Law Enforcement

Wastewater Treatment Plant

Agriculture

Facility Count

35

45

1

1

1

2

1

2

837

19

65

2

2

11

29

1

4

1

1

98

1

9

8

3

1

26

209

12

143

242

2

16

7

26

1

1

4

4.163

Category Type

CUPA

Facility Count

285

Natural Gas Storage 1

Total Unincorporated County 1,352

Source: Butte County GIS

*The Mechoopda Tribal Building in Chico is a critical facility, but was not included in the critical facility list for the County. It was not mapped or included in the tabular analysis.

** A Paradise Irrigation District Water Treatment Plant is a critical facility, but was not included in the critical facility list for the

County. It was not mapped or included in the tabular analysis.

Cultural, Historical, and Natural Resources

Assessing Butte County‘s vulnerability to disaster also involves inventorying the historical, cultural, and natural assets of the area. This step is important for the following reasons:

The community may decide that these types of resources warrant a greater degree of protection due to their unique and irreplaceable nature and contribution to the overall economy.

In the event of a disaster, an accurate inventory of natural, historical and cultural resources allows for more prudent care in the disaster‘s immediate aftermath when the potential for additional impacts is higher.

The rules for reconstruction, restoration, rehabilitation, and/or replacement are often different for these types of designated resources.

Natural resources can have beneficial functions that reduce the impacts of natural hazards, for example, wetlands and riparian habitat which help absorb and attenuate floodwaters and thus support overall mitigation objectives.

Cultural and Historical Resources

Butte County has a large stock of historically significant homes, public buildings, and landmarks.

To inventory these resources, the HMPC collected information from a number of sources. The

California Department of Parks and Recreation Office of Historic Preservation (OHP) was the primary source of information. The OHP is responsible for the administration of federally and state mandated historic preservation programs to further the identification, evaluation, registration, and protection of California‘s irreplaceable archaeological and historical resources.

OHP administers the National Register of Historic Places, the California Register of Historical

Resources, California Historical Landmarks, and the California Points of Historical Interest programs. Each program has different eligibility criteria and procedural requirements.

The National Register of Historic Places is the nation‘s official list of cultural resources worthy of preservation. The National Register is part of a national program to coordinate and support public and private efforts to identify, evaluate, and protect historic and archeological resources. Properties listed include districts, sites, buildings, structures, and objects that are significant in American history, architecture, archeology, engineering, and culture. The

National Register is administered by the National Park Service, which is part of the U.S.

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Department of the Interior.

The California Register of Historical Resources program encourages public recognition and protection of resources of architectural, historical, archeological, and cultural significance and identifies historical resources for state and local planning purposes; determines eligibility for state historic preservation grant funding; and affords certain protections under the California Environmental Quality Act. The Register is the authoritative guide to the state‘s significant historical and archeological resources.

California Historical Landmarks are sites, buildings, features, or events that are of statewide significance and have anthropological, cultural, military, political, architectural, economic, scientific or technical, religious, experimental, or other value. Landmarks #770 and above are automatically listed in the California Register of Historical Resources.

California Points of Historical Interest are sites, buildings, features, or events that are of local (city or county) significance and have anthropological, cultural, military, political, architectural, economic, scientific or technical, religious, experimental, or other value.

Points designated after December 1997 and recommended by the State Historical Resources

Commission are also listed in the California Register.

Historical resources included in the programs above are identified in Table 4.33.

Table 4.33. Butte County Planning Area - Historical Resources

Name (Landmark Plaque

Number)

14 Mile House Site (P636)

A H Chapman House / "The

Little Chapman Mansion" (P573)

Allen--Sommer--Gage House

(N481)

BIDWELL MANSION (N165)

Bidwells Mill Site, Bidwell

Millstones (P90)

BR #12C-8 / Honey Run

Covered Bridge (P3)

Butte County Rairoad Depot

(P575)

California-Oregon Railroad

Depot (P184)

Centerville Schoolhouse (P185)

Chapman, A. H., House (N1008)

Cherokee Townsite And

Adjoining Spring Valley Mine

(P557)

Chico African Methodist

Episcopal Church South (P792)

Chico Forestry Station And

Nursery (840)

National

Register

X

X

X

X

State

Landmark

California

Register

Point of

Interest Date Listed City

X

X

11/16/1984

9/11/1981

Chico

Chico

X

X

X

X

X

X

X

4/13/1977

3/24/1972

6/7/1968

8/5/1966

12/21/1981

1/19/1971

1/19/1971

1/28/1982

Paradise

Chico

12/19/1980 Oroville

3/11/1994

3/20/1970

Chico

Chico

Chico

Paradise

Paradise

Gridley

Chico

Chico

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Name (Landmark Plaque

Number)

Chinese Cemetery (P584)

Chinese Temple (770)

Discovery Site Of The Last Yahi

Indian (809)

Dogtown Nugget Discovery Site

(771)

Durham, W. W., House (N1761)

Fagan House (P727)

Forks Of Butte (N2220)

Garrott's Saw Mill (P116)

Gianella Bridge, BR #12-54 Site

(P812)

Hazel Hotel (N2137)

Honey Run Covered Bridge

(N1562)

Hooker Oak (313)

Inskip Hotel (N355)

Jewish Cemetery (P585)

Lee, Fong, Company (N1057)

Long's Bar (P576)

Lott Museum-Sank Park (P2)

Magalia Community Church

(N985)

Manzanita School (P89)

Mud Creek Canyon (N254)

Old Chinese Cemetery (P413)

Old Suspension Bridge (314)

Oregon City (807)

Oroville Carnegie Library

(N2362)

Oroville Cemetery (P583)

Oroville Chinese Temple (N431)

Oroville Commercial District

(Old) (N1211)

Oroville Inn (N1635)

Oroville Odd Fellows Home Site,

Bella Vista Hotel (P726)

Patrick Ranch House (N149)

Patrick Rancheria (N150)

Rancho Chico And Bidwell

Adobe (329)

Richardson Springs Resort

Hotel, Lodge, And Home (P650)

National

Register

X

X

X

X

X

X

X

X

X

X

X

X

X

X

State

Landmark

California

Register

Point of

Interest Date Listed City

X 3/1/1982 Oroville

X

X

1/31/1962

10/5/1965

Oroville

Oroville

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

1/31/1962

4/2/1992

8/17/1990

1/2/2004

6/6/1969

8/23/1995

7/13/2001

6/23/1988

7/12/1939

5/2/1975

3/1/1982

3/11/1982

6/7/1968

8/14/1973

8/7/1975

7/12/1939

6/28/1965

5/8/2007

3/1/1982

7/30/1976

7/28/1983

9/13/1990

8/17/1990

2/23/1972

2/23/1972

8/8/1939

3/19/1985

Magalia

Durham

Gridley

Paradise

Oroville

Chico

Hamilton City

Gridley

Chico

Chico

Stirling City

Oroville

Oroville

12/21/1981 Oroville

8/5/1966

1/11/1982

Oroville

Magalia

Gridley

Chico

Oroville

Oroville

Oroville

Oroville

Oroville

Oroville

Oroville

Oroville

Oroville

Chico

Chico

Chico

Chico

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Name (Landmark Plaque

Number)

Silberstein Park Building

(N1177)

South Of Campus Neighborhood

(N1700)

National

Register

X

X

Southern Pacific Depot (N1477)

St. John's Episcopal Church

(N999)

Stansbury House (N366)

State Theatre (N1731)

X

X

X

X

Us Post Office--Chico Midtown

Station (N1320)

X

Us Post Office--Oroville Main

(N1321)

X

Source: California Office of Historical Preservation

State

Landmark

California

Register

Point of

Interest Date Listed City

2/17/1983 Chico

6/24/1991

1/29/1987

1/21/1982

6/5/1975

9/13/1991

1/11/1985

1/11/1985

Chico

Chico

Chico

Chico

Oroville

Chico

Oroville

The National Park Service administers two programs that recognize the importance of historic resources, specifically those pertaining to architecture and engineering. While inclusion in these programs does not give these structures any sort of protection, they are valuable historic assets.

The Historic American Buildings Survey (HABS) and Historic American Engineering Record

(HAER) document America‘s architectural and engineering heritage. Table 4.34 lists the HABS

and HAER structures in Butte County:

Table 4.34. Butte County Planning Area - HABS and HAER Structures

Area

Centerville Vicinity

Historic Building/Structure

Centerville Hydroelectric System, Butte Creek, Centerville, Butte, CA

Centerville Hydroelectric System, Powerhouse, Butte Creek, Centerville, Butte, CA

Cherokee Vicinity

Centerville Hydroelectric System, Switch House, Butte Creek, Centerville, Butte, CA

Chico Vicinity

Brewery (Ruins), Cherokee, Butte, CA

Wells Fargo & Company Vault (Ruins), Cherokee, Butte, CA

Oroville Vicinity

Bidwell Mansion, 525 Esplanade Street, Chico, Butte, CA

Bidwell Bar Suspension Bridge & Stone Toll House, Near Lake Oroville (moved from fork of

Feather River), Oroville vicinity, Butte, CA

Bidwell Bar Suspension Bridge & Stone Toll House, Spanning Middle Fork of Feather,

Oroville vicinity, Butte, CA

Paradise Vicinity

Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally

Carr Hill Road), Paradise vicinity, Butte, CA

Source: The Library of Congress, American Memory, http://memory.loc.gov/ammem/collections/habs_haer/

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It should be noted that these lists may not be complete, as they may not include those currently in the nomination process and not yet listed. Additionally, as defined by the California

Environmental Quality Act (CEQA) and the National Environmental Policy Act (NEPA), any property over 50 years of age is considered a historic resource and is potentially eligible for the

National Register. Thus, in the event that the property is to be altered, or has been altered, as the result of a major federal action, the property must be evaluated under the guidelines set forth by

CEQA and NEPA. Structural mitigation projects are considered alterations for the purpose of this regulation.

Natural Resources

Natural resources are important to include in cost/benefit analyses for future projects and may be used to leverage additional funding for mitigation projects that also contribute to community goals for protecting sensitive natural resources. Awareness of natural assets can lead to opportunities for meeting multiple objectives. For instance, protecting wetlands areas protects sensitive habitat as well as reducing the force of and storing floodwaters.

Butte County once supported limited oak savannah and riparian woodland, with an herbaceous layer of perennial grasses and both annual and perennial wildflowers. Vernal pools were scattered in both low and high density clusters throughout the valley grassland habitat. After settlement of the County, many of the native perennial grasses were replaced by Mediterranean annual grasses. However, within the vernal pools native vegetation uniquely suited to spring time inundation survived. Today these vernal pools harbor a number of listed plant and animal species. In addition to vernal pools, other seasonal and emergent wetlands occurred, mostly in association with the many natural drainage systems that previously flowed through the County, but which are now either channelized or confined within a system of artificial levees.

The County of Butte is fortunate to have several locations where vestiges of the once vast and diverse Central Valley natural habitat areas still exist. Habitat areas include riparian zones,

riverine habitats, wetlands, woodlands, and grasslands. These are shown in Figure 4.58. This

map delineates areas considered primarily natural such as riparian zones, marshlands, and oak woodlands. The boundaries are drawn based on review of reports and maps of public and private agencies including the U.S. Fish and Wildlife Service‘s National Wetlands Inventory maps, the

State Department of Water Resource‘s Delta Atlas, the California Department of Fish and

Game's Natural Diversity Database, and aerial photography.

The natural communities in the County were detailed in the Butte Regional Habitat Conservation

Plan (HCP). These include oak woodland and savanna, grassland, riparian, wetland, aquatic, and agriculture. Each of the natural communities is comprised of the land cover types shown in

Table 4.35. Chaparral and conifer-dominated forest, although natural land cover types, are not

proposed as natural communities, because the Butte Regional HCP/NCCP is focused on conservation of lowland communities, and chaparral and conifer-dominated forest are higher

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elevation communities located primarily outside of the plan area and occurring in the plan area only as relatively small inclusions.

The distribution of the natural communities and land cover types in the plan area is presented in

Figure 4.57 and Figure 4.58, respectively, and the extent of natural communities and land cover

types is presented in Table 4.35. Agriculture is the most extensive natural community,

comprising over 49 percent of the total extent of natural communities in the plan area and 44 percent of all landcover types. The following sections describe physical and biological attributes associated with each natural community

Table 4.35. Butte County Planning Area - Extent of Natural Communities and Other

Land Cover Types (acres)

Natural Community and Constituent Land Cover Types

Oak Woodland and Savanna

Blue oak savanna

Blue oak woodland

Interior live oak woodland

Mixed oak woodland

Subtotal

Grassland

Grassland

Grassland with swale complex

Vernal pools

Altered vernal pools

Subtotal

Riparian

Cottonwood-willow riparian forest

Valley oak riparian forest

Willow scrub

Herbaceous riparian and river bar

Dredger tailings with riparian forest/scrub

Subtotal

Wetland

Emergent wetland

Managed wetland

Managed seasonal wetland

Subtotal

Acres

10,580

34,705

2,382

44,893

92,560

68,403

33,525

422

246

102,596

7,613

4,328

2,991

1,658

5,549

22,139

4,458

25,486

2,052

31,996

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Natural Community and Constituent Land Cover Types

Aquatic

Open water

Major canal

Stock pond1

Subtotal

Agriculture

Rice

Irrigated cropland

Irrigated pasture

Orchard/vineyard

Nonnative woodland

Subtotal

Total Natural Communities

Other Land Cover Types

Chaparral

Subtotal

Developed

Urban

Ranchettes

– wooded

Ranchettes

– open

Disturbed ground

Dredger tailings with sparse herbaceous vegetation

Subtotal

Conifer-dominated forest

Total All Land Cover Types

Source: Butte County Habitat Conservation Plan

Acres

8,408

1,897

487 ponds

10,305

120,281

20,437

1,159

108,557

48

250,482

510,078

8,317

8,317

25,396

6,406

7,649

3,534

2,825

45,810

15

564,2203

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Figure 4.57. Distribution of Land Cover Types in the Habitat Conservation Plan Area

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Figure 4.58. Butte County Planning Area- Important Natural Communities

Source: Butte County Habitat Conservation Plan

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Oak Woodland and Savanna

The woodland and savanna natural community is comprised of the following land cover types: blue oak woodland, blue oak savanna, interior live oak woodland, and mixed oak woodland. The oak woodland and savanna natural community occurs along the eastern edge of the County in the foothills of the Sierra Nevada and Cascade Mountains. Oak woodlands and savannas in the plan area are diverse and biologically rich. These communities are essential to the maintenance and sustainability of wildlife populations in the eastern portion of the plan area. Oak communities provide habitat for over 330 species of wildlife, including reptiles, small and large mammals, and birds. These areas function as breeding, foraging, nesting, denning, protection, and migration habitats.

Among the most productive and diverse wildlife habitats in the state, oak woodlands and savannas are valuable because they provide abundant nesting, roosting, and cover opportunities for wildlife species in association with grassland foraging habitats. They also support large decadent trees that are important because they provide abundant cavities that provide nesting sites for birds and foraging opportunities for insect-eating birds. Oak trees are particularly valuable because of the production of acorns, which are an abundant high quality food for many birds and mammals. Downed wood from oak trees also provides food and cover for a variety of arthropods, fungi, and wildlife species. Common wildlife associated with the oak woodland and savanna natural community within the plan area include Columbian black-tailed deer, acorn woodpecker, barn owl, wild turkey, California quail, big brown bat, cottontail, wild boar, and many other mammal, reptile, and bird species.

Grassland

The grassland natural community is comprised of the following land cover types: grassland, grassland with swale complex, vernal pools, and altered vernal pools. Grassland within the plan area typically occur on relatively level valley basin soils, alluvial fans between the basins and the foothills, and gently sloping terraces along the base of the Sierra Nevada foothills.

Grassland is generally bordered by oak woodland and savanna to the east (upslope) and by 26 various types of agriculture and urban development to the west.

Native grasslands within the valley grassland matrix may be dominated or codominated by the same species as valley grasslands, but contain higher percent cover of native species. Several unique vegetation community subtypes can be identified within the native grasslands. Subtypes found in Butte County uplands likely include the foothill needlegrass series, recognized by the presence of Nassella lepida and the purple needlegrass series, recognized by presence of

Nassella pulchra. Numerous native wildflowers are found within these habitats. Examples of common native wildflowers occurring in valley grassland include butter and eggs, miniature lupine, California poppy, turkey mullein, tarweeds, Itherial‘s spear, and clover.

Grassland provides essential habitat for a variety of wildlife that occur in the plan area.

Grassland is located primarily along the eastern edge of the plan area on alluvium and terraces

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and typically occurs on a broad, open landscape with gently rolling topography or in association with oak woodland or oak savanna. Grassland-associated wildlife species include California ground squirrel, California vole, Botta‘s pocket gopher, western harvest mouse, coyote, burrowing owl, savannah sparrow, western meadowlark, ring-necked pheasant, western rattlesnake, gopher snake, and western fence lizard. Grassland also provides foraging habitat for turkey vulture and raptors, including Swainson‘s hawk, red-tailed hawk, northern harrier, and white-tailed kite. Native grasslands provide habitat for native bees and other economically important pollinators for crops in the agricultural lands of the county. Grassland with vernal pools or vernal swales seasonally support crustaceans (e.g., fairy shrimp) and other invertebrates and provide foraging and resting habitat for shorebirds, waterfowl, and other migrant birds.

Vernal pools and swales, discussed below, commonly occur in the grassland plan area that is particularly extensive east of Chico. Several special-status invertebrates are known or to occur in the vernal pool, vernal swale, and other seasonal wetlands in the plan area, including vernal pool tadpole shrimp, vernal pool fairy shrimp, California fairy shrimp, and mid-valley fairy shrimp.

As a result of the significant loss of vernal pool and vernal swale habitats in the Central Valley from urbanization and agricultural conversion, populations of these species have declined throughout their range. Collectively, these species occur and emerge within a range of specific environmental conditions that include soil type, vegetation characteristics, water depth, water temperature, inundation duration, and water quality.

Vernal Pools and Vernal Swales

Vernal pools and/or vernal swales are found within the grassland in areas with shallow soils on relatively flat areas that are underlain by bedrock, hardpan, or claypan. The geologic formations

that support vernal pool and swale terrain are shown in Figure 4.59. Vernal pools are shallow

depressions that seasonally fill with rain water during the wet season and are completely dry by late spring or early summer. Vernal swales are similar, except that they generally form individual or a network of drainages that meander through the landscape. Organisms that thrive in this unique, harsh habitat co-evolved with the geologic and climatic conditions that formed vernal pools and vernal swales and, consequently, these features contain a high number of endemic and rare species of plants, animals, and invertebrates.

Vernal pools and swales contain a unique assemblage of native herbaceous forbs and grasses, including those in the plan area, such as Fremont‘s goldfield, valley goldfield, tidy tips, white navarretia, pogogyny, and yellow carpet.

Three types of vernal pools in the plan area are identified in CNDDB as rare natural communities: Northern Basalt Flow Vernal Pools, Northern Hardpan Vernal Pools, and Northern

Volcanic Mudflow Vernal Pools.

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Figure 4.59. Vernal Pools in the Butte County Habitat Conservation Plan Area

Source: Butte County Habitat Conservation Plan Ecological Baseline Conditions

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Riparian

The riparian natural community is made of the following land cover types: cottonwood-willow riparian forest, valley oak riparian forest, willow scrub, herbaceous riparian and river bar, and dredger tailings with riparian forest/scrub. Riparian communities provide a variety of ecosystem functions including regulating runoff, reducing erosion, providing important fish and wildlife habitat, and providing corridors of habitat through other cover types that are less suitable for wildlife (e.g., urban and agricultural lands). Riparian areas confer benefits to water quality by processing nutrients from uplands and groundwater, and trapping sediments from uplands that could enter streams. The dense vegetation along riparian corridors can slow flood waters and dissipate the energy of stream flows, reducing the potential for erosion and downstream flash flooding. Shade associated with riparian areas reduces algae growth, which can negatively impact oxygen levels and pH levels. In addition, roots help hold soil in place, which reduces erosion and downstream turbidity that can be detrimental to fish, aquatic invertebrates, and wildlife.

Riparian habitats perform many functions that are necessary to support wildlife species; they provide shade, water, food and forage, and nutrients that form the basis of the food web, in a concentrated area. The dense canopy, coupled with available water, provides crucial habitat for a variety of invertebrates and insects, aquatic and terrestrial. More than 225 species of birds, mammals, amphibians and reptiles depend on riparian habitat in California. Of particular note, numerous species of resident and neotropical migratory birds use riparian habitat during the breeding season; many of these species are declining throughout their range, and maintaining adequate habitat across California is critical to their continued survival (RHJV 2004).

Riparian vegetation along stream corridors also provides a number of benefits to aquatic biota, including fish. In general, the plants stabilize the banks and provide instream cover through roots, overhanging vegetation (shade and visual cover from terrestrial predators), and fallen woody debris (logs). Logjams and coarse woody debris within riparian corridors also form important habitat and food sources for fish, amphibians, and aquatic insects. Riparian vegetation provides food and nutrients for all trophic levels in the adjacent aquatic community through falling leaves and insects. Large shrubs and trees provide shade that helps to moderate upper daytime temperatures and reduce algal growth in the aquatic community. In addition to stabilizing the banks, the vegetation slows flood waters that overtop the banks and can provide temporary refuge for fish during floods.

The riparian natural community occurs in north-south and northeast-southwest trending long linear patches bisecting other natural communities (oak woodland and savanna, grassland, agriculture, managed wetlands) and urban land within the County. Significantly reduced in extent since initial European settlement, riparian habitats continue to support the greatest diversity of wildlife species of any wildlife habitat in California. Loss of riparian habitat is directly linked to population declines and range reduction of many dependent species.

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Significant riparian resources in the plan area occur along the Sacramento River, Feather River,

Butte Creek, Big Chico Creek, and several other smaller drainages. These habitats support numerous wildlife species including several special-status species such as Swainson‘s hawk,

Cooper‘s hawk, western yellow-billed cuckoo, yellow-breasted chat, yellow warbler, and ringtail. In addition to nesting birds, riparian systems provide essential habitat for many wintering and neotropical migrant birds that migrate through the plan area each year. Riparian systems also function as important wildlife movement corridors, providing some of the last remaining overstory cover habitat in much of the Central Valley.

Wetlands

Wetlands are common throughout Butte County. Two types of wetlands are mapped in the HCP

Plan Area: emergent wetlands (commonly called marshes) and managed wetlands. Emergent wetlands occur associated with hydric features throughout the HCP Plan Area and large complexes of wetlands occur in the southwestern and western section of the HCP Plan Area.

Wetlands are supported where soils are ponded or saturated for significant portion of the growing season, creating an anoxic or very low oxygen rooting environment suitable for hydrophytes.

The large, managed wetlands within the plan area are associated with the historical natural flood basin of the Sacramento Valley, which dominates the southwestern portion of the HCP Plan

Area. The basin historically flooded frequently for long durations and supported extensive tule and cattail marshes.

More waterfowl come to winter in the upper Sacramento Valley than anywhere else along the

Pacific Flyway. Both natural and managed wetlands in the HCP Plan Area provide valuable nesting, foraging, cover, and breeding habitat for many bird, amphibian, and mammal species.

Wetlands occur as natural features on the landscape as vernal pools and other seasonal wetlands

(discussed previously) and as emergent wetlands along the edges of open water habitats or freshwater marshes; or they occur as managed features on the landscape in association with the agricultural landscape or specifically developed for wildlife management purposes. The largest wetland complexes within the plan area are associated with managed wetland areas, where agriculture lands have been restored to wetlands. In particular, Gray Lodge and other federally managed wetlands are along the Pacific Flyway (in the southwestern section of the plan area where a high water table, internally draining basin features, and hydrologic connectivity to the

Sacramento River provide natural wetland conditions) and represent a large area of suitable habitat for both migratory and resident birds along the Flyway. Millions of birds including over

225 unique species, more than a million ducks, and hundreds of thousands of geese use Gray

Lodge Wildlife Area and other wetland features within the plan area.

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Figure 4.60. Butte County Planning Area - Wetlands

Source: Butte County General Plan 2030: Settings and Trends, Biological Resources

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Essential Functions

Wetlands perform a variety of ecosystem functions including food web support, habitat for insects and other invertebrates, fish and wildlife habitat, filtering of waterborne and drydeposited anthropogenic pollutants, carbon storage, water flow regulation (e.g., flood abatement), groundwater recharge, and other human and economic benefits.

Wetlands provide habitat for insects and other invertebrates that are critical food sources to a variety of wildlife species, particularly birds. There are species that depend on wetlands during all parts of their lifecycle for food, overwintering, and reproductive habitat. Other species use wetlands for one or two specific functions or parts of the lifecycle, most commonly for food resources. In addition, wetlands produce substantial plant growth that serves as a food source to herbivores (wild and domesticated) and a secondary food source to carnivores.

Wetlands slow the flow of water through the vegetation and soil, and pollutants are often held in the soil. In addition, because the water is slowed, sediments tend to fall out, thus improving water quality and reducing turbidity downstream.

Aquatic

The aquatic natural community is comprised of the open water, major canal, and stock pond land cover types. The primary land uses associated with the aquatic community are water storage for irrigation and other uses, recreation, and fish and wildlife habitat. Rivers, streams, and other open water areas have little or no emergent vegetation within high flow areas. Filamentous green algae, however, can be common to abundant where water is clear and shade is moderate to light. Slower moving areas with shallow water can support emergent aquatic vegetation where fine sediments are present.

Aquatic habitats are essential in maintaining the diversity of wildlife found in the Central Valley and in the plan area. Most wildlife species use aquatic habitats at least incidentally for drinking water, some to meet essential life requirements, and others to meet all of their life requirements of nesting, foraging, and cover. In addition to the open water component, most aquatic communities in the plan area consist of other adjacent and associated habitats, such as riparian woodlands or scrub, emergent wetlands, or grasslands. This greatly enhances the value of the aquatic community by providing habitats that support species that rely on aquatic as well as other associated habitat types.

Some species are primarily aquatic, although adjacent uplands are also used for some element of their life history. For example, while nesting in adjacent upland sites, western pond turtle requires lakes, large ponds, or perennial watercourses for foraging and cover. This covered species may be found in aquatic habitats along Butte Creek, Big Chico Creek, and other creeks, sloughs, and waterbodies in the plan area. Giant garter snake, also a covered species, requires slow-moving streams or channels that support submergent and emergent vegetation and an

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upland component for hibernaculae. Amphibian species, such as Pacific tree frog, also rely on these habitats.

Larger waterbodies, such as Thermalito Afterbay, and other large open water habitats, such as those found at Gray Lodge Wildlife Refuge, are particularly important for roosting and foraging waterfowl and other water birds. These sites are also important foraging habitats for bald eagles and osprey. Many insectivorous birds such as swallows, swifts, and flycatchers forage for insects that congregate over open water habitats.

Stock ponds are small impoundments created by ranchers or other livestock managers to improve the distribution and availability of water on the landscape. These provide a year-round supply of water and serve as refugia for many native species including California tiger salamander,

California red-legged frog, western pond turtle, and foothill yellow-legged frog.

Agriculture

The agricultural natural community type is made up of the following land cover types: orchards and vineyards, rice, irrigated cropland, irrigated pasture, and nonnative woodland. Nonnative woodland is included in the agriculture community because this land cover type is comprised of eucalyptus plantations that are planted for commercial purposes (e.g., pulp production). The primary land use associated with the agriculture community is farming for rice and other crops and maintaining orchards for fruit and nut production.

Agricultural lands in the Central Valley represent an extremely altered landscape that retains little resemblance to the historical (pre-European settlement) condition. Formerly consisting of extensive wetlands, open grasslands, broad riparian systems, and oak woodlands, the conversion to agriculture has removed most of these native habitats. However, while generally supporting a less diverse community of wildlife compared with most native habitats, agricultural systems continue to support abundant wildlife and provide essential breeding, foraging, and roosting habitat for many resident and migrant wildlife species.

Ricelands, for example, have become important ―surrogate‖ wetland habitats for over 235 wildlife species in the Central Valley. With the extensive loss of wetland habitats, ricelands provide essential breeding and wintering habitat for waterfowl, shorebirds, wading birds, as well as providing food and cover for some reptiles, amphibians, and mammals. Most significant is the value ricelands provide to waterfowl and other waterbirds using the Pacific Flyway. With less than 300,000 acres of natural wetlands remaining in the Central Valley, the wetland functions provided by ricelands are an important component of waterfowl management in the

Pacific Flyway. Ricelands also play an important role in providing cover, foraging, and roosting habitat for several special-status species, including the state and federally listed giant garter snake and the greater sandhill crane.

Agricultural lands also provide essential upland habitat for many wildlife species. Crop patterns that include a variety of hay, grain, and row crops support abundant rodent populations. Field

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edges, woodlots, and watercourses that support riparian habitat also provide breeding sites and refugia for prey species and other wildlife. Because of this abundance of food, the Central

Valley supports one of the largest concentrations of raptors during the winter and breeding seasons. Raptors such as red-tailed hawk, Swainson‘s hawk, and white-tailed kite nest throughout the Central Valley and forage in a variety of agricultural crop types including hay, grain, row crops and irrigated pastures.

Special Status Species

To further understand natural resources that may be particularly vulnerable to a hazard event, as well as those that need consideration when implementing mitigation activities, it is important to identify at-risk species (i.e., endangered species) in the planning area. The Fish and Game

Department maintains a list of threatened and endangered species in California. State and federal laws protect the habitat of these species through the environmental review process.

Several additional species are of special concern or candidates to make the protected list. The

Department's classification scheme is defined as follows:

A species is a candidate when the Fish and Game Commission has formally noticed it as being under review by the Department to determine whether listing as threatened or endangered is warranted, or when it is the subject of a proposed rulemaking by the

Commission to list as threatened or endangered.

A species is threatened when although not presently threatened with extinction, it is likely to become an endangered species in the foreseeable future in the absence of special protection and management efforts.

A species is endangered when it is in serious danger of becoming extinct throughout all, or a significant portion of, its range due to one or more causes, including loss of habitat, change of habitat, overexploitation, predation, competition or disease.

Table 4.36 summarizes Butte‘s special status animal species.

Table 4.36. Butte County Planning Area - Federally and State Listed Species with

Potential to Occur

Species

Hoover’s spurge

Butte County meadowfoam

Hairy Orcutt grass

Slender Orcutt grass

Greene’s tuctoria

Conservancy fairy shrimp

Vernal pool fairy shrimp

Vernal pool tadpole shrimp

Valley elderberry longhorn beetle

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Federally Listed State Listed

X

X

X

X

X

X

X

X

X

X

X

X

X

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Species

California tiger salamander

California red-legged frog

Mountain yellow-legged frog

Giant garter snake

Bald eagle

Swainson’s hawk

American peregrine falcon

California black rail

Greater sandhill crane

Western yellow-billed cuckoo

Willow flycatcher

Bank swallow

Pacific fisher

Central Valley spring-run Chinook salmon

Sacramento River winter-run Chinook salmon

Central Valley Steelhead

Central Valley fall- and late-fall-run Chinook salmon

Green sturgeon

Sierra Nevada red fox

California wolverine

Source: Butte County General Plan 2030 Settings and Trends Biological Resources

Federally Listed State Listed

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

The California Native Plant Society‘s inventory of rare and endangered vascular plants in

California lists 14 species that have been found in Butte County which are characterized as rare or endangered according to either federal, state or California Native Plant Society definitions

(Table 4.37).

