From Source to Tap: Guidance on the Multi-Barrier Approach to

From Source to Tap:  Guidance on the Multi-Barrier Approach to
From Source to Tap:
Guidance on the
Multi-Barrier Approach to
Safe Drinking Water
Produced jointly by the
Federal-Provincial-Territorial Committee on Drinking Water
and the CCME Water Quality Task Group
PN 1334
FROM SOURCE TO TAP:
GUIDANCE ON THE MULTI-BARRIER APPROACH
TO
SAFE DRINKING WATER
Federal-Provincial-Territorial Committee on Drinking Water
The Federal-Provincial-Territorial Committee on Drinking Water is the national
body that establishes the Guidelines for Canadian Drinking Water Quality,
published by Health Canada. These guidelines deal with microbiological,
chemical and radiological contaminants found in Canadian drinking water
supplies. They are recognized throughout Canada as the standard for water
quality. For more information on the Committee and the Guidelines for
Canadian Drinking Water Guidelines, see: www.hc-sc.gc.ca/waterquality
Canadian Council of Ministers of the Environment
The Canadian Council of Ministers of the Environment (CCME) is the major
intergovernmental forum in Canada for discussion and joint action on
environmental issues of national, international and global concern. The 14
member governments work as partners in developing nationally consistent
environmental standards, practices and legislation.
Canadian Council of Ministers of the Environment
123 Main Street, Suite 360
Winnipeg, Manitoba R3C 1A3
Ph: (204) 948-2090
Fax: (204) 948-2125
Aussi disponible en français
La présente publication est également offerte en français sous le titre De la
source au robinet : Guide d’application de l’approche à barrières multiples pour
une eau potable saine. PN 1335.
ISBN 1-896997-48-1
© Canadian Council of Ministers of the Environment, 2004
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Preface
This document is the companion to From Source to Tap: The Multi-Barrier
Approach to Safe Drinking Water, published in May 2002 by the FederalProvincial-Territorial Committee on Drinking Water (CDW) of the FederalProvincial-Territorial Committee on Environmental and Occupational Health
and the Water Quality Task Group (WQTG) of the Canadian Council of
Ministers of the Environment (CCME).
From Source to Tap can be
downloaded from the following websites: www.ccme.ca and www.hcsc.gc.ca/waterquality
This document provides guidance to drinking water system owners and
operators on how to apply the concept of the multi-barrier approach to Canadian
drinking water supplies from source to tap. It also gives them language and
tools for communicating their activities to decision-makers and consumers. In
addition, the document gives decision-makers at the municipal, provincial and
federal levels a structure for integrating health and environmental issues, for
collaborating and sharing information, and for setting priorities. While much of
the information presented is available elsewhere, this document fills a gap by
bringing all the elements together in one place and presenting them to a
Canadian audience.
Given the importance of drinking water quality issues, this document may be
useful to anyone with an interest in the safety of Canada's drinking water
supplies including regulators, system owners and operators, industry
stakeholders, members of non-profit organisations and associations, academics,
and members of the public. The discussions on source water protection may be
of interest to an even broader audience given that this emerging area affects a
diverse range of stakeholders from a variety of sectors.
The guidance contained in this document is not meant to be prescriptive
and should be adapted to reflect the specific needs of a community or
region.
We encourage readers to consult the specific recommendations,
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legislation, regulations and policies of the various federal, provincial or
territorial jurisdictions.
None of the recommendations in the guide take
precedence over any federal, provincial or territorial legislation, policy or
regulation.
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Acknowledgements
This document was prepared over a two-year period by a dedicated group of
individuals representing both the Federal-Provincial-Territorial Committee on
Drinking Water and the Water Quality Task Group of the Canadian Council of
Ministers of the Environment:
•
•
•
•
•
•
•
•
•
•
•
•
•
Bijan Aidun, Alberta Environment
David Briggins, Nova Scotia Department of Environment and Labour
Pierre-Yves Caux, Environment Canada
Karu Chinniah, Alberta Environment
Paul Jiapizian, Environment Canada
Michèle Giddings, Health Canada
Haseen Khan, Newfoundland Department of Environment (co-chair)
Narender Nagpal, British Columbia Ministry of Water, Land and Air
Protection
Thon Phommavong, Saskatchewan Environment (co-chair)
Will Robertson, Health Canada
Bob Smith, British Columbia Ministry of Health Planning (retired)
Hélène Tremblay, Environnement Québec
Dwight Williamson, Manitoba Conservation
A number of consultants and other organizations contributed source material to
this document: ADI Limited, EarthTech (Canada) Inc, Dillon Consulting Ltd.,
the Canadian Water and Wastewater Association, and the Federation of
Canadian Municipalities. In addition, the working group consulted a number of
experts from across the country whose feedback has proved invaluable to
bringing the document to its present form. While the list is too long to mention
everyone by name, the working group would like to extend a heartfelt thank you
to all who provided input.
The working group would like to extend special thanks to Roberta Smith of
Blue Lantern Communications for her invaluable assistance in preparing this
document.
Funding for this project was provided by Health Canada, Environment Canada,
and the Canadian Council of Ministers of Environment.
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Table of Contents
Preface ............................................................................................................................3
Acknowledgements.........................................................................................................5
1.
2.
3.
1.1
1.2
1.3
Introduction........................................................................................................9
Purpose..........................................................................................................9
Scope of this Document ............................................................................ 11
Structure of the document ........................................................................ 12
2.1
2.2
2.3
The Multi-Barrier Approach to Safe Drinking Water ..................................... 14
Integrated Drinking Water Management .................................................. 14
The Multi-Barrier Approach........................................................................ 15
Rationale for Adopting the Multi-Barrier Approach .................................. 16
3.6
3.7
Commitment and Obligation.......................................................................... 20
Commitment to Drinking Water................................................................. 20
Legislation and Regulation ....................................................................... 22
Jurisdictional Responsibilities ................................................................... 24
3.3.1
Federal government ........................................................................ 24
3.3.2
Provinces and Territories ................................................................ 26
3.3.3
Municipalities and non-municipal system owners ........................ 28
3.3.4
Individuals........................................................................................ 30
Water Quality Guidelines ........................................................................... 31
3.4.1
Environmental Quality Guidelines .................................................. 31
3.4.2
Guidelines for Canadian Drinking Water Quality ........................... 32
On-going Investment and Maintenance Programs................................... 33
3.5.1
Investing in Source Water Protection............................................. 34
3.5.2
Infrastructure Investment and Maintenance................................. 36
Education related to the Drinking Water Program ................................... 38
Research and Development...................................................................... 42
4.1
4.2
4.3
4.4
The Risk Management Process ..................................................................... 45
Identifying Hazards .................................................................................... 45
Assessing Risks.......................................................................................... 46
Managing Risks.......................................................................................... 47
Risk Communication.................................................................................. 49
5.1
5.2
5.3
5.4
5.5
Drinking Water Hazards ................................................................................. 50
Microbiological concerns........................................................................... 52
Chemical and radiological contaminants ................................................. 54
Physical water quality parameters ............................................................ 58
Interactions between contaminant categories......................................... 59
Unexpected Events .................................................................................... 60
3.1
3.2
3.3
3.4
3.5
4.
5.
6.
Source Water Protection ................................................................................ 61
Source Water Assessment ........................................................................ 63
6.1.1
Delineating the Watershed/Aquifer Area....................................... 65
6.1.2
Inventory of Land-use and Contaminants ..................................... 75
6.1.3
Vulnerability Assessment and Ranking.......................................... 83
6.2
Watershed/Aquifer Management Plan..................................................... 89
6.2.1
Management Process ..................................................................... 90
6.2.2
Management Activities.................................................................... 92
6.1
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6.2.3
6.2.4
6.2.5
6.2.6
7.
8.
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SAFE DRINKING WATER
Evaluation of management options .............................................. 93
Developing the protection plan ...................................................... 94
Implementing the plan ................................................................. 102
Performance Evaluation and Plan Readjustment ....................... 104
Drinking Water Treatment and Distribution System Design ...................... 106
7.1
Facility Design, Performance and Monitoring ........................................ 107
7.2
Treatment requirements for systems on surface water or for systems on
groundwater under the direct influence of surface water (GWUDI) .................. 109
7.3
Treatment Standards for Groundwater................................................... 110
7.4
Surface Water Supply .............................................................................. 111
7.4.1
Water Source / Quality.................................................................. 111
7.4.2
Source Water Intake...................................................................... 111
7.4.3
Source Water Storage ................................................................... 112
7.4.4
Source Water Pumping ................................................................. 114
7.5
Groundwater Supply ................................................................................ 115
7.5.1
Siting of Wells ................................................................................ 115
7.5.2
Well Protection............................................................................... 116
7.5.3
Pumphouse Design ....................................................................... 116
7.5.4
Well Disinfection............................................................................ 116
7.6
Treatment Processes............................................................................... 117
7.6.1
Treatment Plant Chemicals and Waste - Handling and Disposal120
7.6.2
Filtration Technologies .................................................................. 123
7.6.3
Disinfection Technologies ............................................................. 125
7.7
Water Distribution System....................................................................... 129
7.7.1
Design and Layout......................................................................... 129
7.7.2
Secondary Disinfection ................................................................. 129
7.7.3
Fire Flows and Hydrants................................................................ 129
7.7.4
Frost protection ............................................................................. 129
7.7.5
Cross-connection Controls ............................................................ 130
7.7.6
Horizontal Separation of Watermains and Sewers...................... 130
7.7.7
Backflow Prevention and Control ................................................. 130
7.7.8
Pumping ......................................................................................... 131
7.7.9
Potable Water Storage .................................................................. 131
7.7.10
Disinfection of Mains and Reservoirs...................................... 132
8.1
8.2
8.3
8.4
8.5
8.6
8.7
Total Quality Management........................................................................... 133
Monitoring, Record-keeping and Reporting............................................ 136
8.1.1
Source Water Monitoring .............................................................. 136
8.1.2
Treatment System and Compliance Monitoring .......................... 138
8.1.3
Record Keeping ............................................................................. 140
8.1.4
Reporting ....................................................................................... 143
Laboratory Selection and Sampling Protocol ......................................... 145
TQM for Watersheds and Aquifers .......................................................... 147
Treatment and Distribution System Operational Procedures................ 148
8.4.1
Disinfectant Residual .................................................................... 149
8.4.2
Cross-Connection Control ............................................................. 150
8.4.3
Flushing Program .......................................................................... 152
8.4.4
Valve and Hydrant Maintenance .................................................. 153
8.4.5
Line Breaks and Commissioning .................................................. 154
8.4.6
Leak Detection............................................................................... 154
Automated Systems................................................................................. 155
Facility Classification and Operator Certification ................................... 156
8.6.1
Facility Classification..................................................................... 156
8.6.2
Operator Certification.................................................................... 156
8.6.3
Continuing Education .................................................................... 157
Tamper Policy........................................................................................... 157
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8.8
Incident and Emergency Response Plans .............................................. 158
8.8.1
Notification Lists............................................................................ 161
8.8.2
Equipment Operations .................................................................. 161
8.8.3
Incident Response: Boil Water Advisories ................................... 162
8.9
Drinking Water Program Evaluations and Audits ................................... 163
8.9.1
Source Water Protection Plan Evaluations .................................. 163
8.9.2
System Vulnerability Assessment................................................. 164
8.9.3
Audits ............................................................................................. 164
8.10 Abatement and Enforcement ................................................................. 167
9.
9.1
Public Awareness and Involvement............................................................. 170
Components of Successful Public Awareness and Involvement........... 173
Appendix A: Municipal Drinking Water Policy ........................................................... 180
Appendix B: Summary of Canadian Source Water Protection Measures .............. 181
Appendix C: Inventory of Potential Contaminants in Canadian Drinking Water
Sources and their Origins .......................................................................................... 186
Appendix D: Case Studies of Water Management Approaches in Canada ............ 190
Appendix E: Municipal Governments and the Protection of Source Waters .......... 195
Appendix F: Municipal Waste Water Treatment and the Multi-Barrier Approach .. 197
Appendix G: Descriptions of Backflow Prevention Devices ..................................... 199
Appendix H: Procedures for Flushing and Pipe Cleaning ........................................ 201
Appendix I: Procedures for Inspecting and Maintaining Valves and Hydrants....... 205
Appendix J: Locating and Remediating Line Breaks................................................ 209
Appendix K: Processes for Detecting Leaks............................................................. 210
Appendix L: List of Measurement Instruments, Alarms, Status Indicators, etc ..... 212
Appendix M: Facility Classifications .......................................................................... 218
Appendix N: Operator Certification ........................................................................... 219
Appendix O: Auditing Processes................................................................................ 220
Acronyms .................................................................................................................... 230
Glossary ...................................................................................................................... 232
Reference List ............................................................................................................ 236
For Further Reading................................................................................................... 240
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1. Introduction
Serious outbreaks of waterborne disease in Canada and elsewhere have
heightened public awareness that threats to water quality and quantity can have
a profound impact on our health, the environment, and the economy. In order to
safeguard public health, and re-instill confidence in Canada's public drinking
water systems, it is imperative for drinking water supplies to be kept clean, safe
and reliable. In order to do so, the components of the water supply system—the
source, the treatment plant and the distribution system—must be understood
and managed as a whole.
In Canada, provincial governments have the primary responsibility for
managing natural resources including protecting water quality and providing
and regulating drinking water services. Provinces have networks of safeguards
in place to ensure the safety of drinking water, including pollution prevention
programs for source water and public health guidelines or standards for drinking
water quality. In addition, it is now being recognised that many goals for safe
drinking water are consistent with other water quality goals, such as the
protection of aquatic life.
The goal of drinking water programs is to protect public health by ensuring the
safety and reliability of the drinking water supply. In order to ensure they are
meeting this goal, it is important for drinking water programs and traditional
safeguards to be periodically reviewed and enhanced. By implementing the
multi-barrier approach from source to tap, as described in this document,
Canadian drinking water supplies will have a better chance of being kept clean,
safe and reliable for generations to come.
1.1
Purpose
Drinking water system owners and operators are under increased pressure from
government regulators and stakeholders—including the public—to manage their
systems efficiently, effectively, and in a transparent manner. This document, as
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the companion piece to From Source to Tap: The Multi-Barrier Approach to
Safe Drinking Water,1 provides guidance to these system owners and operators
on how to apply the concept of the multi-barrier approach to Canadian drinking
water supplies. It also gives decision-makers at the municipal, provincial and
federal levels a structure for integrating health and environmental issues, for
collaborating and sharing information, and for setting priorities.
The principles outlined in this document are applicable to all drinking water
systems in Canada, from small communal systems in rural areas to large
municipal ones in urban centres. In short, it applies to any system with a central
treatment plant and distribution system. Nevertheless, small communal systems
may find it difficult to implement many of the suggestions outlined in this
document given their limited resources. Small system owners and operators are
therefore encouraged to focus improvements in areas that promise the greatest
positive impact on public health.
Individuals who draw their drinking water from sources located on their
privately-owned property may also find the document useful, though not all the
guidance will be relevant for such small-scale operations. For information
geared specifically to their needs, owners of individual systems are encouraged
to contact their provincial or territorial government department responsible for
drinking water issues (either a ministry of health or environment), or Health
Canada’s Water Quality and Health Bureau.
Given the importance of drinking water quality issues, this document may also
be useful to others with an interest in the safety of Canada's drinking water
supplies: regulators, industry stakeholders, members of non-profit organisations
and associations, academics, and members of the public. In addition, because
source water protection is a shared responsibility between the province,
1
From Source to Tap: The Multi-Barrier Approach to Safe Drinking Water was published in
May 2002 by the Federal-Provincial-Territorial Committee on Drinking Water (CDW) of the
Federal-Provincial-Territorial Committee on Environmental and Occupational Health and the
Water Quality Task Group (WQTG) of the Canadian Council of Ministers of the Environment
(CCME). It can be downloaded from the following websites: www.ccme.ca and www.hcsc.gc.ca/waterquality
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municipalities, conservation authorities, public health units, and other
stakeholders, the guidance on source protection should be provided to all those
who will be responsible for its implementation.
1.2
Scope of this Document
This document's primary focus is to provide guidance on how to manage
drinking water systems from source to tap. Because the multi-barrier approach
is not a new concept, many jurisdictions have already worked hard to
incorporate some, or even all, of the elements described in this document. The
document does not focus on wastewater issues or the needs of other users of
water such as wildlife or livestock.
While these subjects are extremely
important, an in-depth discussion is beyond the scope of this document.
Likewise, while protecting public health is the central theme of the document,
information on health effects related to specific contaminants found in drinking
water supplies is not covered as it is easily found in the Guidelines for
Canadian Drinking Water Quality and their supporting documentation
(published by Health Canada, see www.hc-sc.gc.ca/waterquality).
The guidance contained in this document is not meant to be prescriptive
and should be adapted to reflect the specific needs of a community or
region. Readers are encouraged to consult the specific guidance, laws,
regulations and policies of the appropriate federal, provincial or territorial
authority. None of the guidance in this document has precedence over federal,
provincial or territorial laws, regulations and/or policies.
This document covers subjects broadly. Some concepts are only briefly
summarized, especially in cases where more detailed information is readily
available in reference manuals or textbooks. When more detailed information is
required, references are cited in the text. In some instances, more detailed
information and guidance is provided in an appendix. Wherever possible, the
scientific information cited has been peer reviewed and published.
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1.3
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Structure of the document
The document begins with a discussion of the multi-barrier approach as a way
of ensuring drinking water supplies are kept clean, safe and reliable. This
approach
integrates
health
and
environmental
concerns
from
the
watershed/aquifer right through to the consumer's tap. As a risk management
approach, it provides a structure for identifying hazards to the water supply
which could impair the operation of the components of the water system and
result in threats to public health. It also offers suggestions on how to assess the
significance of these hazards and ways to manage or mitigate them. The
ultimate goal is always to protect public health.
Section 3 looks at the commitments which need to be in place in order for
drinking water programs to be run as effectively as possible. These
commitments include legislative and policy tools, resources for research and
development, financial support for infrastructure programs and staff training, as
well as commitments to work with other stakeholders and the public.
Section 4 gives general information about the risk management process which
leads into a discussion in Section 5 of the hazards that can compromise a
drinking water system and have either a direct or indirect impact on the health
of consumers.
Section 6 talks about source water protection and is divided into two sections:
source water assessments and the development of watershed/aquifer
management plans. Since it is not necessary (though recommended) to develop
a watershed/aquifer management plan prior to designing the treatment plant,
readers are given the option of moving to Section 7 after reading about source
water assessments. Watershed/aquifer management plans are very important,
but can be implemented at any time. Section 7 builds on the information given
in Section 6 to deal with the design of drinking water treatment plants and
distribution systems based on the quality of the source water.
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Section 8 is entitled "Total Quality Management" and focuses on how best to
manage and operate the components of the water supply once the elements are
in place. This section includes discussions on monitoring, record-keeping and
reporting; laboratory selection and sampling protocols; operating procedures;
automated systems; facility classifications and operator training; incident and
emergency response plans; program evaluations and audits; as well as
abatement and enforcement programs.
The document ends with a discussion in Section 9 of public awareness and
involvement in the drinking water program. Public awareness is key to the
success of any drinking water program. The public needs to know how their
drinking water system is managed, why disinfection is so important, and what
the true financial costs are for delivering clean, safe and reliable drinking water
in their communities.
References to websites and other recommended reading are given throughout
the document. For ease of searching, these references have been compiled into a
separate list found at the end of the document.
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2. The Multi-Barrier Approach to
Safe Drinking Water
2.1
Integrated Drinking Water Management
In Canada, water suppliers are committed to providing high quality drinking
water at the consumer’s tap. In many jurisdictions this commitment is also a
legal requirement.
High quality water is defined as being free of
both disease-causing organisms and chemicals in concentrations that
Public health considerations
have been shown to cause health problems. Such drinking water has
While treated drinking water
may be used for a variety of
activities beyond direct
consumption—ranging from
crop irrigation and livestock
watering to water used as an
industrial coolant—it is
imperative that the public
health considerations related
to the quality of drinking
water take precedence over
the requirements of other
users.
minimal taste and odour, making it aesthetically acceptable to the
public for drinking.
Traditionally, drinking water suppliers have relied heavily on a
process called compliance monitoring to ensure water is safe to
drink. Compliance monitoring relies on sampling small amounts of
water in a drinking water system and testing those samples for the
presence of known and quantifiable organisms or contaminants. If
those samples comply with established requirements for drinking water quality,
the water is considered safe to drink. However, this approach has major
limitations in its sampling and monitoring techniques and in the range of factors
that affect drinking water quality that can be considered. For instance,
compliance monitoring only deals with microbiological pathogens and/or
contaminants for which a prescribed numerical guideline value or established
method of analysis has been developed, making it nearly impossible to address
the entire range of potential health concerns. Sample analysis also takes time,
during which period consumers will be drinking the water. If the water is
contaminated, some people may become ill before the problem is identified and
resolved.
In order to address these limitations, the drinking water industry has been
shifting its focus in recent years to using more integrated approaches to drinking
water management. For instance, the multi-barrier approach promoted in this
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document recognizes that the key to ensuring clean, safe, and secure drinking
water is to implement multiple barriers throughout the drinking water system,
from source to tap. These barriers act to block or control microbiological
pathogens and chemical contaminants that may enter the water supply system,
regardless of whether these substances have been identified as a concern.
Under the multi-barrier approach, compliance monitoring is used as one tool for
verifying that water reaching consumers is safe to drink.
As will be discussed in Section 3, sustained involvement by key stakeholders is
key to the effective implementation of an integrated drinking water
management system. The type and level of commitment required from each
stakeholder may vary from jurisdiction to jurisdiction and area to area.
2.2
The Multi-Barrier Approach
The multi-barrier approach aims to reduce the risk of drinking water
contamination and to increase the feasibility and effectiveness of
remedial controls or preventative options. The ultimate goal of the
multi-barrier approach is to protect public health.
Figure 2.1 depicts a multi-barrier approach to safe drinking water. The
drinking water system contains three main elements: the source water
The Multi-Barrier
Approach is an integrated
system of procedures,
processes and tools that
collectively prevent or
reduce the contamination
of drinking water from
source to tap in order to
reduce risks to public
health.
(watershed/aquifer), the drinking water treatment plant, and the
distribution system. These elements are managed in an integrated manner using
procedures and tools such as:
•
Water quality monitoring and management of water supplies
from source to tap
•
Legislative and policy frameworks
•
Public involvement and awareness
•
Guidelines, standards and objectives
•
Research and the development of science and technology
solutions
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Figure 2.1: Components of the multi-barrier approach
Clean, safe,
reliable
drinking
water
Source
water
protection
Drinking
water
treatment
Management
Legislative
and policy
frameworks
Monitoring
Public involvement
and awareness
Guidelines,
standards and
objectives
Drinking water
distribution
system
Research, science and
technology
Under the multi-barrier approach, all potential control barriers are identified
along with their limitations. The barriers can be physical, such as the
installation of a filtration system in a drinking water treatment plant, or they can
be processes or tools that improve the overall management of a drinking water
program. Examples of the latter include legislation and policies, guidelines and
standards, staff training and education, and communications strategies that
program staff may use to communicate with the media or the public.
The multi-barrier approach also helps ensure the long-term sustainability of
water supply systems. The elements of the approach are further discussed
throughout this document.
2.3
Rationale for Adopting the Multi-Barrier Approach
The benefits associated with implementing a multi-barrier approach could
include better public health protection, a reduction in healthcare costs, better
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management of water treatment costs, and, indirectly, increased environmental
protection. Specifically, benefits could include:
•
Better and more consistent communication with the public
leading to better public understanding of key aspects of the
drinking water system and the public's role in ensuring its
safety, security and reliability over the long term
•
More effective communication with stakeholders stemming
from the implementation of clear communication channels
•
Better protected source waters stemming from increased
involvement of watershed/aquifer land-use stakeholders and
more opportunities for building consensus on watershed/aquifer
protection strategies or approaches
•
On-going education of all staff including the certification of
drinking water treatment plant and distribution system
operators
•
Better maintained and funded treatment and distribution
systems because elected officials and the public have greater
awareness and understanding of the costs and benefits
•
Better handled emergencies because potential hazards are
understood and barriers or redundancies are in place. When
incidents do take place, barriers either stop hazards from
reaching consumers and/or plans are in place to remediate the
problems efficiently.
These benefits are discussed in greater detail throughout the document.
The key strength of multiple barrier systems is that the limitations or failure of
one or more barriers may be compensated for by the effective operation of the
remaining barriers.
This compensation minimizes the likelihood of
contaminants passing through the entire system and being present in sufficient
amounts to cause illness to consumers.
On the flipside, when drinking water systems are not well managed, poor water
quality can have a serious impact on public health, resulting in both short-term
(acute), and long-term (chronic) health effects. Those members of the public
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who are at greatest risk of developing health problems due to the
microbiological quality of drinking water are the very young, the elderly, and
those with suppressed immune systems
(BCPHO 2001).
Chronic health
effects, such as cancer, can manifest themselves if people are continually
exposed to some contaminants in their drinking water at levels considerably
above the recommended guidelines for human health.
The presence of waterborne parasites in drinking water supplies has
resulted in disease outbreaks that have required medical intervention in a
number of Canadian communities. The outbreak of E-coli in Walkerton,
Ontario, resulted in the deaths of seven people and made more than 2000
It is important to note
that the level of exposure
to contaminants found in
drinking water is often
much lower than
exposure through other
routes such as air and
food.
other people ill. Some of those who became ill will suffer from the
effects of the poisoning for their entire lives.
In North Battleford,
Saskatchewan, the outbreak of Cryptosporidium made several hundred people
ill.
Cryptosporidium in water supplies has previously caused outbreaks in
Cranbrook and Kelowna, B.C., resulting in thousands of people becoming sick
with gastrointestinal illness.
Poor water quality can place a significant burden on the public healthcare
system, mostly from the hospitalization and care of people who become ill after
consuming untreated water.
For example, the Walkerton E. coli outbreak
resulted in more than $7-million in estimated health care costs (Livernois 2002).
It is very important to also take indirect costs to public health into account.
Often the number of people affected by poor water quality who do not seek
hospitalization far outnumber those who do. Although no hospitalization is
sought, they are nonetheless ill and consequently unable to work. Their loss of
productivity can be significant.
Other financial benefits associated with implementing a multi-barrier approach
may stem from source water protection activities. For instance, in some cases it
may be less costly and just as effective to make improvements to a drinking
water source—such as by restricting the access of wildlife or livestock to a
watershed or managing other land-use activities—than it would be to install
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specialized treatment to control the contaminant. (It is important to note that
some treatment, especially disinfection and filtration or ozonation will likely
always be necessary, regardless of how closely a watershed/aquifer is
managed.)
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3. Commitment and Obligation
3.1
Commitment to Drinking Water
In order to be effective and to ensure drinking water supplies are kept
clean, safe, and reliable, Canadian drinking water programs rely on the
commitment of each participating partner to work cooperatively without
losing sight of the ultimate goal of protecting public health. Partners
include public or private water system owners, utility operators, elected
officials, federal government departments, provincial or territorial
government departments, First Nations organizations or governments,
public health officials, the consuming public, service suppliers, and nonprofit organisations and associations. It is important for their
commitment to be based on an awareness and understanding of the
It is imperative that all
stakeholders—including
government
departments, industry,
private sector
companies, nongovernmental
organizations, and the
public—work
cooperatively without
losing sight of the
ultimate goal: the
protection of public
health.
importance of the drinking water program and how the decisions and
actions of each participant affects water quality and therefore public health.
Mindsets may need to shift from simply setting or meeting rules to evaluating
existing programs, identifying deficiencies or gaps, and correcting them.
It is important for all partners to consider formalizing their commitments
and priorities related to drinking water by developing policy statements
that support public health goals. It is important for the policy to state the
general commitment to providing safe drinking water, meeting
consumer expectations, and complying with the legal requirements of
the government. In general, policy statements list the specific areas of
responsibilities assumed, goals for those areas of responsibility, and
guidelines on how to achieve those goals.
The continued active
involvement of decision
makers, senior
management, and
elected officials is key
to establishing and
maintaining the
dedication of each team
member as they strive
to make the drinking
water program a
success.
In addition to providing clarity about the roles and responsibilities of
each partner, these policy statements act as a tool for promoting accountability.
By establishing a water quality policy, regularly reviewing the requirements,
taking action to implement the policy, and involving the participating
partners—including those delivering the water quality management program—
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each member demonstrates his or her commitment to the drinking water quality
management program. Policy statements also provide the means for
communicating with employees and with the consuming public.
A sample drinking water policy is included in Appendix A.
As key partners in the drinking water program, it is important for the actions of
decision-makers to support the effective implementation and maintenance of the
program. A corporate culture that promotes awareness and commitment to high
quality drinking water, continuous improvement, and employee motivation is
essential to the success of a drinking water program. It is very important for the
participants of the drinking water program to have accountable leadership,
appropriate staffing with properly trained personnel, and adequate financial
resources.
Drinking water materials
All partners in the drinking water program—from regulators to system owners to the public—have a role
to play in ensuring that the materials that come into contact with drinking water are safe to use and
don’t contaminate the water.
These materials are used throughout the drinking water system and include treatment and distribution
system components (e.g. pipes, water mains, tanks, faucets), treatment additives (e.g. disinfectants,
coagulants to help filtration processes), and treatment devices (e.g. point-of-use water filters used in the
home). Organizations such as NSF International rigorously test the products on behalf of manufacturers
to verify that the products are safe to use and meet manufacturers’ performance claims (e.g. that a
product removes a particular chemical contaminant or pathogen from drinking water). If products pass
the testing, they are able to carry the mark of the certification body. Consumers can then look for these
marks and know the product they are using is safe and lives up to the manufacturer’s claims.
Certification of drinking water materials includes an auditing process to ensure products continue to
meet the established requirements.
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Legislation and Regulation 2
Readers are encouraged to familiarize themselves with the legislative
requirements which apply in their jurisdiction prior to implementing any of the
guidance contained in this document as the former are legal requirements that
must be met. In some cases, the suggestions in this document go beyond
provincial or territorial requirements; in others, the provincial and territorial
requirements will be more stringent.
In Canada, all levels of government have some responsibility for drinking
water, whether direct or indirect.
Because water is considered a natural
resource, the legislative responsibility for providing safe drinking water to the
public generally falls under provincial or territorial jurisdiction. Each province
and territory has adopted legislation to protect its water resources and to
establish requirements to provide clean, safe and reliable drinking water to its
citizens. The federal government is responsible for drinking water
quality and quantity on federal lands and in areas that fall under
federal
jurisdiction,
such
as
First
Nations
lands
(shared
responsibility), on-board common carriers (e.g., ships, airplanes), and
in national parks. The federal, provincial and territorial governments
collaborate to develop water quality guidelines.
All levels of government have policies and agreements in place which
govern the quality of drinking water, including land-use agreements in
watersheds/aquifers;
water
quality
monitoring
and
inspection
Regular reviews of
legislation and regulations
are important to deal with
emerging issues related to
drinking water safety.
Areas for consideration
beyond the historical areas
of source protection,
system approval, and
verification of water quality
include treatment
performance monitoring,
data management and
reporting, and operator
training and certification.
programs; operator certification programs; and purchasing policies for
materials which come into contact with drinking water throughout the treatment
and distribution chain.
The division of powers between the federal government and the provinces and
territories was largely determined by the Constitution Act of 1867. This Act
2
Legislation and regulations formalize the various responsibilities of governments and
authorize them to oversee the provision of safe drinking water. These legal
requirements form the framework to which governments’ commitment is made.
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allocated the ownership of surface and groundwater to the provinces as part of
their control over natural resources. The territories, which have historically been
federal lands, now have their own governments which have been negotiating
with the federal government over the past 20 years to gain control over the
natural resources, including water, within their boundaries. The provision of
drinking water in all three territories is a territorial, not federal, responsibility.
The federal government works with the provinces and territories to ensure
Canadians receive clean, safe, and secure drinking water.
Municipalities
receive their powers from the provinces and have ability to pass by-laws that
can have an impact on water resources.
To address the broad range of concerns related to water uses and quality,
various departments within a government are usually involved, including those
responsible for natural resource management, land use planning, environmental
protection, and public health. In order to ensure the success of the drinking
water program, all the various activities and programs which affect drinking
water need to be coordinated. This coordination may best be undertaken by a
lead agency for drinking water within a jurisdiction.