Table 4.37. Butte County Planning Area - Endangered, Threatened, and Candidate

Animal Species

Scientific Name

Agrostis hendersonii

Allium jepsonii

Allium sanbornii var. sanbornii

Anomobryum julaceum

Arctostaphylos mewukka ssp. truei

Astragalus pauperculus

Astragalus tener var. ferrisiae

Astragalus whitneyi var. lenophyllus

Atriplex cordulata var. cordulata

Atriplex minuscula

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Common Name

Henderson's bent grass

Jepson's onion

Sanborn's onion slender silver moss

True's manzanita depauperate milk-vetch

Ferris' milk-vetch woolly-leaved milk-vetch heartscale lesser saltscale

Rare Plant Rank

3.2

1B.2

4.2

2.2

4.2

4.3

1B.1

4.3

1B.2

1B.1

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Scientific Name

Atriplex subtilis

Azolla microphylla

Balsamorhiza macrolepis

Betula glandulosa

Botrychium ascendens

Botrychium crenulatum

Botrychium minganense

Botrychium montanum

Brasenia schreberi

Bulbostylis capillaris

California macrophylla

Calycadenia oppositifolia

Calystegia atriplicifolia ssp. buttensis

Campylopodiella stenocarpa

Cardamine pachystigma var. dissectifolia

Carex geyeri

Carex limosa

Castilleja rubicundula ssp. rubicundula

Centromadia parryi ssp. parryi

Centromadia parryi ssp. rudis

Chamaesyce hooveri

Chlorogalum grandiflorum

Clarkia biloba ssp. brandegeeae

Clarkia gracilis ssp. albicaulis

Clarkia mildrediae ssp. lutescens

Clarkia mildrediae ssp. mildrediae

Clarkia mosquinii

Claytonia palustris

Claytonia parviflora ssp. grandiflora

Cuscuta obtusiflora var. glandulosa

Cypripedium californicum

Cypripedium fasciculatum

Darlingtonia californica

Delphinium recurvatum

Didymodon norrisii

Eleocharis parvula

Eremogone cliftonii

Erigeron inornatus var. calidipetris

Erigeron petrophilus var. sierrensis

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Common Name

subtle orache

Mexican mosquito fern big-scale balsamroot dwarf resin birch upswept moonwort scalloped moonwort

Mingan moonwort western goblin watershield thread-leaved beakseed round-leaved filaree

Butte County calycadenia

Butte County morning-glory flagella-like atractylocarpus dissected-leaved toothwort

Geyer's sedge mud sedge pink creamsacs pappose tarplant

Parry's rough tarplant

Hoover's spurge

Red Hills soaproot

Brandegee's clarkia white-stemmed clarkia golden-anthered clarkia

Mildred's clarkia

Mosquin's clarkia marsh claytonia streambank spring beauty

Peruvian dodder

California lady's-slipper clustered lady's-slipper

California pitcherplant recurved larkspur

Norris' beard moss small spikerush

Clifton's eremogone hot rock daisy northern Sierra daisy

4.2

4.2

4.2

1B.2

2.2

4.3

1B.3

4.3

4.3

1B.2

4.2

1B.3

1B.1

4.3

4.2

2.2

1B.1

4.2

4.2

2.2

1B.2

4.2

2.2

1B.2

1B.2

4.2

1B.2

1B.2

1B.2

Rare Plant Rank

1B.2

4.2

1B.2

2.2

2.3

2.2

2.2

2.1

2.3

4.2

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Scientific Name

Eriogonum umbellatum var. ahartii

Eriophorum gracile

Fissidens pauperculus

Fritillaria eastwoodiae

Fritillaria pluriflora

Hesperevax caulescens

Hibiscus lasiocarpos var. occidentalis

Imperata brevifolia

Juncus leiospermus var. ahartii

Juncus leiospermus var. leiospermus

Lagophylla dichotoma

Lasthenia ferrisiae

Leptosiphon acicularis

Lewisia cantelovii

Lewisia kelloggii ssp. hutchisonii

Lilium humboldtii ssp. humboldtii

Limnanthes floccosa ssp. californica

Limnanthes floccosa ssp. floccosa

Meesia triquetra

Microseris sylvatica

Mimulus glaucescens

Mimulus inconspicuus

Mimulus laciniatus

Monardella venosa

Navarretia cotulifolia

Navarretia heterandra

Navarretia nigelliformis ssp. nigelliformis

Navarretia subuligera

Ophioglossum californicum

Orcuttia pilosa

Orcuttia tenuis

Packera eurycephala var. lewisrosei

Packera layneae

Paronychia ahartii

Penstemon heterodoxus var. shastensis

Penstemon personatus

Perideridia bacigalupii

Piperia colemanii

Piperia michaelii

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Common Name

Ahart's buckwheat slender cottongrass minute pocket moss

Butte County fritillary adobe-lily hogwallow starfish woolly rose-mallow

California satintail

Ahart's dwarf rush

Red Bluff dwarf rush forked hare-leaf

Ferris' goldfields bristly leptosiphon

Cantelow's lewisia

Hutchison's lewisia

Humboldt lily

Butte County meadowfoam woolly meadowfoam three-ranked hump moss sylvan microseris shield-bracted monkeyflower small-flowered monkeyflower cut-leaved monkeyflower veiny monardella cotula navarretia

Tehama navarretia adobe navarretia awl-leaved navarretia

California adder's-tongue hairy Orcutt grass slender Orcutt grass

Lewis Rose's ragwort

Layne's ragwort

Ahart's paronychia

Shasta beardtongue closed-throated beardtongue

Bacigalupi's yampah

Coleman's rein orchid

Michael's rein orchid

1B.1

1B.2

1B.2

1B.1

4.3

1B.2

4.2

4.3

4.2

1B.1

4.2

4.3

4.2

4.3

4.2

1B.1

1B.1

4.2

4.2

1B.2

3.3

4.2

1B.1

4.2

4.2

4.2

4.3

4.3

4.3

Rare Plant Rank

1B.2

4.3

1B.2

3.2

1B.2

4.2

1B.2

2.1

1B.2

1B.1

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Scientific Name

Poa sierrae

Polygonum bidwelliae

Polystichum kruckebergii

Rhynchospora californica

Rhynchospora capitellata

Rupertia hallii

Sagittaria sanfordii

Sanicula tracyi

Schoenoplectus subterminalis

Sedum albomarginatum

Sidalcea robusta

Silene occidentalis ssp. longistipitata

Silene occidentalis ssp. occidentalis

Stellaria longifolia

Stellaria obtusa

Streptanthus drepanoides

Streptanthus longisiliquus

Stuckenia filiformis

Subularia aquatica ssp. americana

Trifolium jokerstii

Tuctoria greenei

Common Name

Sierra blue grass

Bidwell's knotweed

Kruckeberg's sword fern

California beaked-rush brownish beaked-rush

Hall's rupertia

Sanford's arrowhead

Tracy's sanicle water bulrush

Feather River stonecrop

Butte County checkerbloom long-stiped campion

Western campion long-leaved starwort obtuse starwort sickle-fruit jewel-flower long-fruit jewel-flower slender-leaved pondweed water awlwort

Butte County golden clover

Greene's tuctoria

Rare Plant Rank

1B.3

4.3

4.3

1B.1

2.2

1B.2

1B.2

4.2

2.3

1B.2

1B.2

1B.2

4.3

2.2

4.3

4.3

4.3

2.2

4.3

1B.2

1B.1

Utricularia intermedia

Utricularia minor

Vaccinium coccineum

Viola tomentosa

flat-leaved bladderwort lesser bladderwort

Siskiyou Mountains huckleberry felt-leaved violet

2.2

4.2

3.3

4.2

Wolffia brasiliensis

Brazilian watermeal 2.3

Source: California Native Plant Species Inventory

Status explanations:

California Native Plant Society

1B = List 1B species: rare, threatened, or endangered in California and elsewhere.

2

3

4

= List 2 species: rare, threatened, or endangered in California but more common elsewhere.

= List 3 species: plants about which more information is needed to determine their status.

= List 4 species: plants of limited distribution.

= no listing.

CNPS Code Extensions

.1 = seriously endangered in California (over 80% of occurrences threatened / high degree and immediacy of threat).

.2

.3

= fairly endangered in California (20-80% of occurrences threatened).

= not very endangered in California (<20% of occurrences threatened or not current threats knows).

Growth and Development Trends

As part of the planning process, the HMPC looked at changes in growth and development, both past and future, and examined these changes in the context of hazard-prone areas, and how the changes in growth and development affect loss estimates and vulnerability. Information from the

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Butte County Housing Element and the California Department of Finance form the basis of this discussion.

More specific information on growth and development for each participating jurisdiction can be found in the jurisdictional annexes.

Current Status and Past Development

The California Department of Finance estimated population of Butte County for January 1, 2012

was 220,465, representing a five-fold increase from just under 43,000 people in 1940. Table

4.38 and Table 4.39 illustrate the pace of population growth in Butte County dating back to 1940

along with more recent population trends for each jurisdiction.

Table 4.38. Butte County Planning Area - Historical Population

1940 1950 1960 1970 1980 1990 2000 2010 2012

Population 42,840 64,930 82,030 102,500 144,900 183,229 203,446 221,768 220,465

Source: California Department of Finance

Table 4.39. Butte County Planning Area - Population Growth for Jurisdictions 2005-

2010

Biggs

Chico

Gridley

2005

1,791

73,710

5,714

2006

1,774

78,870

5,932

2007

1,771

84,430

6,171

2008

1,765

86,806

6,367

2009

1,775

87,684

6,416

2010

1,787

88,228

6,454

2012

1,707

86,566

6,582

2013

1,696

87,500

6,576

Oroville

Paradise

13,398

26,557

13,516

26,441

14,451

26,310

14,412

26,217

14,633

26,276

14,687

26,310

15,512

26,208

15,563

26,147

Unincorporated 93,412 90,066 85,047 83,947 83,889 84,302 83,890 83,791

Total 216,587 218,605 220,187 221,522 222,682 223,778 222,477 223,286

Source: State of California Department of Finance, E-5 Population and Housing Estimates for Cities, Counties, and the State.

Note: Population reports and estimates are for January 1 of each year.

Current Land Use/Zoning

Future land use and growth management strategies in Butte County aim to concentrate future development into and toward existing communities through various policies relating to zoning and minimum development standards and requirements. Zoning designations prescribe allowed land uses and minimum lot sizes for the purpose of supporting efficient infrastructure design,

conservation of natural resources, and to avoid conflicting uses. Figure 4.61 shows current land

use designations in unincorporated Butte County.

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Figure 4.61. Unincorporated Butte County - Land Use Diagram

Source: Butte County General Plan 2030 Land Use Element

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Development since 2007 Plan

In order to determine development in any hazard area, the County and each jurisdiction examined records, from January 1, 2007 to present, to determine significant structures constructed or proposed for construction in that time period. The information is summarized below by jurisdiction.

Butte County (including the City of Biggs)

For new development since the 2007 plan, the breakdown for the past five years is as follows:

575 SFD (55 of which were a new housing area in Oroville (CHIP HOUSING)

338 Manufactured Homes

213 Manufactured homes existing ones placed onto Permanent foundation systems

289 of these structures were most likely in the SRA /WUI areas for high fire hazard

28 Ag buildings were constructed in the flood zone areas

5 aircraft hangers were constructed in the flood zone

16 warehouses for farming were constructed

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City of Chico

The only hazard zones within the City of Chico are FEMA flood zone. Figure 4.62 shows the

results of the number of new structures built in flood zones from 2007 to present. The 45 structures shown in the upper right of the figure were built in the AE and X zones and were approved by a letter of map amendment (LOMA).

Figure 4.62. Chico Development Since 2007

Source: City of Chico

City of Gridley

The City examined permit records from January 1, 2007, to present, to determine significant structures constructed, or proposed for construction, in that time period. The information is summarized below.

Single-Family Dwellings (SFD): Permits were issued for 60 (sixty) dwellings. Construction has been completed on 51 (fifty-one) of the units. Eight (8) are currently under construction.

One (1) is on hold. Three (3) of the dwellings are replacing earlier dwellings that were

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destroyed by fire or demolished.

Multi-Family Residential (MFR): A complex with 56 (fifty-six) rental units (seven, two-story buildings w/eight units each); a community building with a manager‘s unit above it. A total of eight buildings.

Commercial: an 18,014 sq. ft. drug store on Hwy 99; a 7,000 sq. ft. auto parts store on Hwy

99; a 4,000 sq. ft. strip mall on Hwy 99; a proposed 9,000 sq. ft. discount variety store on

Hwy 99 that will start construction before the end of October.

Industrial: two (2) 800 sq. ft. office trailers at commercial bakery site; 4,500 sq. ft. metal, shop/storage building at building & grounds maintenance complex.

Misc: 1,200 sq. ft. metal, shop/garage/storage building on large, residential lot.

Regarding construction in a floodplain:

All building pads are reviewed by our city engineer for conformance with placement above the flood plain elevation. Drawing number 44 of Gridley‘s Public Works Construction

Standards Manual states: ―Building pads shall not be inundated during a 100 year frequency design storm‖. Building pads must be above this minimum elevation or 12‖ above the centerline of the adjacent roadway – whichever is the most restrictive.

The city engineer provided information regarding Gridley‘s FIRM status:

Per the FIRM of 01/06/2011, the City of Gridley is within a shaded Zone X (areas of 0.2% annual chance of flood; areas of 1% annual chance flood with average depths of less than 1.0 foot or within drainage areas less than 1.0 square mile; and areas protected by levees from

1% annual chance flood).

Prior to the FIRM of 01/06/2011, the City of Gridley was within a Zone X (areas that are determined to be outside the 0.2% annual chance floodplain.

City of Oroville

None of these structures are in a flood zone or fire area:

Commercial – 7

Industrial – 1

Residential – 76

Town of Paradise

The entire town is located in a Very High Fire Hazard Severity Zone and outside of any

floodplains. Table 4.41 shows the development in the Town since 2007.

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Table 4.40. Town of Paradise Development

Residential

2007

90

Commercial 7

Industrial 0

*2013 is through 9/9/13

Future Development

2008

62

14

2

2009

6

1

0

2010

20

2

1

2011

23

1

0

2012

22

3

0

2013*

32

4

0

As indicated in the previous section, Butte County has been steadily growing over the last seven decades. Long term forecasts by the California Department of Finance project population growth in unincorporated Butte County continuing through the middle of the century, effectively

adding 52% to the 2010 county population by the year 2050. Table 4.41 shows the population

projections for the County as a whole through 2050. Information on future development in the incorporated jurisdictions can found in their respective annexes to this plan.

Table 4.41. Butte County Planning Area - Population Projections 2010-2050

2010 2015 2020 2025 2030 2035 2040 2045 2050

219,989 231,043 244,417 260,742 276,009 290,186 303,594 318,129 334,579

Source: California Department of Finance Interim Projections for California and Counties: July 1, 2015 to 2050 in 5-year

Increments

Future Growth Areas

New Growth Areas

This General Plan envisions the development of two Planned Unit Developments, the Berry

Creek Area Plan, and a number of Specific Plans. The two planned unit developments (shown

on Figure 4.63) are:

Tuscan Ridge Planned Unit Development

The Tuscan Ridge PUD will determine the mix of uses that will occur in a 172- acre area located along the Skyway at the site of the existing Tuscan Ridge Golf Course.

Residential uses may be developed in this area, provided that the golf course is also maintained.

Paradise Summit Planned Unit Development

The Paradise Summit PUD will determine the mix of uses that will occur in a 333-acre area located southeast of Paradise. The PUD will limit development to not more than 335 dwelling units in a clustered development pattern.

The Berry Creek Area Plan (shown on Figure 4.63) is an area that will be developed by the Berry

Creek community. The intent of the Area Plan will be to maintain the rural character of this community while improving opportunities to locate jobs and services in Berry Creek. Any

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development that occurs prior to adoption of the Area Plan will be subject to the underlying land use designations of General Plan 2030 until and unless the Area Plan is adopted, at which point the land use designations in that Plan will replace the designations in the General Plan. The future Berry Creek Area Plan will limit development to not more than 300 new dwelling units, in addition to existing development at the time of the Plan‘s adoption, at rural residential densities in locations suitable for residential development. The Area Plan will allow a total of approximately 20 acres of retail and office uses, primarily located along major roads and highways, as well as public uses at locations accessible to Berry Creek residents. The remainder of the area will be designated for Agriculture.

There are also seven areas in the county that are intended for development under a Specific Plan.

A ―Specific Plan‖ is defined in the California Government Code (Section 65450 et seq) as a legal tool for detailed design and implementation of a defined portion of the area covered by a General

Plan. A Specific Plan includes detailed regulations, conditions, programs, and/or proposed legislation that are needed to implement General Plan designations and policies on a particular site. These seven specific plan areas are:

Upper Stilson Canyon Specific Plan

The Upper Stilson Canyon Specific Plan will determine the mix of uses that will occur in a 4,264-acre area located east of State Route 32 and northeast of Chico. The Upper

Stilson Canyon Specific Plan will limit development to not more than 300 new dwelling units clustered in the southern portion of the Specific Plan area. Specialty agriculture and retail uses that support agriculture may be included. The remainder of the Specific Plan area shall be set aside for open space and conservation uses. In addition, the Specific Plan will ensure that there are no impacts to land uses to the south, including impacts related to road access, and that there will be adequate water supply and access for the proposed development, including the existing Buzztail Community Service District.

Doe Mill/Honey Run Specific Plan

The Doe Mill/Honey Run Specific Plan will determine the mix of uses that will occur in a

1,444-acre area located east of Chico. The Specific Plan will allow mixed residential development and some commercial uses. If the City of Chico pursues annexation of the

Specific Plan area, the County will negotiate an agreement to maintain adequate revenues to provide countywide services that will serve new development that is annexed into

Chico.

Paradise Urban Reserve Specific Plan

The Paradise Urban Reserve Specific Plan will determine the mix of uses that will occur in a 3,571-acre area located between Neal Road and State Route 191 and south of

Paradise. The Paradise Urban Reserve Specific Plan includes the existing Paradise Urban

Reserve area, which is an area anticipated for future growth by the Town of Paradise. It is envisioned that the Town of Paradise would develop the Paradise Urban Reserve Specific

Plan when the Town requires additional area for growth.

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Southeast Paradise Specific Plan

The Town of Paradise is currently preparing the Southeast Paradise Specific Plan, which will cover both incorporated and unincorporated municipalities. The Specific Plan includes 1,206 acres of unincorporated Butte County west of State Route 191 and south of Paradise. The Town anticipates that approximately 800 new dwelling units will be allowed in this area, as well as approximately 5 acres of new retail uses.

South Ophir Specific Plan

The City of Oroville anticipates the development of the South Ophir Specific Plan in its

General Plan. The Specific Plan area will extend into both incorporated and unincorporated municipalities. The Specific Plan area will include approximately 330 acres of unincorporated land located south of Ophir Road and along Lincoln Boulevard in the southern Oroville area. The Specific Plan will determine the mix of uses that will occur. A primary goal of the Specific Plan is to provide a mix of uses that includes a business/technology park complex for clean industry. Within the entire Specific Plan area, including both incorporated and unincorporated municipalities, 150 to 300 acres of land are assumed to be dedicated to the development of an industrial park. Up to 1,500 dwelling units of mixed residential types may also be included, as well as commercial uses such as a grocery store, drug store or convenience store; a bakery, deli, coffee shop, or café; a gas/service station; a drycleaner, hair salon, health club, or similar neighborhood retail service.

Rio D‘Oro Specific Plan

The Rio D‘Oro Specific Plan will determine the mix of uses that will occur in a 700-acre area located along State Route 70 south of Oroville. The Specific Plan will limit development to not more than 2,700 dwelling units of mixed residential types.

Commercial areas for this Specific Plan are limited to 30 acres of Retail and Office designation to be located along the northern portion of the Specific Plan area. The uses would include, but are not limited to a grocery store, drug store or convenience store; a bakery, deli, coffee shop, or café; a gas/service station; and a drycleaner, hair salon, health club, or similar neighborhood retail service. Smaller areas dedicated to public and commercial uses will be located in the southeast portion of the Specific Plan Area at State

Route 70 and Palermo Road.

Stringtown Mountain Specific Plan (Existing and Proposed Specific Plan)

The proposed Stringtown Mountain Specific Plan will determine the mix of uses that will occur in a 1,239-acre area located adjacent to and east of the existing adopted Stringtown

Mountain Specific Plan, which is 157 acres in size. The proposed Specific Plan will limit development to not more than 2,700 dwelling units of mixed residential types.

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Figure 4.63. Butte County Planning Areas- New Growth Areas

Source: Butte County 2030 General Plan Land Use Element

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4.3.2 Butte County Vulnerability to Specific Hazards

The Disaster Mitigation Act regulations require that the HMPC evaluate the risks associated with each of the hazards identified in the planning process. This section summarizes the possible impacts and quantifies, where data permits, the County‘s vulnerability to each of the hazards

identified as a priority hazard in Section 4.2.19 Natural Hazards Summary. Where specific

hazards vary across the County, additional information can be found in the jurisdictional annexes. The hazards evaluated further as part of this vulnerability assessment include:

Dam Failure

Drought and Water Shortage

Earthquake

Earth Movements: Erosion

Flood: 100/200/500-year

Flood: Localized/Stormwater

Hazardous Materials Transportation

Levee Failure

Severe Weather: Freeze

Severe Weather: Heavy Rain and Storms

Severe Weather: Windstorms

Wildfire

An estimate of the vulnerability of the County to each identified hazard, in addition to the estimate of risk of future occurrence, is provided in each of the hazard-specific sections that follow. Vulnerability is measured in general, qualitative terms and is a summary of the potential impact based on past occurrences, spatial extent, and damage and casualty potential. It is categorized into the following classifications:

Extremely Low—The occurrence and potential cost of damage to life and property is very minimal to nonexistent.

Low—Minimal potential impact. The occurrence and potential cost of damage to life and property is minimal.

Medium—Moderate potential impact. This ranking carries a moderate threat level to the general population and/or built environment. Here the potential damage is more isolated and less costly than a more widespread disaster.

High—Widespread potential impact. This ranking carries a high threat to the general population and/or built environment. The potential for damage is widespread. Hazards in this category may have occurred in the past.

Extremely High—Very widespread with catastrophic impact.

Vulnerability can be quantified in those instances where there is a known, identified hazard area, such as a mapped floodplain. In these instances, the numbers and types of buildings subject to

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the identified hazard can be counted and their values tabulated. Other information can be collected in regard to the hazard area, such as the location of critical community facilities (e.g., a fire station), historic structures, and valued natural resources (e.g., an identified wetland or endangered species habitat). Together, this information conveys the impact, or vulnerability, of that area to that hazard.

The HMPC identified five hazards in the planning area for which specific geographical hazard areas have been defined and for which sufficient data exists to support a quantifiable vulnerability analysis. These five hazards are dam failure, erosion, flood, levee failure, and wildfire. Because these hazards have discrete hazard risk areas, their risk varies by jurisdiction.

For dam failure, erosion, flood, levee failure, and wildfire, the HMPC inventoried the following for each community, to the extent possible, to quantify vulnerability in identified hazard areas:

General hazard-related impacts, including impacts to life, safety, and health

Values at risk (i.e., types, numbers, and value of land and improvements)

Populations at risk (i.e, those residing in the hazard area base on land use and residential occupancy)

Identification of critical facilities at risk

Identification of cultural and natural resources at risk

Development trends within the identified hazard area

For hazardous materials in the planning area, a quantifiable vulnerability analysis was performed on:

Populations at risk (i.e, those residing in the hazard area base on land use and residential occupancy)

The HMPC used FEMA‘s loss estimation software, HAZUS-MH, to analyze the County‘s vulnerability to earthquakes.

General hazard-related impacts, including impacts to life, safety, and health

Values at risk (i.e., types, numbers, and value of land and improvements)

Populations at risk (i.e, those residing in the hazard area base on land use and residential occupancy)

Identification of critical facilities at risk

As a subhazard of earthquake, a parcel hazard analysis was used to evaluate the County‘s vulnerability to liquefaction.

The vulnerability and potential impacts from priority hazards that do not have specific mapped areas nor the data to support additional vulnerability analysis are discussed in more general terms.

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4.3.3 Dam Failure Vulnerability Assessment

Likelihood of Future Occurrence—Unlikely

Vulnerability—High to Extremely High

Dam failure flooding can occur as the result of partial or complete collapse of an impoundment.

Dam failures often result from prolonged rainfall, flooding, or earthquake. The primary danger associated with dam failure is the high velocity flooding of those properties downstream of the dam. A dam failure can range from a small, uncontrolled release to a catastrophic failure.

Vulnerability to dam failures is confined to the areas subject to inundation downstream of the facility. Secondary losses would include loss of the multi-use functions of the facility or critical infrastructure and associated revenues that accompany those functions.

Dam failure flooding would vary by community depending on which dam fails and the nature and extent of the dam failure and associated flooding. Based on the risk assessment, it is apparent that a major dam failure could have a devastating impact on the planning area. Dam failure flooding presents a threat to life and property, including buildings, their contents, and their use (such as water treatment). Large flood events can affect crops and livestock as well as lifeline utilities (e.g., water, sewerage, and power), transportation, jobs, tourism, the environment, and the local and regional economies.

Methodology

The ability to conduct and inundation analysis on all high and significant dams of concern to

Butte County was limited by available GIS inundation layers. As a result, the inundation analysis was limited to the Oroville dam and related structures. Butte County provided inundation data as a GIS layer for the Oroville Dam.

Description of Facilities

Oroville Dam is a rockfill embankment dam on the Feather River east of the city of Oroville,

California in the United States. At 770 feet high, it is the tallest dam in the U.S. and serves mainly for water supply, hydroelectricity generation and flood control. The dam impounds Lake

Oroville, the second largest man-made lake in California with a capacity of more than 3.5 million acre-feet in the Sierra Nevada foothills east of the Sacramento Valley. Construction started in 1961, the towering main embankment was topped out in 1967, with the entire project ready to impound water in 1968.

Inundation Mapping

Butte‘s parcel and associated April 2012 assessor data was used as the basis for the countywide inventory of parcels and structure value. GIS was used to create a centroid, or point representing the center of the parcel polygon. The Oroville Dam Inundation data was then overlaid on the parcel centroids to determine how much value is at risk to a worst case scenario failure. The

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dam inundation layer can be seen on Figure 4.64. Figure 4.65 shows inundation areas from the

California Park Dam. This is shown for reference only, as the dam inundation layer was not available for analysis.

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Figure 4.64. Butte County Planning Area – Oroville Dam Inundation

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Figure 4.65. California Park Dam Inundation

Source: Dam Break Flood Inundation Study

– Pacific Hydrologic Inc.

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Values at Risk

Based on FEMA guidance, content values in the tables are based on percent values of the structure based on their property type. Using values consistent with HAZUS, property types of residential and others are calculated at 50%, agriculture and commercial are 100%, and industrial is 150% of their improved value to estimate content value. The other value field was not used to calculate the content estimation. Improved, other and contents values are summed to project a total loss estimate. Losses are related to a number of potential factors including inundation depth, velocity, and building type and construction. However, due to data limitations associated with this dam break scenario, combined with the potentially catastrophic nature of this event, potential losses are based on the total value (structure + other + contents) of affected improved

parcels. These are shown in Table 4.42 for the planning area and on Table 4.43 for the

unincorporated County.

Table 4.42. Butte County Planning Area - Parcel Count and Structure Value

Vulnerability to Oroville Dam Break Inundation

Jurisdiction

Biggs

Chico

Total

Parcels

759

24,931

Affected

Parcels

Affected

Improved

Value

620

-

$52,122,701

-

Affected

Other Value

$4,119,113

-

Affected

Content Value

Loss

Estimate

(20% of

Total)

$43,334,076

-

$19,915,178

-

% of

Affected

Parcels to Total

82%

-

Gridley

Oroville

2,451

5,970

Paradise 11,493

Unincorporated 47,675

2,120

3,930

-

5,884

$226,944,392

$604,092,938

-

$528,836,473

$7,525,285

$47,985,074

-

$80,516,145

$159,308,329

$529,149,984 $236,245,599

-

$78,755,601

-

$460,433,149 $213,957,153

Total 93,279 12,554 $1,411,996,504 $140,145,617 $1,192,225,537 $548,873,532

Source: Butte County GIS, Butte County 2012

Assessor’s Data

86%

66%

-

12%

13%

Table 4.43. Unincorporated County - Parcel Count and Structure Value Vulnerability to

Oroville Dam Break Inundation

Property

Type

Agriculture

Total

Parcels

5,264

Affected

Parcels

881

Affected

Improved

Value

$93,603,276

Affected

Other Value

$63,450,873

Affected

Content Value

$157,054,149

Total Affected

Loss Estimate

% of

Affected

Parcels to Total

$62,821,660 17%

Commercial

Industrial

Residential

Unclassified

874

297

39,640

1,600

134

46

4,821

2

$27,025,079

$49,104,997

$358,906,913

$196,208

$432,910

$14,395,774

$2,205,118

$31,470

$27,457,989

$95,251,157

$180,556,016

$113,839

$10,983,196

$31,750,386

$108,333,609

$68,303

Total 47,675 5,884 $528,836,473 $80,516,145 $460,433,149 $213,957,153

Source: Butte County GIS, Butte County 2012

Assessor’s Data

15%

15%

12%

0.1%

12%

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Population at Risk

GIS analysis was performed to determine population in the dam inundation area. Using GIS, the

Oroville Dam inundation zone was overlaid on the improved residential parcel data. Those parcel centroids that intersect the dam inundation area were counted and multiplied by the 2010

Census Bureau average household factors for each jurisdiction and unincorporated area.

According to this analysis, there is a total population of 27,574 in the Oroville Dam inundation zone. There are 11,811 people in the Unincorporated County and 8,375 in the City of Oroville at

risk to the Oroville Dam inundation zone. This is shown in Table 4.44.

Table 4.44. Butte County Planning Area - Population in the Oroville Dam Inundation

Area

Jurisdiction

Biggs

Gridley

Oroville

Residential Parcels

583

1,901

3,221

Unincorporated 4,821

Total 10,526

Source: Butte County GIS, US Census Bureau

Population

1,761

5,627

8,375

11,811

27,574

Critical Facilities at Risk

Dam inundation analysis was performed on the critical facility inventory in Butte County and all jurisdictions. GIS was used to determine whether the facility locations intersect a dam

inundation zone. Table 4.45 shows the total number of critical facilities at risk to dam failure in

the planning area. More detail on the individual jurisdictions may be found in their respective annexes. In the unincorporated County, there are 474 facilities in the dam inundation zone as

shown in Table 4.46. Details of critical facility definition, type, name and address and

jurisdiction within the inundation area are listed in Appendix E.

Table 4.45. Butte County Planning Area – Critical Facilities at Risk to Dam Failure

Jurisdiction

City of Biggs

City of Chico

City of Gridley

Facility Count

20

0

74

City of Oroville

Town of Paradise*

Unincorporated County

230

0

474

Total 798

Source: Butte County GIS

*A Paradise Irrigation District Water Treatment Plan is a critical facility, but was not included in the critical facility list for the

County, and was not mapped nor included in this tabular analysis.

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Table 4.46. Unincorporated Butte County – Critical Facilities at Risk to Dam Failure

Category

At Risk Population Facilities

Type

Residential Care / Elder

School

Infant Center

Family Day Care Home

Day Care Center

Adult Residential

Wastewater Treatment Plant*

17

5

6

1

Facility Count

6

4

1

Essential Services Facilities

Helipad

Fire Station

Bridge

Agriculture

7

3

355

1

Hazardous Materials Facilities

Natural Gas Storage

Agriculture

CUPA

1

1

66

Total 474

Source: Butte County GIS

*A Paradise Irrigation District Water Treatment Plan is a critical facility, but was not included in the critical facility list for the

County, and was not mapped nor included in this tabular analysis.

Cultural and Natural Resources at Risk

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. With a significant failure of the Oroville Dam, many of these resources are at risk. Vulnerability analysis of those specific resources at risk to dam failure was not possible due to data limitations.

Development Trends

Although new growth and development corridors would fall in the area flooded by a dam failure, given the small chance of total dam failure and the large area that a dam failure would affect, development in the dam inundation area will continue to occur.

4.3.4 Drought and Water Storage Vulnerability Assessment

Likelihood of Future Occurrence—Occasional

Vulnerability—Medium

Drought is different than many of the other natural hazards in that it is not a distinct event and usually has a slow onset. Drought can severely impact a region both physically and economically. Drought affects different sectors in different ways and with varying intensities.

Adequate water is the most critical issue for agricultural, manufacturing, tourism, recreation, and

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commercial and domestic use. As the population in the area continues to grow, so too will the demand for water.

Based on historical information, the occurrence of drought in California, including Butte County, is cyclical, driven by weather patterns. Drought has occurred in the past and will occur in the future. Periods of actual drought with adverse impacts can vary in duration, and the period between droughts is often extended. Although an area may be under an extended dry period, determining when it becomes a drought is based on impacts to individual water users. The vulnerability of Butte County to drought is countywide, but impacts may vary and include reduction in water supply, agricultural losses, and an increase in dry fuels.

Drought impacts are wide-reaching and may be economic, environmental, and/or societal.

Tracking drought impacts can be difficult. The Drought Impact Reporter from the NDMC is a

useful reference tool that compiles reported drought impacts nationwide. Figure 4.66 show

drought impacts for the Butte County Planning Area from 1850 to August 2012. The data represented is skewed, with the majority of these impacts from records within the past ten years.

Figure 4.66. Drought Impact Reporter for Butte County Planning Area (1850 to 2012)

Source: National Drought Mitigation Center

The most significant qualitative impacts associated with drought in the planning area are those related to water intensive activities such as agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. Mandatory conservation measures are typically implemented during extended droughts. A reduction of electric power generation and water quality deterioration are also potential problems. Drought conditions can also cause soil to compact and not absorb water well, potentially making an area more susceptible to flooding.

It is difficult to quantitatively assess drought impacts to Butte County because not many countyspecific studies have been conducted. Some factors to consider include: the impacts of fallowed agricultural land, habitat loss and associated effects on wildlife, and the drawdown of the groundwater table. The most direct and likely most difficult drought impact to quantify is to

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local economies, especially agricultural economies. The State has conducted some empirical studies on the economic effects of fallowed lands with regard to water purchased by the State‘s

Water Bank; but these studies do not quantitatively address the situation in Butte County. It can be assumed, however, that the loss of production in one sector of the economy would affect other sectors.

The drawdown of the groundwater table is one factor that has been recognized to occur during repeated dry years. Lowering of groundwater levels results in the need to deepen wells, which subsequently lead to increased pumping costs. These costs are a major consideration for residents relying on domestic wells and agricultural producers that irrigate with groundwater and/or use it for frost protection. Land subsidence can also occur when the groundwater table is depleted.

Development Trends

Population growth in the County will add additional pressure to water companies during periods of drought and water shortage. Water companies will need to continue to plan for and add infrastructure capacity for population growth.

4.3.5 Earthquake Vulnerability Assessment

Likelihood of Future Occurrence—Occasional

Vulnerability—Medium

Earthquake vulnerability is primarily based on population and the built environment. Urban areas in high seismic hazard zones are the most vulnerable, while uninhabited areas are less vulnerable.

Ground shaking is the primary earthquake hazard. Many factors affect the survivability of structures and systems from earthquake-caused ground motions. These factors include proximity to the fault, direction of rupture, epicenter location and depth, magnitude, local geologic and soils conditions, types and quality of construction, building configurations and heights, and comparable factors that relate to utility, transportation, and other network systems. Ground motions become structurally damaging when average peak accelerations reach 10 to 15 percent of gravity, average peak velocities reach 8 to 12 centimeters per second, and when the Modified

Mercalli Intensity Scale is about VII (18-34 percent peak ground acceleration), which is considered to be very strong (general alarm; walls crack; plaster falls).

Earthquake losses will vary across the Butte County Planning Area depending on the source and magnitude of the event. A map showing peak ground accelerations in Butte County is shown in

Figure 4.67. Based on this map, Butte County is located in a relatively low seismic area. The

earthquake scenario run for this 2012 Butte County LHMP provides a good estimate of loss to the planning area based on a realistic earthquake scenario. The methodology and results of this scenario are described below.

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Figure 4.67. Butte County Planning Area - Earthquake Shaking Map

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2012 Earthquake Scenarios

HAZUS-MH 2.1 was utilized to model earthquake losses for Butte County. Specifically, the probable magnitude used for Butte County utilized a 7.0 magnitude earthquake. Level 1 analyses were run, meaning that only the default data was used and not supplemented with local building inventory or hazard data. There are certain data limitations when using the default data, so the results should be interpreted accordingly; this is a planning level analysis.

The methodology for running the probabilistic earthquake scenario used probabilistic seismic hazard contour maps developed by the U.S. Geological Survey (USGS) for the 2002 update of the National Seismic Hazard Maps that are included with HAZUS-MH. The USGS maps provide estimates of potential ground acceleration and spectral acceleration at periods of 0.3 second and 1.0 second, respectively. The 2,500 year return period analyzes ground shaking estimates with a 2 percent probability of being exceeded in 50 years, from the various seismic sources in the area. The International Building Code uses this level of ground shaking for building design in seismic areas and is more of a worst case scenario.

The results of the probabilistic scenario are captured in Table 4.47. Key losses included the

following:

Total economic loss estimated for the earthquake was $2.1 billion, which includes building losses and lifeline losses based on the HAZUS-MH inventory.

Building-related losses, including direct building losses and business interruption losses, totaled $2.2 billion.

Over 33 percent of the buildings in the County were at least moderately damaged. 189 buildings were completely destroyed.

Over 52 percent of the building- and income-related losses were residential structures. 21 percent of the estimated losses were related to business interruptions.

The mid-day earthquake caused the most casualties: 70.

30 percent of the households experienced a loss of potable water the first day after the earthquake.

Table 4.47. Butte County Planning Area - HAZUS-MH 2,500-year Earthquake Scenario

Results

Impacts/Earthquake

Residential Buildings Damaged

(Based upon 83,000 buildings)

Building Related Loss

Total Economic Loss

7.0 Magnitude Earthquake

Slight: 18,902

Moderate: 8,757

Extensive: 1,245

Complete: 189

$2,061,170,000

$2,174,450,000

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.207

Impacts/Earthquake

Injuries

(Based upon 2am time of occurrence)

Injuries

(Based upon 2pm time of occurrence)

Injuries

(Based upon 5pm time of occurrence)

7.0 Magnitude Earthquake

Without requiring hospitalization: 527

Requiring hospitalization: 102

Life Threatening: 9

Fatalities: 17

Without requiring hospitalization: 872

Requiring hospitalization: 233

Life Threatening: 37

Fatalities: 70

Without requiring hospitalization: 680

Requiring hospitalization: 180

Life Threatening: 52

Fatalities: 51

Essential Facility Damage

(Based upon 134 buildings)

4 hospitals with at least moderate damage

Transportation and Utility Lifeline Damage Three bridges, one potable water, three waste water, one oil system, one electrical power and eleven communications facilities with at least moderate damage

Households w/out Power & Water Service

(Based upon 76,566 households)

Displaced Households

Power loss @ Day 1: 0

Power loss @ Day 3: 0

Power loss @ Day 7: 0

Power loss @ Day 30: 0

1,700

Water loss @ Day 1: 22,967

Water loss @ Day 3: 18,980

Water loss @ Day 7: 10,865

Water loss @ Day 30: 0

Shelter Requirements

Debris Generation

Source: HAZUS-MH 2.0

1,276

750,000 tons

Fires often occur after an earthquake. Because of the number of fires and the lack of water to fight the fires, they can often burn out of control. HAZUS uses a Monte Carlo simulation model to estimate the number of ignitions and the amount of burnt area. For this scenario, the model estimates that there will be no ignitions.

Figure 4.68 illustrates total loss within Butte County associated with the probabilistic earthquake

scenario shown in Table 4.47, while Figure 4.69 shows building losses for the probabilistic

earthquake scenario shown in Table 4.47.

4.208 Butte County

Local Hazard Mitigation Plan Update

May 2013

Figure 4.68. Butte County Planning Area - Earthquake 2,500-year Probabilistic Scenario

Total Losses

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.209

Figure 4.69. Butte County Planning Area - Earthquake 2,500-year Probabilistic Scenario

Building Losses

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.210

Liquefaction

Seismic hazards like earthquake induced liquefactions are an identified hazard of concern in

Butte County. The County has been mapped into three liquefaction potentials: generally high, generally moderate and generally low. Impacts from liquefaction primarily involve life safety concerns and damage to infrastructure, utility systems, and roads. Road closures can further impact emergency response and evacuation efforts and interrupt business and school activities.

Historically, liquefactions resulting in losses have not occurred within the County. Specific

problem areas are detailed in Figure 4.70. As Figure 4.70 illustrates, there is a higher risk to

liquefaction in the western portions of the county where the majority of the population is located.

Based on available hazard data, the potential for liquefactions to occur within the planning area exists.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.211

Figure 4.70. Butte County Planning Area - Liquefaction Potential Areas

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.212

Methodology

According to the layer provided by the Butte County Development Services there are liquefaction areas with a potential to impact the planning area. The County‘s parcel layer was used as the basis for the inventory of developed parcels. GIS was used to overlay the seismic liquefaction hazard layer with the parcel layer and where the seismic zones intersected a parcel centroid, it was assigned with that hazard zone for the entire parcel. For purposes of this analysis, it was assumed that every parcel with an improved value greater than zero was developed in some way.

Values at Risk

The liquefaction layer was overlaid with the county parcel layer in GIS to obtain results; it is

evident that Butte County has significant assets at risk to liquefaction. Table 4.48 illustrates the

estimated damages jurisdictions and unincorporated Butte County would sustain from an earthquake induced liquefaction event. The majority of risk falls into the generally moderate areas with Chico having the most parcels at 20,011 with 18,623 being improved parcels with an improved value of $3,563,689,600.

Table 4.48. Butte County Planning Area - Assets at Risk to Liquefaction

Zone/

Jurisdiction

Generally High

Total

Parcel

Count

Unincorporated

Total

296

296

Generally Moderate

Biggs 759

Improved

Parcel

Count

161

161

Chico

Gridley

Oroville

20,011

2,451

1,971

Unincorporated 15,291

Total 40,483

Improved Value

$31,247,502

$31,247,502

Improved

Other Value

$18,693,034

$18,693,034

Improved Land

Value

$75,724,913

$75,724,913

Total Value

$125,665,449

$125,665,449

620 $52,122,701 $4,119,113 $16,451,792 $72,693,606

18,623 $3,563,689,600 $52,499,516 $1,697,317,216 $5,313,506,332

2,120

1,423

$226,944,392

$239,800,014

$7,525,285

$37,005,255

$75,841,471

$82,099,974

$310,311,148

$358,905,243

12,413 $1,755,527,340 $205,831,230 $1,157,569,474 $3,118,928,044

35,199 $5,838,084,047 $306,980,399 $3,029,279,927 $9,174,344,373

Generally Low

Chico

Oroville

Paradise

4,920

3,999

11,493

Unincorporated 32,088

4,368

2,980

10,506

21,570

$889,960,696

$442,047,236

$1,251,863,720

$1,997,363,625

$6,419,372

$11,511,039

$13,280,480

$14,568,036

$445,685,828

$117,552,225

$606,285,862

$1,032,304,721

$1,342,065,896

$571,110,500

$1,871,430,062

$3,044,236,382

Total 52,500 39,424 $4,581,235,277 $45,778,927 $2,201,828,636 $6,828,842,840

Grand Total 93,279 74,784 $10,450,566,826 $371,452,360 $5,306,833,476 $16,128,852,662

Source: Butte County Development Services, Butte County 2012 Assessor

’s Data

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.213

Table 4.49. Unincorporated Butte County - Assets at Risk to Liquefaction

Zone/

Jurisdiction

Generally High

Property

Type

Agriculture

Commercial

Unincorporated

County

Industrial

Residential

Unclassified

Total

Generally Moderate

Total

Parcel

Count

Improved

Parcel

Count Improved Value

Improved

Other Value

Improved

Land Value

235

4

4

26

27

296

141

3

3

13

1

161

Total Value

$28,161,503 $17,768,927 $73,956,923 $119,887,353

$115,951

$1,526,280

$1,322,603

$0

$747,780

$0

$39,717

$261,682

$1,330,660

$155,668

$2,535,742

$2,653,263

$121,165 $176,327 $135,931 $433,423

$31,247,502 $18,693,034 $75,724,913 $125,665,449

Agriculture 3,229

Commercial

Unincorporated

County

Industrial

392

238

Residential 10,904

Unclassified 528

2,105

292

$255,878,476 $175,957,876

$89,840,240 $2,932,041

$441,176,417

$35,858,103

$873,012,769

$128,630,384

194 $118,166,172 $21,610,504 $22,990,229 $162,766,905

9,813 $1,291,009,201 $5,299,339 $657,202,756 $1,953,511,296

9 $633,251 $31,470 $341,969 $1,006,690

Total 15,291

Generally Low

Agriculture 1,800

12,413 $1,755,527,340 $205,831,230 $1,157,569,474 $3,118,928,044

Unincorporated

County

Commercial

Industrial

Residential 28,710

Unclassified

478

55

1,045

350

326

34

$31,978,246

$97,754,879

20,855 $1,852,106,264

5 $373,256

$5,259,752

$7,259,432

$15,150,980 $1,268,210

$780,642

$0

$39,199,610

$40,094,870

$6,595,509

$946,210,046

$204,686

$76,437,608

$145,109,181

$23,014,699

$2,799,096,952

$577,942

Total 32,088 21,570 $1,997,363,625 $14,568,036 $1,032,304,721 $3,044,236,382

Source: Butte County Development Services, Butte County 2012

Assessor’s Data

Populations at Risk

Seismic induced liquefaction risk is greatest to those individuals residing in identified liquefaction hazard areas. GIS analysis was performed to determine population in the liquefaction zones. Using GIS, the Butte County Liquefaction layer was overlaid on the improved residential parcel data. Those parcel centroids that intersect the liquefaction zones were counted and multiplied by the 2010 Census Bureau average household factors for each

jurisdiction and unincorporated area. Results were tabulated by jurisdiction (see Table 4.50).

According to this analysis, there is a total population of 32 in the generally high zone but 74,074 in moderate areas of liquefaction. There are 24,042 people in the unincorporated County and

40,393 in the City of Chico at risk to the moderate liquefaction areas.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.214

Table 4.50. Butte County Planning Area - Population at Risk to Liquefaction

Zone/Jurisdiction

Generally High

Unincorporated County

Total Generally High

Generally Moderate

Biggs

Chico

Gridley

Oroville

Unincorporated County

Total Generally Moderate

Generally Low

Chico

Oroville

Paradise

Unincorporated County

Total Generally Low

Grand Total

Source: Butte County GIS, US Census Bureau

Improved Residential Parcels

13

13

583

16,972

1,901

866

9,813

30,135

4,092

2,810

9,884

20,855

37,641

67,789

Critical Facilities at Risk

Population

2,252

24,042

74,074

9,739

7,306

21,448

32

32

1,761

40,393

5,627

51,095

89,588

163,694

Liquefaction analysis was performed on the critical facility inventory in Butte County and all jurisdictions. GIS was used to determine whether the facility locations intersect a liquefaction hazard area provided by Butte County Development Services, and if so, which zone it intersects.

Table 4.51 shows the total number of critical facilities at risk to liquefaction in the planning area.

More detail on the individual jurisdictions may be found in their respective annexes. In the unincorporated County, there are 60 facilities in the generally high liquefaction zone, 788 facilities in the generally moderate zone, and 491 facilities in the generally low zone, as shown in

Table 4.52. Details of critical facility definition, type, name and address and jurisdiction by

liquefaction zone are listed in Appendix E.

Table 4.51. Butte County Planning Area – Critical Facilities at Risk to Liquefaction

Jurisdiction

City of Biggs

City of Chico

City of Gridley

City of Oroville

Town of Paradise

Facility Count

20

758

74

242

209

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.215

Jurisdiction

Unincorporated County

Total

Source: Butte County GIS

Facility Count

1,339

2,642

Table 4.52. Unincorporated Butte County – Critical Facilities at Risk to Liquefaction

Erosion

Generally High

Generally Moderate

Generally Low

Category

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Type

Bridge

Fire Station

CUPA

Natural Gas Storage

Total

Adult Residential

Day Care Center

Family Day Care Home

Group Home

Infant Center

Residential Care / Elder

School

School-Age Day Care

Small Family Home

Agriculture

Airport

3

9

1

1

1

1

Bridge

Fire Station

526

8

Helipad 10

Wastewater Treatment Plant 1

Agriculture

CUPA

Total

1

177

788

1

60

3

11

Facility Count

54

1

4

32

2

1

Adult Residential

Day Care Center

Family Day Care Home

Infant Center

Residential Care / Elder

School

Small Family Home

Airport

Bridge

Fire Station

9

8

33

1

8

20

1

1

247

26

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.216

Erosion

Grand Total

Source: Butte County GIS

Category

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Type

Helipad

Law Enforcement

CUPA

Total

Facility Count

32

1

104

491

1,339

Cultural and Natural Resources at Risk

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. With a significant earthquake, many of these resources are at risk. Vulnerability analysis of those specific resources at risk to liquefaction was not possible due to data limitations.

Development Trends

Although new growth and development corridors would fall in the area affected by earthquake, given the small chance of major earthquake and the building codes in effect, development in the earthquake area will continue to occur.

4.3.6 Earth Movements: Erosion

Likelihood of Future Occurrence—Highly Likely

Vulnerability—Medium

Erosion is the general process whereby rocks and soils are broken down, removed by weathering, or fragmented and then deposited in other places by water or air. The rate of erosion depends on many variables, including the soil or rock texture and composition, soil permeability, slope, extent of vegetative cover, and precipitation amounts and patterns. Erosion increases with increasing slope and precipitation and with decreasing vegetative cover, which includes areas where protective vegetation has been removed by fire, construction, or cultivation. Butte County is traversed by many waterways, both large and small. These locations are all subject to bank erosion. Certain developed areas that abut creeks and rivers in the County are at risk to continued bank erosion. Levees are at risk to erosion as well, due to the channelization due to narrow river channels. Significant erosion can cause degradation and loss of agricultural land,

degradation of streams and other water habitats, and rapid silting of reservoirs. As Figure 4.71

illustrates, there is a higher risk to erosion in the eastern portions of the county. Based on available hazard data, the potential for erosion to occur within the planning area exists and given the size of the areas at risk, the vulnerability of the County is medium.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.217

Figure 4.71. Butte County Planning Area - Erosion Potential

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.218

Methodology

According to the layer provided by the Butte County Development Services there are erosion hazards with a potential to impact the planning area. The County‘s parcel layer was used as the basis for the inventory of developed parcels. GIS was used to overlay the erosion hazard layer with the parcel layer and where the erosion zones intersected a parcel centroid, it was assigned with that hazard zone for the entire parcel.

Values at Risk

The erosion layer was overlaid with the county parcel layer and assessor data in GIS to obtain

results; it is evident that Butte County has significant assets at risk to erosion. Table 4.53

illustrates the estimated damages jurisdictions and unincorporated Butte County would sustain from conditions that can lead to erosion. The majority of risk falls into the moderate areas with

Oroville having the most parcels at 3,338 with 2,485 being improved parcels with an improved

value of $364,513,849. Table 4.54 shows the risk to the unincorporated Butte County broken out

by land use type.

Table 4.53. Butte County Planning Area - Assets At Risk To Erosion

Total

Parcel

Count Jurisdiction

Very High

Unincorporated 4,770

Total

High

Chico

Oroville

4,770

1,482

840

Paradise 1,071

Unincorporated 10,746

Total

Moderate

14,139

Oroville 3,338

Unincorporated 11,071

Total 16,164

Slight

Chico

Gridley

Oroville

8,750

108

1,002

Paradise 10,422

Unincorporated 10,438

Total 30,720

8,172

77

779

9,625

8,908

27,561

881

6,726

9,457

2,485

7,811

11,944

Improved

Parcel

Count

2,190

2,190

1,218

632

Improved Value

$152,409,204

$152,409,204

$290,414,215

$83,395,912

Improved

Other Value

$136,874

$136,874

$385,000

$426,210

Improved Land

Value Total Value

$100,596,618 $253,142,696

$100,596,618 $253,142,696

$139,509,426 $430,308,641

$23,923,514 $107,745,636

$162,020,436

$813,362,611

$6,758,334

$2,573,403

$57,514,152 $226,292,922

$411,564,911 $1,227,500,925

$1,349,193,174 $10,142,947 $632,512,003 $1,991,848,124

$364,513,849 $11,201,449 $95,608,218 $471,323,516

$543,545,315 $9,332,001 $300,590,361 $853,467,677

$1,142,999,953 $22,061,624 $537,557,998 $1,702,619,575

$1,613,897,862 $13,677,562 $779,262,193 $2,406,837,617

$15,680,821

$111,125,278

$35,892

$9,562,994

$6,219,941

$26,239,976

$21,936,654

$146,928,248

$1,089,843,284 $6,522,146 $548,771,710 $1,645,137,140

$1,013,930,260 $62,524,522 $588,648,797 $1,665,103,579

$3,844,477,505 $92,323,116 $1,949,142,617 $5,885,943,238

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.219

Jurisdiction

None

Biggs

Chico

Gridley

Total

Parcel

Count

759

12,944

2,343

Improved

Parcel

Count

620

11,953

2,043

Improved Value

$52,122,701

Improved

Other Value

$4,119,113

Improved Land

Value

$16,451,792

Total Value

$72,693,606

$2,314,397,430 $43,328,152 $1,082,872,006 $3,440,597,588

$211,263,571 $7,489,393 $69,621,530 $288,374,494

Oroville 790

Unincorporated 10,650

507

8,509

$122,812,211 $27,325,641 $53,880,491 $204,018,343

$1,260,891,077 $164,525,500 $864,198,421 $2,289,614,998

Total 27,486 23,632 $3,961,486,990 $246,787,799 $2,087,024,240 $6,295,299,029

Grand Total 93,279 74,784 $10,450,566,826 $371,452,360 $5,306,833,476 $16,128,852,662

Source: Butte County Development Services, Butte County 2012

Assessor’s Data

Table 4.54. Unincorporated Butte County - Assets At Risk To Erosion

Jurisdiction

Very High

Property

Type

Total

Parcel

Count

Unincorporated Agriculture 318

Improved

Parcel

Count

29

Improved

Value

$2,851,832

Unincorporated Commercial 22

Unincorporated Industrial 2

15

0

$7,157,507

$0

Unincorporated Residential 4,202 2,145

Unincorporated Unclassified 226 1

High

Total 4,770 2,190

Unincorporated Agriculture 750

Unincorporated Commercial 105

Unincorporated Industrial 5

135

79

4

$142,348,666

$51,199

Improved

Other Value

$6,730

$76,660

$0

$53,484

$0

$152,409,204 $136,874

$13,820,374

$37,475,998

$261,591

$531,961

Improved

Land Value Total Value

$2,563,296

$1,637,709

$0

$96,293,516

$102,097

$5,421,858

$8,871,876

$0

$238,695,666

$153,296

$100,596,618 $253,142,696

$14,721,071 $29,073,406

$1,716,163 $20,933,149 $60,125,310

$0 $1,001,225 $1,262,816

Unincorporated Residential 9,502 6,504

Unincorporated Unclassified 384 4

Moderate

Total 10,746 6,726

Unincorporated Agriculture 781

Unincorporated Commercial 229

Unincorporated Industrial 31

246

172

16

$761,478,381 $325,279

$326,267

$20,149,293

$39,649,893

$2,251,497

$0

$7,345,928

$556,090

$984,810

$374,795,266 $1,136,598,926

$114,200

$813,362,611 $2,573,403 $411,564,911 $1,227,500,925

$39,646,330

$12,411,157

$1,859,463

$440,467

$67,141,551

$52,617,140

$5,095,770

Unincorporated Residential 9,639 7,373

Unincorporated Unclassified 391 4

Slight

Total 11,071 7,811

Unincorporated Agriculture 778

Unincorporated Commercial 275

554

177

$481,345,817 $445,173

$148,815 $0

$246,651,692 $728,442,682

$21,719 $170,534

$543,545,315 $9,332,001 $300,590,361 $853,467,677

$79,850,678

$49,306,849

$53,301,904 $142,506,374 $275,658,956

$6,339,832 $19,854,093 $75,500,774

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.220

Jurisdiction

Property

Type

Unincorporated Industrial

Total

Parcel

Count

100

Improved

Parcel

Count

92

Unincorporated Residential 9,078 8,083

Improved

Value

$35,720,346

$848,811,258

Improved

Other Value

$1,369,810

$1,336,649

Improved

Land Value

$10,481,614

Total Value

$47,571,770

$415,610,805 $1,265,758,712

Unincorporated Unclassified 207

Total

2

10,438 8,908

$241,129 $176,327 $195,911 $613,367

$1,013,930,260 $62,524,522 $588,648,797 $1,665,103,579

None

Unincorporated Agriculture 2,637 1,632

Unincorporated Commercial 243

Unincorporated Industrial 159

178

119

$54,120,823

$96,609,998

$199,346,048 $137,800,032 $354,895,879 $692,041,959

$1,502,728

$21,271,874

$21,156,582

$16,505,118

$76,780,133

$134,386,990

Unincorporated Residential 7,219 6,576

Unincorporated Unclassified 392 4

$910,453,946

$360,262

$3,919,396

$31,470

$471,392,183 $1,385,765,525

$248,659 $640,391

Total 10,650 8,509 $1,260,891,077 $164,525,500 $864,198,421 $2,289,614,998

Source: Butte County Development Services, Butte County 2012

Assessor’s Data

Populations at Risk

Erosion risk is greatest to those individuals residing in properties in identified erosion hazard areas. Risk to population from erosion is generally low, as the property is generally at risk while those in the property are not. GIS analysis was performed to determine population in the erosion zones. Using GIS, the Butte County Erosion layer was overlaid on the improved residential parcel data. Those parcel centroids that intersect the erosion zones were counted and multiplied by the 2010 Census Bureau average household factors for each jurisdiction and unincorporated

area (see Table 4.55).

Table 4.55. Butte County Planning Area Population at Risk to Erosion

Jurisdiction

Unincorporated County

Biggs

Chico

Improved Residential Parcels

30,681

583

21,064

Gridley

Oroville

1,901

3,676

Paradise 9,884

Total 67,789

Source: Butte County Development Services, US Census Bureau

Critical Facilities at Risk

Population

75,168

1,761

50,132

5,627

9,558

21,448

163,694

Erosion analysis was performed on the critical facility inventory in Butte County and all jurisdictions. GIS was used to determine whether the facility locations intersect an erosion hazard areas provided by Butte County Development Services, and if so, which zone it intersects. There 1,445 facilities in the planning area at risk in the erosion zones, as shown in

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.221

Table 4.56. More details on the individual jurisdictions may be found in their respective

annexes. In the unincorporated County, there are 51 facilities in the very high risk, 215 facilities in the high risk, 230 in the moderate risk, and 256 in the slight erosion risk categories. This is

shown in Table 4.57. Details of critical facility definition, type, name and address and

jurisdiction by erosion zone are listed in Appendix E.

Table 4.56. Butte County Planning Area – Critical Facilities at Risk from Erosion

Jurisdiction

City of Biggs

City of Chico

City of Gridley

City of Oroville

Town of Paradise

Unincorporated County

Total

Source: Butte County GIS

Facility Count

-

317

10

157

209

752

1,445

Table 4.57. Unincorporated County – Critical Facilities at Risk from Erosion

Erosion

Very High

High

Category

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Type

Day Care Center

School

Bridge

Fire Station

Helipad

CUPA

Total

Adult Residential

Day Care Center

Family Day Care Home

Infant Center

Residential Care / Elder

School

Small Family Home

Airport

Bridge

Fire Station

Helipad

CUPA

Total

3

1

8

1

2

6

2

1

132

10

14

35

215

3

8

1

51

Facility Count

1

2

36

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.222

Erosion

Moderate

Slight

Source: Butte County GIS

Category

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Cultural and Natural Resources at Risk

Type

Adult Residential

Day Care Center

Family Day Care Home

Residential Care / Elder

School

Bridge

Fire Station

Helipad

CUPA

Total

Adult Residential

Day Care Center

Family Day Care Home

School

Airport

Bridge

Fire Station

Helipad

Law Enforcement

CUPA

Total

Grand Total

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. Risk analysis of these resources from the affects of erosion was not possible due to data limitations.

Development Trends

Planned developments should take erosion risk areas into account during the construction of new homes and commercial properties. The County will continue to enforce the zoning, subdivision,

and grading ordinances that are discussed in Section 4.4.1.

9

7

1

89

2

4

12

6

1

125

256

752

Facility Count

5

7

20

6

8

127

10

7

40

230

4.223 Butte County

Local Hazard Mitigation Plan Update

May 2013

4.3.7 Flood: 100/200/500-year Vulnerability Assessment

Likelihood of Future Occurrence—Occasional

Vulnerability—High to Extremely High

Historically, Butte County has always been vulnerable to flooding because of its relatively flat terrain in populated areas and the number of water courses that traverse the County. Flood zones in Butte County are quite extensive. High water levels are a common occurrence in winter and spring months due to increased flow from stormwater runoff and snowmelt. Several areas of the

County are subject to flooding by the overtopping of rivers and creeks, levee failures, and the failure of urban drainage systems that cannot accommodate large volumes of water during severe rainstorms.

In addition to the major rivers, there are many streams, channels, canals, and creeks that serve the drainage needs of the County. There is significant threat of flooding in large areas of the county from several of these streams. Many of these streams are prone to rapid flooding with little notice.

Flooding has been frequent in the Butte County Planning Area and the vulnerability to flood damages is high to extremely high. This section quantifies the vulnerability of the planning area to floods. For the purposes of this plan, the watershed delineation set forth by the Butte County

Department of Water and Resource Conservation is used (shown in Figure 4.38).

Methodology

Unincorporated Butte County and its incorporated jurisdictions have mapped FEMA flood hazard areas. GIS was used to determine the possible impacts of flooding within the County and how the risk varies across the planning area by watershed and jurisdiction. The following methodology was followed in determining improved parcel counts and values at risk to the 1% and 0.2% annual chance flood events.

Butte‘s parcel and associated April 2012 assessor data was used as the basis for the countywide inventory of developed parcels, acres, and structure value. The FEMA DFIRM, effective date

January 6, 2011, was used as the flood hazard layer for this analysis.

GIS was used to create a centroid, or point representing the center of the parcel polygon.

DFIRM flood data was then overlaid on the parcel layer. For the purposes of this analysis, the flood zone that intersected a parcel centroid was assigned the flood zone for the entire parcel.

The model assumes that every parcel with a structure value greater than zero is improved in some way. Specifically, an improved parcel assumes there is a building on it. This approach was used to support the parcel layer analysis as there was no associated building layer available for this analysis. Once completed the parcel boundary layer was joined to the centroid layer and values were transferred based on APN. In addition to the centroid analysis, parcel boundary

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.224

analysis was performed to get total acres and flooded acres by flood zone for each parcel. The parcel layer was intersected with the FEMA DFIRM to obtain the acres flooded.

It is important to note that there could be more than one structure or building on an improved parcel (i.e. condo complex occupies one parcel but might have several structures). Only improved parcels and the value of their improvements were analyzed. The end result is an inventory of the number and types of parcels and buildings subject to the flood hazard. Results are presented by the Butte County Planning Area, unincorporated county and incorporated jurisdictions. Detailed tables show counts of parcels by watershed and land use type

(Agriculture, Commercial, Industrial, Residential and Unclassified) within each flood zone.

Each of the flood zones that begins with the letter ‗A‘ depict the Special Flood Hazard Area, or

the 1% annual chance flood event (commonly referred to as the 100-year flood). Table 4.58

explains the difference between mapped flood zones. These zones are shown on Figure 4.72.

Table 4.58. Butte County Planning Area - Flood Hazard Zones

Flood Zone Description

1% Annual Chance 100-year Flood: Also known as the base flood, is the flood that has a 1% chance of being equaled or exceeded in any given year.

A

AE

AH

AO

100-year Flood: No base flood elevations provided

100-year Flood: Base flood elevations provided

100-year Flood: Shallow flooding, base flood depths provided

100-year Flood: Sheet flow areas, base flood depths provided

0.2% Annual Chance 500-year Flood: Areas protected by levees from 1% annual chance

X

Source: FEMA

No flood hazard

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.225

Figure 4.72. Butte County Planning Area - DFIRM Flood Zones

Butte County

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May 2013

4.226

It is important to note, that Table 4.58 includes a 0.2% annual chance flood zone that includes

both the 500-year flood as well as areas protected by levees from a 1% annual chance. The paper FIRM panels (dated the same as the new DFIRMs) show areas as provisionally and fully accredited from surrounding levees. However, this information is not captured in the GIS data; there is no corresponding levee protected attribute in the DFIRM database used for this analysis.