Given changing priorities, it is beneficial for governments to periodically
review their legislation and regulations to ensure they are still relevant and
effective. All Canadian jurisdictions have undertaken such reviews since the
disease outbreaks in Walkerton, Ontario, and North Battleford, Saskatchewan.
That said, the recommendations made as a result of the respective inquiries may
prove to be relevant in the future. It may be desirable to refer to these
recommendations when conducting reviews of drinking water programs.
In addition to setting drinking water quality objectives or standards, effective
drinking water regulatory programs consist of both abatement and enforcement
programs. The abatement component involves working co-operatively with
system owners/operators to prevent and/or solve drinking water supply or
quality problems; the enforcement component involves taking appropriate
action when violations of specific requirements occur. Abatement activities by
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a regulatory agency demonstrate a commitment to actively assist partners in
ensuring the provision of safe drinking water by providing technical advice and
assistance.
Enforcement activities are a necessary demonstration of the
importance that a regulatory agency places on the provision of safe drinking
water. It indicates that non-compliance with requirements are taken seriously.
More information on abatement and enforcement programs is given in
Section 8.
3.3
Jurisdictional Responsibilities
This section looks at the specific responsibilities of five key groups: the federal
government, the provincial and territorial governments, municipalities, source
water protection committees, and individuals. A note has been made where
responsibilities overlap between jurisdictions.
3.3.1
Federal government
The federal government’s responsibilities for drinking water include areas
where the federal government is the water supply owner or where the water
supply systems are on lands under federal control or responsibility, such as in
national parks, at border crossings, or on armed forces bases. Even though
constitutional responsibility for First Nations lands rests with the federal
government, the responsibility for drinking water programs is divided between
the First Nations Band Council, Health Canada, Indian and Northern Affairs
Canada, Environment Canada, provincial governments, municipalities (where
agreements are in place), and the community members.
The federal
government is also responsible for the quality of drinking water on board
common carriers such as airplanes, trains, buses, and marine vessels. It also has
some responsibilities for source waters, regulated by the Fisheries Act, the
Canada Water Act and the Canadian Environmental Protection Act, among
others.
Various federal government departments have added responsibilities that are not
mandated through regulations but are, nevertheless, important to ensuring the
safety of drinking water supplies. For instance, Health Canada develops the
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Guidelines for Canadian Drinking Water Quality in collaboration with
representatives from provincial and territorial drinking water authorities and
Environment Canada. These guidelines focus on public health outcomes. The
provinces and territories establish their own drinking water quality requirements
using these guidelines or other more stringent ones.
Health Canada also works with standards-setting and certification organizations,
industry associations and provincial and territorial authorities to promote the
use of voluntary health-based performance standards for materials that come
into contact with drinking water.
Health Canada also conducts research and scientific assessments related to
water quality and develops drinking water information for public outreach.
Information on Health Canada's research and activities in this area can be found
on the Internet at: www.hc-sc.gc.ca/waterquality.
The federal government often provides financial assistance to drinking water
system owners through various cost sharing arrangements such as infrastructure
development programs.
More information on these programs is given in
Section 3.5.2.
Environment Canada's Federal Water Policy (1987) encourages "the use of
freshwater in an efficient and equitable manner consistent with the social,
economic, and environmental needs of present and future generations." The two
main goals of this water policy are to:
•
Protect and enhance the quality of the water resource
•
Promote wise and efficient management and use of water
With these goals, more than 25 areas of responsibility are described in the
policy including issues such as water use conflicts, inter-basin transfers, climate
change, and fish habitat management. 3
3
A new federal water policy is being drafted that maintains the importance of these
goals.
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Canadian Environmental Quality Guidelines, developed jointly by the federal,
provincial and territorial governments, are nationally endorsed, science-based
goals for the protection of aquatic ecosystems (CCME 1999a). They consist of
numeric values and narrative statements for chemical, physical and biological
parameters for four water quality uses: community water supplies, recreational
use, aquatic life, and agricultural uses.
The legislative authority for
implementation of Canadian EQGs or other water quality criteria lies primarily
with each provincial or territorial jurisdiction, with the exception of federal
lands (CCME 1999a).
3.3.2
Provinces and Territories
Outside of the areas of federal jurisdiction noted in the previous section,
regulatory oversight of drinking water quality is a provincial and territorial
government responsibility. Some provincial and territorial governments
reference drinking water quality criteria directly to regulations. As a result of
the experiences at Walkerton and North Battleford, all provincial and territorial
governments have revisited their respective drinking water programs and have
made or identified improvements that ought to be made.
Most provinces and territories have established legislation and regulations for:
•
Protecting water resources
•
Approving the design, construction, operation, and maintenance
of water treatment and distribution systems
•
Establishing drinking water quality criteria
•
Setting monitoring, remediation, and enforcement activities
Jurisdictions without legislation in these areas have established policies and
guidelines to ensure public health is protected. Provinces and territories also
make significant contributions to infrastructure programs.
In most provinces and territories, the responsibilities related to source water
protection rest with departments of natural resources, environment, municipal
affairs, and agriculture. Drinking water regulation or policies may involve
either or both departments of public health and environment. Monitoring may
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be undertaken by regionalized operations staff while centralized specialists
conduct proposal assessments and approvals. Provinces and territories may also
legislate the creation of either a source water protection committee or a
conservation authority (for more information see Section 6).
A key component of provincial and territorial drinking water programs is setting
compliance and performance monitoring requirements. Compliance monitoring
requirements deal with the quality of drinking water which reaches consumers
while performance monitoring ensures treatment and distribution systems are
functioning as designed and, ideally, at optimal levels.
Provincial and territorial responsibilities include ensuring that the appropriate
legal instruments are in place to require operators to be properly trained and
certified. It is important for provincial and territorial governments to commit to
either generating or adopting appropriate training information for operators,
regardless of whether these are private individuals or operators of complex
treatment systems. Information on operator certification is given in Section 8.6.
Often a separate statute or regulation provides the provincial or territorial
government with the authority to compel a supplier to take action during an
emergency situation where drinking water safety might be compromised. There
are two types of situations which can cause a water system to be compromised.
The first is an event in the source water, usually out of the control of the
drinking water system owner or operator. The other type of event is an
operational interruption. It is important to note that provincial and territorial
governments have established emergency response teams that become the lead
agency when dealing with any emergency situation, including chemical or other
spills in bodies of water used as a source of drinking water. More information
on these types of events and how to deal with them is given in Section 8.8.
Requirements (other than those dealing with water quality) for some very small
water systems may be different than those for municipal systems, depending on
such factors as the number of people served. For instance, monitoring
requirements for very small water supply systems may be less stringent or may
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not be included in a jurisdiction’s drinking water protection regulation or
program. Even though these systems typically have fewer service connections
than other public systems, they do provide water to the public or a significant
number of people. For this reason, it is important for provincial and territorial
governments to consider the risk to public health and implement appropriate
water quality control programs where they are not already in place.
3.3.3
Municipalities and non-municipal system owners
Both municipalities and non-municipal system owners are
responsible for providing clean, safe and reliable drinking water to
Working with industry
consumers.
Municipalities can work
proactively with industry to
initiate cleaner production
programs. Less pollution going
into sewers reduces the
amount of treatment that has
to be done at the wastewater
plant, as well as improving the
quality of the treated
wastewater as it returns to the
environment.
Municipalities are the primary providers of water services to
Canadians and have made a significant investments in this area.
Typically, a municipality's roles and responsibilities are defined in
provincial or territorial regulations.
Municipalities can impact watersheds/aquifers through activities
such as road construction and maintenance; winter control (including salting,
sanding and snow removal); and waste management including the placement
and management of landfills. For this reason, municipalities are encouraged to
examine ways they can reduce their impacts on watersheds/aquifers. At the
organizational level, this can include engaging in the development of a
corporate environmental management plan such as ISO14001, EMAS, and other
variations. These plans provide a consistent and transparent examination of the
activities of each department and provide a management tool for identifying
environmental risks and establishing priorities for action. Because municipal
boundaries are not drawn along watershed/aquifer lines, municipalities also
need to work with other stakeholders to protect drinking water sources. More
information on this topic is given in Section 6.
The management and structure of waterworks systems depend on the type of
ownership and legal requirements under which they are formed. With the
growing recognition of the importance of water resources, it is the responsibility
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of management, regardless of the type of ownership, to achieve quality
performance of the waterworks.
Municipal water purveyors are generally vested with the responsibility to ensure
drinking water provided to consumers is safe for consumption. The utility
organization has a legal and moral responsibility to its users to provide potable
water which does not pose a threat to public health and is
satisfactory in its physical, chemical and aesthetic
characteristics. Similarly, the same obligation is required
in the collection and treatment of wastewater. In this latter
case the obligation relates to the protection of the
environment as well as that of public health.
It is important that water utilities learn to work with other
groups concerned with or who could potentially impact
water related decisions, especially if systems are going to
meet future challenges such as increased demands for
water,
cleaner
water
and
adequate
infrastructure.
Working with agriculture
Agriculture plays an important role in
the economic, social and political
activities of many communities. While
the agricultural sector brings many
benefits and has made improvements
in recent years, the potential for harm
also exists particularly from non-point
sources of pollution.
Establishing partnerships with
organizations in the agricultural sector
can assist in developing credibility,
and gain co-operation from farmers
who may be reluctant to co-operate
with government (including municipal)
approaches.
Stakeholder alliances are helpful in gathering information,
building relationships and reaching consensus.
There is growing recognition that unilateral decisions to water quality issues no
longer work and, in many cases, can result in bitter consequences when
stakeholders are excluded. Many utilities have found that stakeholder alliances
can be an effective forum for open dialogue with potential adversaries and
could:
•
Improve community relations
•
Help initiate new ideas
•
Help promote learning and understanding by all parties
•
Help protect water rights and improve supply reliability and
ability to meet demand
•
Minimize liability claims
•
Help develop legislative allies
•
Help protect or enhance water quality
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Individuals
The public can play an integral role in protecting the integrity of drinking water
supplies. An informed, involved and supportive public forms the foundation of
an effective drinking water program. The daily activities of the public (car
washing, pet hygiene, etc.) in a watershed/aquifer can directly impact the
quality of water that arrives at the treatment plant. Furthermore, the public is
capable of exerting pressure on the governing bodies which manage the
provision of drinking water.
The public has a number of responsibilities related to the success of a drinking
water program, including duties to:
•
Advise the government
•
Comply with requests to sample water quality in their homes
•
Conserve water, especially during periods of drought or when
water use restrictions are in place
•
Select plumbing materials (and other materials that come into
contact with drinking water) for their homes that are certified as
meeting health-based performance criteria
•
Keep informed and participate in public fora
Without a comprehensive, well-planned effort to include the public in the
development and implementation of drinking water management plans, it is
unlikely that the program will be successful.
Providing additional information to owners of private drinking water systems
(groundwater or surface water) is very important as these owners are
responsible for regularly testing the quality of their water. Owners need to know
what to do in case of microbiological or chemical contamination of their
drinking water. Well-owners need to know how to maintain their wells and how
to arrange to decommission wells that are no longer safe or needed. They also
need to be aware of requirements for intake location and construction of a well.
Provinces generally have programs in place to provide instructions for sampling
private water supplies and to help interpret the laboratory results.
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Mismanagement of a private water system can put the residents’ and/or users'
health at risk and also be a source of contamination of the groundwater aquifer
or surface water. Owners are responsible for ensuring they meet any legislation
or regulations in place and for having any required approvals and licenses.
More information on public involvement in, and awareness of, drinking water
programs is found in Section 9.
3.4
Water Quality Guidelines
All Canadian jurisdictions have established guidelines, objectives or standards
for drinking, recreational and ambient water quality within their boundaries and
areas of responsibility.
Guidelines are recommended benchmarks against
which water quality can be assessed, but are not legally enforceable. These
guidelines are developed at the provincial/territorial and/or the federal level.
Objectives are site-specific values for the protection of water users (animals,
plants, and humans). Objectives are based on guidelines, but incorporate sitespecific modifying chemical, physical, and/or biological factors. Standards are
legally enforceable limits for water quality, when referenced in legislation,
which cannot be exceeded for the protection of human or aquatic health.
As described previously, the provincial and territorial governments are
responsible for implementing the guidelines through their respective drinking
water quality and public health programs. The federal government uses the
guidelines as the benchmark against which the quality of drinking water
supplied on federal lands and at federal facilities is measured.
3.4.1
Environmental Quality Guidelines
Environmental quality criteria are commonly used to determine the likelihood
of an adverse effect on biota from exposure to a particular contaminant (the
risk) by comparing ambient levels of that contaminant against a numerical
benchmark.
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The Canadian Council of Ministers of the Environment (CCME), comprised of
the ministers of environment from all provincial, territorial and federal
governments, establishes four sets of guidelines which aim to:
•
Protect aquatic life by setting guidelines for water quality and
sediment quality
•
Ensure the quality of water used in agriculture (for livestock
and irrigation)
•
Protect wildlife that rely on aquatic life as a food source (tissue
residue guidelines)
Provinces and territories may adopt these guidelines, or others, as they see fit.
Meeting Environmental Quality Guidelines is important because we depend on
our water resources for our health, recreation and our livelihoods.
For more information on these guidelines, visit the CCME's website at:
www.ccme.ca
3.4.2
Guidelines for Canadian Drinking Water Quality
The Guidelines for Canadian Drinking Water Quality (the guidelines) are
developed cooperatively by the federal, provincial and territorial governments
4
through the Federal-Provincial-Territorial Committee on Drinking Water
(CDW), a standing Committee under the Federal-ProvincialTerritorial Committee on Environmental and Occupational Health.
Drinking Water Committee
As noted previously, the provinces and territories establish their
The Federal-ProvincialTerritorial Committee on
Drinking Water is committed
to providing public access to
its processes, proceedings,
and decisions.
drinking water quality requirements using these guidelines or other
more stringent ones.
The guidelines are scientifically-based criteria that characterize what
is considered safe, clean, reliable, and aesthetically-pleasing
drinking water, regardless of whether the water is from a public,
Health Canada maintains
Committee information on its
website:
www.hc-sc.gc.ca/waterquality
semi-public, or private supply. The development of the drinking
water guidelines involves the scientific assessment of health risks, the practical
assessment of the costs and potential benefits associated with meeting the
4
Name changed from Subcommittee to Committee on Drinking Water (CDW) in 2002
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guidelines, and consultation with the public, owners, and water supply service
industries.
3.5
On-going Investment and Maintenance Programs
The long-term success of the drinking water program requires a commitment to
adequately fund the on-going operation and maintenance of the system and pay
for the inevitable capital works that will be required to upgrade or replace
components (including reservoirs, dams, and intakes) as they age.
This
commitment also includes funding source water protection activities such as the
development of watershed/aquifer management plans and improvements to
watersheds. These costs are real and need to be acknowledged in the
management and planning processes through, for example, depreciation
reserves funded through water rates.
Ideally, each water system would be self-supporting. A self-supporting water
supplier maintains sufficient revenue to meet all annual budget
needs and to contribute to a reserve fund for future
improvements or emergencies.
It is important for system
owners to commit to funding source water protection activities,
maintenance and operation of existing infrastructure, and longterm infrastructure replacement and upgrading.
In order to determine the true cost of producing treated water, it
is important for system owners to undertake full cost accounting
(FCA) of the drinking water program. FCA is a systematic
Considerations for Funding Plans
Funding plans need to consider
the entire water network.
Funding arrangements need to
include considerations for the
water storage and distribution
network as well as the treatment
plant. Communities are strongly
encouraged to have active repair
and maintenance programs as
well as cross-connection control
programs in place, supported by
municipal by-laws.
approach for identifying, calculating, and reporting the actual
costs of producing safe drinking water. It takes into account past and future
outlays, overhead (oversight and support services) costs, and operating costs.
FCA focuses on three major types of costs that are relatively easy to determine:
up-front, operating and up-coming.
Up-front costs are the initial investments
and expenses necessary to provide safe drinking water: source water protection
plans, initial capital expenditures for the construction of the buildings, intake,
treatment facility, pipelines, etc. Operating costs are the expenses associated
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with managing the water source, facility, and infrastructure on a daily basis. Upcoming costs include expenditures to upgrade and/or expand treatment facilities
and replace and/or repair infrastructure at the end of its useful life.
3.5.1
Investing in Source Water Protection
Source water protection measures, especially in the context of a drinking water
program, are generally preventative in nature. Even during the best financial
times, it is difficult to commit money to these types of programs because the
public is generally much more accepting of funding tangible, visible results
such as road repairs. However, protecting human health is an essential pursuit
of stakeholders and participating partners in the drinking water program. The
absence of illness is a positive result that can be measured, demonstrated and
communicated. Information on source water protection measures is
given in Section 6.
Funding for a watershed/aquifer effort might be found in established
federal, provincial, and/or territorial programs.
Most small-scale
watershed/aquifer groups, however, start by looking for funding locally.
Local utilities, non-profit organizations, municipalities, and others have
funded watershed/aquifer management actions.
Depending on the
amount of funding and other resources at its disposal, a committee may
Between 1990 and 1995,
87 watershed
management projects
were conducted in Ontario,
with reported total project
costs ranging from
$30,000 to $896,000,
with a median value of
$150 000 (Ministry of
Environment and Energy
and Ministry of Natural
Resources 1997).
be required to prioritize its planning activities.5 In doing so, it needs to consider
the following:
•
Available funds
•
Costs/benefits of each action (return on funds to be invested)
•
Time and other non-financial resources
•
Ability to get the action done
•
Early successes motivate more action
•
Some actions rely on other actions for success
5
The structure and functions of Source Water Protection Committees are determined by
each jurisdiction and therefore vary across the country. In general, committees have
little to no direct regulatory control, though they can advise regulators to act. For more
information on Source Water Protection Committees, see Section 6.2.
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Government incentive programs are another form of investment that may be
attractive to governments wanting to encourage industries to prevent pollution
from entering the watershed/aquifer and to promote good stewardship practices.
Examples of incentives to control water quality include:
•
Fees levied on actual or estimated point-source pollutant
discharges to surface waters; fees are intended to defray some
of the costs associated with mitigating environmental damage
and act as an initial discharge deterrent
•
Taxes or subsidies on receiving water quality (these would be
forfeited if pollution control was inadequate)
•
Liability, which makes polluters directly responsible for any
impairment to water quality as a result of their actions (Coote
and Gregorich. 2000)
In addition to the above, incentives can be regulatory in nature.
EXAMPLES
OF
AGRICULTURAL INCENTIVES
FOR
PROTECTING WATER RESOURCES
It is important to note that some of the
incentives discussed below are regulatory
requirements in other jurisdictions.
In Ontario, the Rural Water Quality
Program provides financial
incentives to rural landowners to
establish strategies to improve
surface and groundwater quality
(Coote and Gregorich. 2000).
Funded projects have included
manure storage facilities and
associated nutrient management
plans, milk house washwater
treatment systems, clean water
diversions from manure storages,
and restricted livestock access to
waterways (Coote and Gregorich.
2000).
The Ontario Ministry of Agriculture
and Foods’ (OMAF) Healthy Future
for Ontario Agriculture program
encourages producers to enhance the
quality and safety of food produced
in the province, to increase
exportations and to improve rural
water quality and uses. The last
objective is achieved by funding
agricultural producers who invest
capital in the implementation of new
technologies and better management
practices to preserve source water
quality and reduce water usage.
Alliances of producers, non-profit
agricultural organizations, and rural
municipalities and agencies are
encouraged to participate.
The Ministry of Agriculture,
Fisheries and Food of Quebec's
(MAPAQ) Prime-Vert program is
intended to promote and implement
better management practices, to
improve production systems, to
preserve and protect the
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environment including water, and to
help producers to satisfy to the new
Regulation Respecting the Reduction
of Pollution from Agricultural
3.5.2
TO
SAFE DRINKING WATER
Sources, especially concerning
manure management. The PrimeVert program provides funds
depending on the projects proposed.
Infrastructure Investment and Maintenance
In providing water services, system owners accommodate a range of consumer
demands including residential, industrial, commercial, and institutional uses.
All water consumers typically have a number of expectations about their water
supply, including that it:
•
Be available 24 hours per day
•
Be free of pathogens and toxic chemicals
•
Be free of objectionable tastes and odours
•
Maintain adequate pressure at all times
•
Maintain sufficient volume to meet demands at all times
When water supply infrastructure programs are self-funding, costs are borne by
the ratepayers or service users through normal water billing. While government
"special funding" for water infrastructure is occasionally available and is
important, the user-pay model may better relate the true value of water to
consumers. Self-sufficiency is the only guaranteed method for communities to
ensure sufficient funds are available when required.
Although self-sufficiency is the ideal situation, not all owners have equal
opportunity for funding major water treatment projects due to:
•
The high costs of complex water treatment and monitoring
technologies
•
Benefits of economies of scale available to larger cities
•
Reduced tax base of small communities
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In Canada, regulatory efforts directed at ensuring the provision of safe drinking
water by municipalities has been greatly facilitated by government financial
assistance programs for municipal water supply systems. The overall objective
of such programs is to ensure all municipal waterworks systems meet provincial
requirements. Through financial assistance on capital costs, it is important for
the programs to be structured to maintain a reasonably
equitable per capita debt between municipalities for water
supply work recognizing that larger municipalities enjoy
“economy of scale” benefits not available to smaller
communities. For information on government funding
programs, check the appropriate federal or provincial
government website.
Because public health needs to be protected equally
regardless of the size of the community, it is important to
give special consideration for additional funding support to
small
systems
servicing
rural
communities.
These
communities have access to a much smaller municipal tax
base and are therefore not able to wholly fund infrastructure
works nor to contribute their share of the capital costs
required by funding programs. Small system owners are
encouraged to consider all possible financing solutions—as
well as alternative arrangements such as joining a near-by
municipal system or a regional water supply system—prior
Financing small systems
Costs are generally an important
factor in both the willingness and
ability of a small municipality to plan,
develop and operate good
waterworks. A considerable disparity
exists between the ability of small
and large municipalities to raise the
capital needed to build water supply
systems.
From a regulatory standpoint, it is
therefore very desirable to have
financial assistance programs that
either provide an incentive for small
municipalities to construct good
water supply systems or at least
offset some of the financial concerns
municipalities may have about
meeting regulatory requirements. The
financial assistance program should
be structured to maintain a
reasonably equitable per capita debt
between municipalities, regardless of
size. This approach recognizes that
larger municipalities enjoy
“economies of scale” benefits not
available to smaller communities.
to asking other levels of government for assistance. As part
of this process, it is important to recognize that some solutions may be
expensive at first but may prove cost effective in the long run.
Costs are generally a key factor in both the willingness and ability of a
municipality to plan, develop and operate a good drinking water system. From
a regulatory standpoint, it is desirable to have financial assistance programs
which either provide an incentive for municipalities to construct good drinking
water treatment plants and distribution systems or at least help off-set some of
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the financial concerns municipalities may have with respect to meeting
provincial requirements for water supply works.
In addition, it is important for funding bodies to give funding priority to
infrastructure projects that promise the greatest positive health impact over
those projects that will have minimal health effects. For instance, funding for
drinking water treatment plant maintenance and upgrades that will have a
positive public health impact may be given priority over other infrastructure
projects.
A secondary, but no less important, investment is ensuring that installers and
designers are properly qualified. It is important for system owners to commit
to using certified service agents. More information on this topic is found in
Section 8.6.
For detailed information on financing, investment, and setting water rates, see:
•
5th Edition of Water Supply, by Twort C. Alan, Ratnayaka D. Don and
Brandt J. Malcom. Chapter two - "Organization and Financing of
Public Water Supplies" (pp. 36 to 62). Publisher: Arnold and IWA
Publishing, London (2000)
•
Canadian Water and Wastewater Association materials: “Municipal
Water and Wastewater Rates Primer,” “Municipal Water and
Wastewater Rate Manual” (2nd Edition), “Meters Made Easy: A
Guide to the Economic Appraisal of Alternative Metering Investment
Strategies”
For information on maintaining and operating infrastructure, see Section 8.
3.6
Education related to the Drinking Water Program
The successful operation of any drinking water supply system—from private
wells to managing large watersheds or complex treatment plants servicing large
cities—depends on the skills, abilities, and knowledge of the responsible
owners and employees. Although the level of knowledge required by a home
owner regarding their individual well will differ from a member of a source
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water protection committee or a city employee operating a large plant, each
needs to understand certain basic aspects of drinking water supply
management.
In addition, because of the complexity of water quality issues, and
because public health is at stake, it is critical for all members of a
drinking water program—whether elected officials (including municipal),
System owners and
operators should
become intimately
knowledgeable of the
legislation which
governs their
business.
regulators, scientific staff, utility operators, or others—to have
appropriate levels of knowledge and understanding of the impact of their
activities and decision on the quality of the water. To this end, they need
access to continuing education in this field.
The provincial and territorial governments are responsible for overseeing the
drinking water quality program within their jurisdictions. Changing technology,
regulatory requirements, and a general need for personnel in the water works
industry to remain current, requires continuing education. It is important for
departmental staff to take courses to keep pace with developments in the
drinking water field. As part of this education, it is important for open dialogue
to be maintained between regulators, operators, and industry. Most provinces
and territories now require drinking water treatment plant operators to be
certified and to maintain their water works education requirements.
A robust community education program and community support helps staff and
politicians tackle difficult decisions with confidence. For instance, source water
protection can inspire difficult political decisions that may restrict activities and
the 'right' to use land or water that people may have become used to,
particularly when related to well-entrenched activities. According a high
priority to source water protection may prove to be a challenge for some
municipalities.
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EXAMPLE
OF A
TO
SAFE DRINKING WATER
COMPREHENSIVE EDUCATION PROGRAM:
CROSS-CONNECTION CONTROLS
Some aspects of the drinking water
program may seem too complex or
technical for a broad audience. For
instance, most citizens, including
elected officials, do not understand
what a cross-connection is or the
danger it represents to the public.
However, the key to establishing a
cross-connection control program is
awareness training of the appropriate
utility personnel, municipal
administrators, councillors, mayor,
then public education and public
relations.
Internal educational seminars could
focus on the basics of crossconnection, backflow, hazards, the
administration (including costs) of a
program, and the potential legal
liabilities of not having an effective
program. Public education may need
to focus on the basics, how to
recognize typical cross-connections,
and the consumer's ultimate
responsibility (in most cases) to bear
the costs of any device. A pamphlet
could be sent out in consumers'
routine water service bill. Language
for technical topics needs to be clear,
concise, and free of unexplained
industry jargon.
The skill sets of the people tasked
with completing the crossconnection survey of building, either
internal staff or contractors, are
fundamentally important to the
program. Some provinces have
specific criteria that identifies
suitably qualified people. Others
may rely on third party training
offered by organizations such as
Canadian chapters of AWWA which
offer cross-connection control
surveyors certification. Regardless, it
is imperative that a municipality
understand the difference in skill sets
and hire appropriate personnel.
More information on cross-connection
controls is found in sections 7.7.5 and
8.4.2
On the water treatment and distribution side, it is critical for utility staff to be
competently trained. This training is so important because of the direct impact
drinking water has on a community's well being. All personnel need training
matching their functionary role. It is important for this training to be planned,
delivered, and documented on a continuous basis.
It is important for system owners to commit to obtaining and maintaining their
own level of training. Owners are responsible for their employees and thus
need to know the significance of the information provided by their employees
and the ramifications of the operating decisions being made.
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Treatment plant and distribution system operators have perhaps the most direct
influence on the safety of a community's drinking water supply. For this reason,
it is very important for system owners to require that only system operators with
the appropriate training be hired. The operators' level of competence also needs
to be maintained through continuous education opportunities.
It is important for the level of training to be appropriate to the treatment and
distribution system being managed. All operators require a basic understanding
of water quality issues, especially those related to the microbiological quality of
the water and the need for proper disinfection. It is important for those
responsible to be given specific training on how to optimize, and react to
changes associated with, the more complex treatment processes for any system
that rely on these processes. Training should thoroughly explain monitoring
processes and how to maintain documentation and keep records. Employees
need to fully understand emergency response and reporting procedures. In
addition, education on source water protection issues is important as waste
streams from treatment systems can impact source water quality, especially for
downstream water users.
Training can include formal training at post secondary institutions, water
association training courses, in-house training and mentoring programs, on-thejob experience in consultation with other trained operators or government
specialists, workshops, seminars, courses, and conferences.
Operator
certification ensures that operators are appropriately trained to the level required
for the system they are responsible for. It is important that provincial and
territories governments require mandatory certification, and that system owners
commit to supporting such programs. Because training is an on-going process,
employee training needs to be a continuous commitment.
Detailed information about operator training and certification, along with
facility classification, is found in Section 8.6.
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3.7
TO
SAFE DRINKING WATER
Research and Development
Growing demands on drinking water quality and quantity are creating an urgent
need to link research from a wide range of sources in order to improve drinking
water quality from source to tap. Existing uncertainties in the drinking water
field can only be overcome by a greater scientific understanding of issues. This
understanding is normally attained through research and development, which
enhances our understanding of threats to water supplies. Technology
development provides mechanisms to counter these threats.
Research and
development most often provide interpreted assessments that clarify both
technical and operational issues. In addition, it is recognized that investment in
prevention will always be far less costly than remediation of problems or
dealing with situations of irreversible harm.
It is important for all stakeholders, including governments, to maintain
awareness of the research and development occurring in the national and
international scientific communities. Sharing information between jurisdictions
allows each jurisdiction to determine applications to its local situation.
Stakeholders need to commit to gathering data and maintaining databases on
water quality parameters for which there are water quality guidelines, new and
emerging substances of concern, and associated treatment technologies.
It is important for regulators, consultants, facility operators and other
stakeholders to commit to continually bettering the information and knowledgebase on water treatment processes and hazards, new processes and emerging
issues, improved analytical methodologies, the relationship between water
quality and health outcomes, and local water quality and treatment data
gathering.
Government needs to actively participate with institutional and
public sector researchers and monitor the results of research to ensure priorities
are being met.
Provincial and territorial governments need to maintain their knowledge of the
advances in disinfection and treatment process optimization within and outside
of their jurisdictions. Sharing information allows each jurisdiction to determine
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applicability to its local situation. It is important for provincial and territorial
governments to commit to gathering data and maintaining databases on the
water quality parameters currently included in the guidelines, new and emerging
substances of concern, the treatment technologies and limitation within their
jurisdictions, and the efficiencies of the treatment provided.
Drinking water suppliers also need to commit to gathering data, optimizing their
processes, and to cooperating with the provinces and territories in data
collection to assess public exposure to various substances under consideration
for guideline development or review. Since this information feeds into research
processes, water suppliers and public health officials play an important role by
collecting data about their water systems and the health of the community. They
should be encouraged to cooperate and participate in research activities.
Regional health departments and the various partners involved with delivering
health care also have a role to play by helping gather data on disease occurrence
and prescription and non-prescription medications. This type of data helps
identify whether the contaminants or pathogens in question are entering the
system or are a concern in Canadian drinking water supplies. Comparing water
quality data to local hospital admittance records, medical billing records, or
sales of over-the-counter pharmaceuticals can sometimes indicate relationships
between water quality and potential health effects. This data may form the
basis of new or revised public health policies.
It is important to use scientific information as the basis for making decisions
whenever possible. Drinking water managers are often forced by circumstances
to make decisions based on incomplete knowledge. They compensate by filling
information gaps with reasonable assumptions. Each such assumption carries
the risk of unintended consequences. Use of scientific data in decision making
has the advantage of controlling or measuring many of the important conditions
that affect outcomes; critical assumptions are often carefully spelled out. When
decisions are based on anecdotal experience, less may be known about
conditions that affect outcomes, and key assumptions about these conditions
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may not be explicit. Decisions that draw on scientific information, therefore,
reduce the risk of unexpected outcomes.
As noted, many stakeholders are involved directly and indirectly in water
issues. The goals of stakeholders may differ and thus provide conflicting
interpretations of priorities and responsibilities. For this reason, it is important
for all levels of government and departments to work together in developing
and implementing research and development activities.
Technology should not be developed in isolation. Decision-makers need to
know how technology developed in academia, the private sector or through
government research and development activities can be transferred for use in
day-to-day operations. For example, the identification and control of threats
posed by waterborne pathogens require effective pathogen detection and
treatment techniques.
Similarly, nutrient management plans and codes of
practice need to be developed to reduce nutrient loading from specific sectors
that have broad geographic coverage. Research on environmental indicators,
technologies to recover and recycle nutrients, and management practices that
minimize nutrient losses require greater attention.