Therefore, please refer to Section 4.3.10 of this plan for the levee analysis that provides

additional information on areas, parcels and values associated with accredited and provisionally accredited levees that were in effect on January 6, 2011, when the new regulatory DFIRMs and

FIRMs were issued in final form for Butte County.

Values at Risk

Analysis on values at risk to the County is split into two portions:

Butte County Planning Area

Unincorporated Butte County

The Butte County Planning Area includes both the unincorporated County and each jurisdiction, essentially the entire geographical area of Butte County. Summary tables for the planning area are presented in the next section. Detail tables for each jurisdiction are shown in each jurisdiction‘s annex to this plan. For the unincorporated County, both summary and detail tables are shown and discussed below.

Butte County Planning Area

Improved Area at Risk and Improved Values by Flood Event in the Planning Area

Analysis was done for each watershed in the Butte County Planning Area grouped by 1% and

0.2% annual chance flood zone and showing total improved acres as well as flooded acres for

each category. These are shown in Table 4.59. It is to be noted that for this analysis that the

improved values and the other values were summed together and are all represented in the improved value column to simplify the tables. Greater detail for each jurisdiction is shown in their respective annex.

In addition to the information in Table 4.59, the Sacramento River Reclamation District pointed

out that there are values associated with resources other than the improved parcels in the County.

Values within the Sacramento River Reclamation District of trees with a lifespan of 20-35 years and the annual crop production from those trees is probably equally valuable to the commercial, industrial, residential properties through Pine

Creek.

Butte County

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4.227

While AMEC could not calculate the value of trees and annual crop production for the entire

County, it should be noted that there is substantial economic risk to the County from flood that aren‘t captured in the tables below.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.228

Table 4.59. Butte County Planning Area – All Watersheds – Improved Area at Risk and Value of Improved Parcels by Flood Event

Jurisdiction 1% Annual Chance

Total

Improved

Acres

Improved

Flooded

Acres

Improved

Parcel

Count

Improved

Value

0.2% Annual Chance* Zone X

Total

Improved

Acres

Improved

Flooded

Acres

Improved

Parcel

Count

Improved Value Total

Improved

Acres

Improved

Flooded

Acres

Improved

Parcel

Count

Improved Value

Biggs

Chico

Gridley

Oroville

-

289

-

39

-

246

-

29

-

928

-

45

-

$177,853,926

-

$16,557,924

186

2,327

1,042

306

186

2,276

1,042

277

620

7,905

4,021

783

$56,241,814

$1,165,930,562

$400,643,697

$93,860,157

-

5,205

-

3,582

-

0

-

0

-

14,158

-

7,253

-

$3,168,784,696

-

$978,991,098

Paradise

Unincorporated

-

91,736

-

77,243

-

3,041

-

$529,067,324

-

26,411

-

23,346

-

2,629

-

$347,964,412

8,325

206,744

0

0

10,506

28,474

$1,265,144,200

$3,146,199,031

Total 92,064 77,518 4,014 $723,479,174 30,272 27,126 15,958 $2,064,640,642 223,855 0 60,391 $8,559,119,025

Source: Butte County 2012

Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

4.229 Butte County

Local Hazard Mitigation Plan Update

May 2013

Loss Estimates for Improved Parcels by Watershed by Flood Event in the Planning Area

Table 4.60 shows Butte County Planning Area loss estimates for improved parcels by watershed

and shows improved values at risk by FEMA 1% and 0.2% annual chance flood zones. Contents values were estimated as a percentage of building value based on their land use, using

FEMA/HAZUS estimated content replacement values. This includes 100% of the structure value for agricultural and commercial structures, 50% for residential and unclassified structures, and 150% for industrial land use classifications. Based on FEMA guidance, 20 percent damage factor was applied to each flood zone‘s total value of improvements and estimated content to obtain an overall loss estimate. Big Chico Creek Watershed has the largest loss estimate of $403 million with Feather River/Lower Honcut Creek Watershed having a loss estimate of $244 million. For both of these watersheds the majority of loss comes from the 0.2% annual chance flood zone. Greater detail for each jurisdiction is shown in their respective annex.

Table 4.60. Butte County Planning Area 1% and 0.2% Annual Chance* Flood Loss by

Watershed

Watershed/Flood Zone

Improved

Parcel

Count

Big Chico Creek Watershed

Improved Value

1% Annual Chance

0.2% Annual Chance

384

8,006

$76,882,282

$1,193,308,042

Estimated

Content Value Total Value

$54,305,105

$689,253,171

$131,187,387

$1,882,561,213

Loss Estimate

(20% of Total)

$26,237,477

$376,512,243

$743,558,276 $2,013,748,600 $402,749,720 Total

Butte Creek Watershed

1% Annual Chance

0.2% Annual Chance

Total

8,390

1,190

-

1,190

$1,270,190,324

$233,727,380

-

$233,727,380

Dry Creek/Cherokee Canal Watershed

1% Annual Chance

0.2% Annual Chance

Total

92

681

773

$14,752,849

$78,951,153

$93,704,002

Feather River/Lower Honcut Creek Watershed

1% Annual Chance 751 $98,009,994

$233,727,380

-

$233,727,380

$14,752,849

$78,951,153

$93,704,002

$467,454,760

-

$467,454,760

$29,505,698

$157,902,306

$187,408,004

$93,490,952

-

$93,490,952

$5,901,140

$31,580,461

$37,481,601

$98,009,994 $196,019,988

$511,674,750 $1,023,349,500

$609,684,744 $1,219,369,488

$39,203,998

$204,669,900

$243,873,898

0.2% Annual Chance

Total

4,308

5,059

$511,674,750

$609,684,744

Lake Oroville/Upper Feather River Watershed

1% Annual Chance 8 $464,044

0.2% Annual Chance

Total

-

8

-

$464,044

$464,044

-

$464,044

$928,088

-

$928,088

$185,618

-

$185,618

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.230

Watershed/Flood Zone

Improved

Parcel

Count

Little Chico Creek Watershed

Improved Value

1% Annual Chance

0.2% Annual Chance

Total

1,487

722

2,209

$265,617,803

$88,916,079

$354,533,882

Estimated

Content Value

$265,617,803

$88,916,079

$354,533,882

Total Value

$531,235,606

$177,832,158

$709,067,764

Loss Estimate

(20% of Total)

$106,247,121

$35,566,432

$141,813,553

Pine Watershed

1% Annual Chance

0.2% Annual Chance

90

-

$30,021,523

-

$30,021,523

-

$60,043,046

-

$12,008,609

-

Total 90 $30,021,523 $30,021,523 $60,043,046 $12,008,609

Source: Butte County 2012

Assessor’s Data; Butte County DFIRM, January 2011

Contents replacement value is estimated as a percent of structure replacement value: Agriculture

– 100%; Commercial – 100%;

Industrial

– 150%; Residential – 50%; Unclassified – 50%

For this table the improved values and other values have been combined are represented in improved value totaled together.

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Unincorporated Butte County

Area at Risk and Improved Values by Flood Zone in the Unincorporated County

Additional analysis was done by land use for all watersheds in the unincorporated County grouped by 1% and 0.2% annual chance flood zone and showing total improved acres as well as flooded acres for each category. These, as well as those properties outside the flood zones (Zone

X) are shown in Table 4.61. Within all watersheds agriculture has the most acres in the 1%

annual chance flood zone; however the most value is represented by residential properties. It is to be noted that for this analysis the improved values and the other values were summed together and are all represented in the improved value column to simplify the tables.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.231

Table 4.61. Unincorporated County - All Watersheds – Improved Area at Risk and Value of Improved Parcels by Flood Event

Land Use

Agriculture

Commercial

Industrial

Residential

Total

Improved

Acres

84,552

462

314

6,303

1% Annual Chance

Improved

Flooded

Acres

71,228

382

274

5,254

Improved

Parcel

Count

862 $189,984,776

53

43

Improved

Value

$17,319,307

$46,751,303

2,081 $274,706,647

Total

Improved

Acres

21,854

103

120

4,333

0.2% Annual Chance*

Improved

Flooded

Acres

19,020

101

120

4,105

Improved

Parcel

Count

466

37

21

2,105

Improved

Value

$70,650,132

$12,899,543

$21,093,538

$243,321,199

Total

Improved

Acres

104,411

3,135

765

98,329

Improved

Flooded

Acres

Zone X

0

0

0

0

Improved

Parcel

Count

1,268

531

167

Improved

Value

$254,369,872

$167,683,693

$90,625,085

26,495 $2,632,490,203

Unclassified 106 106 2 $305,291 0 0 0 $0 104 0 13 $1,030,178

Total

91,736 77,243 3,041 $529,067,324 26,411 23,346 2,629 $347,964,412 206,744 0 28,474 $3,146,199,031

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

4.232 Butte County

Local Hazard Mitigation Plan Update

May 2013

Tables 4.62 through 4.68 contain flood analysis results by watershed for the unincorporated

County. These tables show the number of parcels and values at risk to the 1% annual chance and

0.2% annual chance flood events by watershed. Table 4.69 summarizes flood risk to the

unincorporated County from all watersheds.

Table 4.62. Unincorporated County - Big Chico Creek Watershed - Count and Structure

Value of Improved Parcels by Land Use in Detailed Floodplain Zones

Flood Zone Land Use

Agriculture

Zone A

Commercial

Industrial

Improved

Total Acres

Improved

Flooded

Acres

6,041

3

5,667

2

Improved

Parcel

Count

Improved

Value

Improved

Other Value Total Value

103 $13,455,969 $15,415,615 $28,871,584

2 $297,388 $0 $297,388

Residential

Total

Zone AE

Total

Residential

Agriculture

0.2% Annual

Chance*

Commercial

Industrial

Residential

Total

Agriculture

Commercial

13

945

7,002

5

5

779

36

7

687

1,509

17,252

708

13

802

6,484

2

2

173

35

7

544

760

0

0

2 $150,714

234 $40,803,722

$535,760 $686,474

$144,917 $40,948,639

341 $54,707,793 $16,096,292 $70,804,085

4

4

15

16

$417,236

$417,236

$1,329,644

$7,587,542

4 $1,212,322

777 $100,964,475

812 $111,093,983

262

91

$0

$0

$1,723,054

$420,920

$417,236

$417,236

$3,052,698

$8,008,462

$0 $1,212,322

$72,187 $101,036,662

$2,216,161 $113,310,144

$41,739,471 $26,203,426 $67,942,897

$40,603,634 $3,777,865 $44,381,499

Zone X Industrial

Residential

Unclassified

144

12,724

0

0

0

0

89

1

$30,545,967

3,335 $595,685,814

$119,964

$1,411,000 $31,956,967

$716,042 $596,401,856

$0 $119,964

Total 30,829 0 3,778 $708,694,850 $32,108,333 $740,803,183

Grand Total 39,345 7,247 4,935 $874,913,862 $50,420,786 $925,334,648

Source: Butte County 2012

Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

4.233 Butte County

Local Hazard Mitigation Plan Update

May 2013

Table 4.63. Unincorporated County - Butte Creek Watershed - Count and Structure

Value of Improved Parcels by Land Use in Detailed Floodplain Zones

Flood

Zone

Zone A

Total

Land Use

Agriculture

Commercial

Industrial

Residential

Improved

Total Acres

Improved

Flooded

Acres

9,682

2

8,589

2

Improved

Parcel

Count

62

1

Improved

Value

$5,234,786

$560,830

Improved

Other Value Total Value

$31,370

$0

$5,266,156

$560,830

51

524

10,258

50

451

9,092

12

100

$16,718,043

$11,303,704

$8,481,690

$0

$25,199,733

$11,303,704

175 $33,817,363 $8,513,060 $42,330,423

Zone AE

Total

Zone AO

Agriculture

Commercial

Industrial

Residential

Unclassified

Agriculture

Residential

14,513

154

51

1,677

3

16,397

1,984

329

2,313

9,893

151

26

1,563

3

11,636

1,414

324

1,739

192 $26,289,660 $16,515,223 $42,804,883

6 $4,080,446 $635,970 $4,716,416

4 $4,203,644 $1,257,910

663 $115,562,593

$5,461,554

$631,744 $116,194,337

1 $7,799 $0 $7,799

866 $150,144,142 $19,040,847 $169,184,989

28 $2,783,294 $1,810,017 $4,593,311

121 $17,433,688 $184,969 $17,618,657

149 $20,216,982 $1,994,986 $22,211,968 Total

Zone X

Agriculture

Commercial

Industrial

Residential

18,935

508

186

13,171

0

0

0

0

254

146

23

$26,997,639 $12,271,756

$38,066,302

$23,172,953

6,908 $647,807,684

$3,840,562

$625,220

$39,269,395

$41,906,864

$23,798,173

$457,261 $648,264,945

Total

Unclassified 80

32,880

0

0

3 $221,904 $31,470 $253,374

7,334 $736,266,482 $17,226,269 $753,492,751

Grand Total 61,849 22,467 8,524 $940,444,969 $46,775,162 $987,220,131

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

4.234 Butte County

Local Hazard Mitigation Plan Update

May 2013

Table 4.64. Unincorporated County - Creek/Cherokee Canal Watershed - Count and

Structure Value of Improved Parcels by Land Use in Detailed Floodplain

Zones

Flood Zone

Zone A

Total

0.2% Annual

Chance*

Land Use

Agriculture

Commercial

Industrial

Residential

Improved

Total

Acres

6,999

Improved

Flooded

Acres

6,055

Improved

Parcel

Count

63

Improved

Value

Improved

Other

Value

$4,881,724 $944,068

Total Value

$5,825,792

52

57

294

7,401

25

46

183

6,309

2

1

26

92

$803,051

$5,087,000

$3,035,980

$13,807,755

$330

$0

$696

$945,094

$803,381

$5,087,000

$3,036,676

$14,752,849

Agriculture

Industrial

Residential

9,050

53

424

7,892

53

424

66

8

67

$5,530,443

$8,012,558

$275,557

$8,901,315 $4,637,600

$44,560

$5,806,000

$13,538,915

$8,057,118

Total

Zone X

Agriculture

Commercial

Industrial

9,527

14,111

271

104

8,368

0

0

0

141

12

2

$22,444,316 $4,957,717

$5,356,940

$586,739

$372,060

$0

$27,402,033

120 $12,328,521 $1,643,629 $13,972,150

$5,729,000

$586,739

Total

Residential 4,677

19,163

0

0

427

561

$79,609,357 $52,394

$97,881,557 $2,068,083

$79,661,751

$99,949,640

Grand Total 36,090 14,676 794 $134,133,628 $7,970,894 $142,104,522

Sour ce: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.235

Table 4.65. Unincorporated County - Dry Feather River/Lower Honcut Creek Watershed

- Count and Structure Value of Improved Parcels by Land Use in Detailed

Floodplain Zones

Flood Zone Land Use

Zone A

Agriculture

Commercial

Industrial

Improved

Total

Acres

14,866

152

Improved

Flooded

Acres

12,553

147

Improved

Parcel

Count

189

16

Improved

Value

$4,159,656

Improved

Other Value Total Value

$18,514,929 $22,480,624

$110,000

$40,995,553

$4,269,656

Total

Residential

97

1,361

16,475

96

1,112

13,908

13

272

490

$3,543,993 $232,906

$22,236,328 $499,153

$48,454,906 $23,322,683

$3,776,899

$22,735,481

$71,777,589

Agriculture 947 98 13 $695,074 $10,913 $705,987

Zone AE

Commercial

Industrial

Residential

12

3

549

1,511

4

3

277

382

9

1

201

224

$1,740,006

$17,358

$10,691,657

$13,144,095

$0

$0

$0

$10,913

$1,740,006

$17,358

$10,691,657

$13,155,008 Total

Zone AO

Total

Commercial 20

20

18

18

4

4

$520,912

$520,912

$1,860

$1,860

$522,772

$522,772

0.2%

Annual

Chance*

Total

Zone X

Agriculture

Commercial

Industrial

Residential

Agriculture

Commercial

Industrial

Residential

12,025

67

60

3,207

15,360

19,652

802

234

33,623

10,955

65

60

3,123

14,204

0

0

0

0

385

21

$39,015,546 $22,775,888

$4,696,181 $194,900

$61,791,434

$4,891,081

9 $5,290,621 $1,051,680 $6,342,301

1,250 $129,663,876 $1,580,128 $131,244,004

1,665 $178,666,224 $25,602,596 $204,268,820

209

194

$18,851,407

$50,059,857

$6,516,754

$316,059

$25,368,161

$50,375,916

19 $2,775,003 $1,035,388

10,510 $811,489,308 $599,069

$3,810,391

$812,088,377

Total

Unclassified 24

54,335

0

0

9

10,941

$656,840

$883,832,415

$0

$8,467,270

$656,840

$892,299,685

Grand Total 87,701 28,512 13,324 $1,124,618,552 $57,405,322 $1,182,023,874

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.236

Table 4.66. Unincorporated County - Lake Oroville/Upper Feather River Watershed -

Count and Structure Value of Improved Parcels by Land Use in Detailed

Floodplain Zones

Flood Zone Land Use

Zone A

Total

Zone X

Residential

Improved

Total

Acres

5

5

Agriculture 5,766

Commercial 685

Improved

Flooded

Acres

4

4

0

0

Improved

Parcel

Count

8

8

38

59

Improved

Value

$464,044

$464,044

$2,483,899

$14,852,651

Improved

Other

Value

$0

$0

$125,000

$254,050

Total Value

$464,044

$464,044

$2,608,899

$15,106,701

Total

Residential 27,559

34,011

0

0

3,685

3,782

$283,282,797 $77,806

$300,619,347 $456,856

$283,360,603

$301,076,203

Grand Total 34,015 4 3,790 $301,083,391 $456,856 $301,540,247

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.237

Table 4.67. Unincorporated County - Little Chico Creek Watershed - Count and

Structure Value of Improved Parcels by Land Use in Detailed Floodplain

Zones

Flood

Zone

Zone A

Total

Zone AE

Total

Land Use

Agriculture

Residential

Agriculture

Commercial

Industrial

Residential

Agriculture

Commercial

Improved

Total Acres

Improved

Flooded

Acres

9,819

4

8,897

4

9,824

737

36

6

156

935

3,168

27

8,901

651

5

3

116

775

2,272

23

Improved

Parcel

Count

Improved

Value

Improved

Other Value Total Value

35 $8,164,056 $7,764,912 $15,928,968

3 $615,391 $0 $615,391

38 $8,779,447 $7,764,912 $16,544,359

12 $881,382 $263,482 $1,144,864

2

1

$592,084

$129,514

91 $19,198,191

106 $20,801,171

$0

$60,660

$5,877

$330,019

$592,084

$190,174

$19,204,068

$21,131,190

86 $8,787,953 $6,180,434 $14,968,387

8 $3,700,823 $0 $3,700,823

Zone AO

Total

0.2%

Chance*

Industrial

Residential

Residential

37

430

3,662

16

36

392

2,723

14

9

351

11

$3,509,131

$30,499,857

$2,983,415

$2,822,980

$248,111

$0

$6,332,111

$30,747,968

454 $46,497,764 $9,251,525 $55,749,289

$2,983,415

Total

Zone X

Agriculture

Commercial

Industrial

16

21,503

124

97

14

0

0

0

11

307

$2,983,415 $0

$43,921,539 $35,725,852

28 $9,677,487

$2,983,415

$79,647,391

$266,897 $9,944,384

34 $28,999,115 $1,473,700 $30,472,815

Total

Residential 6,204

27,927

0

0

1,608 $208,413,685 $763,877 $209,177,562

1,977 $291,011,826 $38,230,326 $329,242,152

Grand Total 42,363 12,413 2,586 $370,073,623 $55,576,782 $425,650,405

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

4.238 Butte County

Local Hazard Mitigation Plan Update

May 2013

Table 4.68. Unincorporated County - Pine Creek Watershed - Count and Structure

Value of Improved Parcels by Land Use in Detailed Floodplain Zones

Flood Zone Land Use

Agriculture

Zone A

Commercial

Residential

Total

Zone X

Unclassified

Agriculture

Commercial

Improved

Total Acres

Improved

Flooded

Acres

15,796

4

15,138

4

25

103

15,928

7,192

36

24

103

15,269

0

0

Improved

Parcel

Count

79 $17,492,782 $11,386,509 $28,879,291

3 $115,951 $0 $115,951

7

1

Improved

Value

$728,789

$121,165

Improved

Other Value Total Value

$0

$176,327

$728,789

$297,492

90 $18,458,687 $11,562,836 $30,021,523

78 $16,638,507 $8,922,472 $25,560,979

1 $239,329 $0 $239,329

Total

Residential 371

7,600

0

0

22 $3,533,919

101 $20,411,755

$1,190 $3,535,109

$8,923,662 $29,335,417

Grand Total 23,528 15,269 191 $38,870,442 $20,486,498 $59,356,940

Source: But te County 2012 Assessor’s Data; Butte County DFIRM, January 2011

Table 4.69. Unincorporated County - all Watersheds - Count and Structure Value of

Improved Parcels by Land Use in All Floodplains

Flood Zone

Big Chico Creek

Watershed

Butte Creek

Dry

Creek/Cherokee

Canal

Feather

River/Lower

Honcut Creek

Improved

Total

Acres

39,345

61,849

36,090

87,701

Improved

Flooded

Acres

7,247

Improved

Parcel

Count

4,935

Improved Value

$874,913,862

22,467

14,676

28,512

8,524

794

13,324

$940,444,969

$134,133,628

$1,124,618,552

Improved

Other Value Total Value

$50,420,786

$46,775,162

$7,970,894

$57,405,322

$925,334,648

$987,220,131

$142,104,522

$1,182,023,874

Lake

Oroville/Upper

Feather River

Little Chico Creek

Pine Creek

34,015

42,363

23,528

4

12,413

15,269

3,790

2,586

191

$301,083,391

$370,073,623

$38,870,442

$456,856

$55,576,782

$20,486,498

$301,540,247

$425,650,405

$59,356,940

Unincorporated

Grand Total

324,891 100,589 34,144 $3,784,138,467

Source: Butte County 2012 Assessor’s Data; Butte County DFIRM, January 2011

$239,092,300 $4,023,230,767

According to the analysis represented in the watershed summary in Table 4.69, Butte Creek, Big

Chico Creek and Feather River/Lower Honcut Creek watersheds have the highest total values at risk to flooding. In total, there are over $4 billion in improved parcels at risk to flooding.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.239

Loss Estimates for Improved Parcels by Watershed by Flood Event in the Unincorporated

County

Table 4.70 shows unincorporated Butte County loss estimates for improved parcels by watershed

by FEMA Flood Zones 1% and 0.2% annual chance. Contents values were estimated as a percentage of building value based on their land use, using FEMA/HAZUS estimated content replacement values. This includes 100% of the structure value for agricultural and commercial structures, 50% for residential and unclassified structures, and 150% for industrial land use classifications. Based on FEMA guidance, 20 percent damage factor was applied to each flood zone‘s total value of improvements and estimated content to obtain an overall loss estimate. Big

Chico Creek Watershed has the largest loss estimate of $403 million with Feather River/Lower

Honcut Creek Watershed having a loss estimate of $244 million. For both of these watersheds the majority of loss comes from the 0.2% annual chance flood zone.

Table 4.70. Unincorporated Butte County - 1% and 0.2% Annual Chance* Flood Loss by

Watershed

Flood Zone

Improved

Parcel

Count

Big Chico Creek Watershed

1% Annual Chance

0.2% Annual Chance

345

812

Improved Value

$71,221,321

$113,310,144

$184,531,465 Total

Butte Creek Watershed

1% Annual Chance

0.2% Annual Chance

Total

1,157

1,190

-

1,190

$233,727,380

-

$233,727,380

Dry Creek/Cherokee Canal Watershed

1% Annual Chance

0.2% Annual Chance

Total

92

141

233

$14,752,849

$27,402,033

$42,154,882

Feather River/Lower Honcut Creek Watershed

1% Annual Chance 718 $85,455,369

Estimated

Content Value Total Value

$50,881,621

$63,397,974

$114,279,595

$176,495,775

-

$176,495,775

$15,778,011

$30,142,932

$45,920,943

$122,102,942

$176,708,118

$298,811,060

$410,223,155

$0

$410,223,155

$30,530,860

$57,544,965

$88,075,825

0.2% Annual Chance

Total

1,665

2,383

$204,268,820

$289,724,189

Lake Oroville/Upper Feather River Watershed

1% Annual Chance 8 $464,044

$70,638,929

$141,817,969

$212,456,897

$156,094,298

$346,086,789

$502,181,086

0.2% Annual Chance

Total

Little Chico Creek Watershed

1% Annual Chance

-

8

598

-

$464,044

$93,424,838

$232,022

-

$232,022

$71,402,267

$696,066

$0

$696,066

$164,827,105

Loss Estimate

(20% of Total)

$24,420,588

$35,341,624

$59,762,212

$82,044,631

$0

$82,044,631

$6,106,172

$11,508,993

$17,615,165

$31,218,860

$69,217,358

$100,436,217

$139,213

$0

$139,213

$32,965,421

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.240

Flood Zone

0.2% Annual Chance

Total

Pine Creek Watershed

Improved

Parcel

Count

11

609

Improved Value

$2,983,415

$96,408,253

Estimated

Content Value Total Value

$1,491,708

$72,893,975

$4,475,123

$169,302,228

Loss Estimate

(20% of Total)

$895,025

$33,860,446

1% Annual Chance

0.2% Annual Chance

90

-

$30,021,523

-

$29,508,383

-

$59,529,906

$0

$11,905,981

$0

Total 90 $30,021,523 $29,508,383 $59,529,906 $11,905,981

Source: FEMA, Butte County 2012

Assessor’s Data

Contents replacement value is estimated as a percent of structure replacement value: Agriculture

– 100%; Commercial – 100%;

Industrial

– 150%; Residential – 50%; Unclassified – 50%

For this table the improved values and other values have been combined are represented in improved value totaled together.

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Flood Loss Estimates and Loss Ratios for Unincorporated Butte County

Loss ratio tables were also created based on each watershed area. This analysis is represented by grouping all the watersheds by 1% and 0.2% annual chance. Watershed improved values and estimated contents were summed and a 20 percent damage factor was applied. The loss ratio could then be applied by dividing the watershed‘s loss estimate by the total loss estimate for each flood zone. For the 1% annual chance flood zone Butte Creek had a Loss Ratio of 1.2% with a loss estimate of $82 million. For the 0.2% annual chance flood zone, the Feather River/Lower

Honcut Creek was after that with a 1.0% loss ratio that had a $69 million loss estimate.

Table 4.71. Unincorporated County - 1% Annual Chance Flood Loss Ratio by

Watershed

Watershed

Big Chico Creek

Butte Creek

Dry

Creek/Cherokee

Canal

Improved

Parcel

Count

Improved

Value

Estimated

Content Value Total Value

92 $14,752,849 $15,778,011 $30,530,860

Loss Estimate

(20% of Total) Loss Ratio

345 $71,221,321 $50,881,621 $122,102,942 $24,420,588

1,190 $233,727,380 $176,495,775 $410,223,155 $82,044,631

$6,106,172

Feather

River/Lower

Honcut Creek

Lake Oroville/

Upper Feather

River

718

8

$85,455,369

$464,044

$70,638,929

$232,022

$156,094,298

$696,066

$31,218,860

$139,213

Little Chico Creek

Pine Creek

598

90

$93,424,838

$30,021,523

$71,402,267

$29,508,383

$164,827,105

$59,529,906

$32,965,421

$11,905,981

Total 3,041 $529,067,324 $414,937,007 $944,004,331 $188,800,866

Source: FEMA, Butte County 2012 Assessor’s Data

0.4%

1.2%

0.1%

0.5%

0.002%

0.5%

0.2%

2.7%

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.241

Table 4.72. Unincorporated County - 0.2% Annual Chance* Flood Loss Ratio by

Watershed

Watershed

Big Chico Creek

Improved

Parcel

Count

Improved

Value

812 $113,310,144

141 $27,402,033

Estimated

Content Value Total Value

$63,397,974

$30,142,932

$176,708,118

$57,544,965

Loss

Estimate

(20% of Total) Loss Ratio

$35,341,624

$11,508,993

0.5%

Dry

Creek/Cherokee

Canal

Feather River/

Lower Honcut

Creek

Little Chico Creek

1,665

11

$204,268,820

$2,983,415

$141,817,969

$1,491,708

$346,086,789

$4,475,123

$69,217,358

$895,025

0.2%

1.0%

0.01%

Total 2,629 $347,964,412 $236,850,582 $584,814,994 $116,962,999 1.7%

Source: FEMA, Butte County 2012 Assessor’s Data

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

NFIP Insurance Coverage Details

Unincorporated Butte County joined the NFIP on September 29, 1989. NFIP insurance data provided by DWR indicates that as of March 31, 2012, there were 1,771 policies in force in the unincorporated County, resulting in $386,253,000 of insurance in force. There have been 158 closed paid losses totaling $2,883,488. Of these losses, 105 were parcels in A zones and 47 parcels were in X zone. Of the 158 claims, 128 claims were associated with pre-FIRM structures and 24 with post-FIRM structures.

Based on this analysis of insurance coverage, unincorporated Butte County has significant assets at risk to the 100-year and greater floods. Of the 3,041 improved parcels within the 100-year floodplain, only 894 (29.4 percent) of those parcels maintain flood insurance.

Butte County Flood Insurance Analysis

Utilizing the March 31, 2012 NFIP data provided by DWR (which is the most current and valid),

Table 4.73 shows the number of flood policy holders, the number of inundated improved parcels

in the 1% annual chance event, and the percentages of policy holders to those inundated parcels, by jurisdiction.

4.242 Butte County

Local Hazard Mitigation Plan Update

May 2013

Table 4.73. Butte County Planning Area - Percentages of Policy Holders to Inundated

Parcels

Jurisdiction

Butte County

Biggs

Chico

Gridley

Oroville

Paradise

Improved Parcels in 1%

Annual Chance Floodplain

3,041

0

928

0

33

0

Insurance Policies in the

A (1% Annual Chance)

Total 4,002

Source: California Department of Water Resources, FEMA

Zone

894

0

460

0

6

0

1,360

Percentage of 1% Annual Chance

Floodplain Parcels Currently

Insured

29.4%

-

49.6%

-

18.2%

-

34.0%

Repetitive Loss Data

In addition, Butte County‘s vulnerability to flooding is highlighted by its number of Repetitive

Losses. According to the March 31, 2012 data from the state on NFIP communities, there are 25 repetitive loss (RL) buildings in the unincorporated County with 61 paid losses totaling

$879,380.50. Of these RL buildings, 20 are in the A zones and 5 are in the X zone. None of these structures have incurred four or more losses.

Populations at Risk

A separate analysis was performed to determine population in flood zones. GIS analysis was performed to determine population in the flood zones. Using GIS, the Butte County DFIRM layer was overlaid on the improved residential parcel data. Those parcel centroids that intersect the flood zones were counted and multiplied by the 2010 Census Bureau average household

factors for each jurisdiction and unincorporated area (see Table 4.74). According to this

analysis, there is a total population of 9,774 in the 1% annual chance floodplain and 32,665 in the 0.2% annual chance floodplain. The unincorporated County has the greatest population at risk (7,450) to a 1% annual chance event. The City of Chico has the greatest population at risk

(18,813) to a 0.2% annual chance event.

4.243 Butte County

Local Hazard Mitigation Plan Update

May 2013

Table 4.74. Butte County Planning Area - Populations at Risk to the 1% and 0.2%

Annual Chance Floods*

Jurisdiction

1% Annual Chance

Improved

Residential Parcels Population

0.2% Annual Chance

Improved

Residential Parcels Population

Unincorporated

Biggs

Chico

Gridley

Oroville

3,041

0

928

0

33

7,450

0

2,208

0

86

2,629

0

7,905

2,120

433

6,441

0

18,813

6,275

1,126

Paradise 0 0 0 0

Total 4,002 9,744 13,087 32,655

Source: DFIRM, US Census Bureau, Butte County 2012

Assessor’s Data

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Critical Facilities at Risk

A separate analysis was performed on the critical facility inventory in Butte County and all jurisdictions by Flood Zone. GIS was used to determine whether the facility locations intersects a DFIRM flood hazard areas, and if so, which zone it intersects. There are 498 facilities in the

1% annual chance flood event and 515 facilities in the 0.2% annual chance flood event as shown

in Table 4.75. More information on the specific facilities in the floodplains in the jurisdictions

may be found in their respective annexes. Table 4.76 shows the detail by watershed of critical

facilities in the 1% and 0.2% annual chance floodplains in the unincorporated County. Details of critical facility definition, type, name and address and jurisdiction by flood zone are listed in

Appendix E.

Table 4.75. Butte County Planning Area - Critical Facilities in the 1% and 0.2% Annual

Chance* Floodplains

Jurisdiction

City of Biggs

City of Chico

City of Gridley

City of Oroville

Town of Paradise

Facility Count in 1% Annual Chance

20

63

1

15

0

Facility Count in 0.2% Annual Chance

182

16

73

27

0

Unincorporated County 399 217

Total 498 515

Source: FEMA DFIRM January 2011, Butte County GIS

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.244

Table 4.76. Unincorporated Butte County – Critical Facilities in the 1% and 0.2%

Annual Chance* Floodplains by Watershed

Flood

Big Chico Creek Watershed

Category

Unincorporated 1% Annual Chance

Zone A At Risk Population Facilities

Type

Zone A

Zone A

Zone A

Zone AE

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

Essential Services Facilities

Unincorporated 0.2% Annual Chance

0.2% Annual Chance At Risk Population Facilities

0.2% Annual Chance

0.2% Annual Chance

At Risk Population Facilities

At Risk Population Facilities

0.2% Annual Chance

0.2% Annual Chance

Essential Services Facilities

Hazardous Materials Facilities

Butte Creek Watershed

Unincorporated 1% Annual Chance

Zone A

Zone A

Zone A

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Zone A

Zone A

Zone AE

Zone AE

Zone AE

Zone AE

Zone AE

Zone AO

Hazardous Materials Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Essential Services Facilities

Dry Creek/Cherokee Canal Watershed

Unincorporated 1% Annual Chance

Zone A At Risk Population Facilities

Zone A

Zone A

Zone A

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Unincorporated 0.2% Annual Chance

0.2% Annual Chance At Risk Population Facilities

Facility Count

Residential Care / Elder 1

School 1

Bridge

CUPA

Bridge

Total

38

2

4

46

Day Care Center 3

Family Day Care Home 8

Group Home

Bridge

CUPA

Total

1

7

8

27

Bridge

Fire Station

42

2

Wastewater Treatment

Plant

Agriculture

1

1

CUPA 6

Family Day Care Home 3

Residential Care / Elder 1

Bridge 57

Helipad

CUPA

1

8

Bridge

Total

6

128

Small Family Home

Agriculture

Bridge

Helipad

Total

Family Day Care Home

1

1

44

1

47

2

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.245

Flood

0.2% Annual Chance

0.2% Annual Chance

0.2% Annual Chance

Category

Essential Services Facilities

Essential Services Facilities

Type

Hazardous Materials Facilities

0.2% Annual Chance Hazardous Materials Facilities

Feather River/Lower Honcut Creek Watershed

Unincorporated 1% Annual Chance

Zone A

Zone A

At Risk Population Facilities

At Risk Population Facilities

Zone A

Zone A

Zone AE

Zone AE

Zone AO

Essential Services Facilities

Hazardous Materials Facilities

Essential Services Facilities

Hazardous Materials Facilities

Hazardous Materials Facilities

Unincorporated 0.2% Annual Chance

0.2% Annual Chance

0.2% Annual Chance

At Risk Population Facilities

At Risk Population Facilities

0.2% Annual Chance

0.2% Annual Chance

0.2% Annual Chance

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

0.2% Annual Chance

0.2% Annual Chance

Essential Services Facilities

Hazardous Materials Facilities

Lake Oroville/Upper Feather River Watershed

Unincorporated 1% Annual Chance

Zone A Essential Services Facilities

Zone A Hazardous Materials Facilities

Little Chico Creek Watershed

Unincorporated 1% Annual Chance

Zone A Essential Services Facilities

Zone AE

Zone AE

Essential Services Facilities

Hazardous Materials Facilities

Zone AO

Zone AO

Zone AO

Zone AO

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

Bridge

Fire Station

CUPA

Natural Gas Storage

Total

Facility Count

42

1

3

1

49

Day Care Center

Infant Center

Bridge

CUPA

Bridge

CUPA

CUPA

Total

Adult Residential

Day Care Center

1

1

Family Day Care Home 5

Residential Care / Elder 1

School 1

Bridge

CUPA

Total

109

23

141

Bridge

CUPA

Total

7

2

9

Bridge

Bridge

CUPA

Day Care Center 1

Family Day Care Home 1

22

18

3

Bridge

CUPA

Total

14

6

65

2

1

58

8

14

1

1

85

Butte County

Local Hazard Mitigation Plan Update

May 2013

4.246

Flood

Pine Creek Watershed

Category

Unincorporated 1% Annual Chance

Zone A Essential Services Facilities

Type Facility Count

Bridge 18

Zone A Hazardous Materials Facilities CUPA

Total

1

19

Grand Total 616

Source: FEMA DFIRM January 2011, Butte County GIS

*This parcel count only includes those parcels in the 0.2% annual chance floodplain. The 0.2% annual chance flood also includes all parcels in the 1% annual chance floodplain.

Cultural and Natural Resources at Risk

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. Risk analysis of these resources was not possible due to data limitations. However, natural areas within the floodplain often benefit from periodic flooding as a naturally recurring phenomenon. These natural areas often reduce flood impacts by allowing absorption and infiltration of floodwaters.

Development Trends

Where and how to build is generally addressed in local floodplain ordinances. These ordinances should be reviewed and updated as development in new areas is considered.

One of the most effective ways to reduce vulnerability to potential flood damage is through careful land use planning that fully considers applicable flood management information and practices. California‘s 2007 flood legislation (Senate Bill 5) directly linked system-wide flood management planning to local land use planning, requiring local jurisdictions to demonstrate an urban level of flood protection before approving new development in urban and urbanizing areas.

―Urban level of flood protection‖ means the level of protection necessary to withstand flooding that has a 1-in-200 chance of occurring in any given year (California Government Code Section

65007). DWR is developing criteria to guide local jurisdiction compliance with the new requirements. In addition to developing criteria to help local jurisdictions in their land use planning, DWR is preparing criteria for use in the design of levees protecting urban and urbanizing areas. DWR is also working with local partners to develop guidance related to nonurban flood protection levels.

These standards are under development and will become effective over the next several years as ongoing technical studies are performed. Once these standards become effective, cities and counties within the Sacramento-San Joaquin Valley cannot enter into development agreements or issue a permit to construct a new structure in areas located within a flood hazard zone unless the following is established:

Find that existing facilities protect urban and urbanizing areas to a 1-in 200 chance of flooding in any given year or the FEMA standard of flood protection in non-urbanized areas,

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or

Find that the local flood management agency has made adequate progress on the construction of the flood protection system to provide the required level of protection, or

Impose conditions on the development agreement that will provide the required level of protection.

California Department of Water Resources (DWR) is currently developing technical information to assist cities and counties with their compliance with these new requirements.

In addition, another way to reduce flooding issues in areas of existing and future development is to clear vegetation from natural and man-made drains that are critical to flood protection. Both native and invasive species can clog drains, and reduce flows of floodwaters, which slow that natural drainage process and can exacerbate flooding.

California Department of Water Resources Best Available Maps (BAM)

The FEMA regulatory maps provide just one perspective on flood risks in Butte County. Senate

Bill 5 (SB 5), enacted in 2007, authorized the California DWR to develop the Best Available

Maps (BAM) displaying 100- and 200-year floodplains for areas located within the Sacramento-

San Joaquin (SAC-SJ) Valley watershed. SB 5 requires that these maps contain the best available information on flood hazards and be provided to cities and counties in the SAC-SJ

Valley watershed. This effort was completed by DWR in 2008. DWR has expanded the BAM to cover all counties in the State and to include 500-year floodplains.

Different than the FEMA DFIRMs which have been prepared to support the NFIP and reflect only the 100-year event risk, the BAMs are provided for informational purposes and are intended to reflect current 100-, 200-, and 500-year event risks using the best available data. The 100year floodplain limits on the BAM are a composite of multiple 100-year floodplain mapping sources. It is intended to show all currently identified areas at risk for a 100-year flood event, including FEMA‘s 100-year floodplains. The BAM are comprised of different engineering studies performed by FEMA, Corps, and DWR for assessment of potential 100-, 200-, and 500year floodplain areas. These studies are used for different planning and/or regulatory applications. They are for the same flood frequency, however, they may use varied analytical and quality control criteria depending on the study type requirements.

The value in the BAMs is that they provide a bigger picture view of potential flood risk to the

Butte County Planning Area than that provided in the FEMA DFIRMS. This provides the community and residents with an additional tool for understanding potential flood hazards not currently mapped as a regulated floodplain. Improved awareness of flood risk can reduce exposure to flooding for new structures and promote increased protection for existing development. Informed land use planning will also assist in identifying levee maintenance needs and levels of protection. By including the FEMA 100-year floodplain, it also supports

identification of the need and requirement for flood insurance. Figure 4.73 shows the BAM for

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the Butte County Planning Area. BAM maps for each jurisdiction are included in their respective annexes.

Figure 4.73. Butte County Planning Area – Flood Awareness Map

Source: California DWR

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4.3.8 Flood: Localized/Stormwater Vulnerability Assessment

Likelihood of Future Occurrence—Highly Likely

Vulnerability—Medium

Historically, the planning area has been at risk to flooding primarily during the spring months when stream systems in the County swell with heavy rainfall. Localized flooding also occurs throughout the planning area at various times throughout the year with several areas of primary concern unique to each City. Butte County tracks localized flooding areas by District. These

Districts are shown in Figure 4.74 Affected localized flood areas identified by the County (by

District) are summarized in Table 4.77.

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Figure 4.74. Butte County Road Districts

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Table 4.77. Unincorporated Butte County - Road List of Problem Area Reoccurrences

Road

No. Road Name

Paradise Road District

54545-A Bardees Bar

Rd.

76555-F Camp Creek

Rd.

54345-

A1&2

Centerville Rd.

Flooding Washouts

High

Water /

Creek

Crossing

Landslides

/ Mudslides Debris

X

X

X

X

X

X

X

X

45435-A Clear cr. Cem.

52515-

A1&2

Concow Rd.

52513 Concow Rd.

50545-A Dark Canyon

66553

52283-

1&2

91513

Dixie Rd.

Honey Run Rd.

Humbug

Summit

55515-A Jordan Hill

62451 New Skyway

92523 Philbrook

76555-G Pulga Rd.

51261-3 Skyway

51262-1 Skyway

Chico Road District

65065-E Bennett Rd.

54205-

A&B,

54211

Bidwell Ave.

60135-D

&

65065-D

Cana Hwy.

65065-D Cana Pine

Creek Rd.

60135-A Carmen Lane

61201 Cohasset Rd.

32253

49203

Durnell Rd.

Elk Ave.

46213

31151

Fimple Rd.

Nelson Rd.

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X x

X

Downed

Trees Other

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Washboard

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Road

No.

60102

42071

41123

30141 &

30142

Road Name

Nord Hwy.

Ord Ferry Rd.

River Rd.

Seven Mile

Lane

76335-B Vilas Rd.

54123 &

54191

W.Sacramento

Ave.

Flooding Washouts

X

X

X

X

X

X

65065-G

&

60135-F

Wilson Landing

Rd.

Oroville Road District

16505-M Alice Ave.

44605-A Bald Rock Rd.

X

25665-A Black Bart Rd.

29483 Cherokee Rd.

15665-A Darby Rd.

21571,

21574 &

21581

Foothill Blvd.

27581-

1&2,

29745-D

Forbestown

Rd.

27595-A Hurelton Rd.

29515-G

& 29511

Long Bar Rd.

X

X

X

High

Water /

Creek

Crossing

Landslides

/ Mudslides Debris

X

X

X

X

X X

16505-K

&

16515-D

Louis Ave.

27672 &

40805-A

Lumpkin Rd.

37505-A Oregon Gulch

Rd.

16505-C Railroad Ave.

27625-A Stringtown Rd.

44665-A Zink Rd.

Gridley Road District

16181 &

16182

08443

Afton Rd

Central House

Rd

09161 Colusa Hwy

X

X

X

X

X

X

Downed

Trees

X

X

Other

X

X

X

X

X

X

X

X

X

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Road

No.

04451

Road Name

Lower Honcut

Rd.

05505-B Middle Honcut

Rd

Flooding

X

X

Washouts

10445-B

& 10453

Stimpson Rd. X

05263 West Evans

Reimer Rd.

X

Source: Butte County Office of Emergency Management

High

Water /

Creek

Crossing

Landslides

/ Mudslides Debris

Downed

Trees Other

Development Trends

The risk of stormwater/localized flooding to future development can be minimized by accurate recordkeeping of repetitive localized storm activity. Mitigating the root causes of the localized stormwater or choosing not to develop in areas that often are subject to localized flooding will reduce future risks of losses due to stormwater/localized flooding.

4.3.9 Hazardous Materials Incidents: Transportation

Likelihood of Future Occurrence—Occasional

Vulnerability—High

It is often quite difficult to quantify the potential losses from human-caused hazards. While the facilities themselves have a tangible dollar value, loss from a human-caused hazard often inflicts an even greater toll on a community, both economically and emotionally. The impact to identified assets will vary from event to event and depend on the type, location, and nature of a specific hazardous material incident. Given the difficulty in quantifying the losses associated with technological hazards, this section focuses on analyzing key assets and populations relative

to the hazardous materials sites and transportation corridors identified above. Figure 4.75 shows

the hazardous materials transportation corridors in Butte County as well as the two mile buffer zone used this analysis.

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Figure 4.75. Butte County Planning Area - Hazardous Materials Routes and Buffer

Zones

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Values at Risk

During a hazardous materials transportation spill, it is generally the people that are at risk to the effects of the spill. During a spill, buildings and property are at limited risk. Should a propane truck catch fire in a residential area, it may cause a building to burn, but will not burn all buildings inside the buffer zone. As such, no analysis on assets in the buffer zone was performed.

Populations at Risk to Hazardous Materials from Transportation Corridors

To determine the populations at risk from a transportation-related hazardous materials release within identified transportation corridors, an analysis was performed using GIS. A one mile buffer was applied to both sides of Highways 32, 70, 99, 149, 162 and 191 and the Union Pacific

Railroads, creating a two mile buffer zones around each corridor. The buffer distance was based on guidelines in the U.S. Department of Transportation‘s Emergency Response Guidebook that suggest distances useful to protect people from vapors resulting from spills involving dangerous goods considered toxic if inhaled. The recommended buffer distance referred to in the guide as the ―protective action distance‖ is the area surrounding the incident in which people are at risk of harmful exposure. For purposes of this plan, an average buffer distance of one mile was used on either side of the transportation corridor. Actual buffer distances will vary depending on the nature and quantity of the release, whether the release occurred during the night or daytime, and prevailing weather conditions.

Since there is overlapping of the corridors in many locations throughout the county and jurisdictions individual population analysis was performed for each transportation corridor. In

Table 4.78, each buffered transportation corridor was intersected with the residential parcels and

therefore parcels could be counted more than once within this table due to the individual analysis of each corridor. It is important to note that populations associated with commercial, industrial and other property types may also be affected by a hazardous materials release, but no census/population data is associated with these property types and are therefore excluded from this analysis. According to this residential based analysis, there is a total population of 149,985 in the overlapping buffered corridor. There are 45,394 people that live within the two-mile buffer of the Union Pacific Railroad that passes through Biggs, Chico, Gridley and Oroville.

There are 40,647 total people that live within the proximity of Highway 99 that passes through

Biggs, Gridley and Chico. A residential population of 34,030 is within the proximity of

Highway 32 that passes through the City of Chico.

Table 4.78. Butte County Planning Area Population at Risk in Haz-Mat Corridors

Transportation Corridor

Highway 32

Highway 70

Highway 99

Corridor Length (mi)

47.4

65.3

66.7

Cities

26,846

3,203

33,116

Unincorporated

7,183

4,033

7,531

Total

34,030

7,236

40,647

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Transportation Corridor

Highway 149

Highway 162

Highway 191

Corridor Length (mi)

11.1

32.6

11.4

Union Pacific Railroad 122.8

Total

Source: Butte County GIS, US Census Bureau

357.2

Cities

-

6,848

5,080

29,148

104,241

Unincorporated

37

10,170

544

16,246

45,744

Total

37

17,018

5,624

45,394

149,985

Separate analysis was done for jurisdictions found in Table 4.79. This table does not have

duplicated parcels represented but a total population that are within the proximity of this twomile buffer of all the highway and railroad corridors. Using GIS, the buffered corridor was overlaid on the improved residential parcel data. Those parcel centroids that intersect the buffered corridor were counted and multiplied by the 2010 Census Bureau average household factors for each jurisdiction and unincorporated area. According to this analysis, there is a total population of 99,250 in the buffered corridor. There are 34,790 people in the Unincorporated

County.

It was observed that all of these corridors pass through the heart of every town and with the perimeters of one-mile buffer that Biggs, Chico, Gridley and Oroville are all or almost

completely within this buffered zone observed on Figure 4.75.

Table 4.79. Butte County Planning Area - Jurisdictional Populations at Risk in Haz-Mat

Corridors

Jurisdiction

Biggs

Chico

Gridley

Oroville

Paradise

Unincorporated

Total

Butte County GIS, US Census Bureau

Residential Parcels

583

17,931

1,881

3,606

2,341

14,200

40,542

Critical Facilities at Risk

Population

1,761

42,676

5,568

9,376

5,080

34,790

99,250

During a hazardous materials transportation spill, it is generally the people that are at risk to the effects of the spill. During a spill, buildings and property are at limited risk. Should a propane truck catch fire in a residential area, it may cause a building to burn, but will not burn all buildings inside the buffer zone. As such, no analysis on critical facilities in the buffer zone was performed.

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Cultural and Natural Resources at Risk

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. Vulnerability analysis of these resources was not possible due to data limitations.

Development Trends

Development will continue to happen within hazardous materials transportation zones. Those who choose to develop in these areas should be made aware of the risks associated with living within a hazardous materials transportation route.

4.3.10 Levee Failure Vulnerability Assessment

Likelihood of Future Occurrence—Occasional

Vulnerability—High

Levee failure flooding can occur as the result of partial or complete collapse of an impoundment, and often results from prolonged rainfall and flooding. The primary danger associated with dam or levee failure is the high velocity flooding of those properties downstream of the breach.

Section 4.2.15 Levee Failure describes the levee inventory in the Butte County Planning Area.

A levee failure can range from a small, uncontrolled release to a catastrophic failure.

Vulnerability to levee failures is generally confined to the areas subject to inundation downstream of the facility. Secondary losses would include loss of the multi-use functions of the facility and associated revenues that accompany those functions.

Levee failure flooding would vary in the planning area depending on which structure fails and the nature and extent of the failure and associated flooding. This flooding presents a threat to life and property, including buildings, their contents, and their use. Large flood events can affect lifeline utilities (e.g., water, sewerage, and power), transportation, jobs, tourism, the environment, agricultural industry, and the local and regional economies.

Levee Flood Protection Zones

Levee Flood Protection Zones estimate the maximum area that may be inundated if a project levee fails when water surface elevation is at the top of a project levee. Zones depicted on

Figure 4.76 do not necessarily depict areas likely to be protected from flow events for which project levees were designed. Figure 4.76 illustrates the depths of flooding should a levee that

protects that area fail.

Lands within the Levee Flood Protection Zones may be subject to flooding due to various factors, including the failure or overtopping of project or non-project levees, flows that exceed the design capacity of project or non-project levees, and flows from water sources not specifically protected against by project levees. Lands not mapped within a Levee Flood

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Protection Zone are not invulnerable to flood risk, and some may also experience flooding from these or other related events.

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Figure 4.76. Butte County Planning Area - Expected Flood Depths from Levee Failure based on LFPZs

Source: DWR, USGS

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Methodology

Levee analysis was completed through the use of the effective FEMA DFIRMs and Levee layers and tables obtained through FEMA. Due to an oversight in the DFIRM, PAL (Provisionally

Accredited Levees) attributes were not present in the DFIRM layer. The 0.2% annual chance zones that were supposed to be identified as Area Protected by Levee zones had to be manually adjusted based on assistance and additional data from FEMA to show what PALs were in effect at the January 2011 release of the DIFRMs but have since been de-accredited. In addition, since the release of the 2011 DFIRMs areas along Sycamore and Mud Creek that have been fully accredited. The areas of adjustments were primarily in the City of Chico and unincorporated

County areas connected to the same levee system and a small area in the City of Oroville. Parcel analysis was performed in these areas using the converted centroids that intersected the levee areas. The following tables show the break out of parcel centroids for the areas protected by levee as reflected in the January 2011 DFIRMs by watershed, jurisdiction in the Butte County

Planning Area, and by land use for the unincorporated County. These areas will be updated to reflect current levee status at the next DFIRM update anticipated sometime in the next few years.

Values at Risk

Figure 4.77 shows the fully accredited levee segment and the provisionally accredited levee

segments that provide protection to areas with improved parcels. These levee protected areas with improved parcels are contained in two watersheds: the Big Chico Creek Watershed and the

Feather River/Lower Honcut Creek Watershed. The accredited levee provides protection

(certified to the 100-year flood) for areas in the City of Chico and the Unincorporated County.

The two de-accredited levee segments affect the areas of Oroville and the Unincorporated

County, but no are longer considered as providing 100-year level of flood protection, since their

PAL agreements have expired since the 2011 mapping. As previously described in the flood analysis, when the regulatory DFIRMs were issued, the Butte County Planning Area benefited from multiple PAL agreements being in place and recognized those areas behind the PAL levees as being protected from 100-year flood. If these areas are not officially certified and accredited before the next DFIRM mapping update, the affected parcels will be remapped into a Special

Flood Hazard Area (SFHA). Specifically, in the Big Chico Creek Watershed, 117 improved parcels in the unincorporated County valued at $29,615,173 will be remapped into the SFHA. In the Feather River/Lower Honcut Creek Watershed, 32 improved parcels in the City of Oroville valued at $1,538,283 will be remapped into the SFHA.

Based on the DFIRM, there are 7,932 parcels with a structure value of $1.2 billion in the levee

protected zone in Butte County, as shown in Tables 4.80 and 4.81. The extent and depth of

actual flooding and associated damage will vary depending on the nature of a levee break.

Figure 4.77 shows levee protected areas by land use type in the unincorporated County.

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Figure 4.77. Butte County Planning Area - Levee Locations and Status

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Table 4.80. Butte County Planning Area – Values in the Area Protected by Levee from the 1% Annual Chance Flood by Watershed

Flood Zone Land Use

Improved

Total

Acres

Improved

Flooded

Acres

Big Chico Creek Watershed - Accredited Levee

Areas

Protected by Levee from 1%

Annual

Chance

Agriculture

Commercial

Industrial

Residential

Unclassified

70

441

8

2,141

3

8

422

7

2,065

3

Total 2,663 2,506

Big Chico Creek Watershed - De-Accredited Levee

Improved

Parcel

Count

3

251

3

5

Improved

Value

$66,254

$166,349,142 $3,618,390

$1,313,720

$2,737,083

Improved

Other

Value

$0

$0

$0

Total Value

$66,254

$169,967,532

$1,313,720

7,521 $972,925,754 $183,530 $973,109,284

$2,737,083

7,783 $1,143,391,953 $3,801,920 $1,147,193,873

$1,263,390 $1,723,054

$309,199 $0

$1,212,322

$25,048,181

$0

$59,027

$2,986,444

$309,199

$1,212,322

$25,107,208

Areas

Protected by Levee from 1%

Annual

Chance

Agriculture

Commercial

Industrial

Residential

709

2

7

309

165

2

7

215

Total 1,027 389

Feather River/Lower Honcut Creek - De-Accredited Levee

12

2

4

99

117

Areas

Protected by Levee from 1%

Annual

Chance

Commercial

Industrial

Residential

0.2

0.2

8

0.08

0.2

7

Total 9 8

Source: FEMA DFIRM, Butte County 2012 Assessor’s Data

1

1

30

32

$27,833,092 $1,782,081

$76,791

$22,192

$1,439,300

$1,538,283

$0

$0

$0

$0

$29,615,173

$76,791

$22,192

$1,439,300

$1,538,283

Table 4.81. Butte County Planning Area – Values in the Area Protected by Levee from the 1% Annual Chance Flood by Jurisdiction

Land Use Total Improved Acres Improved Flooded Acres Improved Parcel Count Improved Value

Accredited Levee - Big Chico Creek Watershed

Biggs

Chico

-

2,183

-

2,135

- -

7,089 $1,064,063,902

Gridley

Oroville

Paradise

Unincorporated

Total

-

-

-

480

2,663

De-Accredited Levee - Big Chico Creek Watershed

Biggs -

Chico -

-

-

-

370

2,506

-

-

-

-

-

694

-

-

-

-

-

$83,129,971

7,783 $1,147,193,873

-

-

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Land Use

Gridley

Oroville

Paradise

Total Improved Acres Improved Flooded Acres Improved Parcel Count Improved Value

-

-

-

-

-

-

-

-

-

-

-

-

389

389

117

117

$29,615,173

$29,615,173

Unincorporated

Total

1,027

1,027

De-Accredited Levee - Feather River/Lower Honcut Creek

Biggs -

Chico

Gridley

-

-

-

-

-

-

-

-

-

-

-

Oroville

Paradise

9

-

Unincorporated -

Total 9

Source: FEMA DFIRM, Butte County 2012 Assessor’s Data

8

-

-

8

32

-

-

32

$1,538,283

-

-

$1,538,283

Table 4.82. Unincorporated Butte County – Values in the Area Protected by Levee from the 1% Annual Chance Flood

Land Use

Total Improved

Acres

Improved Flooded

Acres

Big Chico Creek Watershed - Accredited Levee

Agriculture

Commercial

70

35

8

34

Residential

Total

375

480

328

370

Big Chico Creek Watershed - De-Accredited Levee

Agriculture 709 165

Commercial

Industrial

Residential

2

7

309

2

7

215

Unclassified - -

Total 1,027

Source: FEMA DFIRM, Butte County 2012 Assessor’s Data

389

Improved Parcel

Count

3

14

677

694

12

2

4

99

-

117

Population at Risk

Improved Value

$66,254

$7,699,263

$75,364,454

$83,129,971

$2,986,444

$309,199

$1,212,322

$25,107,208

-

$29,615,173

A separate analysis was performed to determine population in the levee protected area. Using

GIS, the levee protected areas were overlaid on the improved residential parcel data. Those parcel centroids that intersect the levee protected area were counted and multiplied by the 2010

Census Bureau average household factors for each jurisdiction and unincorporated area. Results

were tabulated by jurisdiction (see Table 4.83). According to this analysis, there is a total

population of 18,572 in the levee protected areas.

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Table 4.83. Butte County Planning Area - Area Protected by Levee from the 1% Annual

Chance Flood – Improved Residential Parcels and Population

Jurisdiction

Unincorporated

Biggs

Chico

Improved Residential Parcels

694

0

7,089

Gridley

Oroville

Paradise

0

0

0

Total 7,783

Source: DFIRM, US Census Bureau, Butte County 2012 Assessor

’s Data

Critical Facilities at Risk

Population

1,700

0

16,872

0

0

0

18,572

In addition to flood analysis a separate analysis was performed on the critical facility inventory in Butte County and all jurisdictions by Levee Accreditation. GIS was used to determine whether the facility locations intersects an Accredited or De-Accredited PAL (Provisional

Accredited Levee) within the DFIRM flood hazard layer, and if so, which accreditation it intersects. All of these PAL areas are within the 0.2% annual chance flood zone and there are

178 facilities in an accredited area protected by levee and 9 facilities in a de-accredited area, as

shown in Table 4.84. Details of critical facility definition, type, name and address and

jurisdiction by flood zone are listed in Appendix E.

Table 4.84. Butte County Planning Area – Critical Facilities in Area Protected by Levee from the 1% Annual Chance Flood

Levee Type

Accredited

De-Accredited

Total

Source: Butte County GIS

Facility Count

178

9

187

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Table 4.85. Unincorporated County – Critical Facilities in the Area Protected by Levee from the 1% Annual Chance Flood

Levee Type

Accredited

Category

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

At Risk Population Facilities De-Accredited

Grand Total

Source: Butte County GIS

At Risk Population Facilities

Essential Services Facilities

Hazardous Materials Facilities

Cultural and Natural Resources at Risk

Type

Day Care Center

Family Day Care Home

Bridge

CUPA

Total

Family Day Care Home

Group Home

Bridge

CUPA

Total

Facility Count

3

7

4

4

18

1

1

3

4

9

27

The Butte County Planning Area has significant cultural and natural resources located throughout the County as previously described. Vulnerability analysis of these resources was not possible due to data limitations.

Development Trends

There is some planned development, but given the current economy these developments are in doubt.

4.3.11 Severe Weather: Freeze and Winter Storm Vulnerability

Assessment

Likelihood of Future Occurrence—Highly Likely

Vulnerability—Medium

Winter storms typically involve snow and ice, occasionally accompanied by high winds, which can cause downed trees and power lines, power outages, accidents, and road closures.

Transportation networks, communications, and utilities infrastructure are the most vulnerable physical assets in the County. The ability for the County to continue to operate during periods of winter storm and freeze is paramount. Although freeze can burst pipes, freeze normally does not impact structures, but is a life safety issue. Areas prone to excessively cold temperatures are identified normally on a nation-wide assessment scale, which doesn‗t allow detailed results on specific structures. Secondary impacts of freeze can affect the supporting mechanisms or systems of a community‗s infrastructure. For example, when extreme cold is coupled with high winds or ice storms, power lines may be downed, resulting in an interruption in the transmission

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of that power shutting down electric furnaces, which may lead to frozen pipes in homes and businesses.

Vulnerable populations to freeze include:

Homeless

Infants and children under age five

Elderly (65 and older)

Individuals with disabilities

Individuals dependant on medical equipment

Individuals with impaired mobility

In addition to vulnerable populations, pets and livestock are at risk to freeze and cold. However many residents of Butte County are self sufficient and accustomed to rural living and the climate extremes that are part of the territory. The residents of nursing homes and elder care facilities are especially vulnerable to extreme temperature events. It is encouraged that such facilities have emergency plans or backup power to address power failure during times of extreme cold.

Freeze can also affect farmers. High value crops, such as almond and citrus trees, can be severely damaged by freeze, causing large economic issues for farmers and the businesses they support.

Development Trends

Future development built to code should be able to withstand snow loads from severe winter storms. Pipes at risk of freezing should be mitigated by either burying or insulating them from freeze as new facilities are improved or added. Vulnerability to extreme cold will increase as the average age of the population in the County shifts. Greater numbers of future senior citizens will result from the large number of baby boomers in the planning area. As identified in the existing development discussion above, many of the residents of Butte County are self sufficient and accustomed to rural living.

4.3.12 Severe Weather: Heavy Rain/Storms Vulnerability Assessment

Likelihood of Future Occurrence—Likely

Vulnerability—High

According to historical hazard data, severe weather is an annual occurrence in Butte County.

Damage and disaster declarations related to severe weather have occurred and will continue to occur in the future. Heavy rain and thunderstorms are the most frequent type of severe weather

occurrences in the County. Wind (discussed separately in 4.3.13) and lightning often accompany

these storms and have caused damage in the past. However, actual damage associated with the primary effects of severe weather has been limited. It is the secondary hazards caused by weather, such as floods, fire, and agricultural losses that have had the greatest impact on the

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County. The risk and vulnerability associated with these secondary hazards are discussed in

other sections (Section 4.3.7 Flood: 100/200/500-year, Section 4.3.8 Flood: Localized, Section

4.3.9 Levee Failure).

Development Trends

New critical facilities such as communications towers should be built to withstand hail damage, lightning, and thunderstorm winds. While deaths have occurred in the planning area in the past due to lightning, it is difficult to quantify future deaths and injuries due to lightning. Future losses to new development should be minimal.