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4. The Risk Management Process
Risk management is a process that identifies all the existing and
potential
hazards
in
a
drinking
water
system
(from
the
watershed/aquifer and intake through the treatment and distribution
chain to the consumer), assesses their potential impact on drinking
water quality and public health, and then finds ways to either mitigate
or eliminate those hazards. The goal of risk management is to protect
public health consistently over the long-term.
The adoption of a risk-based approach, such as the multi-barrier
approach, is essential to the effective management of drinking water
systems. Hazard identification and risk assessment are valuable tools
for understanding the vulnerability of a drinking water supply and for
planning effective risk management strategies to ensure drinking
Risk management
The systematic evaluation
of the water supply
system, the identification
of hazards and hazardous
events, the assessment of
risks, and the
development and
implementation of
preventive strategies to
manage the risks.
Framework for management
of drinking water quality: A
preventive strategy from
catchment to consumer
NHMRC/ARMCANZ
Co-ordinating group, Australia
water is kept clean, safe and reliable. In cases where risks cannot be
quantified (e.g. when there are too many variables to isolate specific hazards or
their potential impact), best management practices may be a useful tool for
addressing risks.
4.1
Identifying Hazards
Hazards can be pre-existing in a drinking water supply, such as
naturally-occurring minerals in a drinking water source that may need
to be removed in order to protect public health over the short- or longterm. Hazards can also be potential, such as flooding or power system
failures during a storm.
In order to determine the inherent, existing and/or potential hazards
within a specific drinking water system, owners and operators need to
consult a number of sources of information. For instance, a detailed
review of historical water quality data can assist in understanding
source water characteristics and system performance both over time
and following specific events (e.g. heavy rainfall). In addition to
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Hazard refers to a source of
(potential) harm to the
functioning of any aspect of
the drinking water system
or to human health.
Hazards can be the result
of natural and/or human
(anthropogenic) activities.
Risk refers to the chance or
possibility of a hazard
causing this harm to the
functioning of any aspect of
the drinking water system
or to human health.
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identifying hazards, this type of review can highlight those aspects of the
drinking water system that require improvement.
When identifying hazards, all water quality data is considered including data
from routine and investigative monitoring. Where possible, data is taken from
source water monitoring, treatment plant and distribution system monitoring,
and indicates the quality of finished water supplied to consumers. It is important
for care to be taken to ensure the data is valid and not misleading, that proper
sampling procedures have been used, and that consideration has been given to
the location of the sampling sites and the season in which the samples have
been taken.
It is important for all potential hazards and hazardous events to be considered
and documented regardless of whether or not the system owner or operator has
direct control over the hazard or its source. Potential source water hazards
include point sources of pollution, such as human and industrial waste
discharge, as well as diffuse sources such as those resulting from natural
processes (e.g. decay of vegetation), agriculture, logging, mining and other
land-use activities.
Continuous, intermittent or seasonal pollution patterns
should also be considered along with extreme and infrequent events such as
droughts or floods. Potential operational hazards include lack of a cross control
program, untrained operators, inadequate treatment, etc. Lack of historical data
and/or source data may make the identification of some operational hazards
more difficult.
4.2
Assessing Risks
Once potential hazards and their causes have been identified, the level of risk
associated with each hazard and/or hazard scenario is estimated so priorities for
risk management action can be established and documented. It is important to
recognize that while countless contaminants can compromise drinking water
quality, not every potential hazard will require the same degree of attention.
The distinction between hazard and risk needs to be understood so attention and
resources can be directed to actions based primarily on the level of risk
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associated with, rather than just the existence of, a hazard.
The level of risk for each hazard/scenario can be estimated by identifying the
likelihood of occurrence. This likelihood of occurrence is then balanced against
the severity of impact and the potential threat to public health posed by
exposure to the hazard and the potential duration of this exposure. In some
cases, such as exposure to some microbiological pathogens, the threat to public
health will be acute even when the duration of exposure is fairly short. In other
cases, such as exposure to some chemical contaminants, the hazard may only
pose a threat to public health if people are exposed continuously over a period
of years. Chemical contaminants, however, may also cause significant changes
to the characteristics of the source water body and may necessitate changes in
the water treatment process. Public perception of such contaminants and failure
to adjust/change the water treatment process can lead to increased public health
risks and a loss of consumer confidence. Consumers may seek other sources of
drinking water that may not be free of pathogens.
Rarely will enough knowledge be available to complete a detailed quantitative
risk assessment; in most cases it will be more appropriate to adopt qualitative or
semi-quantitative approaches.
Risk assessment approaches need to be
transparent and fully understood by involved parties.
The predictive nature of hazard identification and risk management dictate that
substantial uncertainty will always be associated with these activities. An
appreciation of the uncertainties in our scientific tools is an important part of a
precautionary approach to managing risks.
4.3
Managing Risks
Once hazards have been identified and their level of risk has been assessed, they
are prioritized and then managed.
The type of risk management strategy
required depends entirely on the type of hazard requiring attention. For instance,
in order to mitigate the risk associated with a potential power outage during a
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storm, a utility may simply need to arrange to have an alternative power supply
on-site such as a back-up generator.
Other hazards may require much more extensive or complex risk management
solutions. For instance, while diffuse sources of pollution arising from
agricultural and other land use activities are more difficult to manage than point
sources of pollution, their effect on public health can be minimized by adequate
disinfection. The amount of microbiological contamination can
be minimized through the use of best management practices
such as fencing off streams, managing riparian zones and
watering livestock off-stream. Co-operation with landowners
and agricultural advisors in the development of joint land and
water management strategies is important. The proper design
and on-going maintenance of treatment plants and distribution
systems is essential to protecting public health.
Risk management tools and processes often involve costs that
must be weighed against the real or potential benefits
associated with implementing and maintaining them. Often the
calculation of costs vs. benefits is complicated by stakeholders
having differing views on the acceptability of various risks.
Some people may feel that no risk to their health is acceptable,
Weighing risks and benefits
The net change in risk produced
by treatment processes such as
disinfection and the addition of
other essential chemicals is a
trade off between decreasing
infectious disease and increasing
toxicological risk. Where
appropriate information exists, a
quantitative risk assessment
approach should be used to
evaluate the risks. Risk
assessment results should be
considered as tentative because
they are far from being inclusive
of the total microbial and
toxicological risks. Furthermore,
the assumptions that typically
underlie risk assessment models
used are difficult to verify
experimentally.
even if the scientific evidence is ambiguous or lacking and the
cost of implementing a barrier to eliminate the risk is high. Others may feel
more comfortable with some risk of health effects if they know these effects are
minimal and would only affect a very small number of people over the longterm. People at risk such as the immune compromised would
be advised and they could take preventive measures to protect
their own health.
It is important to remember that while no approach will
guarantee 100 per cent protection all of the time, effective risk
management reduces the risk of illness from drinking water and
increase the feasibility and effectiveness of remedial control or
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Prioritizing risks
Many jurisdictions in Canada are
developing procedures for
prioritizing risks to drinking water
from source to tap. For more
information on how this is being
done in your jurisdiction, contact
your provincial or territorial
drinking water authority.
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preventative options. As a safeguard, a key element of the multi-barrier
approach is to ensure contingency plans are put in place to respond to incidents
as they arise, and that redundancies are built into the system wherever feasible.
These actions will mitigate repercussions when and if failures occur in the
system and also help demonstrate that the system owner and/or operator has
acted with due diligence.
4.4
Risk Communication
Risk communication is an equally important component of the risk management
process and should not be overlooked. Risk communication refers to the
exchange of information between interested parties about health or
environmental risks, the significance of these risks and actions aimed at
their management and control.
It is an on-going process; risk
communication should not only be used during a crisis or emergency.
Effective risk communication ensures all participants adequately
understand the risk management process and decisions made. It helps
participants
make
informed
decisions
about
Risk communication is
an integral part of the
decision-making
process, because risk
management decisions
must be acceptable to a
broad range of
interested and affected
parties.
the
factors that can affect their health such as the quality of their drinking water.
(Adapted from Health Canada 2000).
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5. Drinking Water Hazards
This section discusses the most common hazards to the drinking water supply,
from source to tap. The assessment and management of these hazards is
discussed in Sections 6, 7 and 8.
The first step in implementing the multi-barrier approach is to understand the
drinking water supply, including: the quantity and quality of the source water;
the current and potential hazards that could impact that quantity and/or quality;
the treatment processes in place and their limitations; and the condition of the
distribution system.
Drinking water is either taken from surface waters such as lakes and rivers or
groundwater sources such as aquifers. The types of hazards that need to be
assessed and managed vary depending on the type of the source water, its
geographical location, the local geology, and the activities that take place in or
around the watershed/aquifer. For instance, human and animal populations can
contribute microorganisms and nitrate loadings from wastes. Human
development pressure from private sewage disposal systems (e.g. septic fields),
landfills, and industry and agriculture can put source waters at risk of
contamination. Industrial and construction operations can release large amounts
of heavy metals. Farming operations can result in runoff containing fertilizers
and pesticides.
In addition, the destruction of wetlands in many jurisdictions has threatened
source water quality by removing the pre-existing capacity for source waters to
be buffered from pollution sources. The absence of wetlands means pollutants
that would otherwise be effectively filtered by natural biological and physical
processes readily enter source waters. Currently, many federal and provincial
programs are trying to reverse this trend and reclaim areas around source waters
as wetlands.
An examination of existing land uses can, on a preliminary basis, identify the
types of hazards that may exist in source waters. These assessments can guide
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regulators to focus their monitoring efforts on the likelihood of findings
potential contaminants that may be present due to the land use activities.
Once source water has been collected at the intake for treatment and distribution
as drinking water, microbial and chemical constituents can be introduced.
Possible causes of contamination include improper sanitation practices of staff
and visitors, improper construction of works, improper operation of treatment or
distribution system components, misuse of treatment chemicals or additives,
and process failures. It is important that the design and operation of waterworks
systems follow good engineering practices. These practices are discussed in
more detail in Sections 7 and 8.
Potential health impacts of microbial constituents are discussed below. The
health effects of water treatment chemicals and/or additives are difficult to
determine without knowing the precise concentrations of these substances at the
consumer's tap. It is important to note that there are considerable benefits to
using additives such as coagulants, flocculants and filtration compounds as they
enable treatment plant operators to remove significant amounts of viruses and
other microbes, particulates and other substances. Although extremely high
levels of water treatment chemicals could cause adverse health effects, safe
application rates of these substances are well established and published by
organizations such as NSF International.
Scientific research has brought to light questions about the health effects of a
number of microbiological pathogens and chemicals that may be present in
water supplies. These substances include emerging pathogens, pharmaceuticals,
and endocrine disruptors.
For more information on current research, see the Health Canada website at
www.hc-sc.gc.ca/waterquality
For information on guidelines for pathogens and other substances found in
drinking water supplies, see Section 3.4.
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Microbiological concerns
Microbiological pathogens are considered the most significant
threat to public health related to drinking water because the
effects are acute; if ingested, pathogens can give people gastrointestinal illness within a matter of hours or days. In some
cases, consuming microbiological pathogens can result in
permanent damage to internal organs or lead to chronic health
For some groundwater supplies,
the most significant sources of
microbiological contamination are:
•
Feedlots
•
Land applications of biosolids
or manure
•
Irrigation with wastewater
effluent
•
Wastewater disposal fields
•
Wastewater treatment
facilities
problems. In the most severe cases, ingesting pathogens can be
fatal.
Surface water is vulnerable to microbiological contamination
from wildlife and a variety of human activities. Land use
activities will affect to some degree the types of pathogens present. Pathogenic
bacteria and protozoa will occur in watersheds containing livestock and wild
animals and birds. Watersheds containing human populations will also contain
pathogenic viruses. Concentrations of these pathogens at the treatment plant
intake will depend upon factors such as human and/or animal population
densities, source protection measures, pathogen persistence, dilution rates and
proximity of the intake to the source of contamination.
Generally speaking, the microbiological quality of groundwater
sources is better than that of surface waters because most
For surface waters, sources of
microbiological contamination are:
•
Grazing animals and feedlots
•
Sewage discharges
water to reach the aquifer, the lower the probability of
•
Wildlife populations
microbial contamination and the lower the risks to human
•
Recreational activities
health.
•
Unrestricted human access
•
Biosolids/manure
microorganisms are removed as the water seeps through the
soil. The soil acts as a natural filter. The longer it takes for
The overlying soil and strata characteristics
(topography, soil type, soil texture, soil permeability, soil
saturation, and stratigraphy) determine the vulnerability of the
aquifer to contamination.
Understanding the physical characteristics of a
groundwater recharge area is necessary to assess the vulnerability of the aquifer
to contamination. The location of well heads and improper maintenance could
increase the vulnerability of aquifers to contamination.
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Traditionally, micro-organisms have been monitored in source water and
finished drinking water as an indicator of the presence of pathogens (e.g. total
coliforms). There are benefits and drawbacks of this methodology. A detailed
discussion of indicators of microbial water quality can be found in “Water
Quality: Guidelines, Standards and Health” published by the World Health
Organization.
Regardless of the source of drinking water land use activities not only need to
be managed to minimize the contamination of the source and but also
recognized so that appropriate treatment can be provided.
MICROBIOLOGICAL PATHOGENS
IN
DRINKING WATER SOURCES
Microbiological pathogens are microscopic organisms such as viruses, bacteria, and
protozoa. Their presence in source waters, even in small numbers, can cause
disease or death in humans and animals if ingested water is not properly treated.
The kinds of microorganisms typically identified as potential threats to Canadian
drinking water supplies include the bacterium Escherichia coli O157:H7, and the
protozoa Cryptosporidium and Giardia. Less is known about the potential threat of
water-based viruses.
For more information, check out the supporting documentation to the Guidelines
for Canadian Drinking Water Quality or Health Canada's fact sheet series, It's Your
Health, at www.hc-sc.gc.ca/waterquality
Escherichia coli O157:H7
E. coli is a coliform bacterium that
exists exclusively in the intestines of
humans and warm-blooded animals.
As such, it is an ideal indicator of
fecal contamination, and the possible
presence of intestinal pathogens.
More than 50 different strains of E.
coli exist, and most are harmless
(BCPHO 2001). However, some
strains such as E. coli O157:H7 can
cause severe illness in humans.
Illness can result in bloody diarrhea,
and in some cases kidney failure and
potential death from hemolytic
uremic syndrome (BCPHO 2001).
Sources of E. coli contamination are
animal wastes and waste water
discharges which can be readily
carried into ground- and/or surface
waters during heavy precipitation.
Protozoa
Parasitic protozoa that have been
found in Canadian drinking water
supplies include Cryptosporidium,
Giardia lamblia, and Toxoplasma gondii.
Cryptosporidium parbum causes an
illness known as cryptosporidiosis,
while the Giardia parasite can cause
giardiasis (also called 'beaver fever').
Both cryptosporidiosis and giardiasis
are gastrointestinal illnesses.
Toxoplasma gondii causes a flu-like
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illness known as toxoplasmosis
which can cause permanent damage
to the fetus. The main sources of
these parasites in drinking water are
animal and human feces. Cattle
feces are the main source of
Cryptosporidium, while beaver, human,
dog and other animal feces are the
main source of Giardia. Toxoplasma
mainly comes from the feces of
domestic and wild cats. Like fecal
bacteria, these parasites can be easily
transported to source waters through
runoff and percolation into
groundwater. Agricultural, urban,
and wildlife habitat land uses are
potential sources of these parasites
to source waters. Source water
contamination by Cryptosporidium and
Giardia is a great concern because
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these protozoa are more resistant to
disinfection than bacterial pathogens.
Viral Agents
Viruses are extremely small microbes
(<0.3 microns) that pose a risk to
human health in untreated drinking
water sources. They are hardier and
persist longer in water supplies than
bacteria (BCPHO 2001). Viral
agents in source waters could include
hepatitis A and E, rotaviruses (which
cause diarrhea in infants and
immune-compromised adults), and
the Norwalk-like viruses (which
infect healthy adults and children
and may cause such symptoms as
diarrhea, nausea, vomiting, malaise,
fever for up to 48 hours) (BCPHO
2001).
Chemical and radiological contaminants
Health effects from chemical and radiological contaminants in drinking water
tend to be chronic, appearing only after people are exposed to high
levels of the substance consistently over a period of years. Generally
speaking, only a small percentage of the population would see any
effects. Health effects vary depending on the specific contaminant.
Significant sources of
chemical contamination from
human activities are:
•
Industrial operations
•
Mining
groundwater supplies. Groundwater normally contains higher
•
Spills and releases
amounts of dissolved minerals than surface water because it
•
Hazardous waste facilities
percolates slowly through the soil, gathering minerals as it travels.
•
Petroleum products storage
facilities
operational reasons, such as to reduce hardness or concentrations of
•
Agriculture
naturally-occurring iron or manganese. Groundwater sources may
•
Domestic use of chemicals
and personal care products
•
Waste water discharges
Chemicals and radiological compounds can threaten the quality of
Many groundwater sources require treatment for aesthetic or
also have naturally elevated levels of elements such as fluoride,
arsenic, or uranium that can pose a chronic health risk. Treatment is
the only means to control their concentration to acceptable levels.
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The land use within the watershed/aquifer can also affect the chemical quality
of groundwater sources.
For instance, if an industrial operation is located
within the watershed/aquifer, the groundwater might contain industrial
chemicals or heavy metals. Agricultural practices could result in elevated levels
of nitrate-nitrite, nitrogen or pesticides.
Surface water is also vulnerable to chemical contamination from natural sources
and human activities (anthropogenic sources). The types of chemicals present
are site-specific and depend on the activities that take place within a given
watershed/aquifer. For instance, mining activities can cause elevated heavy
metal concentrations and depressed pH; livestock or wastewater discharges can
cause elevated nitrate-nitrite levels, and industrial operations can be a source of
synthetic organic compounds.
CHEMICAL CONTAMINANTS
IN
DRINKING WATER SOURCES
General categories of chemical contaminants include organic chemicals (such
as most pesticides) and inorganic chemicals (such as metals, total dissolved
solids, and nutrients). Historical uses of chemicals that are now banned
from production still pose a risk to source water quality.
Organic Chemicals
Organic chemicals contain carbon
molecules in their structure. Many
organic chemicals have a harmful
effect on human health and can pose
a direct threat to a source water
supply. Organic chemicals are found
in point- and non-point source
releases from a wide variety of users,
including industrial, agricultural,
municipal and residential sectors.
Larger point-source releases may
occur from industrial effluent
discharges and/or accidental
industrial releases.
Pesticides
Pesticides are primarily organic
chemicals used to control pest
organisms such as unwanted plants
and insects. Pesticides are readily
used in urban, agricultural,
aquacultural, and silvicultural
applications, where they can reach
source waters through direct
application, surface runoff, and/or
groundwater percolation. Pesticides
used for herbicidal and insecticidal
purposes in urban and agricultural
regions have been detected in
surface and groundwaters,
demonstrating the need for diligent
monitoring of drinking water sources
for regionally important pesticide
products.
Total Organic Carbon
Total organic carbon (TOC) is a
measure of the amount of organic
material suspended in the water.
TOC is not a direct threat to water
quality but rather an indirect threat.
When organic carbon combines with
chlorine used in the disinfection of
treated drinking water, disinfection
by-products (DBPs) such as
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trihalomethanes (THMs) are
produced.
such as effluent releases and runoff
associated with industrial operations.
Emerging Issues
Scientists are now beginning to look
at more closely at pharmaceuticals
and personal care products (PPCPs),
some of which may also be
endocrine disruptors.
Metals
The presence of dissolved metals in
water supplies can have a negative
impact on human health through
direct toxicity or by compromising
the aesthetic value of source waters.
Metals can enter source waters from
natural weathering processes and
through sources such as industrial
and municipal effluents, mining,
leachate from waste disposal grounds
and pesticide use. Metals of concern
in Canadian drinking water supplies
can include (but are not limited to)
aluminum, arsenic, chromium,
copper, iron and lead (CCME
1999a).
The NWRI has focused research on
endocrine disruptors and PPCPs.
Although there is currently little
research linking human health effects
directly to these substances, there is
preliminary evidence of ecosystemic
effects from endocrine disruptors.
This underlines the need for further
research into their potential human
health effects as both have been
detected in water at extremely low
concentrations. The capacity of
conventional drinking water
treatment to remove these
contaminants is limited and
dependent on their characteristics
(e.g. stability, etc.).
Risks to human health posed by
these contaminants in drinking water
are expected to be low but need to
be studied further. In comparison,
the human health risks of other
contaminants such as pathogenic
microorganisms and arsenic are well
characterized and are currently
considered to be a priority.
Inorganic Chemicals
Inorganic chemicals include metallic
and non-metallic chemicals that can
be dissolved in a water source.
Inorganic chemicals range from
those that have moderate, or no
negative impacts on human health
(i.e., fluoride, chloride), to those that
are highly toxic to humans (i.e.,
cyanide). Potential sources include
both natural processes (i.e.,
weathering and dissolution of salts)
and discharges from human activities
Water quality characteristics such as
pH and the presence of humic
materials can greatly influence the
availability of metals to humans and
biota, and it is therefore necessary to
monitor such site-specific factors
when high metal contents are found
in drinking water sources. Guidance
on the effects of modifying factors
to metal bioavailability can be found
for individual parameters in the
Canadian Environmental Quality
Guidelines (CCME 1999a), and in
the supporting documentation of the
Canadian Drinking Water Guidelines
from Health Canada (2001).
Total Dissolved Solids
Total dissolved solids (TDS) are
inorganic particles and small
amounts of organic matter that are
dissolved in water. The principal
constituents are usually calcium,
magnesium, sodium, and potassium
cations and carbonate, hydrogen
carbonate, chloride, sulphate, and
nitrate anions.
TDS in water supplies originate from
natural sources, sewage, urban and
agricultural runoff, and industrial
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wastewater. Concentrations of TDS
from natural sources vary greatly
depending on the solubilities of
minerals in different geological
regions.
Water supplies, high in TDS, are not
considered a direct public health
threat, other than aesthetic effect.
Its presence does, however, mitigate
the effects of other chemical threats
such as metals (toxicity of some
metals is dependent on TDS in
freshwater) or accentuate the threat
of pathogens in water supplies
(pathogens adhere to TDS particles,
which hinders their disinfection thus
requiring a higher level of treatment).
Therefore, TDS can be an indirect
measure of the presence of other
contaminants.
Nutrients
Nitrogen and phosphorus are two
key nutrients, which contribute to
the growth of algae and plants in
aquatic ecosystems. Nitrogen in its
inorganic form can present both a
direct and indirect threat to a water
supply. Consumption of drinking
water high in nitrate ions (the most
commonly found soluble form of
nitrogen) can cause
methaemoglobinemia in infants, a
condition also known as "blue-baby
syndrome." This condition impairs
the ability of the blood to carry
oxygen and can be fatal to infants
younger than six months old.
Because nitrogen is also an essential
plant nutrient, excessive amounts
can promote the growth of algae in
water. The principle natural sources
of nitrogen to the aquatic
environment come from the
breakdown and recycling of organic
matter and the deposition of
nitrogen compounds from the
atmosphere. Agricultural and
TO
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industrial processes can greatly
increase the amount of nitrogen
reaching source waters.
In contrast to nitrogen, phosphorous
has no direct impact on human
health. However, excessive loading
in water can lead to indirect
deterioration of water quality by
promoting algae growth. Algae can
cause nuisance problems in the water
supply by contributing to taste and
odour. Very high levels can raise
turbidity, leading to interference with
water treatment processes.
The death of algal blooms
contributes to oxygen depletion in
water bodies, which can have severe
ecological effects and can also alter
chemical redox processes. These, in
turn, can influence chemical
speciation.
The influx of phosphorous supports
the growth of most species of
cyanobacteria (blue-green algae)
which can contain toxins that are
released into the water when the
organism dies. These toxins could
result in a direct threat to human and
animal life. For most cyanobacterial
species, the potential for growth is
increased when phosphorus levels
are increased without a
corresponding increase in nitrogen
(i.e. a low Nitrogen to Phosphorous
ratio favors the development of
cyanobacteria blooms).
Phosphorous is naturally released
from the dissolution of phosphorous
rich rocks and minerals. Potential
sources from human-based activities
include run-off and leachate from
agricultural and lawn fertilizers,
sewage (including waste effluent and
septic disposal), manure from
livestock, and industrial effluents.
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Physical water quality parameters
In addition to threats from chemicals and microbiological pathogens, the quality
of source waters can be impacted by a number of physical characteristics. These
site-specific characteristics can result from the amount of organic matter
suspended in the water or its mineral content. Other physical characteristics
include odour, temperature and pH.
Physical characteristics do not normally present a direct threat to human health.
However, they can indicate the presence of other chemical or biological
concerns. Particulate matter, which leads to turbidity, can also interfere with
drinking
water
treatment
processes,
thereby
increasing
the
risk
of
microbiological threats. More information on the physical characteristics of
water is given in the box below.
PHYSICAL WATER QUALITY PARAMETERS
Turbidity
Turbidity refers to the suspension of
small particles of sediment and
organic matter within the water
source that causes an overall cloudy
appearance. Unstable soil conditions
in the riparian zones of watersheds
can contribute to turbid conditions
in source waters. Turbidity generally
increases as water velocity increases
within the stream or river, as
deposited material can become
resuspended in the water column.
Organic and inorganic particulates
have no notable health effects,
however they can often harbour
micro-organisms. In many cases,
elevated turbidity levels protect
micro-organisms from disinfection
processes. Turbidity is an important
water parameter to monitor as
elevated levels can impair several
uses of a water source, including
drinking water, industrial and
recreational uses, and environmental
health.
Colour
Colour is derived from the
backscatter of light passing through
the water, and is influenced by the
dissolved or suspended constituents
in the water. Colour can be the
result of natural factors (e.g.,
dissolution of iron from iron-rich
minerals, and dissolved humic
materials) or factors that result from
human-based activities such as
effluent discharge from industrial
activities.
The source of the colour may
influence the toxic effects of other
contaminants. For example, highly
tea-coloured water resulting from the
presence of humic acids has been
shown to reduce the bioavailability
(and therefore toxicity) of metals
such as aluminum, zinc and copper,
while increasing the bioavailability of
mercury (CCME 1999a).
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Elevated humic levels in highly
coloured waters may also interfere
with water treatment processes, and
result in the production of
potentially carcinogenic by-products
like THMs.
Taste and Odour
Taste and odour problems in source
waters are primarily an aesthetic
concern, however, they can
undermine consumer confidence in
water supplies, and result in millions
of dollars annually in treatment costs
to the water industry (Watson et al.
2002).
Taste and odour problems in the
Great Lakes region and in Western
Canada have been attributed to the
presence of the biological
metabolites geosmin and 2methylisoborneol (MIB) from certain
species of cyanobacteria and/or
actinomycetes. Production of these
compounds may be promoted by
local point-source urban run-off.
pH
pH is a measure of the hydrogen ion
concentration in water (or other
solution). Waters with a pH of 7.0
are neutral, while levels < 7.0 are
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acidic and > 7.0 (up to a maximum
of 14) are alkaline (or basic). A oneunit change in pH represents a tenfold change in hydrogen ion
concentration; therefore, even small
changes in pH can significantly alter
the chemistry of source waters. The
pH of aquatic environments can be
depressed by the release of spring
snowmelt containing atmospherically
deposited SO2 and NOx, or by the
direct release of acid mine drainage
and some types of industrial waste
leachates (CCME 1999b).
Changes in pH levels can alter the
chemical form of some
contaminants. For example, a
reduction in pH may mobilize some
heavy metals into solution.
Temperature
Temperature affects both biological
and chemical functions. Chemical
equilibrium constants, solubilities,
and the rates of chemical reactions
are all temperature-dependent
(CCME 1999c).
For more information on how physical
characteristics of water affect drinking water
treatment, see Section 7
Interactions between contaminant categories
Although the hazards discussed are present in separate categories, it is
important to note that the different types of hazards could interact with one
another. This interaction may result in synergistic (i.e. the toxicity of one
hazard is increased in the presence of another) or antagonistic (i.e. the toxicity
of one hazard is reduced in the presence of another) effects. For example, the
presence of increased turbidity can lead to micro-organisms in a water supply.
Therefore, the potential interactions between contaminant sources should be
considered when identifying potential hazards.
Current drinking water
standards do not consider the effects of exposure to multiple hazards due to the
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variability and complexity of these effects. Continued research is needed on the
potential impacts of multiple hazard exposure.
5.5
Unexpected Events
Unexpected events (either natural, or as a result of human error or
accident) have the potential to impact water quality and therefore
need to be considered in the watershed/aquifer characterization.
The potential for impact from unusual natural events will likely be
identified during the assessment of other watershed/aquifer
characteristics, such as topography and vegetative cover.
Such
events could include rainstorms, blizzards, landslides, mudslides,
floods, etc.
Unusual events caused by human activities would likely be related
to unplanned chemical releases into a watershed/aquifer. Unplanned
releases can occur as a result of operational failure at an industrial
Statistical summaries of
extreme weather events from
regional weather offices would
indicate the probability of
adverse events occurring
which may influence groundand surface source waters,
particularly heavy rains and
flooding.
The type and probability of
unexpected events occurring
within a watershed, and their
potential effect on source
waters, should be assessed
from historical spill records
which may be available from
the provincial/territorial
ministries of environment
and/or transportation.
facility, treatment plant error, or transportation accident.
For more information on incidents and emergencies, including vandalism, see
Section 8.8
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6. Source Water Protection
In any drinking water system, protecting source water is a critical step towards
avoiding drinking water contamination. It is also key to maintaining the quality
of a drinking water source over time. Protected watersheds will improve the
quality of the source water and impact the type of treatment technology needed
to ensure safe drinking water. Regardless of the source water quality, however,
all surface waters should, at a minimum, be disinfected to inactivate pathogens
as these may be present in the most pristine water supplies.
Source water protection (see Figure 6.1) based on watershed/aquifer
management involves a coordinated approach among stakeholders to develop
short- and long-term plans to prevent, minimize, or control potential sources of
pollution or enhance water quality where necessary. Source water protection
planning is an evolving process; management plans should be reviewed
periodically to ensure that the most effective solutions are being applied and
that the experiences of other groups working towards similar goals are
acknowledged and incorporated where appropriate. It is important to note that
because watershed/aquifer management is an on-going, long-term commitment,
not all elements need to be in place prior to a source being treated and used for
drinking water.
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Figure 6.1
TO
SAFE DRINKING WATER
Components of Source Water Protection
Monitoring
Watershed / Aquifer
Delineation
Public Awareness
Inventory of Land-use
and Contaminants
Partnerships
Source Water
Protection
Watershed / Aquifer
Management Plan
Vulnerability Assessment
and Ranking
Guidelines
The components of a source water protection strategy can be divided into a
source water assessment and an implementation plan to deal with the results of
the assessment, achieved through a Watershed/Aquifer Management Plan. A
source water assessment is comprised of:
•
Delineating source water protection areas
•
Identifying
contaminants
of
concern
through
various
inventories (such as contaminant or land use inventories)
•
Assessing the risk vulnerability and rank
Once the assessment has been completed, a Watershed/Aquifer Management
Plan can be developed. This plan introduces measures to reduce the risks
identified in the assessment. The initial assessment also guides the selection
and design of appropriate treatment and distribution systems to ensure the water
reaching consumers is safe to drink.
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TO
For a summary of source water protection measures taken in Canada, see
Appendix B.
For more information on selecting and designing appropriate treatment and
distribution systems, see Section 7.
6.1
Source Water Assessment
The assessment of the drinking water supply forms the basis of all activities
related to providing safe, aesthetically pleasing, and reliable drinking water to
the public. Assessments identify the characteristics of the water source, identify
potential health hazards, how these hazards create health risks to the population
consuming the water, and how these health issues can best be managed. As
such, a source water assessment serves three critical purposes:
1)
To identify whether a body of water is a suitable source for
drinking water
2)
To identify the level of treatment required in order to make
the water safe to drink
3)
To
target
the
activities
of
the
Watershed/Aquifer
Management plan
It is very important for all water supply assessments to be made against the
appropriate provincial or territorial treatment plant performance criteria and
compliance monitoring requirements (see Sections 7 and 8). In addition, the
potential source water needs to be assessed to determine whether it qualifies as
a possible source of drinking water by looking at the potential hazards discussed
in Section 5 and the treatment and/or other barriers that would be required to
minimize the health risks posed by these hazards.
The potential source water should be assessed to determine its quantity,
reliability, vulnerability, quality, and potential for future degradation. If the
water source is insufficient or unreliable, and water balancing or conservation
are not practical, alternative sources need to be considered. The quality of the
source water influences the nature of the treatment processes required to reduce
the potential health risks and produce safe and aesthetically pleasing water to
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consumers (see Section 7). Table 6.1 shows the factors that may affect source
water quality.
Table 6.1
Factors Affecting Source Water Quality
Human Factors
Natural Factors
Non-Point Sources
Point Sources
Climate
Agricultural cropland runoff
Industrial discharges
Topography
Livestock/grazing
Wastewater discharges
Geology
Dairies and feedlots
Hazardous waste facilities
Soil cover
Urban development runoff
Mine drainage
Vegetation
Septic tanks
Spills and releases
Fire
Erosion
Urban runoff
Wildlife
Forest management
Combined sewer overflows
Saltwater Intrusion
Mining
Aquaculture
Density/thermal stratification
Recreational activities
Erosion
Atmospheric deposition
For more information on source water quality monitoring, see Section 8.1.1.
When selecting a water source, the requirements of other administrative
authorities
with
respect
to
water
rights,
ground water exploration,
environmental impacts, planning, and intake siting, etc., should be reviewed and
applicable consultation should be undertaken. As well, it is important to
consider and resolve effects from or on other owners. It is important to obtain
required approvals from other authorities as soon as possible.
All source water assessments should proceed in stages, with each successive
stage providing more layers of detail, until an adequate amount of
watershed/aquifer data is collected to decide how best to minimize risks to their
source waters. The initial step in assessing source water quality is to take stock
of both the quantity and quality of water sources used as a supply of drinking
water, followed by an assessment of who is using those waters, and for what
purposes.
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Delineating the Watershed/Aquifer Area
As mentioned in Section 5, there are two main sources of water supplies:
surface water from lakes and rivers and groundwater sources that supply wells.
Although viewed as separate, they are interconnected since they are both part of
the earth's water cycle (hydrologic cycle), and can exert their influence on one
another. For this reason, each water source should be developed and managed
with careful attention to the hydrologic and ecologic systems of which the
particular source is a part. Surface and groundwater sources should be managed
conjunctively.
The quality of source waters used for drinking water is directly dependent on
the quality of waters supplied by the watersheds/aquifers (e.g., surface runoff,
upstream surface water flow and ground water recharge). Delineation of a
watershed/aquifer involves identifying the surface and subsurface areas of land
that water passes through to reach a drinking water intake point. This allows
water managers to define potential sources of contamination to their water
supply, and because water travel times can be estimated to intake areas,
provides them with an adequate lead time to intervene if a contamination event
occurs.
The watershed/aquifer consists of all land and water areas drained by a
watercourse and its tributaries. Sub-watersheds are areas drained by an
individual
tributary
to
the
main
watercourse
(Watershed
Implementation Project Management Committee 1997).
Planning
The processes for
defining the physical boundaries for a watershed/aquifer relies on establishing
the drainage patterns for the major regional watercourse(s) based on the
topographic relief of the area.
Identifying watersheds/aquifers that feed drinking water sources, and providing
a brief description of their current source status, allows water resource
managers to rank the importance of watersheds/aquifers or sub-watersheds in
supplying source waters to a particular town or municipality.
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Surface Waters
Rivers, lakes and reservoirs act as the principle intake points for the drinking
water resources of many communities. Rivers act as the major conduits for
water movement within the watershed. Adequate protection of water
sources to rivers (e.g. streams, overland runoff, or subsurface
groundwater flow) is critical to ensuring high quality source water
for drinking water.
Lakes and their man-made counterparts, raw water reservoirs, play a
Surface Water Uses
There are many beneficial uses
of surface water that provide
tangible values, and create
economic opportunities within
a watershed (see Figure 6.2).
vital role as massive storage tanks and regulators of water flow.
•
Historical
significantly to the present physical, chemical and biological
•
•
interactions within a lake system (Wetzel 2001), and can therefore
•
geological
lake
formation
processes
contribute
provide valuable information to lake managers in assessing current
and future water quality trends. Both lakes and raw water reservoirs may be
susceptible to direct discharges, pollutant loadings from overland runoff,
atmospheric deposition, and nutrient and bacterial loadings from wildlife and
human communities. In lakes, hydrology, lake stratification, internal cycling
and productivity can also affect water quality (CTIC 2002).
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Drinking and domestic
uses
Recreational
Aquatic and terrestrial
wildlife
Agricultural and
industrial
FROM SOURCE TO TAP:
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Figure 6.2
TO
SAFE DRINKING WATER
Five main water users in Canada (1996)
This pie chart shows that the five main water users in Canada in 1996 were thermal
power generation (64 percent), manufacturing (14 percent), municipal (12 percent),
agriculture (9 percent), and mining (1 percent). The municipal figure (12 percent)
includes 2 percent rural domestic use.
http://www.ec.gc.ca/water/en/manage/effic/e_how.htm
Groundwater
Groundwater is accessed through wells dug or drilled into aquifers.
Aquifers are geologic formations, or groups of formations that
contain sufficient saturated permeable material to yield significant
quantities of water to springs and wells. Groundwater generally
moves quite slowly, particularly under non-pumping conditions,
with velocities ranging from several feet per day to several feet per
year depending on the nature of the aquifer. For this reason,
groundwater can take much longer than surface water to recover
More than 7.9 million
Canadians (or, about 26% of
the population) rely on
groundwater sources for their
domestic drinking water.
Two-thirds of all users are
from rural areas, and the
remaining one-third are
primarily located in smaller
municipalities where
groundwater provides the
principle water supply
source.
from contamination. Gravity and pressure differences are important
factors in groundwater movement. Topography or slope of the land surface can
often be used as an indicator of flow direction and to a certain degree gradient
of the water table. Because groundwater is hidden from plain view beneath the
surface, contamination of groundwater sources can also be concealed. Extra
vigilance is required to prevent breaches in water quality (Environment Canada
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2002a). Figure 6.3 shows the percentage of the Canadian population that relies
on groundwater.
Figure 6.3
Percentage of Canadian Population Reliant on Groundwater
The illustration shows the percentage of the population reliant on groundwater for municipal,
domestic, and rural use only. Based on 1996 figures.
•
•
•
•
•
•
•
•
•
•
•
•
•
Canada: 30.3 percent
Alberta: 23.1 percent
British Columbia: 28.5 percent
Manitoba: 30.2 percent
New Brunswick: 66.5 percent
Newfoundland and Labrador: 33.9 percent
Northwest Territories and Nunavut: 28.1 percent
Nova Scotia: 45.8 percent
Ontario: 28.5 percent
Prince Edward Island: 100 percent
Quebec: 27.7 percent
Saskatchewan: 42.8 percent
Yukon: 47.9 percent
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Sources:
Statistics Canada, Environment
Accounts and Statistics Division,
special compilation using data
from Environment Canada,
Municipal Water Use Database.
Statistics Canada, 1996,
Quarterly Estimates of the
Population of Canada, the
Provinces and the Territories,
11-3, Catalogue no. 91-001,
Ottawa.
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Surface Water under the Influence of Groundwater
Unconfined aquifers interact closely with streams and lakes.
In situations
where groundwater supplies surface waters, the aquifer feeds the stream or lake
by discharging to the surface water. Streams can gain water from groundwater
through the stream bed when the elevation of the water table adjacent to the
stream bed is greater than the water level in the stream. If drinking water is
taken from a surface water source, it is crucial to also assess the nearbyunconfined aquifer near the surface water body.
Groundwater under the Influence of Surface Water
Groundwater Under the Direct Influence of surface water (GWUDI) refers to
groundwater with incomplete or undependable subsurface filtration of surface
water and infiltrating precipitation. Inadequate filtration can result in risks to
human health if drinking water is consumed without appropriate treatment.
When a well near a stream or surface water body begins to pump, the well
initially obtains its supply of water from aquifer storage. The resulting decline
of groundwater levels around the well creates gradients that capture some of the
ambient groundwater flow that would have discharged as base flow to the
stream. Eventually the well may draw upon the stream and induce flow out of
the stream into the aquifer. The sum of these two effects causes stream-flow
depletion. (Sophocleous et al., 1995)
The determination of whether a groundwater source is under the direct influence
of surface water should be based on site-specific measurements of water quality
and/or documentation of well construction characteristics and geology with
field evaluation.
For each groundwater source, direct influence should be
determined in order to make an accurate assessment of a system's vulnerability.
For information on how to determine whether a groundwater source is under
the influence of surface water, see "Investigation of Criteria for GWUDI
Determination" (2001) AWWARF Report No ISBN 1-58321-116-0
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For some examples of how Canadian jurisdictions determine GWUDI, see:
•
Nova Scotia’s “Protocol for Determining Groundwater Under the
Direct
Influence
of
Surface
Water”
(December
2002)
http://www.gov.ns.ca/enla/water/pdf/munguidp.pdf
•
Ontario’s “A Kit for Regulated Non-Municipal Drinking-Water System
Owners (Drinking Water Systems Regulation O. Reg. 170/03)” (July
2003) Ontario Ministry of the Environment ISBN 0-7794-4899-5
Inventorying Drinking Water Intake Points
All current and historical drinking water intake sites should be inventoried, and
geo-referenced (e.g., GPS) to determine the protection areas around these intake
sites.
Improperly maintained or managed intake sites could pose a
contamination threat to current water supplies if improperly managed.
Information on the number of active intake points for drinking water supplies
and their locations can be determined by obtaining records of drinking water
intake licenses from cities and/or municipalities. Permits for well drilling are
issued through some provincial ministries. Data for private and municipal
groundwater wells within a given watershed/aquifer can also be obtained from
this source, though some jurisdictions may not collect data about the presence
or location of private wells.
Delineating and Mapping Protection Areas for Surface Waters
Defining the zone of contribution to a drinking water intake point allows water
managers to establish protection areas for those source waters. The box below
outlines the three methods the US Environmental Protection Agency uses for
delineating surface waters that contribute water to drinking water intake sites:
topographic boundary delineation, streamflow time of travel (TOT), and
setbacks/buffer zones (US EPA 1997b).
METHODS
FOR
DELINEATING SURFACE WATERS
Topographic Boundaries
Topographic maps are used for
establishing watershed/aquifer
boundaries by following the
perimeter of high contour lines
which indicate the direction of
overland water flow within a
geographical region. In the event
that provincial Departments of the
Environment or regional
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Conservation Authorities do not
already possess topographic maps
delineating watershed/aquifer
boundaries, topographic maps are
produced by Natural Resources
Canada (www.nrcan.gc.ca) at the
1:250 000 and 1:50 000 scales. Maps
are also available from provincial
governments.
The source water supply area for a
watershed/aquifer is defined by the
topographic boundary of the area
within the watershed/aquifer that
contributes surface water flow to a
given drinking water intake site.
This area can be easily delineated on
a topographic map by drawing a line
connecting the highest points within
the overall watershed/aquifer that
are uphill of that particular drinking
water intake source, from which
overland flow drains towards the
intake.
Streamflow Time of Travel (TOT)
The TOT method is based on the
amount of time it takes for a
contaminant travelling at the same
velocity as a stream to reach the
water intake point. This method
does not define a protection zone
per se, rather it is intended to directly
protect water quality at the site of
drinking water intake by providing
an early warning system for
contaminants deposited in upstream
waters. The TOT between a
drinking water intake point and a
monitoring site will vary depending
on stream volume, and empirical
hydrogeological flow models can be
used to estimate travel times and
contaminant concentrations at an
intake site. Surface water travel
times are on the order of hours
within a regional watershed/aquifer.
This would allow managers sufficient
TO
SAFE DRINKING WATER
time to take appropriate measures to
avoid the intake of contaminated
waters. Note that this will not afford
any ecological protection for
sensitive species.
Setback/Buffer Zones
Setbacks and buffer zones around
surface waters supplying source
waters are used as a means of
reducing impacts from runoff to
drinking water sources by filtering
overland flow, and encouraging
ground water filtration. Buffer zones
can take several forms, depending on
the type of source water protection
required. For example,
sedimentation and contaminant
transport to surface waters are often
mitigated by riparian vegetation
strips along streams or rivers, or
constructed wetlands, while
grasslands in agricultural areas
reduce inorganic contaminants in
groundwater supplies (Lowrance et
al. 2002). These zones provide more
time for natural remediation
processes for contaminants in the
overland flow, and can provide
valuable wildlife habitat. The width
of these buffer strips will depend on
factors such as topography of the
land, land uses, size of the stream,
political and legal feasibility of
designating the zones, and land
ownership rights. The vegetative
composition of the buffer zones will
influence the amount of contaminant
intervention occurring, with for
example, grass buffers being less
effective at nutrient removal than
forested zones (Lowrance et al.
2002). The recommended typical
riparian buffer width is in the range
of 15 to 60 m (50 to 200 ft),
depending on the degree of impact
from land-based activities (US EPA
1997c; Lowrance 2002).
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Delineating and Mapping Protection Areas for Groundwater
Although it is useful and generally recommended to
also delineate the watershed/aquifer boundaries in
which the source aquifer is located, watershed and
aquifer boundaries are seldom coincident. Large
aquifers can transcend several watersheds and vice
versa. The watershed and topographic data will aid
in
giving
groundwater
a
preliminary
flow
understanding
direction,
gradient
of
and
groundwater divides. Aquifer boundaries can be
groundwater
divides
or
geologic
contacts
representing contrasts in permeability.
Between 2000 and the present, the Ontario
Government invested $19.3 million to
support groundwater dependent
communities to map municipal wellhead
protection areas using sophisticated models,
and to map regional groundwater conditions
and aquifer vulnerability. The studies will
provide valuable information that will help
the communities develop local source
protection measures, and will support the
development of a province-wide source
water-protection framework. By the Spring
2004, over 95% of Ontario communities that
rely on ground water will have a common
base of information on their groundwater.
Figure 6.4 shows an example of a watershed delineation map, overlaid with
indications of land-uses.
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Figure 6.4
SAFE DRINKING WATER
TO
Generalized land-use overlay with watershed delineation
map
Source Water Intake Site
Contour Line
Watershed Boundary
Source Water
Supply Boundary
Industrial
Residential /
Commercial
One of the fundamental concepts of wellhead protection studies is the clear
identification of the area(s) to be protected. Fundamentally, the area of lands
which will likely contribute recharge to the well needs to be established or
"delineated." However, the actual delineation process can be based on a analysis
of a number of criteria and criteria thresholds and the application of any one or
more of a number of delineation methods. The criteria and thresholds define the
technical basis for delineation of protection areas. The delineation methods
apply the criteria in that they are used to develop the protection area boundaries.
Several options are available for delineating wellhead protection areas. These
range in complexity from simple mapping techniques requiring minimal
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geological knowledge to complex mathematical models requiring significant
amounts of field data. The decision on what type of delineation method to use
needs to be based on the aquifer characteristics and the relative risks of
contamination. More sophisticated groundwater modelling may be extremely
useful in areas with several potential sources of contamination to a drinking
water well source.
METHODS
FOR
DELINEATING WELLHEAD PROTECTION AREAS
Establishing an arbitrary fixed
radius (AFR) protection area is as
simple as drawing a radius around
each wellhead in the
watershed/aquifer on a topographic
map. In British Columbia, the zone
of protection is usually set at a
distance of 300 m around the
wellhead. This distance protects
against immediate threats to
groundwater sources and minimizes
difficulties in managing the land
within the protection zone
(Government of British Columbia
2000). This method should only be
used as a temporary measure until
other hydrogeologic information for
the watershed/aquifer becomes
available.
The calculated fixed radius (CFR)
method uses a simple algebraic
formula for readily available wellhead
data, and provides a greater level of
precision for estimating the amount
of area needed to protect against
contamination events. The CFR
represents the amount of time
required for a contaminant at the
outer boundary to reach the drinking
water well, and is usually based on
one, five, and ten-year times of travel
(Government of British Columbia
2000).
While both the AFR and CFR
delineation techniques can be used
for sand and gravel aquifers where
the water table is relatively level and
wells supply no more than 100
connections, it is necessary to define
a zone of capture in
watershed/aquifers with sloping
water tables (Government of British
Columbia 2000). When groundwater
recharge comes from ‘up-gradient’
sources, the capture zone will have
an elongated, parabolic shape rather
than circular shape.
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6.1.2
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Inventory of Land-use and Contaminants
In the next step of the assessment, contaminants that may be of concern to a
water supply should be identified, along with their sources. Typical methods
used for identification include:
•
Inventory of land uses
•
Inventory contaminants sources
•
An evaluation of watershed/aquifer characteristics
•
An
evaluation
of
source
water
quality
monitoring data
Potential Sources of Drinking Water
Contamination Index
The level of effort expended on identifying contaminants of
watershed/aquifer is an essential component of a source
The type of land use within a watershed
may help in identifying the potential
hazards to source waters. Land use
inventories involve identifying the land
uses within an area and then inferring
the nature of the potential hazards
associated with each type of land use.
The EPA has provided a resource guide
for creating such an inventory list. The
presence of the identified land use does
not necessitate the presence of the
associated hazards, nor does include
other potential hazards from existing and
non-identified land uses. The resource
guide can be accessed through the
following link:
water protection plan, as the nature of the hazard will
www.epa.gov/OGWDW/swp/sources1.html
concern will depend on available resources. However, the
common goal of all inventories is to gather existing data on
contaminant sources and levels, and fill any knowledge gaps
with new information from public consultations or field
surveys.
Creating an inventory of specific types of threats that may
reasonably
influence
be
the
expected
type
of
to
occur
treatment
as
within
well
watershed/aquifer management response required.
as
the
the
Most threats to source
waters are the result of human activities within the watershed/aquifer. For
example, a watershed where the primary contaminant of concern comes from
industrial effluent will be managed differently than one where the main threat to
source waters is nutrient enrichment.
An inventory of the likely contaminants that may be found in source waters is
shown in Appendix C.
A few of the common approaches that can be used to identify potential threats
to a water source are outlined below.
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Land-use Inventories
The nature and extent of different land uses are crucial features to investigate in
a watershed/aquifer assessment, as land use will determine the presence or
absence of threats to source water quality from human activities.
Land-use change is often the primary cause of water quality and habitat
degradation in a watershed/aquifer. Knowledge of the type of land use within
an area can help identify the potential threats to source water.
Land use
inventories involve identifying the land uses within an area, and then inferring
the nature of the potential contaminants associated with each
type of land use. Land use inventories should identify the
types
and
percentages
of
each
land
use
in
the
watershed/aquifer and note the types of contaminants
associated with each type of land use.
It is also important for an attempt to be made to quantify the
presence of human activities that could potentially alter
drainage patterns within the watershed/aquifer. For instance,
the construction of impermeable features such as roadways
will change the drainage and infiltration patterns of the
watershed/aquifer by increasing surface runoff while
reducing groundwater infiltration. The Atlas of Canada is an
interactive
mapping
website
that
provides
regional
information on a variety of environmentally sensitive
variables, including road density (NRC 2002b).
Information on land-use within a watershed/aquifer can be
obtained from a variety of sources including aerial
Lands used for agricultural crop
production can result in non-point
source inputs of pesticides and
nutrients from leaching and/or surface
runoff. In areas where livestock
operations occur, the primary threats
to water quality could be
contamination from nutrients and
microorganisms.
In urban areas, the pollution threats
will vary depending on the specific
localized land use (e.g., parkland,
stormwater retention pond, and
commercial zones).
Industrial land uses will present
threats of contamination from effluent
releases, groundwater infiltration, and
overland water flow. Industrial
contaminants could include organic
chemicals, metals and nutrients.
Residential areas can result in
contamination threats from runoff of
domestic chemicals, such as
pesticides and fertilizers, or nutrient
enrichment from sewage disposal.
photographs, municipal zoning maps and area maps. These
information sources are available from the municipal or provincial government
offices. Land use inventory maps for rural Canada are available from Natural
Resources Canada on-line (NRC 2000).
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Maps can be used as an initial screening tool for potential threats by overlaying
major land uses in the watershed/aquifer in relation to source water locations.
This type of exercise can be conducted from municipal records, such as land
titles, developmental zoning records and aerial photos, and therefore may not
require field surveys.
This process serves as a first step in conducting a
contaminant inventory, as it allows managers to focus future efforts on high-risk
areas.
Note: Maps can also be found through the appropriate provincial government
department(s).
Contaminant Source Inventories
Although land use inventory maps can indicate which groups of hazards are
expected in a given area, it is often necessary to identify and inventory the
specific sources of contaminants within each land use area. This involves
identifying point and non-point sources of potential contaminants within the
watershed/aquifer as well as factors that can influence downstream water
quality.
Discharges from point sources are often regulated through
provincial/territorial
licenses
or
permits.
Furthermore,
information on current discharge activities can be obtained
from conducting site surveys, or by soliciting information from
industries, agricultural producers, and municipal operators in
the watershed/aquifer using questionnaires and interviews.
Although conducting interviews and using questionnaires
saves a great deal of time and resources, special attention
needs to be paid to the accuracy and completeness of
Government records can assist in
identification of point source
effluent discharges and the
associated contaminants of
concern.
The National Pollutant Release
Inventory (NPRI) of Environment
Canada maintains an on-line,
publicly-accessible database of
pollution discharge data for
companies releasing specified
amounts of NPRI-listed substances
annually:
http://www.ec.gc.ca/pdb/npri
responses.
Non-point sources are threats caused by surface runoff, leaching and
atmospheric deposition of contaminant sources.
Because non-point source
pollution is hard to identify, the factors contributing to non-point source
pollution may need to be inferred based on the surrounding land use.
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Evaluation of Watershed/aquifer Characteristics
Watershed/aquifer characteristics influence drinking water source quality, and
therefore need to be considered when identifying potential
contaminants in a watershed/aquifer area. Factors such as
population levels and land-use patterns will strongly
influence the quality of downstream receiving waters, as
well as groundwater.
collect
information
However, it is also important to
on
other
watershed/aquifer
characteristics, such as climate, topography, wildlife,
vegetation, and geophysical aspects. The watershed/aquifer
characterization process is not intended to be a massive data
collection exercise in its own right, but rather serve to
provide the appropriate level of detail to allow for the
effective management of multiple source water protection
barriers.
Spatial variability in watershed
characteristics, and their resulting
influences on source waters, are more
easily understood and communicated
in a visual format.
Geographic Information System (GIS)
technology is a useful tool in preparing
a watershed characterization. The
watershed characteristics, their
variations across space, and their
relation to one another can be easily
displayed in a map, or database
formats using this technique. GIS
allows several ‘layers’ of data to be
overlaid on top of each other in a single
topographic map, allowing multiple
watershed characteristics (and their
interrelationships) to be viewed
simultaneously.
Population
Population data can be used as an indication of the amount of human influence
within the watershed/aquifer. Human influences present one of the highest
potential risks to water quality within a watershed/aquifer, making examinations
of population trends within the watershed/aquifer an important component of
characterizing the risk to the watershed/aquifer.
Data collection should focus on population size, density and spatial distribution
within the watershed/aquifer. A dense population can have a direct impact on
water quality through nutrient loading into the watershed/aquifer system from
wastewater or through other releases of pollutants. Other population statistics
that may influence water quality such as growth rate and population trends may
also be considered in the assessment.
Statistics Canada provides national
population and census information on-line (Statistics Canada 2002). Provincial
or territorial departments of health or vital statistics are also a good source of
current information.
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Climate
Climate can influence both the quantity and quality of water in the
watershed/aquifer. Climate determines the amount of water recharged into the
watershed/aquifer via precipitation, the amount of precipitation lost to
evaporation and the timing of low and high stream flow periods. It indirectly
influences the amount of infiltration or surface runoff.
Descriptions of
watershed/aquifer climate should identify the annual and monthly precipitation
amounts and the types of precipitation, the mean annual average temperature
and monthly mean temperatures, the temperature range, the annual
and monthly humidity, the average date of spring runoff, and the
likely occurrence of unusual events such as storms or blizzards.
Any other distinct climate characteristics should also be noted. If
the watershed/aquifer is large or the climate is expected to vary
widely over the area (i.e., from low to high elevations in a
mountainous terrain), the change in climate should be noted.
Seasonal variations of water quality due to a variety of natural and
human influences should also be noted. Human activities can result
in seasonal fluctuations in water quality, such as seasonal run-off of
agricultural manure, fertilizers and pesticides that can result in
impaired water quality. Other seasonal variations that can impact
Climate data for numerous
weather monitoring stations
across Canada is available
on the Internet.
A summary of available
Prairie Province Water Board
Reports including reports
related to precipitation and
streamflow, runoff
distribution and variability
and other topics are
available from Environment
Canada (2002b).
The Geoconnections
Discovery Portal (NRC
2002a) also provides links to
climate data in GIS format.
source water quality include:
•
High ambient temperatures. Higher ambient temperatures in summer
can simulate algal growth in source waters, which in turn can deplete
oxygen in source waters and increase total suspended solids
(eutrophication).
•
Spring runoff. Higher runoff flows caused by spring melt or heavier
periods of rain can increase stream flow and elevate the stage of a water
body, resulting in increased erosion and elevated suspended
solids/turbidity in source waters.
•
Low flow conditions. Watersheds in late summer periods in drier years
can experience significant reductions in streamflow. Reduced flow
results in corresponding reduced assimilative capacities for a water
source. As flows decrease, point source discharges are not diluted
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adequately, resulting in higher pollutant concentrations in source
waters.
•
Recreational use. Depending on the accessibility and size of the source
water body, the summer recreational season may bring increased
recreational use in desirable areas of a watershed/aquifer. Recreational
boat traffic and inefficient small engine personal watercraft can cause
increased erosion, and elevated levels of pollutants from boat motors.
Seasonal water quality data is available from provincial
government offices.
Topography
Elevation contours used to delineate between watersheds and
sub-basins within a watershed are also used to determine slope
gradients. Areas of steep slope gradient are expected to have
more surface water runoff than areas of low slope gradient, and
therefore carry a greater risk for sediment deposition from
erosion into stream channels.
Topographical maps, aerial
photographs and other
topographic data are available
from the Provincial government
natural resources offices. Internet
links to a wide range of GIS data,
including topographic maps, can
be found at the Geoconnections
Discovery Portal (NRC 2002a), and
from the Habitat and
Enhancement Branch of the
Department of Fisheries and
Oceans (DFO 2002).
Geological Characteristics
Geological characteristics of the watershed/aquifer (e.g.
bedrock and surficial geology, and soils) may influence
groundwater
and
surface
water
watershed/aquifer drainage patterns.
chemistry,
and
The watershed/aquifer
characterization should identify soil types, textures and
drainage patterns. Soil texture influences whether precipitation
is likely to infiltrate or run off, and whether sediment will be
eroded from the soil.
A sandy textured, well-drained soil
would be expected to have a higher infiltration capacity than a
poorly drained clay soil. Likewise, a sandy textured soil with
low organic matter content would be expected to be more
susceptible to erosion than a clay soil with a high organic
matter content.
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Information about bedrock and
surficial geology are generally
available from the natural
resources department of provincial
governments.
Soil survey maps are usually
available from provincial agriculture
departments.
Maps and GIS data for major
drainage systems in the Prairie
Provinces are available from
Agriculture and Agri-Food Canada
(AAFC 2002). Geological GIS data
is also available at the
Geoconnections Discovery Portal
(NRC 2002a).
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Examinations of watershed/aquifer geology should note the major geologic
formations, their modes of deposition and their mineralogy.
The geologic
formations surrounding major aquifers and aquitards will influence groundwater
movement throughout the watershed/aquifer and should therefore be carefully
examined to identify the likely paths of groundwater movement. The
mineralogical composition of the watershed/aquifer geology, and the
weathering processes, will determine which chemicals dissolve in water. The
nature of the geology of the area will affect sediment transport to source waters.
Examinations of watershed/aquifer geology can be used to identify vulnerability
to erosion, mass wasting and other degradative processes.
Aquatic Life, Wildlife and Vegetation
Watershed/aquifer health is reflected in the abundance and diversity of flora and
fauna in the ecosystem. As a result, watershed/aquifer categorization needs to
identify the major terrestrial and aquatic species and their
habitats.
The health of aquatic life can give an indication of water
quality in an area and should therefore be noted.
The
presence of stressed aquatic life can be an indication of poor
water quality such as low dissolved oxygen or high
concentrations of contaminants.
Major recent changes in watershed/aquifer vegetation
should also be noted. For example, forest fires or changes
in human land-use activities may result in a change in
species composition. Particular attention should be paid to
the alteration of watershed/aquifer vegetation that may
Data on vegetation in the watershed
can be obtained from land-use
inventories, habitat and vegetation
surveys, and examination of aerial
photographs (for general ecosystem
identification).
Links to forestry GIS data in Canada
can be found at Natural Resources
Canada’s Geoconnections Discovery
Portal (NRC 2002a).
Land capabilities for forestry in rural
Canada are available from the
Canadian Land Inventory (NRC 2000).
Other information on local vegetation
is available from the natural resources
departments of the appropriate
provincial government.
negatively impact source water quality, especially in
wetland and riparian areas.
Terrestrial vegetation, such as plants and trees and submerged aquatic
vegetation all play a role in protecting source waters. Vegetation can directly
influence water quality by acting as a sediment barrier and/or biofilter for
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nutrients and contaminants that would otherwise reach source waters. Due to
the importance of vegetation in sustaining the viability of the watershed/aquifer,
the characterization needs to include a description of the dominant vegetation
types in each ecosystem (i.e. forest, riparian, wetland, aquatic, etc.), what
percentage of the watershed/aquifer is composed of each ecosystem, along with
the floral species composition and the community structure within each
ecosystem.
Evaluation of Source Water Quality Data
Contaminant inventories can also be compiled by collecting historical and
current water quality data in the watershed/aquifer if available. Spatial and
temporal patterns (e.g., to include daily, seasonal, and annual changes) should
also be examined as part of the assessment. These offer the advantage of
providing quantifiable estimates of contaminant loads to specific source waters.
However, relying solely on water quality surveys without prior knowledge of
potential contaminants within the watershed/aquifer may result in the lack of
detection of some contaminants.
Some of the key steps involved in implementing a source water quality
monitoring program are:
•
Reviewing the existing data against environmental quality objectives, or
by statistically analyzing data to look for trends or differences between
regions.
Currently,
procedures
for
establishing
EQOs
for
microbiological parameters in Canada are not standardized. Ideally,
microbiological pathogen concentrations in source waters would be
monitored, and the results submitted to the treatment operators.
•
Identifying gaps in the data that did not allow for thorough assessment
•
Developing a long-term plan to fill missing data gaps, which can then
be used for source water assessments, or water quality modeling.
•
Discussing how coordination of monitoring activities from various
stakeholders or government agencies can allow for an effective future
monitoring program (see section on TQM Source Water Monitoring).
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Vulnerability Assessment and Ranking
For general information on how to determine levels of risk, see Section 4.
Once the hazards within a watershed/aquifer have been identified through the
processes discussed above, it is necessary to determine the vulnerability of the
watershed/aquifer to the identified hazards and to assess their potential impact
on human health. The results will guide watershed/aquifer protection efforts and
help determine the type of treatment required to render the water safe for
drinking. It is important to identify the risk to the source waters from each
threat in the watershed/aquifer.
The assessor (e.g., system owners and operators) is concerned about:
•
The quality of the source water as it influences the nature of the
treatment process required to reduce the potential health risk
and produce safe and aesthetically pleasing water at the
consumers’ tap
•
The quantity, reliability, vulnerability, quality (including
seasonal variability) and potential for future degradation of the
quality
The assessor now needs to determine the risk to the source waters from each
threat in the watershed/aquifer prior to taking action on the design of a water
treatment system and watershed/aquifer protection measures.
In assessing vulnerability or risk, the data from the hazard identification process
needs to be complemented with monitoring data to get an idea of the
concentration at which the chemical/physical parameter or microorganism is
found in the source water and whether the concentration fluctuates over time.
This type of data is gathered through long-term monitoring programs (see
Section 8.1). Concentrations can be modeled (see Section 6.2.2) with such data
as land-use information, watershed hydrogeological and soil characteristics and,
toxic substance physico-chemical properties, however, it is preferable to obtain
real monitoring data at the site-specific level.
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In cases where hazards can be defined numerically (e.g., concentration of a
toxic substance), the risk is a quotient between exposure and hazard. Therefore
a quotient that is greater than “one” would signify a positive likelihood that an
effect may be observed. For the purposes of this section, the hazard will be
defined as a low threshold effects concentration to be represented by an
environmental quality objective (EQOs) (see below). EQOs are often water
quality guidelines (e.g., source water quality guidelines), objectives or standards
set out by most provinces and territories or by Federal/ Provincial/Territorial
committees (see Section 3.4).