4.3.13 Severe Weather: Windstorms Vulnerability Assessment

Likelihood of Future Occurrence—Likely

Vulnerability—Medium

The County is subject to potentially destructive straight-line winds. High winds are common throughout the area, and can happen during most times of the entire year. Straight line winds are primarily a public safety and economic concern. Windstorm can cause damage to structures and power lines which in turn can create hazardous conditions for people. Debris flying from high wind events can shatter windows in structures and vehicles and can harm people that are not adequately sheltered.

Future losses from straight line winds include:

Erosion (soil loss) (discussed in greater detail in Section 4.3.6)

Dry land farming seed loss

Wind blown weeds

Downed trees

Power line impacts and economic losses from power outages

Occasional building damage, primarily to roofs

While there has been some scattered record keeping describing the impacts of dust storms, there is little information to indicate that straight-line winds are little more than a nuisance. For example, while winds can blow weeds that can create an additional expense for farmers, they often cause little long term damage and there is little justification for allocating resources to combat them.

Campers, mobile homes, barns, and sheds and their occupants are particularly vulnerable as windstorm events in the region can be sufficient in magnitude to overturn these lighter structures.

Livestock that may be contained in these structures may be injured or killed, causing economic harm to the rancher who owns both the structure and the livestock. Overhead power lines are vulnerable and account for the majority of historical damages. State highways can be vulnerable

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to high winds and dust storms, where high profile vehicles may be overturned by winds and lowered visibility can lead to multi-car accidents.

Winds have caused downed trees that have fallen on homes and have blocked roadways. This is common in the City of Chico and the Town of Paradise.

Development Trends

Future development projects should consider windstorm hazards at the planning, engineering and architectural design stage with the goal of reducing vulnerability. Development trends in the

County are not expected to increase vulnerability to the hazard.

4.3.14 Wildfire Vulnerability Assessment

Likelihood of Future Occurrence—Highly Likely

Vulnerability—High

Risk and vulnerability to the Butte County Planning Area from wildfire is of significant concern, with some areas of the planning area being at greater risk than others as described further in this section. High fuel loads in the planning area, along with geographical and topographical features, create the potential for both natural and human-caused fires that can result in loss of life and property. These factors, combined with natural weather conditions common to the area, including periods of drought, high temperatures, low relative humidity, and periodic winds, can result in frequent and sometimes catastrophic fires. During the May to October fire season, the dry vegetation and hot and sometimes windy weather, combined with continued growth in the

WUI areas, results in an increase in the number of ignitions. Any fire, once ignited, has the potential to quickly become a large, out-of-control fire. As development continues throughout the planning area, especially in these interface areas, the risk and vulnerability to wildfires will likely increase.

The National Fire Plan is a cooperative, long-term effort between various government agency partners with the intent of actively responding to severe wildland fires and their impacts to communities while ensuring sufficient firefighting capacity for the future. For purposes of the

National Fire Plan, the California Department of Forestry and Fire Protection (CAL FIRE) generated a list of California communities at risk for wildfire. The intent of this assessment was to evaluate the risk to a given area from fire escaping off federal lands. Three main factors were used to determine the wildfire threat in the wildland-urban interface areas of California: fuel hazards, probability of fire, and areas of suitable housing density that could create wildland urban interface fire protection strategy situations. The preliminary criteria and methodology for evaluating wildfire risk to communities is published in the Federal Register, January 4, 2001.

The National Fire Plan identifies the following 24 ―Communities at Risk‖ in Butte County in

Table 4.86.

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Table 4.86. Communities at Risk in Butte County

Community

Bangor

Berry Creek

Butte Creek

Butte Meadows

Chico

Cohasset

Concow

Durham

Feather Falls

Forbestown

Forest Ranch

Hurleton

Inskip

Jonesville

Magalia

Oroville

Oroville East

Palermo

Paradise

Pentz

Robinson Mills

South Oroville

Stirling City

Thermalito

Source: California Fire Alliance

Methodology

State Responsibility Area

Federal Threat

X

X

X

X

X

X

X

X

X

X

X

X

X

Federally Regulated

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

CAL FIRE has a legal responsibility to provide fire protection on all State Responsibility Area

(SRA) lands, which are defined based on land ownership, population density and land use. CAL

FIRE is now responsible for determining parcels subject to the SRA Fire Prevention Fee under

AB X1 29. This dataset (sra11_2) represents SRA status as of 7/1/11 and was used for the final determination of which parcels were potentially eligible for the fee. CAL FIRE‘s State

Responsibility Area layer was used in this analysis to show Butte County‘s values, inventory and population by Local Responsibility Area (LRA), State Responsibility Area (SRA) and Federal

Responsibility Area (FRA). The LRA has the most population with 121,863 and values totaling

64,695 parcels with 56,098 having an improved value of $8.6 billion for Butte County. Fire does

2001

2001

2001

2001

2001

2001

2001

Year

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

2001

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not just affect structural values it can also affect land values so the Assessor‘s land values were accounted for in this analysis and all parcels were used in the analysis to represent total county values at risk; however, the whole county will never be on fire at once. Results can be seen in

Figure 4.78. Locations of each responsibility area are shown in Figure 4.78.

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Figure 4.78. Butte County LRA, SRA, and FRA Wildfire Areas

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Table 4.87. Butte County Planning Area - Assets in Local, State, and Federal

Responsibility Areas by Land Use

Land Use

Total

Parcel

Count

Local Responsibility Area

Improved

Parcel

Count

Agriculture

Commercial

3,561

4,496

2,302

Improved

Building Value

Total Other

Value

Total Land

Value Total Value

$289,652,121 $206,075,870 $720,838,723 $1,216,566,714

3,514 $1,806,766,136 $79,610,837 $743,281,294 $2,629,658,267

Industrial

Residential

Unclassified

833

54,408

1,397

516 $320,398,382 $76,957,614 $125,489,577

49,740 $6,092,448,155

26 $91,805,397

$6,485,243 $3,298,932,024

$460,847 $14,084,199

$522,845,573

$9,397,865,422

$106,350,443

56,098 $8,601,070,191 $369,590,411 $4,902,625,817 $13,873,286,419 Total 64,695

State Responsibility Area

Agriculture

Commercial

1,693

381

Industrial

Residential

Unclassified

83

25,064

563

309

249

$27,728,341

$78,227,605

$2,786,676 $113,070,943

$7,620,891 $41,788,942

$143,585,960

$127,637,438

69 $16,102,656

17,905 $1,705,442,049

5 $377,466

$1,079,980 $7,208,986

$716,530 $1,132,251,921

$110,820 $2,364,043

$24,391,622

$2,838,410,500

$2,852,329

18,537 $1,827,878,117 $12,314,897 $1,296,684,835 $3,136,877,849 Total 27,784

Federal Responsibility Area

Agriculture

Commercial

Residential

Unclassified

63

5

311

421

1

4

144

-

$48,626

$456,034

$21,113,858

$0

$0

$73,670

$7,381

$0

$1,046,091

$339,028

$12,179,899

$2,618

$1,094,717

$868,732

$33,301,138

$2,618

Total 800 149 $21,618,518 $81,051 $13,567,636 $35,267,205

Grand Total 93,279 74,784 $10,450,566,826 $381,986,359 $6,212,878,288 $17,045,431,473

Source: Cal FIRE, Butte County Assessor’s 2012 Data

Fire Hazard Severity

CAL FIRE mapped the SRA Fire Hazard Severity Zones (FHSZs), or areas of significant fire hazard, based on fuels, terrain, weather, and other relevant factors. Zones are designated with

Very High, High, Moderate, Non-Wildland/Urban and Urban Unzoned hazard classes. The goal of this mapping effort is to create more accurate fire hazard zone designations such that mitigation strategies are implemented in areas where hazards warrant these investments. The fire hazard zones will provide specific designation for application of defensible space and building standards consistent with known mechanisms of fire risk to people, property, and natural resources.

CAL FIRE also mapped the LRA Very High Fire Hazard Severity Zones (VHFHSZ). Mapping of these areas is based on data and models of potential fuels over a 30-50 year time horizon and their associated expected fire behavior, and expected burn probabilities to quantify the likelihood

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and nature of vegetation fire exposure (including firebrands) to buildings. The California

Building Commission adopted California Building Code Chapter 7A requiring new buildings in

VHFHSZs to use ignition resistant construction methods and materials. These new codes include provisions to improve the ignition resistance of buildings, especially from firebrands. The updated very high fire hazard severity zones will be used by building officials for new building permits in LRA. The updated zones will also be used to identify property whose owners must comply with natural hazards disclosure requirements at time of property sale and 100 foot defensible space clearance. It is likely that the fire hazard severity zones will be used for updates to the safety element of general plans.

The combination of the ―Recommended‖ FHSZ and VHFHSZ layers yielded gaps in data for

Butte County so the DRAFT Fire Hazard Severity Zoning Map was used to supplement these areas to get a complete coverage of Fire Hazards.

Analysis was performed using these three datasets. Using GIS, the parcel layer were overlaid on the FHSZ, VHFHSZ and the Draft FHSZ layers. For the purposes of this analysis, if the parcel centroid intersects the zone‘s area, it will be assumed that the entire parcel is in that area. This analysis illustrates the Fire Hazard Severity Zones specific to the planning area.

Values at Risk

Fire Severity

Results are presented by total planning area, unincorporated county, and by jurisdiction (in their respective annexes), and detailed tables will show improved parcel counts and their structure values by occupancy type (residential, industrial, etc.) within each severity zone. According to

the information in Table 4.89, unincorporated Butte County and the Town of Paradise are the

only two jurisdictions with assets in the Very High Fire Severity Zone. Unincorporated Butte

County has 9,610 improved parcels and roughly $800,276,799 of structure value in the very high fire severity zone. Of the 9,610 parcels, 9,391 are residential. There are 8,649 improved parcels in the high fire severity zone, 5,860 of which are residential. The Town of Paradise has 10,426 parcels and roughly $1.2 billion in structure value. The cities of Chico and Oroville have the next greatest fire risk. Based on CAL FIRE data, the cities of Biggs and Gridley do not have any areas mapped in the fire hazard zones. Although it should be noted that these cities have extensive grassland areas that should be considered at risk to fire ignitions.

Analysis results for the entire Butte County planning area are summarized in Table 4.88, which

summarizes total parcel counts, improved parcel counts and their structure values by occupancy

type as well as the percents of parcels affected by fire. Table 4.89 breaks out the details of fire

severity class and land use type for the unincorporated County.

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Table 4.88. Butte County Planning Area - Count and Structure Value of Improved

Parcels by Fire Severity Class

Jurisdiction

Total

Parcel

Count

Very High Fire Severity

Improved

Parcel

Count

Improved

Building Value

Biggs

Chico

-

-

-

-

Total Other

Value

Gridley

Oroville

Paradise

Total

-

-

11,375

Unincorporated 15,501

26,876

High Fire Severity

-

-

-

-

-

-

Total Land

Value

-

-

-

-

Total Value

10,426 $1,235,383,375 $13,281,621 $635,331,725 $1,883,996,721

9,610 $800,276,799 $7,543,158 $583,071,497 $1,390,891,454

-

-

-

-

20,036 $2,035,660,174 $20,824,779 $1,218,403,222 $3,274,888,175

% of

Affected

Parcels to Total

12%

17%

29%

-

-

-

-

Biggs

Chico

Gridley

Oroville

-

1,588

-

415

Paradise 14

Unincorporated 8,649

Total 10,666

-

-

379

7

-

-

$30,192,153

$1,349,393

6,112 $746,709,995

-

-

$4,920

$0

-

1,328 $323,846,836 $2,650,988 $206,253,053

-

$12,671,414

$1,011,967

-

$532,750,877

-

$42,868,487

$2,361,360

$881,272 $497,977,702 $1,245,568,969

7,826 $1,102,098,377 $3,537,180 $717,914,136 $1,823,549,693

-

2%

-

0.4%

0.02%

9%

11%

Moderate Fire Severity

Biggs

Chico

Gridley

Oroville

Paradise

Unincorporated

-

2,179

-

1,937

104

8,069

- -

1,821 $399,886,822

-

1,104

73

5,679

-

$169,349,212

$15,130,952

$704,942,636

- -

$665,391 $220,405,807

-

$13,833,510

$9,193

$12,208,346

-

$86,541,917

$7,661,334

$467,275,493

-

$620,958,020

-

$269,724,639

$22,801,479

$1,184,426,475

2%

-

2.1%

0.1%

9%

13% Total 12,289 8,677 $1,289,309,622 $26,716,440 $781,884,551 $2,097,910,613

Non-Wildland/Urban Fire Severity

Biggs

Chico

72

210

6

88

3363432

$76,478,806

0

$1,657,220

2251930

$50,979,700

$5,615,362

$129,115,726

0.08%

0.2%

Gridley

Oroville

Paradise

26

3

-

Unincorporated 6,438

Total 6,749

6

1

-

4,576

4,677

$4,812,928

$1,942,106

-

$5,190,031

$0

-

$630,315,997 $209,006,651

$716,913,269 $215,853,902

$3,254,748

$291,006

-

$883,812,395

$940,589,779

$13,257,707 0.03%

$2,233,112 0.003%

- -

$1,723,135,043

$1,873,356,950

Urban Unzoned Fire Severity

Biggs

Chico

687

20,954

614 48759269 4119113 16921482 $69,799,864

19,754 $3,653,437,832 $53,945,289 $1,844,274,540 $5,551,657,661

7%

7%

0.7%

22%

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Jurisdiction

Gridley

Oroville

Paradise

Total

Total

Parcel

Count

2,425

Improved

Parcel

Count

Improved

Building Value

Total Other

Value

2,114 $222,131,464 $2,369,524

Total Land

Value Total Value

$81,802,005 $306,302,993

% of

Affected

Parcels to Total

3%

3,615

-

2,919

-

$480,363,779

-

$34,684,914

-

$161,408,810

-

$676,457,503

-

4%

-

Unincorporated 9,018

36,699

8,167

33,568

$901,893,040 $19,935,218 $449,679,763

$5,306,585,384 $115,054,058 $2,554,086,600

$1,371,508,021

$7,975,726,042

Grand Total 93,279 74,784 $10,450,566,826 $381,986,359 $6,212,878,288 $17,045,431,473

Source:

Butte County Assessor’s 2012 Data; CAL FIRE

10%

39%

100%

Table 4.89. Unincorporated Butte County - Count and Structure Value of Improved

Parcels by Fire Severity Class and Land Use

Very

High

Very

High

Very

High

Fire

Threat

Class Land Use

Agriculture

Total

Parcel

Count

809

Improved

Parcel

Count

Improved

Building Value

62 $3,877,001

Total Other

Value

Total Land

Value Total Value

$342,579 $31,986,919 $36,206,499

% of

Affected

Parcels to Total

1.7% Very

High

Very

High

Commercial 244 155 $46,329,611 $6,923,267 $25,487,559 $78,740,437 0.5%

Industrial 4 1 $756 $0 $23,982 $24,738 0.01%

Residential 13,800

Unclassified 644

9,391

1

$750,043,735

$25,696

$166,492

$110,820

$524,498,506 $1,274,708,733

$1,074,531 $1,211,047

29%

1.4%

Total

High

High

Agriculture

Commercial

15,501

472

99

9,610 $800,276,799 $7,543,158 $583,071,497 $1,390,891,454

108 $9,811,500

74 $28,352,832

33%

$307,457 $37,681,988 $47,800,945 0.99%

$147,751 $10,906,972 $39,407,555 0.2%

High

High

High

Total

Industrial

Residential

Unclassified

72

7,834

172

8,649

Moderate Agriculture 639

Moderate Commercial 156

Moderate Industrial 86

Moderate Residential 6,901

Moderate Unclassified 287

Total 8,069

66 $14,095,005

5,860 $694,098,888

4 $351,770

6,112 $746,709,995

5,306 $625,629,310

3 $284,945

$87,920

$338,144

$0

$881,272

$408,516

$0

$5,340,665

$442,760,745 $1,137,197,777

$1,287,332

$362,549,818

$161,123

$19,523,590

$1,639,102

$497,977,702 $1,245,568,969

213 $23,286,197 $8,258,077 $72,605,704 $104,149,978

111 $36,568,522 $775,853 $18,835,779 $56,180,154

$988,587,644

$446,068

5,679 $704,942,636 $12,208,346 $467,275,493 $1,184,426,475

0.15%

16%

0.4%

18%

1.3%

0.3%

46 $19,173,662 $2,765,900 $13,123,069 $35,062,631 0.18%

14%

0.6%

17%

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Fire

Threat

Class Land Use

Total

Parcel

Count

Improved

Parcel

Count

Improved

Building Value

Total Other

Value

Total Land

Value Total Value

2,190 $277,407,210 $199,450,102 $685,332,939 $1,162,190,251 Non-

Wildland/

Urban

Agriculture 3,301

% of

Affected

Parcels to Total

7%

47 26 $7,376,175 $581,077 $3,559,372 $11,516,624 0.1% Non-

Wildland/

Urban

Commercial

Non-

Wildland/

Urban

Industrial 24 22 $34,141,483 $3,601,160 $2,241,650 $39,984,293 0.05%

2,335 $311,073,756 $5,166,515 $191,982,106 $508,222,377 6% Non-

Wildland/

Urban

Residential 2,693

Non-

Wildland/

Urban

Unclassified 373

Total 6,438

Urban

Unzoned

Agriculture 43

3 $317,373 $207,797 $696,328 $1,221,498

4,576 $630,315,997 $209,006,651 $883,812,395 $1,723,135,043

23 $1,636,317 $236,324 $2,040,345

0.8%

14%

$3,912,986 0.09%

Urban

Unzoned

Commercial 328

Urban

Unzoned

Industrial 111

Urban

Unzoned

Residential 8,412

Urban

Unzoned

Unclassified 124

255

96

7,789

4

$69,083,930

$67,432,526 $17,171,514

$763,592,379

$147,888

$2,190,854

$336,526

$0

$31,562,940

$16,547,368

$102,837,724

$101,151,408

$399,456,939 $1,163,385,844

$72,171 $220,059

0.7%

0.2%

18%

0.3%

Total 9,018 8,167 $901,893,040 $19,935,218 $449,679,763 $1,371,508,021 19%

Grand

Total

47,675 34,144 $3,784,138,467 $249,574,645 $2,881,816,850 $6,915,529,962 100%

Source: Butte County A ssessor’s 2012 Data; CAL FIRE

4.277 Butte County

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Figure 4.79. Butte County Fire Severity Zones

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Population at Risk

The Fire Severity dataset was overlayed on the residential population data. Those parcel centroids that intersect the severity zones were counted and multiplied by the 2012 Census

Bureau average household factors for each jurisdiction and unincorporated area. Results were tabulated by jurisdiction. According to this analysis, there is a total population of 163,695

residents of Butte County Planning Area at risk to wildfire. This is shown in Table 4.90.

Individual jurisdiction numbers are shown in their respective annexes.

Table 4.90. Butte County Planning Area - Count of Improved Residential Parcels and

Population in Fire Severity Zone

City of

Oroville

Town of

Paradise

Unincorporated

County Totals

- 21,279

975 15

23,008

14,357

44,287

18,393

2,720

3

154

-

5,860 -

9,558 21,448

13,000

19,989

5,721

19,083

5,889

75,137

75,168 163,695

Table 4.91. Unincorporated Butte County - Count of Improved Residential Parcels and

Population in Fire Severity Zone

Fire Severity Class

Very High

High

Moderate

Improved Residential Parcels

9,391

5,860

5,306

Non-Wildland/Urban

Urban Unzoned

Total

Source:

Butte County 2012 Assessor’s Data; CAL FIRE

2,335

7,789

30,681

Critical Facilities at Risk

Population

23,008

14,357

13,000

5,721

19,083

75,168

Wildfire analysis was performed on the critical facility inventory in Butte County and all jurisdictions. GIS was used to determine whether the facility locations intersect a wildfire hazard areas provided by CAL FIRE, and if so, which zone it intersects. There are 376 facilities in the very high fire severity zone, 201 facilities in the high fire severity zone and 377 facilities

in the moderate fire severity zone, as shown in Table 4.92. Details of critical facility definition,

type, name and address and jurisdiction by fire severity zone are listed in Appendix E.

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Table 4.92. Butte County Planning Area – Critical Facilities at Risk to Wildfire

Fire

City of Biggs

-

City of Chico

High

Moderate

City of Gridley

-

City of Oroville

High

-

Category

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

-

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

At Risk Population Facilities

Hazardous Materials Facilities

-

Type

Adult Residential

Day Care Center

Family Day Care Home

Infant Center

School

Bridge

Fire Station

CUPA

Total

Day Care Center

Family Day Care Home

Residential Care / Elder

School

Bridge

Fire Station

CUPA

Total

-

Chico Grand Total

Family Day Care Home

CUPA

Total

1

1

2

-

82

2

1

14

1

26

48

2

4

1

12

34

2

2

1

2

10

2

-

Facility Count

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Fire

Moderate

Category

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Town of Paradise

Hazardous Materials Facilities

Very High At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

High*

Moderate

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Essential Services Facilities

At Risk Population Facilities

Type

Adult Residential

Day Care Center

Family Day Care Home

Residential Care / Elder

School

School-Age Day Care

Airport

Bridge 19

Helipad 1

Wastewater Treatment Plant 1

1

2

1

1

Facility Count

3

2

1

CUPA

Total

Oroville Grand Total

Adult Day Care

Adult Residential

Day Care Center

Family Day Care Home

Foster Family Agency

Foster Family Agency Sub

Group Home

Infant Center

Residential Care / Elder

24

56

58

2

15

7

26

1

1

4

1

9

School

School-Age Day Care

Transitional Housing

Bridge

Fire Station

Hospital

Law Enforcement

CUPA

Total

Bridge

Total

Adult Residential

Total

Paradise Grand Total

98

207

1

1

1

1

209

4

1

1

8

3

1

25

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Fire Category

Unincorporated County

Very High At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

High

Hazardous Materials Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

Hazardous Materials Facilities

Type

Adult Residential

Day Care Center

Family Day Care Home

Residential Care / Elder

School

Bridge

Fire Station

Helipad

Law Enforcement

CUPA

Total

Adult Residential

Day Care Center

Family Day Care Home

Residential Care / Elder

School

Small Family Home

Airport

Bridge

Fire Station

Helipad

CUPA

Facility Count

Moderate At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

At Risk Population Facilities

Total

Adult Residential

Day Care Center

Family Day Care Home

Group Home

Infant Center

Residential Care / Elder

164

2

3

6

1

1

4

At Risk Population Facilities

Essential Services Facilities

Essential Services Facilities

Essential Services Facilities

School

Bridge

Fire Station

Helipad

6

169

4

6

Hazardous Materials Facilities CUPA

Total

70

272

Unincorporated Grand Total 605

Source: Butte County GIS, CAL FIRE

**A Paradise Irrigation District Water Treatment Plan is a critical facility, but was not included in the critical facility list for the

County, and was not mapped nor included in this tabular analysis. It would be included in the High category in the table above.

9

66

19

23

1

3

2

7

1

38

169

1

1

9

2

4

2

1

101

5

9

29

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Cultural and Natural Resources at Risk

Butte County has substantial cultural and natural resources located throughout the County as previously described. In addition, there are other natural resources at risk when wildland-urban interface fires occur. One is the watershed and ecosystem losses that occur from wildland fires.

This includes impacts to water supplies and water quality as well as air quality. Another is the aesthetic value of the area. Major fires that result in visible damage detract from that value.

Other assets at risk include wildland recreation areas, wildlife and habitat areas, rangeland, and timber resources. The loss to these natural resources can be significant.

Development Trends

The pattern of increased damages is directly related to increased urban growth spread into historical forested areas that have wildfire as part of the natural ecosystem. Many WUI fire areas have long histories of wildland fires that burned only vegetation in the past. However, with new development, a wildland fire following a historical pattern now burns developed areas. WUI fires can occur where there is a distinct boundary between the built and natural areas or where development or infrastructure has encroached or is intermixed in the natural area. WUI fires may include fires that occur in remote areas that have critical infrastructure easements through them, including electrical transmission towers, railroads, water reservoirs, communications relay sites or other infrastructure assets.

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4.4 Butte County’s Mitigation Capabilities

Thus far, the planning process has identified the natural hazards posing a threat to the planning area and described, in general, the vulnerability of the County to these risks. The next step is to assess what loss prevention mechanisms are already in place. This part of the planning process is the mitigation capability assessment. Combining the risk assessment with the mitigation capability assessment results in the County‘s net vulnerability to disasters, and more accurately focuses the goals, objectives, and proposed actions of this plan.

The HMPC used a two-step approach to conduct this assessment for the County. First, an inventory of common mitigation activities was made through the use of a matrix. The purpose of this effort was to identify policies and programs that were either in place, needed improvement, or could be undertaken if deemed appropriate. Second, the HMPC conducted an inventory and review of existing policies, regulations, plans, and programs to determine if they contributed to reducing hazard-related losses or if they inadvertently contributed to increasing such losses.

This section presents Butte County‘s mitigation capabilities and discusses select state and federal mitigation capabilities that are applicable to Butte County. Information about capabilities specific to the other participating jurisdictions can be found in the annexes.

Similar to the HMPC‘s effort to describe hazards, risks, and vulnerability of Butte County, this mitigation capability assessment describes the County‘s existing capabilities, programs, and policies currently in use to reduce hazard impacts or that could be used to implement hazard mitigation activities. This assessment is divided into four sections: regulatory mitigation

capabilities are discussed in Section 4.4.1; administrative and technical mitigation capabilities

are discussed in Section 4.4.2; fiscal mitigation capabilities are discussed in Section 4.4.3; and

mitigation outreach and partnerships are discussed in Section 4.4.4. A discussion of other mitigation efforts follows in Section 4.4.5.

4.4.1 Butte County’s Regulatory Mitigation Capabilities

Table 4.93 lists planning and land management tools typically used by local jurisdictions to

implement hazard mitigation activities, and indicates those that are in place in Butte County.

Excerpts from applicable policies, regulations, and plans and program descriptions follow to provide more detail on existing mitigation capabilities.

Table 4.93. Butte County Regulatory Mitigation Capabilities

Regulatory Tool (ordinances, codes, plans)

General plan

Zoning ordinance

Subdivision ordinance

Y/N Date

Yes 10/26/2010

Yes 7/8/2011 DRAFT

Yes

Comments

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Regulatory Tool (ordinances, codes, plans)

Growth management ordinance

Floodplain ordinance

Other special purpose ordinance

(stormwater, steep slope, wildfire)

Building code

BCEGS Rating

Fire department ISO rating

Erosion or sediment control program

Stormwater management program

Site plan review requirements

Capital improvements plan

Economic development plan

Local emergency operations plan

Community Wildfire Protection Plans

Flood insurance study or other engineering study for streams

Elevation certificates

Other

Source: AMEC Data Collection Guide

Y/N

No

Yes

Yes

Date Comments

Stormwater, per State/Federal requirements

Yes

Yes

Version: 2010 California Building Code

Rating:

Yes Public Works

Yes Certain building permits

Yes 3/29/2011 Capital Improvements Program

Yes 2/2011

Yes 2008

Yes

Yes 1/6/2011 FIRM and FIS incorporated, by Ordinance, into

Butte County Code.

Required for building permits within FEMA identified flood plain/floodway.

As indicated in the table above, Butte County has several plans and programs that guide the

County‘s mitigation of development of hazard-prone areas. Starting with the Butte County

General Plan, which is the most comprehensive of the County‘s plans when it comes to mitigation, some of these are described in more detail below.

Butte County General Plan (2010)

The Butte County General Plan is a comprehensive, long-term framework for the protection of the County‘s agricultural, natural, and cultural resources and for development in the County.

Designed to meet state general plan requirements, it outlines policies, standards, and programs and sets out plan proposals to guide day-to-day decisions concerning Butte County‘s future. It is a legal document that serves as the County‘s blueprint for land use and development. It is broken into the following sections:

Land Use Element

Housing Element

Economic Development Element

Agriculture Element

Water Resources Element

Circulation Element

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Conservation and Open Space Element

Health and Safety Element

Public Facilities and Service Element

Area and Neighborhood Plans Element

Goals and policies related to mitigation of natural hazards can be found in the discussion below.

Land Use Element

The Land Use Element is the central focus of the General Plan. This Element sets policy for land uses in the unincorporated county through 2030, establishing the foundation for future land use and development. The Land Use Element designates the distribution of land uses, such as residential, commercial, industrial, agricultural, open space, recreation and public uses. It also addresses the permitted density and intensity of the various land use designations as reflected on the County‘s General Plan Land Use Diagram.

This Element presents land use and overlay designations and the associated land use map, and discusses the Area Plans, Specific Plans, and Planned Unit Developments that are anticipated under this General Plan. The Land Use Element is divided into the following sections:

Background Information. Provides details on jurisdictional boundaries, existing land uses, and planning efforts in Butte County. An expanded discussion about land use in Butte

County is available in Chapter 1 (Land Use) of the Butte County General Plan 2030 Setting and Trends Report.

General Plan Land Use Designations. Describes the characteristics and intensity of each land use designation and contains a map of the application of these designations.

General Plan Overlays. Describes the characteristics of each General Plan overlay.

Area Plans, Specific Plans, and Planned Unit Developments. Describes the Area Plan,

Specific Plans, and Planned Unit Developments that are to be developed under this General

Plan, and provides a general overview of how these areas will develop in the future.

Land Use Map. Illustrates the location and extent of land use designations on each parcel of land in the unincorporated area.

Goals, Policies, and Actions. Provides guidance to Butte County related to land use decisions.

Goals

The related mitigation goals and policies of the Land Use element are:

GOAL:

Goal LU-1 Continue to uphold and respect the planning principles on which the County's land use map is based.

Objective: The County shall conserve important habitat and watershed areas, while protecting the public safety of

County residents.

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GOAL:

Goal LU-1 Continue to uphold and respect the planning principles on which the County's land use map is based.

Objective: The County shall limit development in foothill and mountain areas that are constrained by fire hazards, water supply, migratory deer habitat, or infrastructure.

GOAL: Goal LU-11 Effectively coordinate planning efforts with the municipalities.

Objective:

The County shall continue to collaborate on planning and building within the municipalities’ spheres of influence in order to establish consistent development standards.

Specific Plans

There are seven areas in the county that are intended for development under a Specific Plan. A

―Specific Plan‖ is defined in the California Government Code (Section 65450 et seq) as a legal tool for detailed design and implementation of a defined portion of the area covered by a General

Plan. A Specific Plan includes detailed regulations, conditions, programs, and/or proposed legislation that are needed to implement General Plan designations and policies on a particular site. The underlying designations for these areas shall remain in effect until and unless the

Specific Plan is adopted, at which point the land use designations in that Plan will replace the designations in this General Plan. Specific plans in the County are:

Upper Stilson Canyon Specific Plan

Doe Mill/Honey Run Specific Plan

Paradise Urban Reserve Specific Plan

Southeast Paradise Specific Plan

South Ophir Specific Plan

Rio D‘Oro Specific Plan

Stringtown Mountain Specific Plan (Existing and Proposed Specific Plan)

Housing Element

The Housing Element presents the goals, policies and actions that will guide Butte County‘s efforts in housing production, rehabilitation, and preservation over the forthcoming five-year

Housing Element planning period. The goals of the Butte County Housing Element Update include the following:

Goal 1: Provide for the County's regional share of new housing for all income groups and future residents as identified in the Housing Needs Assessment.

Goal 2: Encourage the provision of affordable housing in the unincorporated area.

Goal 3: Partner with property owners to preserve and rehabilitate the existing supply of housing.

Goal 4: Collaborate with existing service providers to meet the special housing needs of homeless persons, elderly, large families, disabled persons, and farmworkers.

Goal 5: Ensure equal housing opportunity.

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Goal 6: Promote energy conservation.

The Housing Element works in conjunction with the Land Use Element to ensure that housing developments are not located in any regulated hazard zone.

Economic Development Element

This Element addresses Butte County‘s local economy, job creation and the County‘s fiscal health. There are no goals or policies that relate to mitigation activities in this portion of the general plan.

Agriculture Element

This Element includes goals, policies and actions intended to conserve agricultural land, promote agricultural uses and maintain the natural resources necessary to foster agricultural growth.

Mitigation related activities in the Agriculture Element are:

GOAL:

Goal AG-5 Reduce conflicts between urban and agricultural uses and between habitat mitigation banking and agricultural uses.