Setting Environmental Quality Objectives (EQOs)
Deciding on which EQOs are to be met for drinking water
sources is the responsibility of the authority governing
watersheds and/or aquifers (see Sections 3 and 6.2). Utility
owners and other stakeholders may be asked for their input.
EQOs based on the protection of aquatic organisms alone may
be too conservative, given that the majority of source waters
will undergo some form of treatment prior to distribution for
human consumption. As an example, in their source to tap
approach for protecting public drinking water sources, the
province of Newfoundland and Labrador has adopted the
Guidelines for Canadian Drinking Water Quality. These are
not used as source water guidelines per se, but rather as
reference values to indicate the extent of treatment required to
meet tap water standards, especially for microbiological
parameters (Government of Newfoundland and Labrador
2001). This practice, however, has not been adopted in other
jurisdictions.
When ambient contaminant levels are consistently below
provincial guidelines, several options are available for setting
Environmental Quality Objectives
(EQOs) are established limits or
thresholds of biological and/or
chemical contaminants in water
set by watershed/aquifer
committees or other governing
bodies in order to ensure
sustained protection of source
waters for drinking water. EQOs
may be narratives or numerical
limits. The premise for setting
EQOs is that they are relevant,
economically and technically
feasible and easily understood by
risk assessors and managers.
To be relevant in the risk
management process for the
protection of public health (see
Section 2), EQOs should be set for
hazards in source waters that are
linked to hazards in the water
supply system (e.g., turbidity, total
organic carbon, microbiological
pathogens). Only then will
mitigative efforts to curtail
hazards in source waters
contribute to the overall reduction
of risk to human health.
site-specific EQOs. Objectives can be adjusted downwards or upwards to some
point below or above the provincial guideline to account for site-specific
physico-chemical properties, or sensitive species, which may be endemic to
those waters but were not represented in the original toxicological screening
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process for deriving the guideline. These site-specific objectives (SSOs) can be
set at the background levels to reflect good water quality, thereby preventing
any further deterioration.
This decision is often based more on public
perception than any scientific justification for reducing the values. That said, it
is important that high quality water not be degraded to the level set by an EQO
or SSO if the water is of better quality to begin with. A CCME guidance
document on deriving SSOs is now available to water managers (MacDonald et
al. 2002). Finally, if there are no site-specific modifying factors that may alter
toxic responses in resident biota, or humans, then the established guideline
thresholds may be used and the ambient levels can simply be accepted as nonthreats. Figure 6.5 shows a framework for using EQOs in a source water
protection program.
In the event that ambient levels are consistently higher than provincial
guidelines it will be necessary to determine if there is a risk to public health. If
there is, the governing body or the authorities may need to try to find the
sources of the contaminant.
If there are no loading sources from human
activities in the watershed/aquifer, ambient levels will likely reflect natural
background levels. In this instance, water authorities may want to establish
SSOs for this compound at the ambient levels. If there are known loading
sources of the parameter(s) exceeding provincial guidelines, watershed/aquifer
loading models may need to be used to determine the extent of the impact from
discharge sources, and therefore determine the potential for corrective measures
(i.e., load reductions) to reduce ambient levels.
Figure 6.5
Framework for Using EQOs in a Source Water Protection
Program
Compile Watershed
Knowledge Base
Identify and
Assess Issues
Establish Watershed
Goals and Objectives
Implement
Environmental
Quality Objectives
1
2
3
4
Stakeholder
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Conduct Targeted
Research and
Monitoring
5
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Approaches that incorporate the use of environmental quality objectives in risk
determinations and ranking techniques are discussed below.
Ranking Schemes
The processes discussed thus far for source water assessment and setting EQOs
for a source water body allow water managers to make an informed assessment
of the risks associated with each of the contaminants present. The level of
detail required in a risk assessment will likely increase with demands placed on
a given drinking water source. It is important to keep in mind, however, that
the primary purpose of a risk assessment is to provide water managers and
stakeholders with the required information they need to prioritize protection
efforts for contaminants found in the watershed/aquifer.
In its most basic form, a risk assessment can simply be a ranking of hazards
against designated benchmarks for the protection of the health of consumers. In
the example in Table 6.1, two options would be available for ranking the risks
associated with these contaminants of concern: those parameters that exceeded
the EQO by the greatest magnitude could represent the greatest risk, and can be
ranked according to their maximum exceedence ratio; alternatively, parameters
which have frequently exceeded the EQO could exhibit the greatest risk.
In some instances, the relative risk provided by these ranking schemes can be
misleading, and should be properly interpreted. For example, the risk provided
by a contaminant slightly exceeding its EQO could far outweigh the risk of
another contaminant far exceeding its EQO. Decision rules can be established
whereby the top-ranking risks from both categories are given a high priority for
protection measures. The outcome of the ranking will also aid in determining
the effectiveness and level of treatment required.
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Table 6.1 Sample risk assessment ranking scheme based on measured
water quality variables and established environmental quality
objectives
Parameter of
concern
Parameter A
Parameter B
Parameter C
Parameter D
Parameter E
Environmental
Quality
Objective1
(mg/L)
0.025
Maximum
concentration
found (mg/L)
Maximum
exceedence
ratio
Ranking
(A)
Total no. of EQO
exceedences per
year
Ranking
(B)
1.4
4
1
4
0.005
45
0.035
0.020
80
4
1.8
2
3
5
15
2
1
0.05
1
0.02
12
0.4
12
5
1
0
2
5
3
It is also possible to rank the vulnerability of source waters themselves rather
than the dangers associated with a particular contaminant. For the use of
groundwater sources, there are a number of methods that can be used to assess
the vulnerability of aquifers to potential contamination from the soil surface.
These include DRASTIC, and the Ontario Ministry of the Environment’s
Aquatic Vulnerability Index (AVI).
DRASTIC is an acronym based on seven parameters which all are evaluated
and given a value from 0 to 10:
D: Depth to water table
R: Recharge
A: Aquifer media
S: Soil media
T: Topography
I: Impact of vadose zone
C: Conductivity
These scores are then added to obtain an index value. High values indicate
higher risks of contamination of groundwater sources. The index approach
makes it possible to then rank the relative vulnerability of selected aquifers (or
regions of the aquifer) within a watershed.
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A risk assessment may also categorize, rather than rank, relative hazards within
the watershed/aquifer.
In the watershed management plan for the City of
Rossland, British Columbia, each potential chemical and microbial threat to
source water quality was rated according to:
Hazard: The likelihood that the process or activity will release
contaminants
• Rated: low (L), moderate (M), or high (H)
Susceptibility: The consequence to the water source if the
activity/process does release contaminants. Related to the
proximity of the activity/process to the source water (see
Figure 3.15 for sample susceptibility determination)
• Rated: low (L), moderate (M), or high (H)
Risk: The product of Hazard and Susceptibility defined as the risk of
the water source being contaminated by the specified
activity/process
• Rated: low (L), moderate (M), high (H), or very high (VH)
(Dobson Engineering 2002)
Table 6.2 provides an example output table for this type of risk assessment. A
separate table should be completed for each watershed/aquifer, or subwatershed contributing to the source water supply. The level of detail included
for the processes/activities will likely vary between SWP programs, depending
on the resources available for the assessment.
Table 6.2
Process/Activity
Natural erosion,
landslides
Timber harvesting
Sample risk assessment categorization scheme for processes
and activities at the watershed level.
Hazard
M
L
Roads/utilities
H
Other land use
H
Susceptibility
M
Comments
Some steep and potentially unstable
terrain
L
L
Some satisfactorily restocked cutblocks
in upper watershed; roads in various
states of deactivation
H
VH
Highway x parallels creek; city roads in
western portion; natural gas pipeline
intersects lower watershed
M
H
Industrial parks, auto wrecker,
cemetery located within watershed
(adapted from Dobson Engineering 2002)
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Risk
M
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In summary, this section described methods for conducting a source water
vulnerability assessment and ranking risks. System owners and operators can
now either use this information to design, evaluate or upgrade a water treatment
system (go to Section 7) or to take steps to ensure the long-term protection of
their source water through their involvement in the development of
watershed/aquifer management plan (continue below).
6.2
Watershed/Aquifer Management Plan
The purpose of a watershed/aquifer management plan is to implement
management actions that serve to maintain or improve the quality of source
waters. Once treated, these waters will provide clean, safe, and reliable drinking
water over the long-term. Focusing on water quality for drinking water is a
good mechanism for creating common ground among
stakeholders who may have conflicting uses for the water
in the watershed/aquifer.
At the municipal level,
watershed/aquifer management planning goes hand-inhand with land-use planning.
The development of a watershed/aquifer management
plan entails evaluating management options based on the
ranked hazards identified in the source assessment,
prioritizing actions, implementing them to maintain or
improve source water quality and evaluating their
efficiency over the long term.
Membership in a Source Water
Protection Committee should reflect as
many of the interest groups as possible,
and could include technical persons who
can offer expertise in support of
watershed protection initiatives, such as:
•
•
•
•
•
•
•
•
•
Water department/utilities staff
Planning /zoning department staff
University professors/science
teachers
Conservation groups
Chamber of commerce members
Financial/lending institutions
Elected officials
Industrial managers/agricultural
sector
Residents of the watershed
The watershed/aquifer plan is an innovative management
process that examines all factors affecting the entire watershed (such as air,
land, and water resources) while focusing on the highest priority problems. The
approach involves all stakeholders in the planning, decision-making, and
implementation processes, including First Nations peoples, private institutions,
public institutions, government agencies, environmental groups, and the public.
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A watershed/aquifer plan reconfirms the choice of Environmental Quality
Objectives (EQOs) that were chosen in the source water assessment (see
Section 6.1) as the management targets or goals against which management
actions will be evaluated. In the risk management process and overall reduction
of risk, EQOs should be set for hazards in source waters that are relevant to
those in the water supply system (e.g., turbidity, total organic carbon,
microbiological pathogens).
Figure 6.6
Watershed Committee Action Process
Implementation
Watershed Resources
Management Plan
Revised
Policy
Frameworks
BMPs
Formulation of Alternate
Management Strategies
Land Use
Changes
Financial
Incentives
Goal Setting /
Prioritization
Known
Problems and
Impediments
Point Sources
Problem Identification
Non-point
Sources
Identify Physical /
Chemical Pollutants
Watershed
Description
6.2.1
Inventory of
Watershed Resources
Management Process
It may be useful for a Source Water Protection (SWP) committee to oversee
both the source water assessment (see Section 6.1) and the watershed/aquifer
management plan.
It is important for such a committee to partner with
stakeholders outside of its circle to access further resources (human and
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financial) and to obtain community acceptance. The committee should have a
mandate, terms of reference and a decision-making process. An example of a
committee action process is shown in Figure 6.6.
SWP committees can balance potentially competing interests for source water
uses within a watershed/aquifer. These committees can facilitate dialogue and
long-term relationships between the various watershed/aquifer residents and/or
users. A SWP committee is composed of all stakeholder groups or individuals
that use the water resources, including recreational, private and public users,
and municipal and private owners of public drinking water distribution systems.
It is important for all interested parties to be committed to developing a local
watershed/aquifer management plan to protect and sustain a clean, safe, and
secure drinking water supply.
Some organizations and individuals will have competing interests in water uses,
and will therefore champion their own interests. For this reason, it is important
to provide a balanced committee that is not unduly
weighted by any one interest sector.
A further
complication is that watersheds/aquifers can potentially
cross municipal, provincial and even national boundaries.
Productive
SWP
committees
require
effective
partnerships that focus on common interests, respecting
viewpoints from all participants and remain manageable
in size (US EPA 1997a).
It is important for membership in the SWP committee to
be long-term. Effective management and protection of
the watershed/aquifer requires long-term planning and
therefore needs stability and consistency in committee
membership. It may be beneficial to raise both the profile
Role of Municipalities in Source Water
Protection Planning
As some watersheds may be partially or
wholly contained within municipal
boundaries, municipalities may have a
direct effect on protection measures.
Municipalities may be aware of the
specific concerns of their communities
and able to foster community
involvement and ownership in water
protection issues.
Implementation of measures at the
municipal level can provide groundwork
for further involvement from other
entities. It is key for municipalities share
their experiences and issues with other
municipalities and other stakeholders.
For more information, see the FCM
document in the appendices.
and prestige associated with actually participating on an
SWP committee whose purpose is ultimately the sustainability of the local
ecosystem and the preservation of public health. Participants on the committee
need
to
encourage
the
creation
and
continuation
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TO
watershed/aquifer issues and active, collaborative decision-making by all
participants. Successful partnerships take time to develop.
6.2.2
Management Activities
During the planning process, stakeholders confirm issues of concern within the
watershed/aquifer and set priority management needs and are involved in
negotiating resolutions to conflicting land-use within the watershed/aquifer and
develop consensus-based strategies.
All stakeholders will be involved in
implementing the source water protection plan. Government agencies may be
required to ensure land-use activities in the watershed/aquifer are consistent
with the plan. Governments may also provide technical assistance in
implementation. Other stakeholders may be involved in other capacities, for
example, non-profit conservation groups may be involved in watershed/aquifer
restoration activities.
As shown in figure 6.7, the plan development process is a four-stage process:
1. Evaluation of management options from source water
assessment results. This includes confirming concerns and
objectives, defining challenges/opportunities
2. Developing the protection plan.
This includes setting
management action priorities, negotiations and developing
strategies for addressing concerns and achieving objectives.
3. Implementing the plan. This includes mobilizing resources
and
taking
focused
actions
on
priority
issues
using
4. Performance evaluation and plan readjustment.
This
watershed/aquifer management instruments.
involves comparing monitoring data to EQOs, reassessing
management actions and/or EQOs and make the improvements
where necessary.
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Figure 6.7
TO
SAFE DRINKING WATER
Watershed / Aquifer Management Process
Comparison to
Environmental
Quality Objectives
Watershed
Management
Instruments
Performance
Evaluation and Plan
Readjustment
Plan Implementation
Monitoring
Focused Priority
Actions
Strategies
Goal Setting /
Prioritization
Confirmation of
Concerns
Plan Development
Watershed
Modeling Tools
Evaluation of
Management
Options
Definition of Challenges
and Opportunities
Source Water Assessment
6.2.3
Evaluation of management options
This step consists of evaluating concerns and objectives determined in the
source water assessment and valued features of the watershed/aquifer (e.g.,
landscape traits, annual spawning run, old growth forests). The purpose of the
evaluation is to ensure the accuracy and comprehensiveness of the problem
definition, and that this is well understood by stakeholders. It is important to
consider concerns combining water and other natural resources issues,
regulatory requirements, local economy, and social matters, whether factual or
perceived.
During the source water assessment (see Section 5.1), several features of the
source water area were identified that are especially valuable ecologically,
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economically or socially, and help maintain or improve source water quality
which once treated, will ensure clean, safe, and reliable drinking water over the
long-term. These valued features need to be weighed against the problems and
concerns (noted above) with providing good source waters. The risk of negative
impacts upon a valued feature of the watershed/aquifer is a good basis for
evaluating the concerns and setting priorities for action.
At this stage, it is important for stakeholders to identify potential challenges and
opportunities.
Challenges may be scientific or socio-economic. Scientific
challenges pertain to filling scientific data gaps that address uncertainties in the
science. Socio-economic challenges are those that impact the livelihood of
communities in the watershed/aquifer area. Opportunities are, for example, the
creation of partnerships among stakeholders leading to good communication
and coordination/consolidation of efforts (e.g., data-sharing). This promotes a
sustainable use of the shared resource.
6.2.4
Developing the protection plan
By this stage, all stakeholders will have provided some input on the concerns
(during the evaluation process discussed above). It is important for priorities to
be established in order to focus resources and efforts on mitigating risks to
source water quality. Priority-setting may be guided by the following set of
principles:
•
Focus on water quality for drinking water: This is a good
mechanism for creating common ground among stakeholders
who may have conflicting uses for the water in the
watershed/aquifer.
•
Principle of Protecting Water Systems: Watershed/aquifer
systems such as streams, springs, groundwater, lakes and
related riparian systems are recognized as valuable natural
features requiring protection.
Restoration of degraded
ecosystems back to their functional character should be
attempted where possible.
•
Ecosystem Principle: The interconnection of the environment
is a fundamental principle of watershed/aquifer planning. A
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Source
Water
TO
Protection
SAFE DRINKING WATER
plan
will
promote
the
watershed/aquifer area as the basis of sound environmental
planning and management of water resources. (CCME 1996)
•
Innovative
Technology
approaches/technologies
that
Applications:
address
New
watershed/aquifer
management needs and administrative requirements should be
encouraged.
•
Proactive
Management:
Cost-effective,
proactive,
and
preventative management of watershed/aquifer assets should be
favoured
over
cost-intensive,
reactive
watershed/aquifer
management.
•
Economic Considerations: Short and long-term economic
considerations should be considered.
•
Land Owner Rights, Privileges, and Responsibilities:
Societal and individual rights, privileges and responsibilities
should be recognized throughout the watershed/aquifer
planning process.
•
Consultation: When undertaking watershed/aquifer resource
management actions, direct consultation between government
agencies, municipalities, and public stakeholders is important.
•
Fair and Equitable Considerations: Social, economic, and
ecological considerations associated with watershed/aquifer
protection planning need to be applied with fairness and equity.
•
Education: Sharing and communicating watershed/aquifer
protection information and watershed/aquifer characteristics is
essential to develop community awareness that in turn fosters
informed decision-making processes.
Using these principles, a targeted watershed/aquifer approach is an effective
means by which to direct available resources to areas within the
watershed/aquifer where public health benefits can be realized.
In the
assessment process, vulnerable zones within the watershed/aquifer should be
identified, leading to the assignment of high priority to vulnerable areas in the
targeted watershed/aquifer approach. In some situations, a vulnerable zone may
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require aggressive protection, such as required land use restrictions. Prioritizing
using a targeted approach includes the following:
•
Identifying watershed/aquifer zones with the most critical water
quality problems and directing programs and resources to the
solution of these problems.
•
Directing programs and resources to watershed/aquifer zones
with the highest potential for improvement.
•
Protecting existing high quality water resources from future
impairment through a preventative approach to water quality
management.
•
Identifying watershed/aquifer zones where there is a need to
coordinate multiple remedial/protective priorities.
Stakeholders need to work together to obtain consensus on prioritizing,
including determining which problems/opportunities to pursue and in what
order.
Often it is beneficial to categorize watershed protection efforts into several main
protection areas such as streams with point source concerns, streams with nonpoint source concerns, lakes; and groundwater. Within these main areas, issues
identified can be further prioritized on the basis of both preventative and
restorative measures.
•
Preventative Measures are selected to ensure existing high quality
source waters are protected such as highly desirable biological
habitat sources and other provincially protected water sources
identified as habitat for endangered species, and streams used as a
source for drinking water.
•
Restorative Measures are selected to identify the most critical
source waters in need of remedial action in order to achieve water
quality objectives and attain full use of their established designated
uses.
Proposed measures should directly or indirectly mitigate the impact or reduce
the contaminant (chemical or biological) load of concern. The plan should
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include components such as actions and contingencies, costs and incentives,
roles and responsibilities, an implementation schedule, implementation
guidance and an evaluation / performance step (see Figure 6.7).
Tools for Developing the Watershed/Aquifer Management Plan
Many predictive models are available to stakeholders active in the development
of watershed/aquifer management plans and are discussed below.
Surface Water Models
When combined with good monitoring datasets, properly calibrated, tested, and
verified hydrologic models provide extremely powerful water assessment tools.
The models offer insight into impacts associated with known and anticipated
land use activities within the watershed/aquifer, which can provide valuable
forecasting information for assisting with management plan development and
management actions.
Although hydrological modelling may be the
preferred
option,
many
system owners
and
communities may not have the financial resources
to undertake such a program. In these cases, it is
important to gather as much information on flow
patterns and the potential risks as available to assist
in the development of a plan. In these types of
cases, a checklist should be developed to ensure all
risks are identified and, where possible, appropriate
management practices are implemented.
Watershed-scale models are specifically used to
simulate and predict localized pollutant loading,
transport, and transformation.
More Information on Models
For detailed information about specific
models available and their uses, check out
the following websites:
US EPA: www.epa.gov/waterscience/wqm
and www.epa.gov/ada/csmos/models.html
(Groundwater Models)
Surface Water and Water Quality Models
Information Clearinghouse:
http://smig.usgs.gov/SMIC
US Army Corps of Engineers:
www.wes.army.mil/el/elmodels
Natural Resources Conservation Service
(US Department of Agriculture):
www.wcc.nrcs.usda.gov/water/quality/
frame/waterqal.html
There are three
major types of watershed-scale models that can be used in the development of a
Source Water Protection plan:
•
Loading models predict the transport of pollutants from
watershed/aquifer sources to the receiving waters
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•
Receiving
water
models
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predict
the
transport
and
transformation of pollutants through water bodies such as
rivers, lakes and streams
•
Integrated models combine models and data with a convenient
user interface that can be used to create GIS-based spatial
representations of model outputs.
Groundwater Models
Several methods are available to delineate wellhead protection areas. Computer
models can be valuable tools in the development of wellhead protection plans.
A variety of software is available that will model groundwater flow and
contaminant transport. Each of the flow and transport models is based on
governing equations that are specific to the intent of the model. These equations
can be resolved either analytically or numerically.
Analytical models use exact closed form solutions of the appropriate differential
equations. The solutions are continuous in time and space. Although analytical
models provide exact solutions, they use many simplifying assumptions. When
the system being modelled is simple, reasonable estimates of groundwater flow
can be attained. However, these types of models have limitations with complex
flow systems as well as with temporal or spatial variations in the system.
Numerical models can simulate the three dimensional boundaries of
an aquifer using numerical equations. Numerical models can be
expensive and they do require a detailed dataset that accurately
characterizes the source aquifer. Numerical modelling provides the
most scientifically defensible basis of calculating groundwater flow
In referring to these tools, it
is important to recognize the
legislative and management
differences between the
jurisdictions where the tools
were derived and the
jurisdictions wishing to adopt
them.
based protection zones, provided they are based upon sufficient data
to accurately represent the flow system.
Numerical models are beneficial when assessing risks associated with particular
land uses or potential contaminant sources that are located within the recharge
area. Use of other delineation methods (e.g., distance criteria or arbitrary fixed
radius) could result in the protection of areas that are not actually contributing
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water to the well or conversely do not provide sufficient protection to high risk
areas within an aquifer zone exhibiting high groundwater velocity towards the
well.
Numerical models can serve as a predictive tool to help answer questions such
as:
•
How much water can safely be extracted from the aquifer over the
long term? This can incorporate influences such as stream aquifer
interaction and other demands on the aquifer including those from
domestic wells.
•
What are the effects of adding additional pumping wells or
increasing the pumping rates?
•
What separation distances are appropriate between the pumping
wells to minimize the potential of well interference?
Data Collection and Measurement Tools
An excellent repository of data collection and measurement tools is available
from the US EPA Office of Water (USEPA 1995).
This listing includes
references to useful data collection and measurement tools for microbial and
other pollutants such as:
•
Analytical Methods for the Determination of Pollutants in
Wastewater Environmental Indicators
•
Small Watershed Monitoring
•
Volunteer Lake Monitoring: A Methods Manual
•
Watershed Screening and Targeting Tool
Hydrologic Receiving Water/Watershed Modeling Tools
When properly calibrated, tested, and verified, hydrologic models are useful in
the development of a watershed/aquifer protection plan because they can predict
the long-term effects of watershed/aquifer management decisions on water
quality. Watershed-scale models are specifically used to simulate and predict
localized pollutant loading, transport, and transformation for microbial and
other pollutants.
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The goal of applying a loading model in a water quality investigation is to
predict pollutant movement from the land surface to water bodies. Loading
models range in complexity from simple loading rate
assessments to complex simulation techniques that show the
detailed processes of rainfall, runoff, sediment detachment,
and transport to receiving waters. Some loading models
work at the watershed/aquifer scale and sum all loads in the
watershed/aquifer; others enable the watershed/aquifer to be
subdivided into contributing sub-basins. Field-scale models
are focused on a small, local scale.
Integrated modelling systems link the models, data, and user
interface within a single system.
Recent advances in
modelling systems have supported geographical information
systems and database management systems to conduct
modelling and analysis. Geographical Information Systems
(GIS) allow data preparation for watershed/aquifer and
receiving water-modeling applications.
Hydrological tools for watershed
management include:
Hydrologic Simulation Program (HSPF)
by US EPA: simulates sediment
transport and movement of
contaminants from agriculture/urban
storm runoff. Continuous and single
event model.
Soil and Water Assessment Tool
(SWAT) by USDA ARS: predicts effects
of land management on water
sediment and chemical yields on large
river basins. Continuous simulation.
Water Erosion Prediction Project
(WEPP) by USDA ARS: predicts soil
erosion and sedimentation.
Continuous simulation, suitable for
small watersheds.
Storm Water Management Model
(SWMM) by US EPA: simulates urban
runoff. Continuous and single event
model.
Hydrological tools use modelled simulations to predict
hydrological impacts within a watershed/aquifer. Examples
are listed in the sidebar.
The previously mentioned groundwater models can also be
valuable tools in the development of wellhead protection
plans as well as delineating wellhead protection areas.
Simulator for Water Resources in Rural
Basins – Water Quality (SWRRBWQ) by
USDA ARS: simulates hydrologic,
sedimentation, and nutrient and
pesticide transport in a large, rural
watershed. Continuous simulation.
Agricultural Non-Point Source Pollution
Model (AGNPS) by USDA ARS:
examines water quality impact of
agriculture and urban areas. Single
storm event model.
GIS-aided Watershed Planning Tools
GIS-aided watershed/aquifer planning tools are extremely powerful and
efficient tools for interpreting large quantities of data pertaining to a
watershed/aquifer. Available GIS-aided tools include:
•
Better Assessment Science Integrating Point and Non-Point
Sources (BASINS) by US EPA: this tool offers integration of
ArcView ver. 2.0 GIS software with U.S. watershed/aquifer
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data, and environmental assessment and modeling tools such as
NPSM, TOXIROUTE and QUAL2E ver. 3.2.
•
Watershed Decision Support System (WAMADSS) by
CARES: integration of Arc/Info GIS with Agricultural NonPoint Source Model (AGNPS), Soil and Water Assessment
Tool (SWAT), and Cost and Return Estimator (CARE)
program.
•
Watershed – The System by Linnet Geomatics Int.: a soil and
water conservation system for local organizations.
Socio-economic Tools
Socio-economic tools offer analysis of anticipated social and economic impacts
associated with considered watershed/aquifer management policies. Tools in
the category include:
•
Cost and Return Estimator (CARE) by USDA NRCS: generates
costs and returns for crop enterprises.
•
FLIPSIM by Texas A&M University: simulates the impacts of
alternative farm and natural resource policies on the survival
and profitability of representative farms.
•
A Guide for Cost-Effectiveness and Cost Benefit Analysis of
State and Local Water Protection Programs: the guide shows
how to use cost-effectiveness and cost-benefit analysis to
evaluate groundwater programs. The tools are presented in a
step-by-step fashion so those unfamiliar with formal economics
can still use them.
Decision Support Systems
Watershed planning and management can be complex. Making decisions that
benefit stakeholders while maintaining watershed objectives can be challenging.
The decision-making process is multidisciplinary in nature and must integrate
variables such as scientific, socioeconomic and political knowledge.
Fortunately, decision support systems (DSS) that make use of complex,
dynamic knowledge from a number of disciplines, generally in a user-friendly
graphical user interface, are available to decision makers. These systems allow
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users to organize information, design alternative watershed management plans
and assess the consequences of these to stakeholders. It is recommended that
people conducting long-term sustainable watershed planning and management
consider the use of DSS.
6.2.5
Implementing the plan
Implementation of the plan consists of carrying through with the management
actions recommended in the plan. Resources (human and monetary) will need
to be mobilized and managed accordingly. An implementation schedule for
conducting management activities will need to be developed and updated on a
continuous basis. Effective schedules may include an order for addressing
watersheds/aquifers that balances workloads from one year to the next; and a
specified time limits for each assigned watershed/aquifer management action.
The range and severity of each particular watershed/aquifer problem will dictate
the time required in the implementation schedule.
Implementation instruments
Many instruments are available to stakeholders to help them implement the
watershed/aquifer management plan. Some of these instruments take the form
of legislation, government incentives, regulatory mechanisms and best
management practices. These instruments generally focus on the management
and/or prohibition of specific contaminants or land-uses within a given
protection area.
Commonly used land-use and source control methods include both regulatory
and non-regulatory controls. For examples of controls, see the box below.
REGULATORY
AND
NON-REGULATORY TOOLS
FOR
LAND-USE
CONTROL
Regulatory tools
Zoning: Consists of dividing the
municipality into districts and
applying land use restrictions to the
districts. Zoning generally restricts
future development rather than
existing land uses using mechanisms
such as:
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•
•
•
•
•
•
prohibition of certain land
uses and contaminants
special permitting to regulate
uses
performance standards to
regulate development
reduction of undesirable
land uses
growth controls for the
location and timing of
development
transfer of development
rights to areas outside the
protected areas.
Design and Operating Standards:
Design standards usually control the
standards for new engineering
projects whereas operating standards
control the operating standards for
various engineering works and are
generally administered through the
use of by-laws, health regulations or
performance standards. Standards
for development projects other than
drinking water treatment plants can
include:
•
siting criteria used to guide
developments (e.g.
residential)
•
setback/buffer criteria to
minimize detrimental
impacts
•
Storm water drainage
diversion
Environment and Health
Regulations: Enforcement of existing
provincial and federal legislation
developed for the protection of
human health and the environment.
Non-regulatory tools
Land Acquisition: Used to control
land use through purchase of one or
more of the protected areas or the
use of easements to limit
development and land use practices
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Land Use Planning and Designation
of Protection Plans/Areas: May
require inter-governmental
agreements and cooperation.
Examples include watershed plans
and management and protection
plans.
Voluntary and Municipal
Contributions:
•
public education to inform
the community of the
relationship between land
use and drinking water
quality;
•
advisory committees to
provide expertise and plan
events
•
hazardous waste collection
•
water conservation
programs
•
stream clean ups
•
Best Management Practices.
Capital Works Improvements:
Improvements that could be
completed with the protection area
could include:
•
installation or extension of
treatment facility or
municipal sewer
•
removal or clean up of
contaminant sources
•
installation of spill
prevention, containment
and monitoring systems
•
outright purchase of areas
requiring protection.
Other non-regulatory avenues
involve close supervision of water
supply areas to identify and respond
to contamination events or
involvement of the public in
protection initiatives. These
measures are on the whole
favourable and supplement nearly
any source water protection
program.
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As part of their watershed/aquifer management strategy, municipalities may
want to consider purchasing the land that makes up the watershed/aquifer from
which they draw their drinking water. Rather than the entire watershed/aquifer,
municipalities can also look at purchasing key parcels of land within the
watershed, such as areas vulnerable to groundwater contamination or areas
surrounding municipal wellheads. Some of the pros and cons of this approach
are listed in the adjacent box. More often, partnerships will need to be
established with other municipalities, organizations, landholders, and land users
in many smaller municipalities. Often the area that needs protection will cross
municipal boundaries. In that case, linking with other
municipalities
is
a
key
component
of
watershed/aquifer management.
Other methods of controlling contamination, not yet
commonly used in Canada, are based on the concept of
total load allocations. Total load allocations establish
the maximum amount of a pollutant a water body can
receive, over a specific period of time, while
continuing to meet federal and provincial water quality
guidelines and objectives. The total load allocation
policy for a water body should consider baseline levels
of the pollutant prior to setting limits. An example of
this instrument in a regulatory context is the Total
Maximum Daily Loads (TMDLs) program used by the
Purchasing a watershed
Pros:
1. High level of control over activities
2. Land can be identified as private
property through signage
3. Violations can be dealt with as
trespassing
4. Potential for forestry and rental revenues
Cons:
1. Purchase price can be high
2. Expense and liability of boundary
maintenance
3. Occupier's liability
4. Patrol and enforcement costs
5. Property maintenance costs
Alternatives:
1. Controlling access points (rather than the
entire area)
2. Establishing partnerships with other
municipalities, organisations,
stakeholders and land-users
(Yates 2001)
city of Winnipeg. TMDLs specify the maximum amount of a pollutant that a
water body can receive and still meet the water quality standards, allocating
pollutant loadings among point and non-point pollutant sources. The TMDL
for a water body includes a safety factor to ensure that the carrying capacity for
the contaminant is not exceeded by all point and non-point sources.
6.2.6
Performance Evaluation and Plan Readjustment
The on-going evaluation of watershed/aquifer management activities, progress
and impacts is necessary to assess effectiveness of a watershed/aquifer
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protection plan. Review of monitoring data is critical in the evaluation of
preventative and restorative source water efforts. This evaluation can be
supplemented through consultation with watershed/aquifer stakeholder focus
groups and the general public through open houses and questionnaires. Most of
the evaluation effort can be managed by the Source Water Protection
Committee.
The key to assessing the effectiveness of the watershed/aquifer management
plan and its implementation is to compare source water monitoring data (see
Section 7.1) to EQOs. This comparison is done to track progress towards
achieving EQOs. Through this exercise, the Committee can refine the EQOs,
review the management plan, and make adjustments as necessary.
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7. Drinking Water Treatment and
Distribution System Design
This section deals with the design of drinking water treatment plants and
distribution systems based on the quality of the source water as determined in
Section 6. This section starts with a discussion of regulatory requirements (7.1,
7.2 and 7.3) and then moves on to discuss how to design treatment and
distribution systems in order to meet those requirements. On-going operational
considerations are discussed in Section 8.
Remember that regulatory requirements vary across the country. Owners and
operators are strongly encouraged to first understand and meet the regulatory
requirements of their particular jurisdiction before considering the guidance
laid out in this document.
The source water assessment outlined in Section 6 is followed by the selection
of the appropriate technology to treat the source water.
Water treatment
process selection is a complex task involving many factors. The selection of
the treatment processes is dictated by the need to produce acceptable water
quality in a cost effective manner. The choice of water treatment depends on:
•
Source water quality and quantity
•
Finished water quality
•
Reliability of process equipment
•
Operational requirements and operator capabilities
•
Flexibility in dealing with changing water quality
•
Capital and operating costs
The impact of treatment processes on the environment also needs to be
considered and minimized. Waterworks should be designed and approved by
qualified professionals.
Water transmission and distribution mains are also a vital component of the
waterworks system to ensure safe delivery of drinking water. To ensure water
transmission and distribution mains do not adversely affect the quality of the
water being conveyed, standards and guidelines have been established for pipe
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sizing, material, layout, and burial. Cross connection control and disinfection
are also addressed.
In establishing standards and guidelines for water
transmission and distribution mains, the principal intent is to protect against
contamination. In this regard, it is important for the standards and guidelines to
be based on both on good engineering practices and on standards and
guidelines that have either been set by other jurisdictions such as USEPA and
WHO or set by standards/guidelines developing agencies/associations, e.g.
CSA, AWWA and NSF.
Much of the guidance in this section has been adapted from Alberta
Environment’s Standards and Guidelines for Municipal Waterworks,
Wastewater and Storm Drainage Systems (1997).
7.1
Facility Design, Performance and Monitoring
Adequate waterworks systems
Ensuring the adequacy of waterworks systems from a design and process
standpoint is considered a major element of any public health protection and
safe drinking water program. This may be achieved by:
i.
Developing and publishing performance standards, design
standards and design guidelines for municipal waterworks
systems
ii.
Undertaking project design reviews and issuance of approvals
for the construction of the works based on compliance with
standards and guidelines
Good operation of the waterworks system
The proper operation and maintenance of waterworks system is essential to
ensure sustained production and delivery of good quality drinking water. This
may be achieved by:
i.
Issuing operating approvals for the waterworks system with
system performance monitoring requirements
ii.
Sponsoring/organizing operator training programs
iii.
Certifying operators
iv.
Inspecting facilities and reviewing plant optimization
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In cases where certifying operators is not possible because an official program
does not exist, or in cases where operators are certified but would like to add to
their knowledge, operators are encouraged to take it upon themselves to find
alternative training opportunities.
Comprehensive drinking water quality monitoring
As discussed in Section 8.12, it is important for provinces to establish
reasonable and appropriate monitoring requirements for waterworks systems,
which may include:
i.
Operational monitoring conducted by the local authority to
control/monitor the performance of water treatment processes
ii.
Compliance monitoring conducted by the local authority to
determine
compliance
with
regulatory
quality
standards/guidelines
iii.
Baseline or issue oriented monitoring conducted by the
province and the local authority to develop/expand databases,
to address a specific concern/problem, and to assess the need
for, or implications of, a possible new drinking water quality
guideline limit.
Appropriate abatement and enforcement
As discussed in Section 8.10, a comprehensive drinking water program
includes both an abatement component (which involves working cooperatively
with owners to prevent and/or solve drinking water supply or quality problems)
as well as an enforcement component (which involves taking appropriate action
when violations of specific requirements occur). Abatement and enforcement
activities may involve:
i.
Providing field assistance to operators and undertaking
operational modifications to improve water quality
ii.
Undertaking compliance monitoring reviews
iii.
Investigating for non-compliance
iv.
Undertaking enforcement action for non-compliance
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Materials and chemical agents used in the provision of drinking water need to
be appropriate for their intended use. In this respect, guidelines that have either
been set by other jurisdictions such as USEPA and WHO or set by
standards/guidelines developing agencies/associations (e.g. CSA, AWWA,
ULC and NSF International) may be used. It is important for regulators to
commit to requiring standards that are considered acceptable in cases where
such standards are not already required.
7.2
Treatment requirements for systems on surface water or for systems
on groundwater under the direct influence of surface water (GWUDI)
Water treatment systems relying on surface water or GWUDI6 should filter the
water following a number of accepted processes to reduce the turbidity, colour,
organic load and the concentration of microbiological organisms (protozoa,
bacteria, viruses, etc). In general, treatment facilities for a surface water source
or groundwater source directly affected by surface water include screening,
coagulation/flocculation, sedimentation, filtration, taste and odour control, and
disinfection.
At minimum, treatment requirements for surface water systems or for systems
on GWUDI is filtration and disinfection to ensure greater than:
•
99.9 per cent (3-log) reduction of Cryptosporidium;
•
99.9 per cent (3-log) reduction of Giardia lamblia; and
•
99.99 per cent (4-log) reduction of viruses,
at or before the first consumer. For systems with a distribution system, it is
important for a residual of disinfectant to be maintained at all times.
Filtration of a surface water source or a groundwater source under the direct
influence of surface waters may not be necessary if all the following conditions
are met (adapted from the US EPA Surface Water Treatment Rule):
i.
Disinfection reliably achieves at least a 99% (2-log) reduction
of Cryptosporidium oocysts, a 99.9% (3-log) reduction of
6
For information on determining whether groundwater is under the influence of surface
water (GWUDI), see Section 6.1.1
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Giardia lamblia cysts and a 99.99% (4-log) reduction of
viruses. Overall inactivation must be met using a minimum of
two disinfectants. More than a 99% (2-log) reduction of
Cryptosporidium oocysts and more than a 99.9% (3-log)
reduction of Giardia lamblia cysts must be achieved if source
water cyst/oocyst levels are greater than 1/100 L. Background
levels for Giardia lamblia cysts and Cryptosporidium oocysts
in the source water must be established by monitoring every
quarter or more frequently during the periods of expected
highest levels (e.g., during spring runoff or after heavy
rainfall).
ii.
Prior to the point where the disinfectant is applied, the source
water E.coli concentration does not exceed 20/100 mL, or the
total coliform concentration does not exceed 100/100 mL, in at
least 90% of the weekly samples from the previous six months.
iii.
Average daily source water turbidity levels measured at equal
intervals (at least every four hours) immediately prior to where
the disinfectant is applied do not exceed 5.0 NTU for more
than two days in a 12-month period.
iv.
A
watershed/aquifer
control
program
(e.g.,
protected
watershed/aquifer, controlled discharges, etc.) is maintained
that minimizes the potential for faecal contamination in the
source water.
7.3
Treatment Standards for Groundwater
In general, groundwater treatment plants are less complex than surface water
treatment plants.
The minimum treatment requirement for systems on
groundwater is disinfection to ensure greater than 99.99 per cent (4-log)
reduction of viruses, at or before the first consumer.
Under certain
circumstances, system specific exemptions for disinfection may be granted by
some jurisdictions.
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Dissolved minerals such as iron, manganese and, in some cases, dissolved
metals can also be an issue.
Therefore, in addition to disinfection, other
treatment processes may be required. The type of treatment will depend on
which substances are present and in what concentrations.
7.4
Surface Water Supply
7.4.1
Water Source / Quality
Source water from a selected source should be of sufficient quality that it can
be economically treated to produce finished water that complies with the
drinking water quality and treatment performance requirements. Factors that
influence the choice of the source water should include reliability, treatability,
environmental impact, and economics.
As the level of treatment required is dependent on the source water quality, the
local authorities may develop watershed/aquifer protection programs to reduce
any potential risk of source pollution. The local authorities may maintain a
sanitary control area around all sources to protect them from existing and
potential sources of contamination (see Section 8.9). As discussed in Section
6.2, the local authorities, in concert with other stakeholders, may also develop a
watershed/aquifer control program, identifying land ownership and activities
that may adversely affect source water quality. Watershed/aquifer control
measures would then be developed, including documentation of ownership and
relevant written agreements, and monitoring of activities and water quality (see
Section 6.2).
7.4.2
Source Water Intake
Various components of waterworks systems should have a design life that is
compatible with the function of the component. For example, a water treatment
plant should be designed for a minimum period of 10 years with provision for
expansion to handle a 20 or 25 year design flow. Intakes and outfall structures,
which have high base construction costs, should be designed to be able to
handle increases in water demand for longer than the design horizon, which is
usually about 25 to 50 years.
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Intake design should account for wave action and should provide adequate
protection against the effects of ice and boat anchors.
Intakes should be
identified with buoys or reflectors where in proximity to shipping or
recreational activities. It is important for the designer to be familiar with the
requirements as legislated under the Navigable Waters Act and the Fisheries
Act.
The inlet should be located to prevent bottom sediments from being picked up.
For small intakes, consideration should be given to providing means for
back-flushing the intake, if practical.
The design of river intakes differs from that for lakes and stagnant water bodies
since more secure anchoring is required to resist bottom scouring and stream
velocities. River intakes should be equipped with trash racks and should also
be located well upstream from potential sources of pollution.
An acceptable alternative design to direct intake is an infiltration gallery intake.
This type of intake is suitable when the river-bed is composed of gravels and
rocks or if the floodplain is demonstrated to have a high water table that is
connected to the nearby watercourse. Items to be considered are:
i.
The sediment load in the river (may necessitate backwashing or
aeration provisions)
ii.
The use of filter cloth
iii.
The depth of perforated infiltration pipes (to be located as deep
as possible in the aquifer so as not to be affected by seasonal
fluctuations)
7.4.3
Source Water Storage
Source water storage improves water quality by providing pre-sedimentation of
solids, ensures an adequate supply when a stream or lake source is intermittent,
and provides standby against failure of intake facilities. It also enables the
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operator to avoid the undesirable practice of drawing water during periods of
poor source water quality, allowing a low rate of withdrawal at the source.
Facility Planning
It is important for the designer to assess the need, location, and sizing of the
source water storage reservoir before proceeding with final design. Reservoir
sizing should be determined by assessing the availability of water and the
nature of upstream activities. It is also important for the designer to consider
any potential adverse effects on the water intake, storage, or treatment facilities;
design features should be used to minimize the effects of fluctuating source
water turbidity.
Multi-Cell Provision
Source water reservoirs should be constructed with a minimum of two cells.
This feature enables the plant operator to withdraw source water from the
second cell when the first cell is being filled or repaired. For reservoirs that
may be filled only once annually, each cell should be sized to retain about 75%
of the annual source water needs. In areas of drought, the number of cells and
the storage capacity of each should be increased to overcome long-term
droughts.
Control structures should enable the plant operator to isolate each cell, to drain
each cell, and to enable the cells to be operated in series or in parallel. A
bypass around the reservoirs may also be provided to obtain water during those
periods when reservoirs are out of service.
Each cell should be deep enough to restrict light penetration within the depth of
the reservoir to mitigate the development of ideal habitats for aquatic plants.
It is important to armor the inside slopes of the cells, where required, to prevent
erosion. It is also important to account for the impact of ice formation on
winter storage in the design.
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Reservoir Management
It is important for the local authorities to have a reservoir management program
that identifies the current condition of the reservoir, the necessary storage
capacity, and the necessary management procedures to respond to changes in
reservoir conditions.
Reservoirs need to be managed to avoid any difficulties with taste, odour,
colour, iron and manganese in drinking water.
In-reservoir management
techniques should address problems with algae, weeds, low dissolved oxygen,
and loss of storage capacity.
Artificial circulation, aeration, phosphorus precipitation, sediment removal,
dilution, and flushing are reservoir management techniques that improve water
quality.
For more information on operational issues, see Section 8.
Lining
Source water reservoirs should be designed to minimize seepage. If necessary,
the reservoirs should be lined.
7.4.4
Source Water Pumping
Pumps should be specified so the full range of anticipated flows can be
provided with pumps operating close to optimum efficiency, with due regard
paid to the hydraulic design of the discharge piping.
This is often
accomplished by selecting pumps that have wide band efficiencies and a
relatively flat operating curve.
The number of pumps should be consistent with the pattern of flow required
and the method of flow control. It is recommended that at least three pumps be
provided for operating flexibility; a minimum of two pumps is required, one as
standby. Pump capacities should be such that with the largest unit out of
service, the remainder will be able to supply the treatment plant capacity.
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The station design should allow for future additional pumping units and where
possible, the pipework should be large enough for an increase in pump size to
be accommodated. Adequate space should be provided for the installation of
these additional units, and to allow safe servicing of all equipment.
Adequate space should be provided to remove the pumps. In the case of vertical
turbine pumps, it may be necessary to provide a roof access for removing the
units and sectional discharge pipes so that they can be completely removed
from the source water well.
All piping should be arranged so there is sufficient room to service all valves
and other parts, and to permit their removal with minimum disturbance to the
system.
A bridge crane, monorail, lifting hooks, hoist or other adequate
facilities should be provided for servicing or removing equipment.
The pumps should be capable of supplying the water over the entire range of
flows to be treated. This could be achieved through the provision of pumps
with variable speed motors or through control valves. At small treatment plants
where substantial seasonal variations in flow exist, it may be necessary to
provide duplicate flow control systems - one suitable for very low flows (which
normally occur in winter) and one suitable for the plant design flow.
7.5
Groundwater Supply
7.5.1
Siting of Wells
Wells should be located to avoid proximity to sources of pollution and/or
flooding. Wells should be at least 100 m upgradient from pollution sources
such as septic tanks, drainage fields, cesspools, or wastewater stabilization
ponds; wells should not be located near sanitary landfill sites, underground fuel
storage tanks, or cemeteries. Reasonable access should be provided for repair
and maintenance.
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7.5.2
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Well Protection
In order to protect the finished supply structure from external contamination,
the following should be provided:
i.
Water-tight construction to at least 6 m below ground level.
This depth may be increased if local conditions present a
danger of surface contamination
ii.
An annular opening of at least 40 mm outside the protective
casing, filled with an approved grouting material
iii.
Other precautions in the design to seal off undesirable
subsurface formations and surface contamination
7.5.3
Pumphouse Design
The design criteria for well pumping stations generally follow those
presented
for
raw
surface
water
pumping,
and
standby-pumping
facilities should be provided which are capable of maintaining normal
servicing
standards.
Design
should
include
features
to
prevent
contamination of the well. In particular, return pipes that will permit
water to be recirculated down the well should be avoided as they may cause
contamination of the well.
7.5.4
Well Disinfection
Prior to using a water well, it should be disinfected in accordance with
provincial/territorial requirements or to AWWA Standard C654-97. In general,
chlorine should be applied to ensure that a concentration of 50 mg/L is present
in the well for a period of twelve hours. Dosage should be calculated on the
basis of the amount of water required to provide mixing throughout the entire
well volume.
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Treatment Processes
Treatment processes, particularly for municipal water supplies, generally
include filtration and disinfection.
Various filtration and disinfection
technologies are discussed later on in this section.
Selection of a suitable water treatment process for a given utility is always a
complex task. Conditions are likely to be different for each water utility;
adoption of an appropriate water treatment process by a water utility is
influenced by the necessity to meet the regulatory guidelines, the desire of the
utility and its customers to meet other water quality objectives and the need to
provide water service at the lowest reasonable cost.
A water treatment plant should be designed considering the fact that it should
supply continuous and safe water to the customers regardless of the source
water characteristics and the environmental conditions.
The source water quality is the single most important factor in determining the
type and the extent of treatment required for a particular source of water. Thus,
as discussed in Section 6, a thorough evaluation of the source water types
should precede the selection of a treatment process.
The major source water characteristics are microbiological quality, turbidity,
pH, alkalinity, colour, TOC, TSS, iron, manganese, algal counts, and
temperature. Table 7.1 shows a choice of filtration processes, based on some
key source water parameters.
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Table 7.1
Generalized
capability
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of
filtration
systems
to
accommodate source water quality conditions
Treatment
General Restrictions
Total Coliforms
Turbidity
(#/100 mL)
(NTU)
Colour
(TCU)
Conventional with pre or inplant disinfection*
< 20,000***
No
restrictions
< 75
Conventional without
pre or in-plant disinfection*
< 5,000
No
restrictions
< 75
Direct filtration**
< 500
< 7-14
< 40
Slow sand filtration
< 800
< 10
<5
*
**
***
Note:
Must ensure control of disinfection by-products
When TOC > 3 mg/L turbidity reduction is impaired
When total coliforms > 20,000/100 mL, or colour > 75 TCU,
additional treatment may be required
Ideally pilot testing should be conducted to demonstrate the efficacy
of the treatment alternatives.
Preferably a five year history that characterizes the main source water types
would be collected. While such data collection is possible for locations where
a water treatment plant already exists, it could be impractical for new locations.
Therefore, data that characterizes the main water types for at least one year
should be collected as a minimum.
Facilities located upstream and/or
downstream from a proposed site may be able to provide valuable information
on the source water characteristics.
Conventional treatment is often the treatment of choice in producing safe
drinking water. Chemical mixing is often the first and also an important step in
the process train. Mixing is critical for uniform dispersion of the coagulant
with the source water in order to avoid over or under treatment of the water.
An understanding of water chemistry and the process of coagulationflocculation is extremely important in the design of the components of a
rapid-mix unit. The water quality, mode of destabilization, and the type of
coagulant all play a part in the selection and design of the appropriate unit.
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Table 7.2 provides some basic information on the selection of treatment
methods and primary coagulants for different source water quality.
The
designer is well advised to verify this by undertaking bench-scale or pilot tests.
Table 7.2
Treatment Methods
Water Quality
High Inorganic
Turbidity,
High or Low Alkalinity
High TOC,
High or Low Alkalinity
Low Inorganic
Turbidity,
High or Low Alkalinity
Low TOC,
High or Low Alkalinity
Primary Mode of
Destabilization
Enhanced
Coagulation
Charge
Neutralization
Enhanced
Coagulation
Charge
Neutralization
Enhanced
Coagulation
Charge
Neutralization
Primary
Coagulant
Flocculant
Aid
Treatment
Method
Recommended
Rapid Mixer
Inorganic
Salt
If required
Conventional
ILM
Inorganic
Salt
Inorganic
Salt
Polymer,
inorganic
salt
Inorganic
Salt
Yes
Conventional
ILM
Yes
Conventional
No
Direct
Filtration
ILM, S, BM,
PJ**
ILM, S*, PJ*,
BM*
Yes
Conventional
ILM, S, PJ**,
BM
No
Direct
Filtration
ILM, S*, PJ*,
BM*
Polymer,
Inorganic
Salt
*S, PJ and BM may be used with polymers only; *PJ may be used for waters with low alkalinity
PJ=Pressured Water Jets; BM=Backmix Reactor ; ILM=In-line Mechanical Mixer; S=In-line Static Mixer
Typical Ranges
High Inorganic (Turbidity) > 100 NTU
CaCO3
Low Inorganic (Turbidity) < 10 NTU
CaCO3
High TOC (Colour) > 5 mg/L
High Alkalinity > 100 mg/L as
Low TOC (Colour) < 2 mg/L
Low Alkalinity < 30 mg/L as
Notes:
1. For enhanced coagulation, waters with low alkalinity should be buffered if inorganic salts that would
lower the pH are used.
2. Charge neutralization by inorganic salt, compared to enhanced coagulation, would require lower
dosage of the salt.
3. A combination of inorganic salts and polymers could be used for optimizing the process, and often
provides the best results.
4. Chemicals used as flocculant aid should be added after the addition of primary coagulant, prior to or
at the flocculation unit.
5. Colour is best removed in the pH range of 4 to 5.5 with inorganic salts (alum) by charge
neutralization; this pH range may not be the optimum for turbidity removal.
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7.6.1
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Treatment Plant Chemicals and Waste - Handling and Disposal
It is important to provide for proper treatment and/or disposal of all water
treatment plant chemicals and wastes, including sanitary wastes, filter
backwash, filter-to-waste.
Water Treatment Chemicals
a.
Labels and Materials Safety Data Sheets
Federal and most provincial jurisdictions require hazardous products stored at
worksites to be labeled and information be made available to workers through
Material Safety Data Sheets. Workers are required to be knowledgeable about
the Workplace Hazardous Materials Information System (WHMIS).
Most chemicals used for water treatment are "controlled products.”
For
appropriate use of the chemical, water treatment operators should be aware of
the chemical purity (concentration), shelf life, expiry data, maximum dosage
and use restrictions. This information can usually be found on the supplier
labels but may be added to the worksite label for ease in use.
More specific information on the hazardous ingredients, hazards, health and
safety risks, safe handling instructions, emergency and first aid measures are
contained on a Material Safety Data Sheet (MSDS). MSDS obtained from the
supplier and not more than three years old must be available at the worksite for
all "controlled products" unless it is laboratory product where the label may
contain all the information required on a MSDS.
b.
Storage and Handling
Chemical storage areas should be segregated from the main areas of the
treatment plant, with separate storage areas provided for each chemical. Where
chemicals in storage may react dangerously with other materials in storage,
segregated storage should be provided. The storage and feed equipment areas
should be arranged for convenience of operation and observation, and located
to provide easy access for chemical deliveries.
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In general, storage areas should be arranged to prevent any chemical spills. As
much as possible, all chemical storage should be at or above the surrounding
grade. Storage areas should have eye-wash and/or deluge shower facilities,
adequate facilities for cleaning up chemical spills, space for cleaning and
storage of the recommended protective equipment, and adequate warning signs
to identify hazards.
Chemical ventilation systems should be arranged so that air is exhausted
outside the building and also so that slight negative pressures are maintained
where dry chemicals are in use, as a dust control measure. Ventilation systems
should be designed specifically for corrosive service, and special measures
should be taken to prevent build-up of static or other explosive conditions.
Sanitary Wastes
It is important for all sanitary wastes from water treatment plants to be handled
by direct discharge to a sanitary sewer system or to an approved wastewater
treatment facility. These sanitary wastes should be kept separate from other
process wastes to avoid the need to treat all plant wastes in the same manner as
the sanitary wastes.
Filter Backwash
Backwash waste may be discharged directly to a sanitary sewer system, if the
sewers and the wastewater treatment plant can withstand the hydraulic surges.
Backwash waste may not be discharged directly to an open body of water.
Exceptions may be made only if it can be demonstrated that there are no
significant adverse effects on the receiving body of water.
Based on the
quantity and quality of backwash waste and the sensitivity of the receiving
body of water, regulatory agency may request for an impact assessment study
to ascertain the need for backwash waste treatment before discharging to the
environment.
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Discharge of filter backwash water into a raw water reservoir or to the head
works should not be permitted unless it receives off-line treatment or is
returned to a location upstream of the coagulant dosage point so all the
processes of a conventional or direct filtration plant are employed. Off-line
treatment may be acceptable depending on the treatment method used in
treating the backwash water.
For more information on filter backwash, see the US EPA’s “Filter Backwash
Recycling Rule” (www. epa.gov/OGWDW/filterbackwash.html)
Filter-to-Waste
Filter-to-waste may be discharged directly to a sanitary sewer system, if the
sewers and the wastewater treatment plant can withstand the hydraulic surges.
Filter-to-waste may also be recycled to the pre-treatment works or to the source
water reservoir.
Clarifier blow-down
Disposal of clarifier blow-down (alum sludge) is generally determined on a
site-specific basis.
The following are a number of alternative methods of
handling and disposing of aluminum sludge from water treatment plants:
a. Direct discharge to a wastewater treatment plant or sanitary sewer.
Consideration should be given to the potential beneficial and
adverse effects on the wastewater treatment facility;
b. Lagooning. Lagoons can be used as permanent storage facilities,
long-detention settling lagoons to provide freeze/thaw cycle with
supernatant disposal, or drying beds using evaporation;
c. Mechanical thickening and dewatering.
Once thickened and
dewatered, sludge can be placed at a disposal site, usually a landfill
site used exclusively for sludge;
d. Direct discharge to a stream. This option should be considered
only where there is a negligible environmental impact and it has
been demonstrated that the aesthetics and downstream water users
will not be affected; and
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e. Land disposal.
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Land disposal to a sanitary landfill site or
agricultural land of dilute or thickened and dewatered sludge is
potentially harmful and should be reviewed with the regulatory
authority prior to implementation.
7.6.2
Filtration Technologies
The filtration and disinfection treatment technologies identified below are not
intended to be a comprehensive or exclusive list. Local authorities may choose
alternative treatment technologies (i.e., technologies not listed) that may be
effective in producing water to meet the health based limits. Once again, the
designer may conduct a pilot study to determine whether new emerging
technologies meet the requirements.
For information on operating and maintaining filters, see "Filter Maintenance
and Operations Guidance Manual" (2002) AWWARF Report ISBN 1-58321234-5
FILTRATION TECHNOLOGIES
Conventional Filtration
Conventional filtration includes
chemical coagulation, rapid mixing,
and flocculation, followed by floc
removal via sedimentation (or
flotation). The clarified water is then
filtered. Common filter media
designs include sand, mono-media,
dual-media, and tri-media,
combining sand, anthracite, and
other media. Design criteria are
influenced by site-specific conditions
and thus the criteria for individual
components of the treatment train
may vary between systems.
Conventional treatment has
demonstrated removal efficiencies
greater than 99% for viruses and 97
to 99.9% (rapid filtration with
coagulation and sedimentation) for
Giardia lamblia.
Direct Filtration
Direct filtration has several effective
variations. In general, though, all
direct filtration systems include a
chemical coagulation step followed
by rapid mixing, and all exclude the
use of a other clarification step such
as sedimentation prior to filtration.
Following the chemical mix, water is
filtered through dual- or mixedmedia filters using gravity units.
Slow sand filtration
Slow sand filters are similar to single
media rapid-rate filters in some
respects, but there are crucial
differences in the mechanisms
employed. The schmutzdecke, or
top-most, biologically active layer of
filter, removes suspended organic
materials and microorganisms by
biodegradation and other processes,
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rather than by relying solely on
simple filter straining or physiochemical sorption. Advantages of
slow sand filtration include its low
maintenance requirements (since it
does not require backwashing and
requires less frequent cleaning) and
its efficiency (which does not
depend on actions of the operator).
However, slow sand filters do
require time for the schmutzdecke to
develop after each cleaning. During
this “ripening period,” however,
filter performance steadily improves.
The ripening period can last from six
hours to two weeks, but typically
requires less than two days. A two
day filter-to-waste period is
recommended for typical sand filters
Diatomaceous earth (DE)
filtration
DE filtration, also known as precoat or diatomite filtration, can be
used to directly treat source water
supplies with low turbidity or
chemically coagulated, more turbid
water sources. DE filters consist of
a pre-coat layer of DE,
approximately 1/8-inch thick,
supported by a septum or filter
element. To properly maintain the
DE pre-coat layer, and to maintain
porosity, treatment is supplemented
by a continuous-body feed of
diatomite and recycled filtered water.
Intermittent operation of DE filters
is not advised unless the system
recycles water through the filter
during production down times.
Maintaining the filter in this manner
optimizes performance, extends the
filtration cycle, and lowers filter
maintenance requirements.
Manganese Greensand Filtration
Manganese greensand is commonly
used to removal iron and manganese
from groundwater supplies. In some
cases, it has been used to remove
arsenic. The greensand media is
typically regenerated by a continuous
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feed of potassium permanganate
and/or chlorine ahead of the filter.
The membrane filtration process can
be pressure or vacuum driven.
Membrane Filtration Processes
The four treatments listed below are
membrane processes which make
use of pressure-driven semipermeable membrane filters.
Membranes are manufactured in a
variety of configurations, materials
and pore size distributions. The
selection of membrane treatment for
a particular drinking water
application is determined by a
number of factors: source water
quality characteristics, treated water
quality requirements, membrane
pore size, molecular weight cutoff
(MWCO), membrane materials and
system/treatment configuration.
Pre-filtration and scale-inhibiting
chemical addition may be used to
protect membranes from plugging
effects, fouling and/or scaling, and
to reduce operational and
maintenance costs.
Reverse osmosis (RO) treatment
operates in a high-pressure mode,
and is effective in removing salts
from brackish water and seawater.
Due to typical RO membrane pore
sizes and size exclusion capability (in
the metallic ion and aqueous salt
range), RO is effective for removing
cysts, bacteria and viruses; however,
RO produces the most wasted water
(between 25-50% of the feed).
Disinfection is still recommended to
ensure the safety of water.
Nanofiltration (NF) treatment
operates in a medium pressure
mode, and is effective in removing
calcium and magnesium ions
(hardness) and/or natural organics
and disinfection byproducts. Due to
typical NF membrane pore sizes and
(1 nanometer range), NF is effective
for removal of cysts, bacteria and
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viruses. Disinfection is still
recommended to ensure the safety
of water.
have also shown that filtrate
turbidity may be kept consistently at
or below 0.1 NTU.
Ultrafiltration (UF) treatment,
characterized by a wide band of
MWCOs, pore sizes and size
exclusion capability (0.01 micron,
molecular/ macromolecular range),
operates in a low pressure mode and
is effective in removing specific
dissolved organics (e.g., humic
substances, for control of
disinfection by-products) and
particulates. UF is also effective for
absolute removal of Giardia cysts
and partial removal of bacteria and
viruses. When used in combination
with disinfection, UF would control
these microorganisms in water. Tests
Microfiltration (MF), as with
ultrafiltration operates in a low
pressure mode, and is effective in
removal of particulates. Due to
typical MF membrane pore sizes and
size exclusion capability (0.1 to 0.2
micron, macromolecular/
microparticle range), it is effective
for absolute removal of Giardia cysts
and partial removal of bacteria and
viruses. When used in combination
with disinfection, MF would control
these microorganisms in water. Tests
have also determined that filtrate
turbidity may be kept low, typically
at or below 0.1 NTU.
Table 7.3 shows various filtration technologies and the degree to which they are
able to remove microbiological pathogens. The effectiveness of these processes
on pathogen removal depends on water characteristics and operational
conditions.
Table 7.3
Unit Processes and Their Ability for Removal of
Pathogenic Microorganisms
Microorganism Reduction (log)
Process
Giardia
Viruses
Direct filtration /In-line filtration
1.5 to 4.0
1.0 to 2.0
Conventional filtration
2.0 to 6.0
1.0 to 3.0
Slow sand filtration
>3.0
1.0 to 3.0
Membrane filtration
>6.0
>2.0
7.6.3
Disinfection Technologies
Disinfection is an integral part of water treatment because it inactivates
pathogens that are not physically removed by filtration.
The degree of
inactivation required is dependent on CT. CT refers to the product of the
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residual disinfectant concentration in mg/L, “C,” and the disinfectant contact
time in minutes, “T.” “T” is the effective disinfection contact time, which is
actually “T10” – time for 10% of the water to pass through the point where “C”
is measured. There is a relationship between CT values and inactivation rates
(or log inactivation) for a given disinfectant. Since the determination of log
inactivation of a microbiological contaminant is more technically demanding
than the calculation of CT, CT is used as a surrogate for log inactivation for a
given disinfectant under specific water quality conditions (e.g., temperature,
pH).
DISINFECTION TECHNOLOGIES
Chlorine
Chlorine has several forms and is the
most widely used disinfectant in
public water supplies. Hypochlorites
are available in solid (tablet or
granule), liquid (solution pump-fed)
or gaseous forms. The use of
gaseous chlorination at small water
supplies may not be among the best
disinfection options due to the
hazardous nature of the material.