Objective: AG-P5.5 To protect agricultural areas from flooding, all urban/residential development projects shall provide a drainage plan prepared by a registered civil engineer that, at a minimum, addresses: a. Pre-development drainage conditions for the development site, including peak runoff rates and runoff volumes. b. Post-development drainage conditions, including changes in peak runoff rates and runoff volumes. c. Off-site drainage or flooding impacts and proposed or recommended mitigation measures. d. Mechanisms for maintenance of drainage facilities.

Water Resources Element

This Element includes goals, policies and actions intended to protect and conserve Butte

County‘s water sources, stormwater management, water service providers, water storage facilities, the supply and demand of water in Butte County and the County‘s management efforts for water resources. Mitigation related goals and policies in this element include:

GOAL: Goal W-5 Protect water quality through effective stormwater management.

Objective: W-P5.2 New development projects shall identify and adequately mitigate their water quality impacts from stormwater runoff.

Objective: W-P5.3 Pervious pavements shall be allowed and encouraged where their use will not hinder mobility.

Objective: W-P5.4 Temporary facilities shall be installed as necessary during construction activities in order to adequately treat stormwater runoff from construction sites.

Objective: W-P5.5 Stormwater collection systems shall be installed concurrently with construction of new roadways to maximize efficiency and minimize disturbance due to construction activity.

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GOAL: Improve streambank stability and protect riparian resources.

Objective: W-P6.1 Any alteration of natural channels for flood control shall retain and protect riparian vegetation to the extent possible while still accomplishing the goal of providing flood control. Where removing existing riparian vegetation is unavoidable, the alteration shall allow for reestablishment of vegetation without compromising the flood flow capacity.

Objective: W-P6.2 Where streambanks are already unstable, as demonstrated by erosion or landslides along banks, tree collapse, or severe in channel sedimentation, proponents of new development projects shall prepare a hydraulic and/or geomorphic assessment of on-site and downstream drainageways that are affected by project area runoff

Circulation Element

State law requires that a Circulation Element specify the general location and extent of existing and proposed major streets and other transportation facilities. The Element is correlated with the

Land Use Element to provide adequate pedestrian, bicycle, motor vehicle, transit, air transportation and emergency access to serve both new and existing land uses. The Element also addresses transit-oriented development; cooperation with other agencies, such as the California

Department of Transportation; and the environmental effects of transportation, such as air quality and greenhouse gas emissions. The circulation of infrastructure related to energy, water, wastewater and stormwater are discussed in the Water Resources, Conservation and Open Space, and Public Facilities and Services Elements. Mitigation related goals and policies in this element include:

GOAL: Goal CIR-9 Provide a circulation system that supports public safety.

Objective: CIR-P9.1 All new road systems, both public and private, shall provide for safe evacuation of residents and adequate access to fire and other emergency services by providing at least two means of emergency access to an interconnected collector system. New road systems will include reduction and maintenance of roadside vegetation.

GOAL: Goal CIR-10 Facilitate the mobility of Butte County residents with special mobility needs.

Objective: CIR-P10.1 The County encourages the Butte County Association of Governments to provide transit services that meet the needs of youth and seniors, by improving connections to schools, parks, libraries, social services, medical offices and shopping.

Conservation and Open Space Element

This Element combines two elements required under State law: the Open Space Element and the

Conservation Element. It addresses the six types of open space identified by State law: open space for the conservation of natural resources, open space used for the managed production of resources, open space for public health and safety, open space in support of the mission of military installations, and open space for the protection of Native American sacred sites. This

Element also addresses greenhouse gases, energy, air quality, biological resources, timber resources, mineral and soil resources, cultural resources and scenic resources. This Element is divided into the following sections:

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Greenhouse Gases

Energy

Air Quality

Biological Resources

Timber Resources

Mineral and Soil Resources

Military Installations

Cultural Resources

Scenic Resources

Mitigation related goals and policies in this element include:

GOAL: Goal COS-8 Maintain and promote native vegetation.

Objective: COS-P8.1 Native plant species shall be protected and planting and regeneration of native plant species shall be encouraged, wherever possible, in undisturbed portions of development sites.

Objective: COS-P8.2 New landscaping shall promote the use of xeriscape and native tree and plant species, including those valued for traditional Native American cultural uses.

Objective: COS-P8.3 Native plants shall be used wherever possible on County owned and -controlled property.

Objective: COS-P8.4 Introduction or spread of invasive plant species during construction of development projects shall be avoided by minimizing surface disturbance; seeding and mulching disturbed areas with certified weed-free native mixes; and using native, noninvasive species in erosion control plantings.*

GOAL: Goal COS-11 Protect timber resources and promote sustainable timber production.

Objective: COS-P11.2 The County shall support and cooperate with CAL FIRE in its responsibilities related to timber and forest practice laws.

GOAL:

Goal COS-12 Protect economically viable mineral resources and related industries while avoiding land use conflicts and environmental impacts from mining activities

Objective: COS-P12.5 New mineral haul routes shall avoid landslides, highly erodible soils, residential areas and schools, when feasible.

Health and Safety Element

This Element combines two elements required under State law: the Noise Element and the Safety

Element. It provides information about risks in Butte County due to natural and human made hazards, and contains goals, policies and actions designed to protect the community and its property from hazards and noise. The Health and Safety Element addresses noise problems, quantifies current and projected noise levels from a variety of sources, and establishes noise compatibility guidelines for different land uses. It also addresses risks associated with flooding and dam or levee inundation; seismic and other geologic hazards; fire hazards; and hazardous materials. This Element also addresses emergency response, disaster preparedness and community health. Mitigation related goals and policies in this element include:

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GOAL: Goal HS-2 Protect people and property from flood risk.

Objective: HS-P2.1 The County supports the efforts of regional, State and federal agencies to improve flood management facilities along the Sacramento River while conserving the riparian habitat of the river.

Objective: HS-P2.2 The County supports the efforts of private landowners and public agencies to maintain existing flood management facilities.

Objective: HS-P2.3 The County supports the Flood Mitigation Plan and the Flooding Mitigation Action Plan in the

Butte County Multi- Jurisdictional All-Hazard Pre-Disaster Mitigation Plan (MHMP).

Objective: HS-P2.4 Development projects on lands within the 100-year flood zone, as identified on the most current available maps from FEMA, shall be allowed only if the applicant demonstrates that it will not: a. Create danger to life and property due to increased flood heights or velocities caused by excavation, fill, roads and intended use. b. Create difficult emergency vehicle access in times of flood. c. Create a safety hazard due to the height, velocity, duration, rate of rise and sediment transport of the flood waters expected at the site. d. Create excessive costs in providing governmental services during and after flood conditions, including maintenance and repair of public facilities. e. Interfere with the existing water conveyance capacity of the floodway. f. Substantially increase erosion and/or sedimentation. g. Require significant storage of material or any substantial grading or substantial placement of fill that is not approved by the County through a development agreement, discretionary permit, or other discretionary entitlement; a ministerial permit that would result in the construction of a new residence; or a tentative map or parcel map. h. Conflict with the provisions of the applicable requirements of Government Code Sections 65865.5,

65962 or 66474.5.

Objective: HS-P2.5 The lowest floor of any new construction or substantial improvement within Flood Zones A,

AE, AH and shaded Zone X, shall be elevated 1 foot or more above the 100-year flood elevation.

(County Flood Ordinance Sec. 26-22). Within urban or urbanizing areas, as defined in Government

Code 65007, the lowest floor of any new construction or substantial improvements shall be elevated a minimum of 1 foot above the 200-year flood elevation.

Objective: HS-P2.6 After General Plan 2030 and the Zoning Ordinance are amended to be consistent with the

Central Valley Flood Protection Plan, scheduled for adoption in July 2012, the County shall make specific findings prior to approval of a development agreement, subdivision or discretionary permit or other discretionary entitlement, or any ministerial permit that would result in the construction of a new residence. The County shall make findings that it has imposed conditions that will protect the property to the urban level of flood protection, as defined in Government Code Section 65007, in urban and urbanizing areas, or to the national Federal Emergency Management Agency standard of flood protection in nonurbanized areas.

GOAL: Goal HS-3 Prevent and reduce flooding.

Objective: HS-P3.1 Watersheds shall be managed to minimize flooding by minimizing impermeable surfaces, retaining or detaining stormwater and controlling erosion.

Objective: HS-P3.2 Applicants for new development projects shall provide plans detailing existing drainage conditions and specifying how runoff will be detained or retained on-site and/or conveyed to the nearest drainage facility and shall provide that there shall be no increase in the peak flow runoff to said channel or facility.

Objective: HS-P3.3 All development projects shall include stormwater control measures and site design features that prevent any increase in the peak flow runoff to existing drainage facilities.

Objective: HS-P3.4 Developers shall pay their fair share for construction of off-site drainage improvements necessitated by their projects.

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GOAL: Goal HS-4 Reduce risks from levee failure.

Objective: HS-P4.1 The County supports the efforts of regional, State or federal agencies to study levee stability throughout the county, particularly levees that were designed and constructed to provide a minimum

100-year level of protection.

Objective: HS-P4.2 The County supports the efforts of levee owners and regional, State, or federal agencies to design and reconstruct levees that do not meet flood protection standards (200-year for urban or urbanizing areas, 100-year for all other areas) to bring them into compliance with adopted State and/or federal standards.

Objective: HS-P4.3 New development proposals in levee inundation areas shall consider risk from failure of these levees.

GOAL: Goal HS-5 Reduce risks from dam inundation.

Objective: HS-P5.1 New development proposals in dam inundation areas shall consider risks from failure of these dams.

GOAL: Goal HS-6 Reduce risks from earthquakes.

Objective: HS-P6.1 Appropriate detailed seismic investigations shall be completed for all public and private development projects in accordance with the Alquist-Priolo Earthquake Fault Zoning Act.

Objective: HS-P6.2 Geotechnical investigations shall be completed prior to approval of schools, hospitals, fire stations and sheriff stations, as a means to ensure that these critical facilities are constructed in a way that mitigates site-specific seismic hazards.

GOAL: Goal HS-7 Reduce risks from steep slopes and landslides.

Objective: HS-P7.1 Site-specific geotechnical investigations shall be required to assess landslide potential for private development and public facilities projects in areas rated ―Moderate to High‖ and ―High‖

GOAL: Goal HS-8 Reduce risks from erosion.

Objective: Site-specific geotechnical investigations shall be required to assess erosion potential for private development projects and public facilities in areas rated ―Very High‖

GOAL: Goal HS-10 Avoid subsidence from groundwater withdrawal.

Objective: HS-P10.1 Continue to work with water providers and regulatory agencies to ensure that groundwater withdrawals do not lead to subsidence problems.

Objective: HS-P10.2 Existing programs to monitor potential subsidence activity shall be supported.

GOAL: Goal HS-11 Reduce risks from wildland and urban fire.

Objective: HS-P11.1 Fire hazards shall be considered in all land use and zoning decisions, environmental review, subdivisions review and the provision of public services.

Objective: HS-P11.2 Create communities that are resistant to wildfire by supporting the implementation of community wildfire protection plans and wildfire fuel load reduction measures in coordination with the appropriate government, community group, or non-profit organization and California Department of

Forestry and Fire Protection (CAL FIRE).

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GOAL: Goal HS-11 Reduce risks from wildland and urban fire.

Objective: HS-P11.3 The County supports the Wildfire Mitigation Action Plan, the Butte County Multi-Jurisdictional

All-Hazard Pre-Disaster Mitigation Plan (MHMP), and the Butte Unit Community Wildfire Protection Plan prepared by California Department of Forestry and Fire Protection (CAL FIRE) and will cooperate with the Butte County Fire Department and the Butte County Fire Safe Council in implementing these plans.

Objective: HS-P11.4 New development projects shall meet current fire safe ordinance standards for adequate emergency water flow, emergency vehicle access, signage, evacuation routes, fuel management, defensible space, fire safe building construction and wildfire preparedness.

GOAL: Goal HS-12 Protect people and property from wildland or urban fires.

Objective: HS-P12.1 Regulations regarding vegetation clearance around structures, including the removal of ladder fuels, shall be maintained and enforced.

Objective: HS-P12.2 Fuelbreaks shall be required along the edge of developing areas in High and Very High Fire

Hazard Severity Zones.

Objective: HS-P12.3 Fire resistant landscaping and fuelbreaks shall be required in residential areas.

Objective: HS-P12.4 All development projects in wildland urban interface areas in High or Very High Fire Hazard

Severity Zones shall provide, at a minimum, small-scale water systems for fire protection.

Objective: HS-P12.5 After wildfires, the County shall assess risks of landslide, erosion and flooding in burn areas and cooperate with other appropriate agencies on plans to mitigate these risks.

GOAL:

Goal HS-13 Identify safe and effective evacuation routes and access for fire prevention and suppression.

Objective: HS-P13.1 New development in High or Very High Fire Hazard Severity Zones shall identify access and egress routes and make improvements or contribute to a fund to develop, upgrade and maintain these routes.

GOAL: Goal HS-14 Reduce risks from the harmful effects of hazardous materials.

Objective: HS-P14.1 The County supports the Hazardous Materials Emergency Response Plan (Area Plan).

Objective: HS-P14.2 Hazardous materials carrier routes shall be designated to direct hazardous materials transport away from populated areas.

Objective: HS-P14.3 Hazardous and toxic materials shall be transported only along the designated highway and rail routes in the County.

Objective: HS-P14.4 Proponents of new hazardous waste management facilities shall demonstrate that potential environmental impacts can be mitigated as a condition of approval.

Objective: HS-P14.5 Environmental assessment and/or investigation shall be required prior to General Plan

Amendment or Rezone approval that would allow uses with sensitive receptors, such as residential developments, schools, or care facilities, on sites previously used for commercial, industrial, agricultural or mining uses to determine whether soils, groundwater and existing structures are contaminated and require remediation. Policies and oversight authority shall follow Health and Safety Code Division 20,

Chapters 6.5 and 6.8 when determining jurisdiction.

GOAL: Goal HS-15 Ensure that Butte County is prepared for emergency situations.

Objective: HS-P15.1 The County shall conduct continuous advance planning to anticipate potential threats and improve emergency response effectiveness.

Objective: HS-P15.2 Critical emergency response facilities such as fire, police, emergency service facilities and utilities shall be sited to minimize their exposure to flooding, seismic effects, fire, or explosion.

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GOAL: Goal HS-15 Ensure that Butte County is prepared for emergency situations.

Objective: HS-P15.3 Emergency access routes shall be kept free of traffic impediments.

Objective: HS-P15.4 Streets and developed properties shall be clearly marked to enable easy identification.

Public Facilities and Services Element

This Element assesses the current state of public services and facilities within the county, including general government services, fire protection and emergency medical services, sheriff services, public education, libraries, parks and recreation, solid waste and waste diversion, and wastewater. Mitigation related goals and policies in this element include:

GOAL:

Goal PUB-2 Provide adequate fire protection and emergency medical response services to serve existing and new development.

Objective: PUB-P2.1 The County supports the expansion of fire volunteer services, especially in remote areas, as warranted by Standards of Cover criteria.

Objective: PUB-P2.2 The adopted Standards of Cover for fire protection shall be maintained and implemented.

Objective: PUB-P2.3 New fire stations shall be located on sites that are easily accessible, close to existing or future development and/or close to fire hazard areas.

Butte County Ordinances

The Butte County General Plan provides policy direction for land use, development, open space protection, and environmental quality; however, this policy direction must be carried out through numerous ordinances, programs, and agreements. The following ordinances are among the most important tools for implementing the General Plan and/or are critical to the mitigation of hazards identified in this plan.

Emergency Organization (Butte County Code Chapter 8.1)

The declared purposes of this chapter are to provide for the preparation and execution of plans for the protection of persons, the environment, and property within the County of Butte in the event of an emergency, the direction of the emergency management organization and the coordination of the emergency functions of the County of Butte with the Cities of Chico,

Oroville, Gridley, Biggs and the Town of Paradise and all other affected public agencies, corporations, organizations and private persons within the County of Butte.

Building Code (Butte County Code Chapter 26-1)

This ordinance establishes the adoption of the 2010 California Building Code as the building code applicable to the County, which are based on the International Building Codes. The building code includes the Building, Electrical, Mechanical, Plumbing, Energy, Fire, and the

NEW Green Building Code - A Guide to the California Green Building Standards Code (Low-

Rise Residential).

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Butte County Land Grading Ordinance (Butte County Code, Chapter 13.1)

The purpose of this article is the control of erosion and siltation, the enhancement of slope stability, the protection of said resources and the prevention of related environmental damage by establishing standards and requiring permits for grading. Butte County is noted for its scenic natural beauty, for its streams, creeks, and vernal pools, for its diversity of vegetation including rare and endangered plant species, for its fish and other wildlife, and for its sources of water. All of the said resources are subject to serious damage by improper and uncontrolled grading, including, but not limited to, erosion and siltation jeopardizing or destroying fish and other wildlife and the disruption or contamination of sources of water being used for domestic and other purposes.

Fire Prevention and Protection (Butte County Code Chapter 38A)

It is the intent of this chapter to require the owners and occupants of real property in the unincorporated areas of the county to maintain said properties to:

Reduce the risk of uncontrolled fires and the harm they may cause to individuals;

Minimize the spread of any fire to other properties and buildings;

Reduce obstructions to fire suppression efforts if a fire does occur;

Increase the opportunity for firefighters to successfully protect lives, residences and other valuable buildings from wildfires;

Protect populated areas, such as metropolitan areas, suburban areas, and urban and rural subdivisions from encroaching wildfires;

Reduce the spread of residential and other building fires into the wildland vegetation; and

Prevent interference with fire hazard abatement activities.

It is the further intent of the county to seek voluntary compliance with this chapter and to provide remedies if such compliance is not obtained.

Zoning Ordinance (Butte County Code Title 24)

This chapter divides the unincorporated territory of the county into geographical districts designated as zoning districts. It establishes regulations limiting the use of land and structures, location, height and bulk of the structures, the open spaces about buildings and provides for such other measures as will accomplish the purposes of this chapter. This chapter is adopted to promote and protect the public health, safety and general welfare for the following more particularly specified purposes:

To assist in providing a definite plan of development for the county, and to facilitate, encourage, guide, control and regulate the future growth of the county.

To protect the character, social and economic stability of agricultural, residential, commercial, industrial and other areas within the county; to assure the orderly and beneficial development of such areas; and more particularly, to provide adequate light and air; to avoid

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undue concentration of population; to facilitate the adequate provision for transportation, water, sewage, drainage facilities, schools, parks and other public developments; to conserve and develop natural resources; to protect the food supply; to conserve property values; to conserve energy; and to promote efficient urban design and arrangement, and to secure economy in governmental expenditures.

To obviate the menace to the public safety resulting from the location of buildings, and uses of buildings and of land, adjacent to streets and highways which are a part of the streets and highways element of the general plan of the county, or other thoroughfares, so that existing or prospective traffic circulation on said highways will be facilitated.

To implement the policies of the Butte County general plan.

It is expressly declared that all of the provisions of this chapter shall apply to all property within the unincorporated territory of Butte County whether owned by private persons, firms or corporations, or by the government of the United States of America, or any of its agencies, or by the State of California or any of its political subdivisions or agencies, unless the federal or state activity is specifically exempted from local review, or by any county including the County of

Butte, town or municipal corporation or any of its or their agencies, or by any district formed under the laws of the State of California.

The board of supervisors shall have the authority to decide any question involving the interpretation or application of any provision of this chapter. Said provisions of this chapter and the applications thereof shall be held to be the minimum requirements necessary to promote the public health, safety and general welfare. Except as specifically herein provided, it is not intended by this chapter to repeal, abrogate, annul or in any way to impair or interfere with any existing provision of law or ordinance, or any rule, regulation or permit previously adopted or issued or which may be adopted or issued pursuant to law relating to the use of buildings or premises, or relating to the erection,, construction, establishment, moving, alteration or enlargement of any building improvement; nor is it intended by this chapter to interfere with or abrogate or annul any easement, covenant or other agreement between parties or to annul or abrogate the public improvements emplaced and paid for by property owners pursuant to previously adopted county plans; provided, however, that in cases in which this chapter imposes a greater restriction upon the erection, construction, establishment, moving, alteration or enlargement of buildings or the use of any such building or premises in said several districts, or any of them, than is imposed or required by such existing provisions of law or ordinance, or by such rules, regulations or permits, or by such easements, covenants or agreements, then in such case the provisions of this chapter shall control.

Subdivision Ordinance (Butte County Code Title 20)

This chapter is enacted to facilitate and insure orderly development of lands in the unincorporated areas in the county. This chapter shall implement the objectives established for the development of the county in conformance with its general plan, and the master streets and highways plan. A proposed subdivision or land division shall be considered in relation to such

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plans. This chapter shall provide standards governing the surveys, designs and improvements of subdivisions; and the submission of maps, plans and specifications for the construction of improvements.

This chapter shall provide for governing standards for health and sanitation requirements, and the construction and installation of streets, roads, highways, public utilities and other improvements.

The Butte County Board of Supervisors shall provide a fee schedule for services rendered by the county. This chapter shall provide for the creation of reasonable building sites by establishing adequate road widths, proper alignment of roads, adequate lot sizes and means of ingress and egress to and from the property.

This chapter shall control the division of land which is subject to inundation by flooding from natural streams or artificial ponding caused by man, and other detrimental influences which may cause land to be unsuitable for satisfactory development. This chapter shall control the division of land which may be subject to dangerous or unsuitable soil conditions of any type, or subject to any other impediments affecting the use of the land for human habitation. This chapter shall provide rules and regulation governing the contents of tentative and final subdivision maps, land divisions and parcel maps; it shall establish methods for the processing and filing of the maps and regulate other related matters.

This chapter shall provide for the numbering of all final subdivision maps in addition to the name given by the subdivider. Such numbers shall give the last two (2) digits of the year in which the map was filed and the number, in order, of the subdivision map submitted in that year.

Floodplain Management Ordinance (Butte County Code Chapter 26, Article IV)

The department of Development Services is authorized and directed to enforce all the provisions of this article. The director of the Department of Public Works or his duly authorized designee is designated as the "flood plain administrator."

Additional requirements in flood hazard zones

Within flood hazard Zones A, AE, AH and AO, on the official maps there are additional requirements in conjunction with the issuance of development permits for new construction, substantial improvements and other developments, including the placement of manufactured homes and pre-fabricated buildings, as set forth in this article.

Application

To obtain a development permit in said zones, the applicant shall first file an application therefore in writing on a county form furnished for that purpose by the Department of

Development Services and approved by the Director of Development Services. Every such application shall:

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Identify and describe the work to be covered by the permit for which application is made;

Describe the land on which the proposed work is to be done by lot, block, tract and house and street address, or similar description that will readily identify and definitely locate the proposed building or work;

Indicate the use or occupancy for which the proposed work is intended;

Be accompanied by plans and specifications for the proposed development drawn to scale, and showing the dimensions and elevation of the site on which the proposed work is to be done, existing and/or proposed structures, fill, storage of materials and drainage facilities;

Be signed by the permittee or his authorized agent who may be required to submit evidence to indicate such authority;

Be accompanied by:

The proposed National Geodetic Vertical Datum ("NGVD") elevation of the lowest floor of all structures or, in the case of any nonresidential structure which will be floodproofed, the proposed NGVD elevation to which it will be floodproofed; or

In AO zones, the minimum vertical distance above the highest adjacent grade for the lowest floor;

Be accompanied by all appropriate certifications required for lowest floor elevations for all structures, floodproofing of nonresidential structures, wet floodproofing and floodway encroachments;

Give such other information as reasonably may be required by the county.

Stormwater Management and Discharge Control Ordinance (Butte County Code Chapter

50)

This chapter implements the Butte County Storm Water Management Program (Program) (2003) which is a comprehensive program comprised of various elements and activities designed to reduce storm water pollution to the maximum extent practicable and eliminate prohibited nonstorm water discharges in accordance with federal and state laws and regulations. These laws and regulations are implemented through National Pollutant Discharge Elimination System (NPDES) municipal storm water discharge permits. The plan includes processes for accomplishing the goals of minimizing construction site runoff as well as post-construction stormwater management in newly developed and redeveloped areas.

Butte County Plans/Studies

Paradise Irrigation District Urban Water Management Plan (2010)

The purpose of the Urban Water Management Plan is to inform the public and state agencies of the Paradise Irrigation District‘s water supply availability, exposure to droughts, conservation efforts, and plans for future supply. Urban Water Management Plans are prepared by

California‘s urban water suppliers to support their long-term resource planning and ensure adequate water supplies are available to meet existing and future water demands. This plan shows current supply calculations, what impacts a customer can expect during drought periods

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and the impacts to water supply into the future. This Plan also delineates future storage project the District could undertake to reduce the risks to drought.

Butte Creek Watershed Floodplain Management Plan (2005)

The overall purpose of the Butte Creek Watershed FMP is to provide guidance to agencies and the public responsible for and interested in protecting life, property, and livestock, involved in land use planning, responsible for administering the Federal Emergency Management Agency

(FEMA) National Flood Insurance Program (NFIP), and responsible for responding to flood emergencies within the Butte Creek watershed. Important in formulating the Butte Creek

Watershed FMP was to ensure that proposed mitigation measures to address flooding hazards would not adversely affect fish and wildlife, and would maximize the potential to enhance fish and wildlife habitat. The Butte Creek Watershed FMP, intended as a tool to characterize and mitigate hazards related to flooding within the Butte Creek watershed, does not challenge past efforts and efforts currently underway to enhance riparian habitat and to assist the fish population growth. The goal and objectives, reviewed by the public at several public meetings was adopted by the Steering Committee. These served as a guide in the planning process of developing the

Butte Creek Watershed FMP. The goal and objectives include:

Goal: Minimize environmental impacts of required flood management.

Objective 1: Utilize relevant information to develop flood protection measures that protect life and property and enhance fish and wildlife habitat.

Objective 2: Support improved performance and coordination among and within agencies responsible for providing flood protection, post-flood restoration, and protection of habitat.

Objective 3: Support the development of pre-flood emergency response management.

Objective 4: Establish criteria for development within the floodplain, which would not adversely impact the floodplain, flood flow capacity, or neighboring properties.

Objective 5: Develop the document to comply with the Disaster Mitigation Act of 2000

(DMA 2000), Local Hazard Mitigation Plan.

Butte County Stormwater Management Plan (2003)

The Butte County Storm Water Management Program (Program) is a comprehensive program comprised of various elements and activities designed to reduce storm water pollution to the maximum extent practicable (MEP) and eliminate prohibited non-storm water discharges in accordance with federal and state laws and regulations. These laws and regulations are implemented through National Pollutant Discharge Elimination System (NPDES) municipal storm water discharge permits.

Butte County recognizes the importance of effective storm water management and has utilized resources to develop and implement the Program. It is foreseen that the Public Works Land

Development Division will coordinate management and administration of the County‘s Program.

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The Department of Public Works and the Development Services Department are responsible for planning, inspection, enforcement, and permit clearances for construction projects within the

County. The Department of Public Works is responsible for the County‘s storm water drainage conveyance system.

Sacramento and San Joaquin River Basins Comprehensive Study (2002)

This study was a joint effort by the State of California Reclamation Board (now the Central

Valley Flood Protection Board) and the U.S. Army Corps of Engineers (USACE) in coordination with Federal, State and local agencies. It provides a Comprehensive Plan for Flood Damage

Reduction and Ecosystem Restoration within the two river basins, and a strategy for implementation. Numerous technical analyses were performed for this study using computer modeling tools developed by the USACE and DWR to simulate the hydrology, hydraulics, ecosystem function, flood risk and associated economic damages in the Sacramento and San

Joaquin river systems. DWR, USACE, and others will use these models in developing future flood management and environmental improvement projects in the Sacramento and San Joaquin river basins.

Butte Regional Conservation Plan (In Process)

The Butte Regional Conservation Plan (BRCP) is intended to establish and implement an effective program to conserve ecologically important resources in the lowland and foothill region of Butte County (the ―Plan Area‖), including sensitive, at-risk species and their habitats, natural communities, and biodiversity. Important to the success of the BRCP is the continued ecological and economic function of working landscapes, including certain farming and ranching practices, and the preservation of open space. The BRCP addresses state and federal endangered species compliance requirements for the County of Butte, the City of Oroville, the City of Chico, the

City of Biggs, the City of Gridley, the Butte County Association of Governments (BCAG), the

California Department of Transportation (Caltrans), Western Canal Water District (WCWD),

Biggs West Gridley Water District, Butte Water District, Richvale Irrigation District, and the

BRCP Implementing Entity that will be established to implement the Plan (collectively, the

―Permit Applicants‖ prior to permit issuance or ―Permittees‖ following permit issuance) for activities and projects in the Plan Area that they conduct or approve. This Plan provides a more efficient, consistent, and effective alternative to project-by-project permitting that may be costly and time consuming for applicants and often results in uncoordinated and biologically ineffective mitigation.

BRCP Goals and Objectives

As described in the Planning Agreement, the BRCP planning goals include the following:

Provide for the conservation and management of covered species within the Plan Area;

Preserve aquatic and terrestrial resources through conservation partnerships with the Local

Agencies;

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Allow for appropriate and compatible growth and development consistent with applicable laws;

Balance open space, habitat, agriculture and urban development;

Protect the rights of property owners;

Provide a means to implement covered activities in a manner that complies with applicable state and federal fish and wildlife protection laws, including CESA and ESA, and other environmental laws, including the California Environmental Quality Act (CEQA) and the

National Environmental Policy Act (NEPA);

Provide a basis for permits necessary to lawfully take covered species;

Provide a comprehensive means to coordinate and standardize mitigation and compensation requirements of ESA, CEQA, NEPA, and NCCPA within the Plan Area;

Provide a less costly, equitable, more efficient project review process that results in greater conservation values than project-by-project, species-by-species review; and

Comply with the ESA

County Departments/Agencies

Butte County has structured its governmental organization to mitigate and respond to natural hazards. The discussion below highlights offices that have either direct or indirect responsibility for planning for or responding to natural hazards.

Office of Emergency Management

The Butte County Office of Emergency Management (OEM) is the emergency management agency for Butte County. Butte County OEM is headquartered in the City of Oroville, the

County seat. The office provides service countywide, in cooperation with cities and special districts, such as the fire department and law agencies.

OEM also provides updated preparedness and emergency-related information to the public on

their website, shown in Figure 4.80. This site provides disaster information, which includes

guidance on protecting your home from winter storms, where to get sandbags, preparation for what to do before, during and after floods, etc. Also provided are links community evacuation plans. Plans and maps available are:

Berry Creek Evacuation Map

Berry Creek Evacuation Plan

Paradise/Upper Ridge Evacuation Map

Paradise/Upper Ridge Evacuation Plan

Yankee Hill Area Evacuation Map

An example is shown in Figure 4.81.

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Figure 4.80. Butte County OEM Website

Source: http://buttecounty.net/Office%20of%20Emergency%20Mgmt/Disaster%20Preparedness.aspx

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Figure 4.81. Paradise Evacuation Map

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Agricultural Commissioner

The Agricultural Commissioner monitors agriculture related commodities entering and exiting

Butte County. The agricultural division:

Protects and perpetuates agriculture, the #1 industry in Butte County, by ensuring a safe and healthy agriculture product.

Promotes and provides confidence of buyers and sellers by ensuring fairness in local, national and international trade.

Protects the public by enforcing pesticide laws and regulations, monitors applications for safety and environmental compliance, investigates pesticide related illnesses and complaints, and provides education to industry and the public on lawful pesticide usage.

Monitors pest conditions and provides for the safe and efficacious control of those pests through issuance of restricted pesticide materials permits or alternative management methods.

Monitors and facilitates the eradication of exotic pests harmful to California agriculture, including inspection of wholesale nursery stock and all plant material shipped to the County through the postal, express and freight systems.

Protect and promote the well being of all our customers and our community through the fair, equitable application of agricultural and weights and measures standards, emphasizing education and cooperation, including the use of technology to enhance customer service.

Collects and compiles crop and livestock statistics and prepares reports on crop damage and crop production.