Use of gaseous chlorine places
greater demand on the need for
isolated plant space, trained and
attentive operating staff and
protection from any hazards.
Use of hypochlorite solutions also
warrants some precautions. With
time, the disinfectant strength of the
solution decreases and toxic chlorate
levels in solution can increase.
Awareness regarding the potential
for producing elevated levels of
halogenated disinfection by-products
(e.g., trihalomethanes, inorganic
byproducts, and others) is also
essential.
Chloramines
Chloramines, while possessing
certain advantages over other
disinfectants (e.g., long residual
effects and low production of
disinfection by-products), are not
widely used due to high costs and
the complexity in operation.
Compared to free chlorine and
ozone, chloramines possess less
potency as a germicidal agent, and
would therefore require longer CTs.
Chloramine disinfection requires
careful monitoring of the ratio of
added chlorine to ammonia. Failure
to do so can result in odor and taste
problems or biological instability of
water in the distribution system.
Excess ammonia (i.e., low
chlorine:ammonia) can promote
growth of nitrifying bacteria, which
convert ammonia to nitrites and
nitrates. The dose of ammonia
should be tempered by any natural
ammonia occurring in the source
water.
Chlorine Dioxide
Chlorine dioxide, although a
powerful oxidant, may be more
difficult to handle than other forms
of chlorine. Chlorine dioxide
requires trained staff to manage its
use and is so reactive that it may not
provide a residual disinfectant in the
distribution system.
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Chlorine dioxide may be used for
either taste and odour control or as a
pre-disinfectant. Total residual
oxidants (including chlorine dioxide
and chlorite, but excluding chlorate)
may not exceed 0.30 mg/L during
normal operation or 0.50 mg/L
(including chlorine dioxide, chlorite
and chlorate) during periods of
extreme variations in the source
water supply.
Chlorine dioxide provides good
Giardia and virus protection but its
use is limited by the restriction on
the maximum residual of 0.5 mg/L
ClO2/chlorite/chlorate allowed in
finished water.
Where chlorine dioxide is approved
for use as an oxidant, the preferred
method of generation is to entrain
chlorine gas into a packed reaction
chamber with a 25% aqueous
solution of sodium chlorite
(NaClO2).
Dry sodium chlorite is explosive and
can cause fires in feed equipment if
leaking solutions or spills are allowed
to dry out.
Ozone
Ozone is a powerful oxidant with a
high disinfectant capacity. Ozone is
very effective in inactivating cysts,
bacteria and viruses. Inactivation of
4-log to 6-log reduction can be
achieved within very short contact
periods. Design of ozone as a
primary treatment should be based
on simple criteria including ozone
contact concentrations, competing
ozone demands, and a minimum
contact time to meet the required
cyst and viral inactivation
requirements.
Ozonation technology requires
careful monitoring for ozone leaks
which pose a hazard. Use of
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ozonation may also increase
biodegradable organics in water
which may affect distributed water
quality. Additional treatment, such as
granulated activated carbon
filtration, may be used as necessary
to mitigate the problem. Also,
where bromides are present in
source water there is an increased
potential for the formation of
disinfection by-products (i.e.,
brominated organics and bromate)
which should be minimized.
Secondary disinfection with chlorine
or chloramines may help in this
regard by balancing treatment needs
with the need for also protecting
distributed water quality.
UV Radiation
Ultraviolet (UV) radiation is an
effective disinfectant in treating
relatively clean source waters. UV is
a useful disinfection technology
option given its simplicity of
installation, ease of operation and
maintenance, and low costs relative
to chemical disinfection.
UV radiation as a germicidal agent is
effectively applied at a wavelength of
253.7 nanometers through the
application of low or medium
pressure mercury lamps. UV dose is
expressed in units of millijoule per
square centimeter (mJ/cm2), the
product of the intensity (I) of the
UV lamp (mW/cm2) and time (T) of
exposure (sec). UV treatment of
water is therefore comparable to the
CT as described above for chemical
disinfection, since UV dose is
expressed in terms of the IT values.
At a germicidal fluence of 40
mJ/cm2, UV has been effective in
inactivating Giardia to achieve 3-log
reduction, Cryptosporidium and
Bacillus subtilis at 4.5-log reduction,
and MS2 coliphage at about 2-log
reduction.
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Natural organics, iron, calcium
hardness, suspended solids, and
other factors can reduce UV
transmission and cause lamp fouling,
thus decreasing the effectiveness of
disinfection. In addition to pretreatment and automatic cleaning
systems to remove dissolved and/or
suspended materials, which foul the
lamps and impede UV performance,
a secondary disinfectant is necessary
to provide residual protection in
distribution systems. UV intensity
sensor readings, flow through the
reactors, and temperature and lamp
status should be monitored
continuously to determine the daily
average and minimum UV dose per
reactor. Remote alarms, automatic
cleaning of UV components, and
annual UV sensor maintenance are
also important design components
to prevent deposition or scaling and
to minimize on-site operator
attention.
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A full-scale equipment validation is
paramount. It is extremely
important for all UV units to have
undergone manufacturer
performance testing to verify the
unit’s capability with respect to
inactivation of the target organisms.
The validation protocol should be
in accordance with one of:
•
German Association on Gas
and Water protocol
(DVGW Technical Standard
W294, UV Systems for
Disinfection in Drinking
Water Supplies –
Requirements and Testing)
•
Austrian protocol
(ONORM M 5873-1);
•
NWRI/AWWA document
titled Ultraviolet
Disinfection: Guidelines for
Drinking Water and Water
Reuse
•
Proposed USEPA UV
Guidance Manual for
Drinking Water.
The effectiveness of the various alternative disinfection technologies on various
pathogens is shown in Table 7.4. The effectiveness may vary according to
water temperature and the concentration of disinfectant.
Table 7.4
Effectiveness of Alternative Disinfectants on Different
Pathogens
Disinfectant
E. Coli
Micro organism E-coli and Inactivation Ability
Giardia
Cryptosporidium
Viruses
Chlorine
Very effective
Effective
Not effective
Very effective
Ozone
Very effective
Very effective
Very effective
Very effective
Effective
Not effective
Not effective
Not effective
Chlorine dioxide
Very effective
Very effective
Effective
Very effective
Ultraviolet radiation
Very effective
Very effective
Very effective
Effective
Chloramines
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7.7
Water Distribution System
7.7.1
Design and Layout
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It is important for the water distribution system to be designed to sustain the
minimum operating pressure at the maximum hourly flows.
Distribution
systems should also be designed to eliminate dead-end sections. In cases where
dead-end mains are unavoidable, measures should be taken to prevent
stagnation. Where pipe performance standards exist, all materials that are used
in the construction of the transmission and distribution systems should meet or
exceed provincial/territorial requirements or AWWA, NSF or CSA standards.
7.7.2
Secondary Disinfection
To minimize the effects of accidental contamination within the distribution
system and to prevent the re-growth of microbiological contaminants, a
disinfection residual is required throughout the distribution system. Chlorine or
chloramines are common secondary disinfectants due to the ability of these
agents to provide a long-lasting residual.
7.7.3
Fire Flows and Hydrants
The provision of fire protection is solely the decision of the local authority.
Where hydrants are provided, the leads should be valved for easy maintenance.
Where groundwater levels are above the hydrant drain port, the drains should
be plugged and the barrels pumped dry for winter conditions.
For details regarding fire protection requirements in municipal waterworks
system design, the designer should refer to provincial/territorial requirements or
the most current Fire Underwriters Survey publication entitled Water Supply
for Public Fire Protection - A Guide to Recommended Practice.
7.7.4
Frost protection
To prevent freezing and damage due to frost, it is important for pipes to have a
minimum cover above the crown of the pipe. The depth of frost penetration for
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the location may be calculated using the coldest three years during the past 30
years, or, where this period of record is not available, the coldest year during
the past 10 years with an appropriate safety factor.
7.7.5
Cross-connection Controls
In order to avoid a physical connection between a watermain and a sanitary or
storm sewer, which may allow the passage of wastewater into the potable water
supply, cross-connection controls are necessary. They will work to prevent
contaminants from entering the water distribution system.
For information on backflow prevention devices, see Appendix G
7.7.6
Horizontal Separation of Watermains and Sewers
It is important to maintain a horizontal separation between a watermain and a
storm or a sanitary sewer to avoid any contamination.
Most jurisdictions
maintain at least 2.5 meters. Unusual conditions including excessive rock,
dewatering problems, or congestion with other utilities may prevent the normal
required horizontal separation of 2.5 m. Under these condition(s), a lesser
separation distance may be allowed, provided that the crown of the sewer pipe
is at least 0.5 m below the watermain invert. Where extreme conditions prevent
maintaining the required vertical and horizontal separation, the sewer may be
constructed of pipe and joint materials which are equivalent to watermain
standards.
7.7.7
Backflow Prevention and Control
Backflow preventers are to be installed at any location where a connection is
made to a distribution system located outside the service boundary of the
approved waterworks system. Backflow preventers need to be installed in
accordance with the latest edition of the Cross Connection Control Manual,
published by AWWA (Western Canada).
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7.7.8
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Pumping
In general, the requirements for treated water pumping station are similar to
those outlined in for source water pumping.
The distribution system by pumping should be designed with at least two
pumps. With one pump out of service, the remaining pumps should be able to
deliver the maximum hourly design flow at the design operating pressure.
In order to supply water economically during low demand periods, at least one
pump should be provided with a variable speed motor or an appropriately sized,
small pump may be installed.
Standby power or an auxiliary gas powered pump should be provided to supply
water during power outages or other emergencies. Fuel should be stored above
ground and outside the water treatment plant building.
7.7.9
Potable Water Storage
The total water storage requirements for a given water supply system where the
treatment plant is only capable of satisfying the maximum daily design flow
may be calculated using the following empirical formula:
S = (A + B + C) + D
where S =
Total storage requirement, m3
A=
Fire storage, m3
B=
Equalization storage (approximately 25% of projected
maximum daily design flow), m3
C=
Emergency storage (minimum of 15% of projected
average daily design flow), m3
D=
Disinfection contact time (T10) storage to meet the CT
requirements, m3
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The level of storage may be further reduced if the water treatment plant is
capable of supplying more than the maximum daily design flow or if there is
sufficient flow data to support a lower peaking factor than would be normally
used for the given population range.
It is important for the designer to recognize that the given formula for
calculating treated water storage requirements needs to be supplemented with
the storage required for the operation of the water treatment facility, i.e. filter
backwash and domestic use.
7.7.10 Disinfection of Mains and Reservoirs
It is extremely important for all new or repaired watermains to be disinfected.
Disinfection may be done in accordance with the American Water Works
Association (AWWA) Standard for Disinfecting Water Mains.
New lines
should be thoroughly flushed and chlorinated. In repairing breaks, care needs
to be taken to exclude dirt and ditch water. The section should be thoroughly
flushed and disinfected. Following disinfection of all new watermains, it is
important to assess the bacteriological quality of the water and to demonstrate
that it is of acceptable quality before putting the mains in service.
It is also important to disinfect and flush treated water storage reservoirs, in
accordance with the AWWA Standard, before putting them into service.
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8. Total Quality Management
This section deals with the on-going operation and maintenance of the drinking
water system, from source to tap.
Remember that regulatory requirements vary across the country. Owners and
operators are strongly encouraged to first understand and meet the regulatory
requirements of their particular jurisdiction before considering the guidance
laid out in this document.
Once the components of the drinking water system are in place, from source to
tap, they must be managed and operated effectively and consistently in order to
provide a reliable supply of clean and safe drinking water. Internal activities
such as daily, weekly, and monthly systems checks, full-cost accounting,
appropriate operator training, emergency response planning, and a corrective
actions program are all part of routine operational procedures. It is also
important to hire appropriately skilled individuals and ensure they receive
training to keep up-to-date. For their part, staff need to be aware of the
requirements related to their work and exercise due diligence when carrying out
their duties.
The information in this section looks at ways drinking water system owners and
operators can ensure they are managing and operating their drinking water
systems from source to tap as effectively as possible. Verification procedures
include monitoring, record-keeping, reporting, evaluation processes such as
auditing, and reviews and corrections of deviations.
One tool for ensuring the multiple barriers in the drinking water system are
functioning effectively is to follow the Hazard Analysis and Critical Control
Points (HACCP) approach. HACCP was originally developed by NASA and
the Pillsbury Company for ensuring the safety of food used by astronauts, and
is now the universally-accepted strategy for ensuring food safety.
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When applied to drinking water, HACCP is an operational tool that requires
programs to analyse their systems from source to tap to identify critical points
where contaminants could enter the drinking water supply. Barriers are then
implemented to block or control these contaminants. The principles of the
approach are outlined in the box below.
HAZARD ANALYSIS
AND
CRITICAL CONTROL POINTS (HACCP)
HACCP is based on seven principles
and five preliminary steps. Before
the HACCP principles can be put in
place, five preliminary steps must be
taken. The first step is to create a
multi-disciplinary team to analyze
the drinking water system from
source to tap. The team will be
responsible for identifying existing
and potential hazards in the system
and conducting the hazard analysis.
The second step is to describe the
water system including the source
water, water treatment processes,
water storage and distribution
systems, and any special
considerations that need to be taken
into account in order to keep
drinking water clean, safe and
reliable. The third step is to identify
the intended uses of the water and
what information consumers may
need, especially during times when
the water may not be safe to drink
(e.g. during a boil water advisory) or
when certain people may need to
take extra precautions (e.g. the elderly
or immuno-compromised). The
fourth step is to create a flow
diagram which shows all the steps
used in the operation of the drinking
water system, starting from the point
at which a utility's responsibility
starts and ending where its direct
responsibility ends. The fifth and
final step is to verify that the flow
diagram is accurate and covers all
pertinent information.
Once these five steps have been
carried out, the seven HACCP
principles can be followed. These
principles are:
1. Conducting a hazard
analysis to identify hazards
that must be prevented,
eliminated or reduced to
produce safe drinking water.
2. Determining Critical
Control Points (CCPs) to
figure out where controls
can be applied in the system
to eliminate or reduce each
hazard to an acceptable
level.
3. Establishing critical
limit(s) for each CCP to
determine the absolute cutoff points to ensure water
safety is maintained.
4. Establishing a system to
monitor each CCP to
make sure the critical limits
are not exceeded.
5. Establishing the
corrective action to be
taken when monitoring
indicates a particular CCP
is not under control.
6. Establishing procedures
for verification to confirm
that the HACCP system is
working effectively.
7. Establishing
documentation
concerning all procedures
and records appropriate
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to these principles and
their application.
For more information on applying
HACCP to drinking water systems, see
TO
SAFE DRINKING WATER
the American Water Works Association's
2002 workshop manual, "The How,
Where, and Why of Applying HACCP to
Water."
Figure 8.1 shows the steps involved in determining Critical Control Points.
Figure 8.1
Flow Chart for Determining Critical Control Points
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8.1
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Monitoring, Record-keeping and Reporting
As discussed throughout this document, it is important for drinking water
systems to be managed and operated in a holistic manner from source to tap, in
order to ensure drinking water is kept clean, safe and reliable over the long
term. It is important for watershed/aquifer management to follow the
Watershed/Aquifer Management Plan as developed in Section 6 (and further
discussed in Section 8). Drinking water treatment plants and distribution
systems should be operated to meet the minimum performance expectations
outlined in design manuals for treatment and distribution system components.
Additionally, the treated water must, at a minimum, meet all drinking water
quality standards as specified in applicable provincial or territorial regulations.
Additionally, system operators should strive to meet or do better than national,
provincial or territorial guidelines and objectives including the Guidelines for
Canadian Drinking Water Quality.
In order to demonstrate the above and to assist owners and operators in
managing and operating their drinking water systems, accurate records need to
be kept.
Tidy plans and record forms promote a sense of workmanship,
operator pride, and make routine and emergency tasks easier.
Routine reporting, typically part of the operating approval, to regulatory
agencies or preparedness for an audit is significantly easier with an accurate
record keeping system. Additionally, ease of report/auditing helps assure a
regulator that the owner and/or operator is capable of consistently producing
safe drinking water.
8.1.1
Source Water Monitoring
Source water quality monitoring is an important component of the multi-barrier
approach and drinking water quality management. Knowledge of source water
quality and the assessed risks to public health help determine the need for
source water protection efforts and the level of treatment required. Consistent
and attentive monitoring practices provide valuable assessment data to staff.
Monitoring provides key information for:
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•
Understanding and confirming threats and hazards
•
Conducting assessments and determining the vulnerability of
source waters
•
Targeting source water protection and management strategies
towards issues of concern
•
Creating tools for promoting public awareness and community
involvement (e.g. water quality indexes, status and trend
reports)
Although monitoring can be costly and time consuming, its contribution to
source water protection measures is invaluable. It is important for monitoring
programs to be as comprehensive as possible. With specific water quality
objectives in mind, all or some of the following elements should be included
when considering monitoring approaches:
•
Early warning or detection using a few core parameters as
rapid detection indicators
•
Systematic screening or periodic surveillance of targeted
contaminants or activities (e.g. agricultural practices)
•
Routine, long-term monitoring of characterized source waters
and groundwater recharge zones
Once a monitoring program is in place, it is important to have an up-to-date
inventory of known contaminants in the watershed/aquifer which have the
potential to impact source waters. A contaminant inventory serves as a list of
parameters that require periodic screening (see Appendix C). All source waters
should be monitored for a baseline set of parameters, including bacteriological
contamination, turbidity, natural organic matter and some chemical
contaminants.
The
prevailing
land-use
and
natural
features
of
the
watershed/aquifer should be kept in mind. It is important for water quality
monitoring programs to be maintained over the long-term since contaminant
levels respond to changes in land-use and watershed/aquifer management
activities. Many provincial governments and local authorities have already
implemented on-going water quality monitoring programs of surface water
sources and should be consulted during this assessment. Monitoring of sub-
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watersheds (e.g. creeks, stormwater drains) and other protective activities may
help determine the sources of contaminants. As a best practice, it is important
to co-ordinate with other programs that collect monitoring data.
8.1.2
Treatment System and Compliance Monitoring
Reasonable monitoring requirements for water systems verify that treatment
and operational processes are effective in providing safe drinking water.
Monitoring is normally required for operational compliance established by
regulatory agency and follow-up or incident purposes.
Compliance monitoring differs from operational or performance monitoring in
that it is the minimum required by regulation or the operating authorization and
is a legal requirement. Operational or performance monitoring goes beyond
what is legally required and involves more in-depth and more frequent checks
on the conditions that could affect the treatment, such as water alkalinity, pH,
and temperature. It demonstrates how well the various stages of the multibarrier system are working. Performance monitoring can serve as an early
warning system whereby process changes can be implemented before treated
water quality compliance is compromised.
Water system owners and operators are ultimately responsible for complying
with
the
monitoring
programs
established
within
their
jurisdiction.
Compulsory monitoring requirements are included in drinking water programs
because the ramifications to public health as the result of a failure within the
water supply system are too great to rely solely on any one person or on
monitoring results obtained after the water has reached the consumer. Each
member of the drinking water program needs to actively participate by being
aware of all the compliance monitoring requirements, ensuring that the
requirements are being undertaken, and evaluating and responding to reported
results.
If not already in place, it is important for the provincial or territorial
government to establish compliance monitoring programs within their
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jurisdictions to provide checks on, and directions to, the water owner and/or
operators. The government drinking water specialists might detect a situation
that was not recognized by the water supplier and can provide emergency
assistance when necessary. Public health officials and the officials responsible
for the drinking water management program need to establish what monitoring
is essential to ensure that the drinking water provided is safe. Although such a
program needs to include monitoring the finished product for health protection,
this monitoring is reactive and describes an existing health exposure.
As
discussed previously, rapid and (ideally) continuous process monitoring is
essential to producing safe water.
Compliance monitoring normally includes in-plant daily monitoring of the
disinfection process.
In-plant compliance monitoring should also include
monitoring of the treatment process against the established performance
standards. It is important to focus attention on significant changes to water
quality parameters. For example, where a source water has a significant risk of
protozoan contamination and the treatment employed includes coagulation,
flocculation, sedimentation, filtration, and disinfection, the monitoring
requirement should include raw water turbidity, settled water turbidity,
continuous turbidity monitoring of each filter, as well as, disinfectant contact
(flow and concentration), pH, and temperature. Mandatory monitoring of these
process conditions emphasizes the preventative priority of these processes,
maintains a record of conditions that indicate adequate treatment, and
establishes a routine that prevents a pathogen from passing through the plant.
Many provinces and territories have disinfectant monitoring programs which
require samples to be taken at a minimum number of approved residual
measurement locations. Compliance with a program is, however, a minimum
required level of effort which owners and/or operators may need to exceed for
their own operational purposes. It is advantageous for a owner and/or operator
to continuously monitor disinfectant residual, particularly at the point where
finished water is leaving the treatment plant.
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A chlorine residual should be maintained in the distribution system at all times.
To confirm that adequate residual disinfectant is present throughout the
distribution system, measurements should be taken (and properly recorded) on
a daily basis. Representative sampling locations include sites throughout the
different pressure zones (if present), exit points from water storage, areas near
to water main size changes, and at the far ends of the distribution system.
It is important for the operator to review the past routine measurements prior to
his or her daily rounds in order to recognize a sudden change in, or absence of,
the residual. Such a change should alert the operator to the possibility of a
potential problem. He or she may need to take immediate action such as
retaking the measurement, checking the equipment, and searching for the cause
of contamination that is exerting the strong chlorine demand.
Disinfectant monitoring should also accompany routine tests, and any re-tests,
for coliform bacteria. Sites returning sporadic residual measurements, low
sporadic coliform values, and taste-odour complaints should be sampled for
heterotrophic plate counts. This action should be coupled with an investigation
of the surrounding building for cross-connections. Consistently low residuals,
in spite of flushing and residual boosting, may indicate the age or condition of
the water main materials.
It is important for owners and operators to meet the various compliance
monitoring requirements set by regulators. Minimum monitoring standards
reflect the needs associated with hazards posed by local conditions. Various
methods may be used to ensure test results are accurate and reported properly.
Compliance monitoring requirements typically deal with source water, in-plant
treatment performance, finished water, and water within the distribution
system.
8.1.3
Record Keeping
Records are needed for many reasons. In general, they promote the efficient
operation of the water system. Records can remind the operator when routine
operation or maintenance is necessary and help ensure that schedules will be
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maintained and required operation or maintenance will not be overlooked or
forgotten. Records can be used to determine the financial health of the utility,
provide the basic data on the system's property, operator training and
employment files, and help in the preparation of monthly and annual reports.
Accurate and comprehensive records are key to an effective maintenance
program. The onus rests on the water system owner to maintain extensive
records as the regulatory agency normally acquires only a baseline amount of
information. Typically, regulatory agencies only require owners to submit
periodic water quality and operational records.
Another reason for keeping accurate and complete records of system operations
relates to the utility's legal liability. Such records are required as evidence of
what actually occurred in the system. Good records can help when threatened
with litigation.
complaints.
Records also assist in answering consumer questions or
It is very important for care to be taken where samples are
recovered from private property to ensure a suitable degree of data privacy. In
particular, it is important to keep personal data, including information that
would identify the household, private. Finally, clear, concise records are
required to effectively meet future planning needs.
Records may be tailored to meet the demands of the particular system; it is only
necessary to keep records that are known to be useful. It is important for
operators to determine what type of information will be of value for their
system and then prepare maps, forms, or other types of records on which the
needed information can be easily recorded and clearly shown. Records should
be prepared as if they will be kept indefinitely.
It is good practice for all records to bear the signature of the operator in charge
of the water system. It is important for system owners to keep these records
available for inspection.
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The following are examples of the types of records that should be kept:
•
Source/system assessment
•
Bacteriological and turbidity analysis results
•
Chemical analysis results
•
Records of daily source meter readings
•
Other records of operation and analyses may be required by the
regulators
•
Laboratory reports including any summary tables
•
Records of action taken by the system to correct events or
violations of drinking water guidelines
•
Copies of Engineer's reports, project reports, construction
documents and related drawings, inspection reports and
approvals
•
Results of sanitary survey (if applicable)
•
Where applicable, daily records including:
o
temperature at each residual concentration sampling
point
o
pH if using chlorine
o
peak flow
o
filled capacity/depth of clear water tank
o
disinfectant contact time T, and corresponding
concentration C
o
inactivation ratio
o
Residual
disinfectant
concentration
entering
the
distribution system, and at representative points within
the distribution system.
•
Water treatment plant performance including but not limited
to:
o
type of chemicals used and quantity
o
amount of water treated
o
results of analyses
o
turbidity
o
Control point meter readings
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Other information as specified by the regulatory
agency
•
Additional information such as:
o
consumer complaints
o
water main flushing and cleaning
o
cross-connection control
o
unusual events (e.g., extreme weather)
Common records identified above may be requested by regulators at any time.
8.1.4
Reporting
Regular reporting and feedback mechanisms are key operational and
management practices. It is important for operations staff to be
given the right tools to communicate information to management
and, when appropriate, to the public.
The degree of reporting for drinking water systems required by the
various regulatory agencies varies substantially across Canada.
Generally speaking, traditional reporting falls into two principle
categories:
•
Routine
water
monitoring
results
to
show
The fact that most water
system infrastructure is
buried and “out of sight-out
of mind,” means many water
system purveyors struggle for
funds with more “visible”
projects. Mayor and council
should be regularly appraised
of the operation of the water
system and their
responsibilities and liabilities
and be forewarned of
anticipated major capital
improvements on the
horizon.
operational conditions and/or compliance with requirements
•
Upset or poor treatment performance conditions which (may)
affect public health.
Upset or poor treatment system performance reporting is based on the fact that
diligent operators are the first to discover minor or major system events.
A third consideration is the growing demand for more information to be made
available to the public.
System owners are encouraged to communicate
actively with consumers and exceed the minimum reporting criteria of their
province/territory.
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Routine reporting of water quality results from analytical laboratories has also
evolved over the past decade. There is an increasing onus on laboratories to
simultaneously transmit sample test results to the owner and/or operator and the
regulatory agency(s), the premise being that non-compliant results are more
likely to be acted upon or forced to be acted upon.
Internal communication is also of primary importance.
It is
important for water system owners and/or operators to ensure that
open lines of communication exist among their staff as well as
between operations staff and management. It is also extremely
important for formal communication to exist between the
In small- to medium- sized
Canadian municipalities,
communication between the
mayor, council, administration
and water system operators is
fundamentally important for
the consistent and safe
provision of drinking water.
management of a water system, regulators, and municipal councils.
This
formal communication should be supplemented by regular, informal means of
communication. Frequent and factual communication between decision makers
is paramount to the long term, efficient functioning of a water system.
Operation staff have an obligation to inform decision makers, and decisionmakers have a similar obligation to users to act upon the information with
which they are provided. Any breakdown in reporting can be catastrophic to a
community’s health.
Funding allocations may also be dependant on good, frequent reporting. Prior
to the budgeting process, it is important to have a realistic representation of the
operating costs for the planning period, as well as an accurate inventory of
assets. It is also important to forecast anticipated capital costs so appropriate
funds can be allocated, borrowed, or reserved as needed. Frequent
communication between operations staff, management and accounting
personnel can help explain the requirements as well as providing decisionmakers with details as to the consequences of not appropriating required funds.
Without frequent communication between decision-makers who hold the
financial control (and ultimate responsibility), the water utility can easily be
neglected in terms of funding for operating and capital costs.
In complying with regulations set out by the appropriate regulatory agencies,
operations personnel are required to complete and document a variety of
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inspections and tests. Although compliance tools vary from jurisdiction to
jurisdiction, it is important for specific and precise guidelines for
communicating discrepancies
to be clearly and definitively outlined in
advance. It is also important to follow appropriate auditing procedures to
monitor that required procedures are being followed.
It is very important for monitoring results to be reported directly to the drinking
water authority. These results may also need to be made available to the
public, if requested. It is imperative that a reporting system be in place to
inform the chain of command when test results show drinking water presents a
potential health risk or to explain changes in aesthetic quality. It is particularly
important to have protocols in place prior to embarking on any formal internal
or external communication.
8.2 Laboratory Selection and Sampling Protocol
In order to ensure the accuracy of water quality data, it is
important for drinking water utilities to have appropriate
sampling protocols in place and to use accredited laboratories
for compliance monitoring purposes. For other types of
monitoring (e.g. monitoring done to ensure the treatment plant
is
optimized
or
performing
as
required),
system
owners/operators may use the laboratory of their choice.
The system owner and/or operator is responsible for
collecting the appropriate samples at the correct locations, and
for preserving and transporting the samples according to
standard procedures. Once the samples are received at the
In Canada, the Standards Council
of Canada (SCC) is the focal point
for standardization and conformity
assessment. The SCC, in
cooperation with the Canadian
Association for Environmental
Analytical Laboratories
(SCC/CAEAL), delivers a program
for accrediting environmental
testing laboratories (not
necessarily drinking water
laboratories). SCC/CAEAL define
accreditation as “the formal
recognition of the competence of a
laboratory to carry out specific
tests.” The SCC/CAEAL program
accredits laboratories for individual
parameter analyses.
laboratory, owners/operators no longer have control over the
quality of the results. The correctness of the results is dependent on the quality
of the analysis and data management procedures at the laboratory.
The
laboratory is, therefore, an essential participating partner in the drinking water
program. Laboratory services are to be chosen carefully, considering the lab's
commitment to quality.
Laboratories with acceptable quality control and
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quality assurance programs usually have higher costs associated with
maintaining these standards. It is important for laboratory users to understand
the benefits associated with using quality laboratory services and commit to the
higher costs associated with quality results, especially for legally-required
compliance monitoring tests.
It is important for each jurisdiction to have approval processes in place for
selecting laboratories or quality assurance programs. Laboratories need to use
standardized methods, have quality control programs for their analytical work,
and have quality assurance measures to ensure the data produced by the
laboratory are valid. Laboratories should be accredited to perform the specific
analyses required. Remember that laboratories are not always accredited to do
all types of water analyses. For instance, it is extremely important that
approved microbiological tests be those developed for drinking water;
methodologies for environmental sample analysis are not appropriate in this
situation.
Some university and private laboratories in Canada provide a proficiency
testing service to drinking water laboratories.
accredited for the analysis specified.
The laboratory should be
It is important for the responsible
provincial and territorial governments to require all laboratory analysis
conducted in response to compliance monitoring requirements be carried out by
a laboratory accredited for that parameter and at concentrations present in
drinking water. It is important for these governments to also maintain data
tracking and auditing practices to identify situations where laboratory services
and sampling practices compromise the data quality.
Each jurisdiction has its own sample collection and preservation protocols
and/or specific criteria for sampling. In general, it is important for these
protocols to be based on the latest edition of the “Standard Methods for the
Examination of Water and Wastewater,” published by the American Public
Health Association, American Water Works Association, and the Water
Pollution Control Federation. One exception to this is microscopic particulate
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analysis (MPA) method which relies on a modified version of a USEPA
consensus method.
8.3
TQM for Watersheds and Aquifers
System owners and operators have a clear role to play in implementing the
watershed/aquifer management plan and on the source water protection
committee (see Section 6). Owners and operators are encouraged to verify that
the plan set out by the committee has been implemented, is managed effectively
and that there is progress towards meeting the agreed upon environmental
quality objectives (EQOs). The watershed/aquifer approach is a consensusbased approach among stakeholders that sets priorities and ultimately EQOs for
the watershed/aquifer that focus on water quality for sources of drinking water.
These objectives are performance criteria for source waters.
In many cases, system owners and operators will work closely with government
agencies at the provincial, territorial and municipal level who have a lead role
on the committee. The committee7 will have terms of reference
which includes a mandate and outlines roles and responsibilities
of stakeholders, decision-making and conflict resolution
processes, and other organizational/functional requirements.
System owners and operators will have to work effectively
within this multi-sectoral context to better influence decisionmaking at the watershed/aquifer level.
The watershed/aquifer management plan developed in Section 6
defined the problem and prioritized actions to meet EQOs.
Certain sectors (e.g., municipal waste water, agriculture, mining,
forestry, pulp and paper) may be engaged more than others at
Municipal wastewater TQM
focuses on municipal wastewater
treatment, residential on-site
wastewater treatment, storm
water management, biosolids,
wastewater reuse, legislation,
source control activities
(industrial discharges) emerging
issues, R&D and total quality
service management.