Butte County Fire Department

The Butte County Fire Department is the largest fire department north of Sacramento, California to Eugene, Oregon. It is a combination of career and citizen volunteer firefighters that the

200,000 plus citizens of Butte County; and the 102,000 unincorporated residents of Butte

County, the 2,700 citizens of the City of Biggs and the 5,000 citizens of the City of Gridley.

Through automatic and mutual aid agreements, it also serves the cities of Oroville and Chico as well as each of the surrounding counties. From the 42 Fire Stations, it operates 64 fire engines, 1 ladder truck, 2 heavy rescues, 16 water tenders and 2 bulldozers. The Department also operates a myriad of other apparatus from Air Tankers to Air Attack Units to Rescue Squads to Breathing

Support Units to Hazardous Materials Units.

Public Works

The Public Works Department maintains approximately 1,300 miles of roadways, including over

500 bridges and drainage structures and more than 18,000 road signs. The Department of Public

Works includes the following divisions related to mitigation:

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Engineering

The Engineering Division of Public Works is responsible for the design of new roads and bridges, and oversight of the maintenance of existing bridges. The Bridge Section oversees more than 500 structures within County right of way ranging from bridges to culverts. Approximately

255 of these structures are managed in conjunction with the Federal Highway Bridge Program

(HBP). This program provides an opportunity for funding the replacement and or rehabilitation of many structures in the County that have been deemed Functionally Obsolete or Structurally

Deficient. Progress is continually being made in maintaining and upgrading the current state of the bridges within the County through the administration of various construction contracts and the diligent efforts put forth by the County Bridge Maintenance Crew.

Land Development

The Land Development Division of Public Works processes abandonments and formation of assessment districts and County Service Areas (CSA‘s). This division provides checking of all subdivision, parcel map, waiver of parcel map, lot line adjustments and certificate of merger to ensure all conditions with prior creation of lots or movement of property lines. In addition, this division provides map checking, construction and drainage plan checking, development construction inspection, flood control project coordination with all Local, State and Federal

Agencies, provides information for the Local Agency Formation Commission (LAFCo), administration of County Service Areas, and the County Surveyor functions. This division also provides clearance of difficult building permits, private road name determinations, flood zone interpretation, Storm Water Plan development and representation at the Planning Commission and Board of Supervisors' meetings. This division ensures that development and use of all lands are done in a safe manner to protect both the landowners and the community.

Department of Development Services

The Department oversees consolidated development services consisting of Building, Planning and Administrative Divisions. The Department provides recommendations to the Board of

Supervisors, other County agencies, and citizens seeking building and planning permits.

The Building Inspection Division serves a customer base that includes owner-builders, contractors and citizens who live in or use structures built in unincorporated Butte County. The

Building Division ensures that the end- user is provided with a safe structure through enforcement of the provisions of the new State 2010 California Code of Regulations and recently adopted updated County Building Code throughout the plan check/permitting/construction process. This includes serving a key role in maintaining and coordinating the County‘s electronic permitting system – TrakIT. The Code Enforcement Section of the Building Division investigates complaints, issues citations for the violation of Butte County Codes and implements the Abandoned Vehicle Abatement (AVA) and Nuisance Abatement Programs. The Building

Division provides support to the Building Code Board of Appeals, the Disabled Access Board of

Appeals, and the Code Enforcement Advisory Board.

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The Planning Division provides staff support for the Board of Supervisors, Planning

Commission, Land Conservation Act Committee, Airport Land Use Commission,

Interdepartmental Development Review (IDR) Committee, Mining Committee, and other Butte

County departments as directed. In addition, the Planning Division is responsible for developing land use plans, processing land use permits, General and Specific Plan amendments, and making land use related recommendations to the various committees and commissions. The department is providing significant resources to a comprehensive update to the County‘s General Plan and

Zoning Ordinance, known as Butte County General Plan 2030 (www.buttegeneralplan.net).

Water and Resource Conservation

The Department of Water Resources provides drainage, flood control, water supply, rain and creek level information, regulation and permits, flood insurance program and stormwater management services to various service areas of the County and its jurisdictions.

Drought Capabilities

Butte County Drought Preparedness Plan

In 2005 the Butte County Board of Supervisors adopted the Drought Preparedness and

Mitigation Plan. The intent of the Plan is to set up an institutional framework for a timely response and mitigation to a drought. Through the Drought Preparedness Plan, the Drought Task

Force is established and charged with continuous surveillance (Phase 1) of water resource conditions and the responsibility to report to the Water Commission and Board of Supervisors.

If based on their review of data and drought conditions, the Drought Task Force could recommend to the Water Commission and the Board of Supervisors to move to a Phase 2 or 3 levels. The Phase 2 level triggers the activation of the Interagency Coordinating Group chaired by the Chair of the Board of Supervisors. The Interagency Coordinating Group may activate specific Working Groups.

Flood Capabilities

FloodSAFE California

FloodSAFE is a multifaceted and collaborative statewide initiative to improve public safety through integrated flood management. A long-term initiative, FloodSAFE is focused on the following goals: 1) Reduce the chance of flooding, 2) Reduce the consequences of flooding, 3)

Sustain economic growth, 4) Protect and enhance the ecosystems, and 5) Promote sustainability.

FloodSAFE will accomplish these goals through four types of activities: 1) improving emergency response, improving flood management systems, improving operations and maintenance, and informing and assisting the public.

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Central Valley Flood Protection Plan (CVFPP)

The Central Valley Flood Management (CVFMP) Program is one of several programs managed by DWR under FloodSAFE California (FloodSAFE), a multifaceted initiative launched in 2006 to improve integrated flood management in the State of California. The CVFMP Program addresses flood management planning activities within the Central Valley that require State leadership and participation.

The Central Valley of California has experienced some of the State‘s largest and most damaging floods. The existing flood management system, consisting of a number of projects (e.g., dams, reservoirs, weirs, levees, channels, bypasses and other features) individually constructed over the last 150 years, provides varying levels of flood protection. However, this legacy system is now characterized by aging infrastructure constructed using outdated techniques. This system is now relied on to provide benefits and levels of protection that were not envisioned when its elements were first constructed. As currently configured, the system is prone to erosive river forces, is easily distressed from high water, and does not support healthy ecosystem functions and natural floodplain habitats. Further, funding and other constraints have made it difficult to carry out adequate maintenance programs. At the same time, escalating development in the Central Valley floodplains has increased the population at risk and the potential for flood damages to homes, businesses, communities and critical statewide infrastructure. This increased vulnerability of the

Central Valley to catastrophic floods threatens the life safety, property and the financial stability of the State. As a result, in 2008, the DWR embarked on the CVFMP Program, a long-term planning effort to improve integrated flood management within the Central Valley.

The 2012 CVFPP (adopted on June 28, 2012) will have three primary elements: vision for flood management in the Central Valley, a framework for implementing future projects to achieve this vision, and initial recommendations for improvements.

Sutter Basin Floodplain Management Plan (2013)

This Floodplain Management Plan (FMP) has been developed for the Sutter Butte Flood Control

Agency (SBFCA) as an in-kind contribution to the US Army Corps of Engineers (USACE)

Sutter Basin Pilot Feasibility Study (SBFS). The primary focus of this FMP is to identify potential measures, practices, and policies which will reduce the impact of future residual flooding, help preserve levels of protection provided by the SBFS project, and preserve and enhance natural floodplain values.

The study area is located in north-central California and encompasses a portion of Sutter County and Butte County. The study area is comprised of a region that is bordered by the Feather River,

Sutter Bypass, Wadsworth Canal, Sutter Buttes, and Cherokee Canal. The study area has a population of approximately 95,000 and includes the communities of Yuba City, Live Oak,

Gridley, Biggs, and numerous rural properties in the unincorporated areas of Sutter and Butte

County. Flood waters with the potential to impact the study area originate from the Feather

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River watershed, the Sacramento River watershed, the Butte Basin, Cherokee Canal, Wadsworth

Canal, and local interior drainage.

Invasive Species Capabilities

The Pest Exclusion Program

Administered by The California Department of Food and Agriculture (CDFA), executed and enforced by The County Agricultural Departments, the mission of Pest Exclusion is to protect agricultural and the environment by keeping exotic pests out of California and to prevent or limit the spread of newly discovered pests within the state. The program has three main components:

Detection: The primary responsibilities of the Pest Detection/Emergency Projects Branch

(PD/EP) are the early detection of serious agricultural pests. This is accomplished through the operation of a statewide detection trapping program, special detection surveys, and the maintenance of emergency projects response teams. The Branch administers the statewide detection trapping program through trapping contracts with 46 county departments of agriculture.

Eradication: The primary objective of the emergency project response component is to quickly and efficiently eradicate incipient infestations of serious agricultural pests, thereby preventing permanent establishment and subsequent spread in California.

Management: When a pest population cannot be eradicated in a timely manner and becomes established, a management program is instituted to addressing the adverse health, environmental and economic issues related to an uncontrolled invasive pest. Quarantine areas may be required. Management procedures and activities are developed based on the biology of the invading pest and often include components of both detection and eradication strategies. The under pinning idea is damage control by systematically and eventually eradicate the invader or bring it into balance with the environment. A combination of mechanical, chemical (pesticide application) and bio-control agents are the standard tools of management. The Management stage of Pest Exclusion is usually the most expensive solution because it may take a very long period of time to resolve the environmental and economic effects of the infestation. The best hazard mitigation is a robust invasive species

Detection and Eradication program.

Levee and Streambank Erosion Capabilities

Throughout the Central Valley, levees provide essential protection for both urban and rural lands, preventing possible catastrophic flooding and loss of life. On February 24, 2006, following sustained heavy rainfall and runoff, Governor Arnold Schwarzenegger declared a State of Emergency for California‘s levee system, commissioning up to $500 million of state funds

(AB142) to repair and evaluate State/federal project levees. This declaration was a necessary step in preventing possible catastrophic consequences of hurricane Katrina-like proportion.

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Following the emergency declaration, Governor Schwarzenegger directed the California

Department of Water Resources (DWR) to secure the necessary means to fast-track repairs of critical erosion sites. In addition, California's lengthy environmental permitting process was streamlined without compromising the protection of the important aquatic and terrestrial species inhabiting the river's ecosystem.

Repairs to State/Federal project levees are being conducted under the Levee Repairs Program funded by Section 821 of the Disaster Preparedness and Flood Prevention Bond Act of 2006

(Proposition 1E).

To date, nearly 300 levee repair sites, some of which are in Butte County, have been identified, with more than 100 of the most critical sites having already been completed with AB142 funds.

Repairs to others are either in progress or scheduled to be completed in the near future, and still more repair sites are in the process of being identified, planned, and prioritized.

Feather River West Levee Project

The Sutter Butte Flood Control Agency is planning to improve 44 miles of levees from

Thermalito Afterbay south to the Sutter Bypass (see Figure 4.82). The goal of the project is to

reduce flood risk and remove more than 34,000 properties from FEMA Special Flood Hazard

Areas. Levee repairs will be completed in two separate phases (see Timeline below).

Levees along the west bank of the Feather River do not provide 100-year flood protection

(protection against a flood that has a one percent chance of occurring in any given year), because they suffer from potential underseepage and through-seepage. Similar problems caused major levee failures in Yuba City in 1955, and Yuba County in 1986 and 1997.

Levees can be made stronger by building deeper cutoff walls (also known as slurry walls), stability berms and seepage berms. These levee improvements block or slow the flow of water through and underneath the levees. Not all 44 miles of levees will need each of these improvements. More than 80 percent of the needed levee repairs will involve the construction of slurry walls, some as deep as 110 feet. In a few select areas, seepage berms constructed on the land side of the levee were determined to be the best fix.

The levee improvement program is expected to:

Increase public safety by providing 200-year flood protection to Biggs, Gridley, Live Oak, and Yuba City, and improve flood protection for the less populated areas south of Yuba City.

Save property owners tens of millions each year in mandatory flood insurance costs by delaying, preventing, or cutting short FEMA floodplain mapping.

Allow cities and counties the freedom to implement general plans, which will soon be severely restricted for any urban or urbanizing community without 200-year flood protection.

This would not apply to rural communities (areas with fewer than 10,000 residents).

Maintain the rights of property owners to make substantial improvements to property without

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new state or federal land use restrictions.

Sustain and grow the local economy by creating construction jobs, protecting property values, and allowing for responsible residential, commercial and industrial development.

Project Timeline

Levee repairs will be completed in two separate phases:

Phase I, the Feather River West Levee Project, will include work from Thermalito Afterbay to Star Bend, just south of Yuba City.

Phase II will include the area south of Star Bend to the confluence of the Feather River and the Sutter Bypass. Phase II work includes repairs to the Sutter Bypass, and is in the planning stages.

The Feather River West Levee Project is on schedule and within budget. Agency engineers are working on the levee project design and preparing requests for necessary permits from state and federal agencies. Environmental specialists are also collecting information that is needed for environmental permit approvals. Design and environmental work is expected to be completed in

2012. Early stages of construction are expected to start in mid-2013, with project completion slated for late 2015. Anticipated costs are $312 million, with the State paying as much as 77% of the costs.

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Figure 4.82. Feather West Levee Project Map

Source: Sutter Butte Flood Control District

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California Levee Database

California has over 13,000 miles of levees that protect residential and agricultural lands. The levee failures resulting from hurricane Katrina prompted the State and the Department of Water

Resources (DWR) to initiate development of a state-of-the-art California Levee Database (CLD) for the purpose of better understanding and managing levees in California. The CLD is an efficient tool for assessing levee reliability risk factors using a GIS-enabled geospatial database.

Starting in 2005, partnering with the Federal Emergency Management Agency (FEMA) under the auspices of FEMA's Map Modernization Management Support program, the Department has started assembling critically needed levee information on ownership, location, and risk assessment factors for all the levees in California. Recognizing that other agencies are engaged in similar efforts, DWR is actively participating on national committees organized by FEMA and the U.S. Army Corps of Engineers (USACE) to ensure compatibility and coordination with other national efforts.

Currently, the California Levee Database has location information for more than 10,000 miles of levees and flood control structures throughout California. Major features of the CLD include

Levee centerlines for both State-Federal project levees and non-project levees. The project levees use surveyed levee centerlines from USACE's National Levee Database.

Boundaries, such as those of levee districts, state levee maintenance area, cities, federal congressional districts, state assembly districts, and hydrologic sub-basins.

Feature locations, such as those of boreholes, burrow sites, cross sections, encroachments, high water marks, levee stress, levee failures, and levee relief wells.

These features are continuously refined and populated for all identified levees in California.

Additionally, web-based levee profile viewer, levee information viewer, and technical resources viewer will be developed and released to the public in the near future.

Wildfire Capabilities

CAL FIRE-Butte Unit Strategic Fire Plan/CWPP (2012)

The CAL FIRE-Butte Unit Strategic Fire Plan has been developed upon the priority goals and objectives identified by the Department and by local collaborators. This plan addresses the prefire strategies and tactics that will be implemented in cooperation with the fire agencies in Butte

County, the Butte County Fire Safe Council, local community groups, and landowners. The

Butte Unit intends to implement this plan and place emphasis on the following goals and objectives:

Engage and participate with local stakeholder groups (i.e., fire safe councils and others) to validate and prioritize the assets at risk.

Promote an increasing level of compliance with defensible space laws and regulations.

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Educate landowners, residents and business owners about the risks and their incumbent responsibilities of living in the wildlands, including applicable regulations, prevention measures and preplanning activities.

By implementing a multi-faceted plan, using a combination of pre-fire treatments, including fuels reduction, prescribed burning, defensible space inspections, fire-resistant building construction standards enforcement, land use planning, and fire safety education, the Unit strives to increase life safety and to reduce property destruction, environmental impacts, and fire suppression costs.

The CAL FIRE - Butte County Fire Department annually updates the Fire Management Plan

(Community Wildfire Protection Plan – CWPP, as defined by the Healthy Forests Restoration

Act). This plan has many projects related to mitigation. Completed mitigation projects are

shown in Table 4.94. Future and ongoing projects are shown in Figures 40 and 4.84

Table 4.94. Butte County Fire Plan/CWPP Completed Projects (by Location and

Battalion)

Batt.

Start

Year

1 2010

1

1

1

1

1

1

1

1

1

2010

2000

2003

2003

2003

2003

2004

2004

2004

Location Project Name

Paradise Trail way Fuels Reduction Paradise FSC/

Paradise Fire

Department

Paradise Skyway Shaded Fuel

Break

Sponsor

B C F S C / Paradise

Fire Department

Description

shaded fuel break project shaded fuel break project along

Skyway in both County and Town of

Paradise

Paradise Paradise VMP

Paradise

Paradise

Paradise

Paradise

Paradise

Paradise

Paradise

Paradise Valley View

Citizens Fuel Reduction

West Branch Fuel

Reduction Project

Canyon Edge Fuel

Reduction Project

Dean Rd Roadside Fuel

Reduction

Evacuation Plan Print &

Mail - 2004

Top of Paradise Fuel

Reduction Project -

Canyon Edge FRP

Youth Wildland Fire

Council

Paradise Fire

Department

Honey Run to Neal Rd. 300' under power lines

Paradise Citizens Fuels Reduction project around homes shaded fuel break project Paradise Fire

Department

Paradise Fire

Department

3 mile fuel reduction project along eastern edge of Paradise.

One mile of roadside fuel reduction east of Paradise.

B L M &

Paradise Fire

Department

Paradise FSC/

Paradise Fire

Department

Paradise FSC/

Paradise Fire

Department

Paradise FSC/

Paradise Fire

Department

19,000 of the Wildland Fire

Evacuation Plan printed and mailed to residents of Paradise and the

Upper Ridge including Stirling City.

6 mile fuel reduction project in upper Paradise on both the northeastern and northwestern flank.

Pilot program to involve teenagers in the Fire Safe Council.

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Batt.

Start

Year

1 2007

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2007

2010

2003

1999

2000

2001

2002

2004

2004

2006

2010

2010

2008

2010

2011

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Location Project Name

Paradise Honey Road Fuel

Reduction

Paradise Dry Creek Shaded Fuel

Break and W a t e r s h e d

Protection Project

Paradise

Paradise

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Upper

Ridge

Quail Trails Fuel

Reduction

Town Radio - AM 1500

Wildland Safety Fair

Compton Rd.

Upper Ridge Radio 1460

AM

Sponsor

Paradise FSC/

Paradise Fire

Department

Paradise FSC/

Paradise Fire

Department

BLM

Paradise Fire

Department

Don Steele

BLM

Description

shaded fuel break project shaded fuel break project

Project completed July 2010.

CCC crews cut and piled brush east of homes along the canyon -

1 acre

A M 1 5 0 0 r a d i o s t a t i o n w i t h coverage to approximately 25,000 residents.

Wildland Fire Safety Fair held at the

POA in Paradise Pines that occurred during the lighting caused fire siege in August 1999. Ashes were falling on the fair.

BLM land treated using Cal-Fire crews

AM 1460 emergency radio station that reaches about 80% of the residents on the Upper Ridge.

Maintenance Plan for greenbelt PPOA Greenbelt Fuel

Reduction

PPOA Dooryard Education

Program

Upper Ridge Preservation

Alliance

Coutolenc Shaded Fuel

Break and Watershed

Protection Phases I-III

Don Steele

Don Steele

Don Steele

BCFSC

New Skyway Shaded Fuel

Break

BCFSC

Magalia Reservoir Shaded

Fuel Break

BCFSC

Paradise Lake Paradise Irrigation

DIstrict

Humbug Rd. Shaded Fuel

Break

BCFSC

Magalia PUSD BCFSC

Individual visits to homeowners upon request to provide customized information on wildland fire safety at their home.

To assist in the formation of a group that would take on the task of developing and implementing a maintenance plan for the 17 mile fuel break

A 200' fuel break along the

Coutolenc Road area provides watershed and protection and community protection during a wildland fire

Shaded Fuel Break Project

Shaded Fuel Break Project

Paradise Lake Access

SFB from intersection of Nimshew to Skyway

Fuel reduction on 60 acre PUSD parcel north of Rosewood

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Batt.

1

1

1

2

2

2

2

2

2

3

3

3

3

3

3

5

5

Start

Year

2011

2001

2010

2008

2003

2005

1999

2000

2001

2001

2001

2001

2005

2008-

2009

2008-

2009

2003

2005

Location Project Name

Upper

Ridge

Powellton Rd. SFB

Upper

Ridge

Upper Ridge Fuel

Reduction Project 17 mile shaded fuel break

Sponsor

BCFSC

Cal-Fire & PID

Upper

Ridge

Old Dog Town Rd.

Butte Creek Butte Creek Canyon

Shaded Fuel Break

Cohasset Development of

Community Evac Plan

Cohasset

Community

Association

Cohasset Cohasset Rd Shaded Fuel

Break

Cohasset

Community

Association

Citizens of Forest

Ranch

Forest

Ranch

Forest Ranch Wildfire

Defense Plan

Hwy 32 Demo Site Forest

Ranch

Forest

Ranch

Forest Ranch area

Forestwise Landscaping

Brochure

Yankee Hill/

Concow

Cherokee Clean- up

Paradise Irrigation

District

BCFSC

Citizens of Forest

Ranch

Citizens of Forest

Ranch

YHFSC

Description

From Doe Mill Rd. to Lovelock

17 miles of Fuel Reduction around

Paradise Pines and up to and along

Nimshew Rd. and behind Fir Haven

Community

Shaded Fuel Break Project

Shaded Fuel Break Project

Developed an evacuation plan for the 2000 residents on the Cohasset

Ridge.

Roadside Fuel reduction along 4 miles of Cohasset Rd booklet on living safely with wildfire

Created a community demonstration site booklet on living safely with wildfire

Yankee Hill/

Concow

Yankee Hill/

Concow

Yankee Hill FSC Calendar

2003

Poe Fire Clean-up

YHFSC

YHFSC

An illegal dumpsite, arson hit site, was cleaned up, 350 tires removed plus other debris, then gated off.

Community Calendar produced as a way to get fire prevention messages into the home.

14 parcels abandoned were cleaned up with assistance from 58 community volunteers and some contractual assistance to removing cars and debris.

Yankee Hill/

Concow

Crain Ridge Fuel Break and Watershed Protection

YHFSC fuel break along a ridgeline above the Concow basin and Yankee Hill community. shaded fuel break project Yankee Hill/

Concow

Crain Ridge/Rim Road

Shaded Fuel Break and

Watershed and Protection

YHFSC

Yankee Hill/

Concow

Community Demonstration

Sites

Berry Creek Berry Creek Evacuation

Plan

YHFSC Expand and create new demonstration sites located at;

Detlow Rd., Lunt Rd., Shuman Ln. - completed 2010, new site along

Concow Lake 2012

Berry Creek FSC Developed first community

Evacuation Plan and distribution

Berry Creek Community Demonstration

Area

Berry Creek FSC Fire Safe Community

Demonstration area located at Bald

Rock Rd. and Sugar Pine Dr.

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Batt.

5

5

5

5

5

5

5

Start

Year

2005

2007

2008

2008-

2009

2003

1996

2008-

2009

Location Project Name

Berry Creek Berry Creek Fire Safe

Calendar

Sponsor Description

Berry Creek FSC 2005/2006 Community Calendar produced with fire prevention messages and information

Berry Creek Fire Safe Home Visit

Program

Berry Creek Lake Madrone Shaded

Fuel Break

Berry Creek Firewise Demonstration

Area

Berry Creek FSC

Berry Creek FSC

Training of community members to conduct fire safe home visits

Shaded fuel break project

Berry Creek FSC Drought tolerant and Native planting located at Fire Station 61

Harts Mill

Berry Creek Emergency Advisory

Radio

Berry creek Brush Creek DFPZ

Clipper Mills Evacuation Planning,

Community Education and

Fuels Reduction

Berry Creek FSC AM 1250 Emergency Advisory

Radio System

USFS Plumas NF Fuels Reduction Projects on USFS lands

BCFSC Evacuation Planning, Community

Education and Fuels Reduction

5

5

6

2007

2008

2004

2003

Feather

Falls

Feather

Falls

Oroville

County wide

Feather Falls Shaded Fuel

Break

Feather Falls Evacuation

Plan

BCFSC 8 miles shaded fuel break on

Lumpkin Rd.

Feather Falls FSC Community Evacuation Plan

Northeast Oroville

Community Education and

Outreach

BCFSC

Wild Fire Vs. Your Home

Video

BCFSC

This developed a community

"demonstration site" to educate homeowners about thinning vegetation, also a booth was set up and many residents received brochures on how to create their defensible space around the home

Provides homeowners with practical steps to make their home safer from wildland fire.

Source: Butte County CWPP 2011

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Figure 4.83. 2012 Butte County Fire Plan Planned Projects

Source: Butte County Fire Plan 2012

Status Guide: A = Active, P = Planning, O = Ongoing, M = Maintenance

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Figure 4.84. 2012 Butte County Fire Plan Planned Projects (continued)

Source: Butte County Fire Plan 2012

Status Guide: A = Active, P = Planning, O = Ongoing, M = Maintenance

Butte County Fire Safe Council

The Butte County Fire Safe Council (FSC) is a non-profit, public-benefit corporation formed in

March of 1998. The Butte County Fire Safe Council strives to reduce damage and devastation through its mission ―to provide safety in Butte County through wildfire hazard education and mitigation.‖

The Butte County Fire Safe Council operates with a staff of two and a Board of Directors consisting of 16 residents representing community members from throughout the County as well as stakeholders from local, state, and federal agencies with a vested interest in wildfire preparedness and prevention.

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Programs & Projects

The FSC mission is accomplished through a variety of free fire prevention programs, projects, educational materials, and community outreach which includes:

The Chipper Program—A brush-chipping service available to residents throughout Butte

County.

Fire Safe Home Visit Program—A voluntary opportunity for residents of Butte County to receive one-on-one wildfire prevention and preparedness training tailored specifically to each home.

Resident's Assistance Program—A program that provides defensible-space assistance for qualifying low income, senior, and physically disabled residents in Butte County.

Fuels Reduction Projects—Assisting in or carrying out fuels reduction projects in which roads are made safer for evacuation and fire-fighting access.

Sixth Grade Education Program—Provides wildfire education for sixth-grade students.

Home Owners' Guide to Fire-Wise Landscaping—Brochures illustrating how defensible space can be created in grassland, brushland, and timberland environments.

Community Evacuation Plans—Provide critical information to residents for emergency evacuation.

Accomplishments

The Chipper Program—Has provided service to 1,114 residents and treated hazardous fuels on 1,064 acres since the program began in 2003.

Dooryard Education Program—80 home visits were conducted between 2004-2006.

Residents' Assistance Program—Funding is available for future development of program.

Fuels Reduction Projects—Since 2001 the Council has collaborated in nine roadside fuelsreduction projects, which total over 30 miles of roads throughout Butte County.

6th Grade Education Program—585 fifth-grade students have received life-saving wildfire education in the Paradise Union School District and the Golden Feather School District.

Home Owners' Guide to Fire-Wise Landscaping—Brochures created by the Council have been adopted by the State Fire Safe Council and used throughout California.

Community Evacuation Plans—Community evacuation plans have been created in four communities: Yankee Hill, Berry Creek, Upper Ridge, and the Town of Paradise.

4.4.2 Butte County’s Administrative/Technical Mitigation Capabilities

Table 4.95 identifies the County personnel responsible for activities related to mitigation and loss

prevention in Butte County.

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Table 4.95. Butte County Administrative/Technical Mitigation Capabilities

Personnel Resources

Planner/Engineer with knowledge of land development/land management practices

Engineer/Professional trained in construction practices related to buildings and/or infrastructure

Planner/Engineer/Scientist with an understanding of natural hazards

Personnel skilled in GIS

Yes/No

Yes

Department/Position

Public Works/ Land

Development

Development Services/ Building

Division

Yes

Full time building official

Floodplain Manager

Emergency Manager

Grant writer

Other personnel

GIS Data

– Hazard areas

GIS Data - Critical facilities

GIS Data

– Building footprints

GIS Data

– Land use

GIS Data

Warning Systems/Services (Reverse 9-11, cable override, outdoor warning signals)

Other

– Links to Assessor’s data

Source: AMEC Data Collection Guide

Yes

Yes

Yes

Yes

Yes

No

Yes

Yes

Yes

IS, Public Works &

Development Services

Development Services

Public Works

Administration/

Emergency Services Officer

Development Services/ General

Plan and Zoning

Certain ownership data not all property value information.

Sheriff’s Dept/

County Watch

4.4.3 Butte County’s Fiscal Mitigation Capabilities

Comments

Table 4.96 identifies financial tools or resources that the County could potentially use to help

fund mitigation activities.

Table 4.96. Butte County Fiscal Mitigation Capabilities

Financial Resources

Community Development Block Grants

Capital improvements project funding

Authority to levy taxes for specific purposes

Fees for water, sewer, gas, or electric services

Accessible/Eligible to Use (Y/N)

Yes

Comments

Very limited CDBG funds available, competitive

Yes

Yes

No

No specific revenue source known at this time.

Requires public vote, unlikely to be approved

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Financial Resources

Impact fees for new development

Incur debt through general obligation bonds

Incur debt through special tax bonds

Incur debt through private activities

Withhold spending in hazard prone areas

Other

Source: AMEC Data Collection Guide

Accessible/Eligible to Use (Y/N)

Yes

Comments

Very small revenue stream, and very little development is occurring

Yes

Yes

Yes

Requires public vote, unlikely to be approved

Requires public vote, unlikely to be approved

Debt can occur, but there is no private revenue source known at this time to make debt service payments

4.4.4 Mitigation Outreach and Partnerships

The County has many mitigation partners. The County has worked with, is working with, or will work in the future with the following entities:

Butte County Fire Safe Council

Butte County Public Health - Exercises, Pan Flu, National Preparedness Month, Heat Plan,

Area Transportation during emergency/disaster, DME/CME Cache Inventory

Department of Employment & Social Services (DESS) and Red Cross - Shelter start up kits

PG&E - Pipeline Safety, Community Preparedness Fair

Department of Water Resources (DWR) - Exercises and Face to Face meetings

South Feather Water & Power (SFW&P) - Exercises and Face to Face meetings

Emergency Medical Care Committee (EMCC)

Disaster Council - members include city mayors, city administrators, county fire, county sheriff, county office of education, county administration. Meetings open to the public

Butte County Fire Chief's Association

Butte County Training Officers Association

Adult Services Coordinating Council (ASCC) - AFN - member of steering committee,

Special Needs Awareness Program (SNAP) and In Case of Emergency (ICE) program run from our office

Mutual Aid Regional Advisory Committee (MARAC)

North Valley Animal Disaster Group (NVADG)

Sutter Butte Flood Control Agency

4.4.5 Other Mitigation Efforts/Projects

Butte County – Storm Ready – December 13, 2011

Yankee Hill – Firewise Community – 2009

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The Butte County Fire Safe Council noted the following efforts and projects:

Community Wildfire Protection Plan has lead to increased agency partnerships.

The Chipper Program has provided service to 2,027 homes and treated hazardous fuels on

2,280 acres since the program began in 2003.

Residents' Assistance Program has provided free defensible space to 15 homes and 20 acres since 2006.

Since 2001 BCFSC has collaborated in nine fuels reduction projects which total over 365 acres and 60 linear miles throughout Butte County.

The 6th Grade Education Program ―Wildfire in the Foothills‖ has been taught to over 600 sixth grade students in the Paradise Union School District and Golden Feather School

District.

50,000 ―Homeowners Guide to Firewise Landscaping‖ brochures were created by the

BCFSC. These brochures impacted the state through adoption by the State Fire Safe Council and multiple local Fire Safe Councils throughout California.

Through the Dooryard Education Program 80 home visits have been conducted between

2004-2007.

Over 20,000 community evacuation plans have been provided to four communities: Yankee

Hill, Berry Creek, Upper Ridge and Town of Paradise.

―Fire on the Ridge‖ community education event held for 5 years provides outreach to over

1,000 households.

Community fire safe presentations have been given to over 30 local community organizations.

Every day fire safety assistance has been available to Butte County residents at the BCFSC office.

Media campaign outreach from 2004-2007 has included fire safe bill boards, radio and TV commercials.

The BCFSC web page has provided thousands of residents with vital fire safety information since 2003.

The ―Wildfire Vs. Your Home‖ DVD was created in 2006. 5,000 copies were made available free to homeowners.

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