Professional and technical
Associations of the operators
enable this process to take place
and devise Operational Plans,
SOPs, and BMPs closely related
to two international Standards
series: ISO 9000 and ISO 14000.
reducing their contaminant load and may need to re-examine the
TQM within their industry to assess whether they are meeting the discharge
contaminant levels set out in their permits.
Most have adopted or are
developing TQM approaches within their industry that seek a balance between
7
Because a committee structure varies depending on the water body size and location,
the management structure will vary accordingly
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environmental, social and financial interests.
SAFE DRINKING WATER
Municipal waste water is
discussed in the adjacent box as an example of an industry with a discharge to
source waters.
Applying TQM approaches to diffuse or non-point source
pollution such as agriculture is challenging as compared to a point source
discharge.
One option that can assist these managers with TQM is the
development of standards for the industry. These provide goals and targets for
the industry to optimize and improve on their TQM.
For case studies of water management approaches in Canada, see Appendix D.
For information on municipal governments and the protection of source waters,
see Appendix E.
For more information on municipal wastewater treatment and its place in the
multi-barrier approach, see Appendix F.
8.4
Treatment and Distribution System Operational Procedures
It is important for treatment plant and distribution system operators to follow
established procedures for their facilities. They should also be given the
opportunity to modify these procedures as necessary to ensure the water leaving
the plant and moving through the distribution system is of the highest quality
possible. At a minimum, it is very important for the facility to meet the
minimum treatment performance requirements outlined in Section 7, as well as
those mandated by the regulator.
When results of an inspection conducted by a regulatory agency or when
operational data indicate conditions are, or may pose, a risk to public health, it
is important for the owner and/or operator to take immediate corrective actions.
Records should be made of the improvement activities.
As a precaution, it is also important for appropriate backup capabilities to be in
place to protect against failures of the power supply, treatment process(es),
equipment, or structure. Security measures should be adopted to protect the
safety of the water source, water treatment processes, water storage facilities
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and the distribution system. The security measures used should be consistent
with the probability of the occurrence of an unplanned event. In many
jurisdictions, the regulatory agency must be notified of a significant system
malfunction or upset. More information about incident and emergency
response planning is given in Section 8.7
The following components are briefly reviewed to illustrate their importance:
disinfectant monitoring, cross-connection control, watermain flushing program,
valve and hydrant maintenance, line breaks and line commissioning, and leak
detection.
For more information on optimizing water quality in the distribution system,
see the AWWA document entitled, "Guidance Manual for Maintaining
Distribution System Water Quality" and the AWWA manual M14,
"Recommended Practice for Backflow Prevention and Cross-Connection
Control."
8.4.1
Disinfectant Residual
On an operational level, maintaining and monitoring for a disinfectant residual
in a distribution system is advantageous because:
•
Routine residual detection provides a real time operation
parameter
•
The presence of a residual provides protection against
bacteriological regrowth
Water entering a distribution system after treatment is of high quality.
However, water quality can deteriorate since:
•
The water is disinfected not sterilized
•
Plumbing materials are not 100 per cent inert in water
•
Intrusions (cross-connections, line breaks) to the piping occur
•
Most water will precipitate some amount of compounds
(calcium carbonate, iron, etc.) which provides a growth
location for organisms
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Bacteriological regrowth can lead to taste and odour complaints. Without a
residual disinfectant, regrowth provides sites for enhanced corrosion of metal
pipes.
It should be noted that little evidence supports the concept that
pathogenic organisms (should they be present) could become lodged in slime
formed by organisms already established in the water mains.
8.4.2
Cross-Connection Control
The goal of a cross-connection control program is to stop the backflow of any
source of pollution or contamination from entering the drinking water system.
Backflow refers to any unwanted flow of water or substance from any
domestic, industrial, or institutional piping system that enters into the potable
water system. The direction of flow under these conditions is in the reverse
direction from that normally intended.
Backflow may be caused by two specific conditions: a loss or
reduction of pressure in the public water main causing flow
outwards through a cross-connection (called backsiphonage),
or excess pressure generated within a consumer's building
which forces contaminants outwards through the crossconnection (called backpressure).
In a back siphonage
situation, the contaminant is siphoned back into the
distribution system polluting some or all of the consumer's
building system. It is also possible that the contaminated
water could continue to backflow into the public distribution
system. To prevent backflow from occurring at the point of a
"Cross connection means any actual
or potential connection between a
potable water system and any
source of pollution or contamination.
Bypass arrangements, jumper
connections, removable sections,
swivel or change-over devices, or any
other temporary or permanent
connecting arrangements through
which backflow may occur are
considered to be cross connections."
Source: CAN/CSA-B64.10-01/B64.10.1-01,
Manual for the Selection, Installation,
Maintenance, and Field Testing of Backflow
Prevention Devices -- Plumbing Products and
Materials, A National Standard of Canada
2001.
cross-connection, a backflow prevention device should be
installed. However, it is important the backflow prevention device match the
particular hydraulic conditions at that location and is suitable to protect against
the degree of hazard present.
Consumers can be protected in two ways from waterborne illness caused by
backflow through cross-connections: by isolating the hazard at the point of
connection or by providing the appropriate backflow prevention device on the
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service line as it enters the consumer's building. The second option is
fundamentally important for the protection of the public water supply.
Waterworks systems can be protected from contamination due to crossconnection if they are designed and operated in accordance with the National
Plumbing Code and CAN/CSA Standard B64.10.
For a description of the various types of backflow prevention devices, see
Appendix G.
For more information, see:
•
"Manual for the selection, installation, maintenance, and field testing
of backflow prevention devices-Plumbing products and materials: A
National Standard of Canada 2001"
•
"AWWA's Manual M14 Recommended Practice for Backflow
Prevention and Cross-Connection Control and the University of
Southern California Foundation for Cross-Connection Control and
Hydraulic Research (USC-FCCHR) Manual of Cross Connection
Control."
As mentioned in Section 3, the key to establishing a cross-connection control
program is awareness training of the appropriate utility personnel, municipal
administrators, councillors, mayor, then public education and public relations.
Most citizens, including elected officials, do not understand what a crossconnection is or the danger it represents to the public.
The municipality should lead by example and survey its own buildings to
identify existing cross-connection hazards followed by (as a minimum)
appropriate backflow device installation.
Concurrent with the internal
activities, the municipality has to decide how to establish authority (control)
over the threats represented by cross-connections.
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Once the program is underway, the municipality has an obligation to track
devices, notify consumers of required testing, provide maintenance and
inspection services, and enforce non-compliance as required.
8.4.3
Flushing Program
Flushing is done to clean out distribution pipelines by removing any
impurities or sediment that may be present in the pipe, as these may
result in taste, odour, and turbidity problems. Sand, rust, incrustations,
and biological materials cause quality problems and are relatively
common in pipelines.
The frequency of routine flushing can usually be determined by
Flushing should not be
considered as the only
solution to distribution
system water quality
problems. The water utility
should always try to prevent
water quality degradation
through proper design,
operation and treatment.
consumer complaints and the types of material found during the
flushing procedure, though water mains should be flushed before consumers
start complaining about poor water quality. Flushing should be conducted
during periods of low water demand (spring or fall), when the weather is
suitable.
Prior planning and good communications allow the flushing crew to conduct
the flushing operation quickly and without confusion. A significant part of
prior planning requires that the owner and/or operator develop current water
distribution system plans, illustrating locations of all valves, hydrants, and line
sizes.
If flushing does not provide relief from water quality problems or from
problems in maintaining the carrying capacity, mechanical cleaning devices are
often used to clean pipes.
Recommended procedures for flushing and pipe cleaning are set out in
Appendix H.
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8.4.4
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Valve and Hydrant Maintenance
Distribution system shutoff valves are provided primarily to isolate small areas
for emergency maintenance. Operators should know exactly where to go to
shut off any valves at any time in case of a line break or other emergency. A
program of inspection, exercising and maintenance of valves on a regular basis
can help water utilities avoid problems when the need to use a valve arises
since most of these valves suffer from lack of operation rather than from wear.
An important factor in maintaining distribution system valves are the
availability of current and correct maps of the distribution system. Each utility
should verify their maps often so that they are accurate, and keep the map up to
date by immediately recording any changes such as replacements or additions.
Operators responsible for hydrant inspections should be familiar with the
various types of hydrants used in their distribution system. The supplier should
be contacted whenever necessary to obtain descriptive literature, operation and
maintenance instructions, parts manuals or assistance on particular problems.
In general, fire hydrants should be inspected and maintained as required. These
operations are often done in the spring and the fall. However, each hydrant
should also be inspected after each use.
Procedures for inspecting and maintaining valves and hydrants are given in
Appendix I.
Additional information on valve and hydrant maintenance programs can be
found in the manufacturers' product information, AWWA Standards C500,
C502, C600, and AWWA Manuals M17 (Installation, Field Testing and
Maintenance of Fire Hydrants) and M44 (Distribution Valves: Selection,
Installation, Field Testing, and Maintenance)
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Line Breaks and Commissioning
Breaks in water mains can occur at any time. It is extremely important for every
owner and/or operator to have an established, written response plan. A break
may be obvious, such as water spouting from a main as a result of a traffic
accident, an earthquake or a washout. At other times, consumers may complain
of a lack of pressure or no water at all and an underground break will have to be
located. Ideally, before shutting off any valves, all affected consumers should
be notified that they will be out of water for an estimated length of time.
Advance notification allows consumers to make any necessary preparations for
the period of time when water will not be available.
Prior to commissioning, lines should be disinfected, following the proper
protocol as identified in the latest edition of AWWA C650 series standards.
Details on how to locate line breaks and remediate the situation are found in
Appendix J.
For more information, see "Guidance Manual for Maintaining Distribution
System Water Quality" (2002) AWWARF
8.4.6
Leak Detection
Even under the best conditions, all types of metal, concrete, and asbestoscement pipe are subject to some deterioration.
This deterioration may be
revealed as a loss of water carrying capacity, leaks or degradation of water
quality.
Leak detection programs are an effective means for some water utilities to
reduce operating and maintenance costs. If a leak detection crew can reduce
the flow of leaks and produce cost savings greater than the cost of maintaining
the field crew, then the leak detection program is economically justified. Leak
detection programs can also be justified in terms of early detection and repair of
leaks while they are small, before serious failure occurs with resulting
contamination, property damage, crew overtime, delays of other projects and
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similar problems.
TO
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Also, a water shortage may require an effective leak
detection program.
The total amount of leakage is also affected by the type of soil surrounding the
pipes. In coarse soils (sands) the leakage may continue for an extended period
without detection, whereas in finer soils (clays) leaks are detected sooner on the
surface.
The process for detecting leaks is detailed in Appendix K.
For more information, see "Guidance Manual for Maintaining Distribution
System Water Quality" (2002) AWWARF
8.5
Automated Systems
Automated sensors and alarms provide enhanced monitoring capability, in
some systems process control, and notification of alarm situations. Where
feasible, automated systems should be installed, operated and maintained per
the manufacturer's recommended schedule. The degree of automation should be
consistent with facility size, number of staff, and operator ability.
Prior to installing supervisory control and data acquisition (SCADA)
equipment, the following conditions should be in place:
•
A certified operator should be on standby status to respond to
alarm notifications in a timely fashion.
•
A certified operator should complete weekly system checks to
ensure the accuracy of sensing equipment and to perform
routine calibrations per the manufacturer's recommended
schedule.
•
The operations manual should include procedures for
understanding automated control systems including upset
conditions such as power interruptions.
Automated systems are well-suited to continuously monitor disinfection, which
may be the principle treatment process for small water utilities.
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For a list of recommended measurement instruments, alarms and status
indicators, field instruments, and process controls, see Appendix L.
For more information, see "Water Treatment Plant Design 3rd Edition" AWWA
and ASCE (pp576-604): McGraw Hill, 1998
8.6
Facility Classification and Operator Certification
Provinces and territories have their own certification programs for drinking
water treatment and distribution system operators. Typically, these programs
include two components: facility classification and operator certification.
8.6.1
Facility Classification
There are typically four classes of water and wastewater system categories. The
classification of water treatment facilities is based on a range of points while
the classification of water distribution systems is based upon the population
served by the facilities. The purpose of classifying treatment and distribution
systems is to identify and standardize the complexity of the facility such that
appropriately certified people are assigned to its operation and maintenance.
Details on facility classification are given in Appendix M.
8.6.2
Operator Certification
Day-to-day operations of waterworks systems should be supervised by one or
more persons who hold a valid certification for the type and class of facility
concerned. This person(s) should be fully responsible for the operation and
maintenance of the facility. Typically, the approval for each facility should
state their required level of certification. The level of operator certification
should match or exceed the classification of the water treatment/distribution
facilities.
The required operator certification level for a particular treatment facility and
distribution system is defined by the preceding classification system. Once a
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system is classified and the operators have been certified, it is normally the
responsibility of certified operators to know and understand the terms and
conditions in the regulatory agency's operating approval for their facility.
It is important that water system managers have a staffing plan(s) in place so
that certified operator requirements are met during planned absences (e.g.,
vacation), unplanned absences (e.g., illness), or change of staff (e.g.,
retirement).
In cases where no official certification program exists for drinking water
treatment plant operators, operators are encouraged to take it upon themselves
to find appropriate training opportunities.
A more complete description of staffing requirements, the education, and
experience requirements for certified operators is found in Appendix N.
8.6.3
Continuing Education
Changing technology, regulatory requirements, and a general need to remain
current, requires continuing education. As part of this education it is also
recommended that open dialogue be maintained between operators, industry
and regulators. There is a trend towards mandatory professional development
which is common to many professions.
Most Canadian provinces and
territories currently rely on voluntary efforts by utilities and individuals to
maintain their water works education requirements.
8.7
Tamper Policy
The purpose of a tamper policy is to establish who can work on and who has
access to the drinking water system. The reasons for a policy are to ensure
procedures when used and materials in contact with drinking water are properly
disinfected, meet recognized quality of material standards and minimize the
risk of cross contamination.
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Access to the water system is generally for four main requirements:
fighting, flushing, construction, and acquiring bulk water.
fire
For routine
waterworks system operation and maintenance, the tamper policy should
specify the degree of training and experience of personnel working on the
waterworks system in addition to disinfection, materials and additive
specifications.
In the case of bulk water hauling, the policy should be reinforced by penalty
clauses in a by-law. Dedication of a relative few control fire hydrants or a
similar bulk loading site should be viewed as a priority water quality security
measure. The bulk filling station should be classified as a severe hazard and
equipped with the appropriate backflow prevention device.
For more information see CSA Standard B64.10
8.8
Incident and Emergency Response Plans
There are two types of situations which can impact on the system owner's or
operator's ability to provide safe drinking water to consumers. The first is an
event in the source water which is generally out of the control of the owner
and/or operator. The second is an operational interruption for which the owner
or operator has direct responsibility. All owners and operators need to be aware
of these situations and have an incident and emergency response plan in place
to deal with events as they arise.
Incident and emergency response plans ensure the safety of the people who use
the water from the drinking water system and are generally required in order to
meet regulatory requirements. Responding rapidly and correctly to incidents
and emergencies helps prevent unnecessary problems, protects consumers, and
may save money by preventing further complications.
Properly prepared, well-thought out plans outline in specific detail the steps to
take when an incident occurs, including who to call and what information they
will need. In order to be effective, plans need to detail all the potential
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situations which could occur within the drinking water system in question and
then outline specific solutions for each of those problems. The process of
identifying potential problems may also serve to highlight ways in which
emergencies can be avoided.
Common incidents could include line breaks, valve replacements, or extended
electrical power outages. It is important that any work on the wells, standpipe,
and distribution system follow proper disinfection protocol as identified in the
latest edition of AWWA C650 series standards (C651-92, C652-92, C653-97,
C654-87). Other possible incidents could include failure of a pump in one of
the production wells; a highway accident involving fuel or chemical containers
near the well field; one chlorinator failure; or failure of automated pump
controls, switching, and/or recording instruments; the detection of E. coli in the
water supply; large fires involving a business or more than one home; or a
massive line break at the standpipe. Emergencies, particularly those involving
the detection of E. coli in the water distribution system, require notification of
the community using an up-to-date notification list which has the appropriate
contact numbers.
TYPES
OF
EVENTS
WHICH COULD
IMPACT
A
DRINKING WATER
SYSTEM
Experience in Canada indicates water
system infrastructure is subject to a
variety of event or threats. A number
of these are described below.
Mechanical failures
Mechanical failures can include
incidents such as pump breakdowns
and valves jamming. Regular
maintenance helps avoid problems
before they begin, especially if
employees are encouraged to be
proactive about fixing and/or
replacing aging equipment that is not
yet broken but has a higher
likelihood of breaking down. Backup equipment should be on hand.
Environmental
Weather event extremes including
floods, ice storms, hurricanes and
forest fires should be assessed in
terms of their impact on a water
system. These events are normally
short in duration and somewhat
unpredictable and can affect source
water quality, and the infrastructure
which treats, stores and distributes
the drinking water. Protective
measures could include construction
dykes or other barriers around the
well and related treatment facilities.
Vandalism/Civil Disturbance
Sabotage can be subtle and difficult
to predict. Protective measures
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include review to detect where
maximum damage can be
accomplished with minimum effort,
material, and danger for the saboteur
and establishing barriers to prevent
it.
Disgruntled Employee/Recently
Released Employee
A troubled employee requires the
consideration of their immediate
manager and possibly others within
the utility. The possibility of grossnegligence or disruptive action is
problematic for a water owner
and/or operator.
An employee who is to be
transferred or released from the
water utility should be required to:
•
return all keys (metal and/or
credit card style)
•
Turn in any sensitive
materials
•
Return parking permits and
associated passes/privileges
provided as part of the
water utility position
The utility needs to consider rekeying locks and changing electronic
codes for doors. Web-based
computer accounts and SCADA
system access codes should be
changed regularly and definitely
when there is employee turnover.
Passwords should be difficult to
guess and the software should have
virus protection.
Contamination
Regardless of the contaminant type,
effective protective procedures or
facilities could include:
•
Monitoring, detection, and
identification
•
Alternative sources of water
•
Alternative intake structures
at varying reservoir depths
•
System (on-line) storage in
covered tanks
•
Water purification facilities
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•
Developing an
understanding of the type
and character of the
contaminant
One of the most likely sources of
contamination is accidental spills of
gasoline, oil, chemicals, or other
hazardous materials.
The problem of contamination of
reservoirs is best handled using
closed or covered tanks, which make
the intentional addition of
contaminants more difficult.
However, even the best protective
measures need to be backed up by
monitoring equipment and the
capability to isolate contaminated
storage from the water system.
Power Outages
The on-site generation of electricity
requires fuel and the distribution of
power requires transmission
facilities. To prevent or reduce the
effect of power disruption, utilities
can: ensure the availability of standby
generators, provide sufficient on-line
reservoirs and gravity-flow lines to
maintain limited distribution, make
available portable generators. With
on-site generation of electricity, the
utility should have proper design and
containment of any stored fuels,
preferably outside of the immediate
well house, treatment plant, etc.
Communication Disruption
Communication failures fall into two
basic categories: failure of automatic
signal equipment and associated
telemetry, and failure of
communications that link people.
Protective measures for telemetry
might include precoded operations at
pumping stations, elevated
reservoirs, intakes, treatment works,
etc., which would put equipment on
an automatic operating schedule in
the event of signal failure.
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Personnel contact can be best
maintained by using a radio net that
ties in control with remote stations,
maintenance crews, and the homes
of key employees. Use of cell
phones greatly improves
communication with employees
working away from the office site.
8.8.1
TO
SAFE DRINKING WATER
Transportation failure
Transportation failure can be
expected during adverse weather
conditions . Protective measures
include stockpiling basic materials,
such as chemicals, chlorine, and
critical spare parts.
Notification Lists
The purpose of developing and maintaining a current and complete notification
list(s) including names, phone and fax numbers and e-mail addresses is to
minimize the time and effort to notify municipal officials, at risk consumers,
significant water users, and the regulatory agency(s). Depending on the type of
incidents or emergency, all or some of these groups may require immediate
notification.
In the event of a failure of a key component of the water treatment process
(filter, chlorinator, etc.) or detection of E. coli at risk users such as (but not
restricted to) seniors apartments-complexes, nursing homes, hospitals, daycares,
and schools should be advised immediately. Significant water users could
include food processing facilities and restaurants.
The provincial/territorial
water regulatory agency(s) typically have pre-determined criteria for mandatory
notification.
Regardless, the owner and/or operator should ensure current
contact information, perhaps for multiple people to guarantee access. Media
(TV, radio, newspaper) notification can be required in some water works
situations such as advisement of a boil water order. The media can play an
important role to provide occasional reminders to the public in situations where
the boil order continues for an extended period of time.
8.8.2
Equipment Operations
Standard operating procedures for switching to alternative power supplies
and/or maintaining generators (including schematics of electrical systems in
pump houses) should also form part of the emergency response plan. These
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equipment procedures and plans should be kept next to the equipment to which
they refer.
8.8.3
Incident Response: Boil Water Advisories
A boil water advisory is one example of a response to an incident or emergency.
Advisories are usually only issued in cases of confirmed or suspected
microbiological contamination. They are issued to protect public health while
contamination of the water source is being confirmed and/or while the situation
is being remediated.
Restrictions other than boiling the water may be required in the event of the
presence
of
excessive
inorganic,
organic,
or
radiologic
parameters
concentrations, where boiling water is ineffective.
Regardless of the contaminants the owner and/or operator should have a process
in place to determine the cause(s) of the concern, correct the problems, record
the corrective action and to notify their consumers and regulatory agency(s).
Part of the investigative efforts includes recovering water samples. Testing
should be planned in order to obtain more information; it should not be viewed
as a search for acceptable numbers in the absence of corrective actions.
Boil orders may be issued by the owner and/or operator, the community and/or
the local Medical Officer of Health in situations where the water is causing, or
may possibly cause, illness to the consuming public. Most provincial territorial
regulatory agencies have a protocol in place for issuing and rescinding boil
orders. Owners and/or operators should obtain and discuss the protocol with
their regulators. Generally speaking, issuing and rescinding boil orders should
be a well thought-out course of action, particularly in the absence of an
assessment of the system, absence of waterborne illness in the community, or
limited microbiological data (i.e., little or no confirmed presence of E. coli).
During the boil order, consumers will either boil their drinking/food preparation
water or seek an alternative safe supply. Particularly in the case of smaller
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communities, some people resort to using road side springs, shallow dug, or
shallow drilled wells. These type of alternative supplies, without adequate
disinfection and possibly additional treatment, are not considered a safe supply.
Community assistance should be provided during boil orders to elderly people
who live on their own. Generally speaking, it is preferable that the elderly not
be boiling their own water due to an increased risk of scalding. This makes it
necessary for someone else to carry in the heavy containers of bottled or other
alternative supplies of drinking water.
As part of the water owner and/or operator's due diligence involving some water
quality circumstances, issuance of a public statement to localized areas is
warranted. The statement is intended for a situation that has a localized effect,
such as an accident which breaks off a fire hydrant, a water main break, or the
replacement of a portion of a water line. As part of being ready for situations
before they arise, system owners may want to develop standardized procedures
that are available for use at any time.
For more information on emergency planning, see "Emergency Planning for
Water Utilities - Manual of Water Supply Practices M19" AWWA (2001)
For more information on boil water advisories, see “Guidance for Issuing and
Rescinding Boil Water Advisories” (2001) Health Canada
8.9
Drinking Water Program Evaluations and Audits
8.9.1
Source Water Protection Plan Evaluations
On-going evaluation of watershed/aquifer management activities, progress and
impacts is necessary to assess the effectiveness of a watershed/aquifer
protection plan. This evaluation can be conducted through stakeholder focus
groups and open houses and questionnaires aimed at the general public. Most of
the evaluation effort can be managed by the Source Water Protection
committee. Scientific data gathered through monitoring efforts is critical in
evaluating preventative and restorative source water efforts.
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System Vulnerability Assessment
A vulnerability assessment involves a critical review of all parts of a water
system to document potential security weaknesses. This review should include
all possible access points to every part of the water system from source to
consumer service connection.
Secondly, a list should be developed which
identifies what can be improved or implemented to prevent access to that item.
The assessment should include a review of existing policies and emergency
preparedness plans.
The overall vulnerability analysis identifies the potential threats, the probability
of the threat and consequence if the threat occurs. Prioritization of the threat by
frequency of occurrence and magnitude of impact should assist in dedicating
personnel and funds to minimize the issue.
For more information, see CWWA’s CD-Rom publication “Vulnerability
Assessment Template” (June 2003)
8.9.3
Audits
It is recommended that the type of audit described below be conducted every 3
to 5 years to ensure that the quality of the water and service provided by the
water owner and/or operator is maintained. This time period is suggested since
the time and effort needed to conduct a comprehensive audit may make it
impractical for it to be conducted annually. Audits should look at the entire
drinking water system, from source to tap.
Preparation for the Audit
The party chosen to conduct the audit should not only have a broad knowledge
in water system operation, maintenance, treatment, monitoring, public health
concepts and they should have a full grasp of the local regulatory requirements.
They also should have skill sets which are pertinent to the water system which
is to be audited.
An audit can involve three phases, including planning,
conducting, and compiling the final report.
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Planning the Audit
Prior to conducting an audit, there should be a detailed review of the water
system. The review should pay particular attention to past audits and
documentation describing previously identified problems and the solutions.
These should be noted, and action/inaction regarding these problems should be
specifically verified in the field. Other information to review includes: any
general documentation, water system plans, chemical and microbiological
sampling results, operating reports, and engineering studies. This review will
aid in the familiarization with the past history and present conditions, and the
regulator's past interactions with the owner and/or operator.
The initial phase of the audit will comprise reviewing the owner and/or
operator's monitoring records. Records should be reviewed for compliance with
applicable microbiological, inorganic chemical, organic chemical, and
radiological guidelines, and also for compliance with the appropriate
monitoring requirements. The audit should provide an opportunity to review
these records with the owner and/or operator, and to discuss solutions to any
parameter non-compliance.
The audit will also provide an opportunity to
review how and where samples are collected, and how field measurements
(turbidity, chlorine residual, fluoride, etc.) are made.
The pre-audit file review should generate a list of items to check in the field,
and a list of questions about the system. It will also help to plan the format of
the audit and to estimate how much time it may take. The next step is to make
the initial contact with the system management to establish the survey date(s)
and time. Any records, files, or people that will be referenced during the audit
should be mentioned at the outset. Clearly laying out the intent of the audit up
front will greatly help in managing the system, and will ensure that the audit
goes smoothly without a need for repeat trips.
Conducting the Audit
The on-site portion of the audit is most important and will involve interviewing
those in charge of managing the water system as well as operators and other
technical people. The audit should also review all major system components
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from the treatment point to the distribution system.
A standard form is
frequently used to ensure that all major components and aspects of each system
are consistently reviewed.
As the audit progresses, any deficiencies that are observed should be brought to
the attention of the water system personnel, together with a discussion of
suggested corrective measures. It is far better to clarify technical details and
solutions while standing next to the problem. Points to cover include:
•
Is the operator competent in performing the necessary field
testing for operational control?
•
Are any on-site testing facilities and equipment adequate, and
do reagents used have an unexpired shelf life?
•
Are field and other analytical instruments properly and
regularly calibrated?
•
Are records of field test results and water quality compliance
monitoring results being maintained?
•
Conduct any sampling which may be part of the survey.
Also, detailed notes of the findings and conversations should be taken so that
the report of the audit will be an accurate reconstruction of the survey.
Audits can be conducted for the a variety of systems including treatment,
filtration, distribution and administration.
Details on what to expect during the audit process, including the types of
questions an auditor will ask, can be found in Appendix O.
Reporting the Audit
A final report of the audit should be completed as soon as possible to formally
notify the owner and/or operator and/or the regulator of the findings. The report
may be used for future compliance actions and inspections; it should include as
a minimum:
•
The date of the survey
•
Who was present during the survey
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•
The findings of the survey
•
The recommended improvements to identified problems
•
Recommended dates for completion of any improvements.
The utility should be fully aware of the contents of the final report before
receiving it.
More information on the various types of audits is given in Appendix O.
For more information on audits in general, see the USEPA Handbook:
“Optimizing Water Treatment Plant Performance using the composite
correction program”
8.10
Abatement and Enforcement
Abatement and enforcement should be considered totally separate functions
handled by different staff working in the regulatory agency. The separation of
enforcement activities from abatement activities means that abatement staff can
focus on co-operative problem solving and prevention while maintaining a
necessary image of advisors or resource people. Enforcement staff, on the other
hand, should have no link or involvement with facilities on a routine basis so
they can deal with enforcement issues in a more detached and impartial manner.
Abatement activities related to municipal waterworks systems may include:
•
Regular inspections of a plant to examine the general operation
and maintenance of the facility
•
Follow-up letters and meetings with facility operators regarding
any operational performance or reporting problems identified in
the monthly/annual reports
•
Assistance where operational modifications could result in
significant drinking water quality improvements
Response to significant drinking water quality problems that require immediate
resolution.
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Since the continuous proper operation of a waterworks system is an essential
aspect of providing safe drinking water, it is important to build a strong and cooperative link between the regulatory agency and municipalities with respect to
facility operation and maintenance. The above abatement activities forge such a
link. For example, the inspection activities ensure regular and direct contact
between the regulator and the municipality and result in the establishment of
specific operational-related contacts. To be effective, this contact should be
seen as beneficial by the municipality.
The link with facility operators is further strengthened by the provision of direct
in-field assistance on an as-requested or as-needed basis or when a significant
problem or emergency arises. Assessments and evaluations of different water
treatment chemicals and dosages, tracer studies to determine plant hydraulics,
advice on chemical feed equipment and monitoring devices, general system
operational reviews, and advice on maintenance requirements or needs are
examples of specific abatement activities that can be undertaken by the
regulatory agency.
Through a strong abatement program, many operational and performance
problems can be prevented, or at least minimized, to optimize the performance
of waterworks systems. This optimization results in the best possible quality of
drinking water being produced by a facility on a continuous basis. Therefore,
operational- and maintenance-related abatement activities are a necessary
component of any safe drinking water program.
Enforcement activities should also be an integral part of the drinking water
program. If an inspection of a facility or an investigation of an incident reveals
a contravention of the legislation, the regulatory agency may use enforcement
measures, including:
•
Warning letters
•
Tickets
•
Administration penalties
•
Enforcement orders
•
Prosecutions
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The intention of enforcement is to ensure appropriate remedial action and
monitoring requirements are implemented to protect the quality of drinking
water.
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9. Public Awareness and
Involvement
Public awareness and involvement in the drinking water program is extremely
important for achieving the program's goals and objectives and should not be
underestimated. Effective public involvement ensures stakeholders recognize
and understand the drinking water program's policies and activities. It also
enhances the legitimacy of decisions made and ensures the program's goals
reflect public concerns, values and priorities (SERM 1995).
Public participation is important because it:
•
Builds networks among key individuals in a community
•
Identifies community needs and priorities with respect to
drinking water quantity and quality
•
Provides education and information to all residents of a
community
•
Focuses public attention on issues of concern
•
Sets up a framework for community support of protective
action
•
Builds momentum for the program
•
Provides the benefit of input and experience from a broad
cross-section of the community
Public involvement initiatives can be incorporated into all aspects of the
program, including:
•
Source water protection planning
•
The development of new, or expansion of existing, drinking
water sources, including reservoirs
•
The planning and development of infrastructure projects,
especially those that require the approval of elected officials
•
The development of new legislation, guidelines, programs
and/or policies
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In addition, the public should be kept informed of:
•
Major repairs and maintenance of infrastructure, especially if
disruptions to service will occur
•
Water quality testing results that may affect their health
•
Boil water advisories
•
Measures that governments and/or utilities take to improve
service
•
Areas that need to be improved in order to ensure public health
is safeguarded
•
How water is being treated and why, and how water rates are
set
•
Where they can go for more information or to register a
concern
Protecting the quality of drinking water begins with the public. The people who
live in the source water area of a watershed/aquifer have a very important role
to play. The kinds of things they do on a daily basis, as well as the pressures
they exert on the governing bodies, have a direct effect on the quality of
drinking water. The more people understand their role in both protecting and
impacting water quality, and the more they participate in taking action to
safeguard water quality, the better the management of the water resource, and
the better the health of people in the community. Without a comprehensive,
well-planned effort to include the public in development and
implementation of drinking water programs, it is unlikely these
programs will be successful.
Public opinion has become a necessary consideration for managers of
water systems. As drinking water consumers, the public is demanding
greater access, timely reporting, and detailed information regarding
Mismanaged public
relations causes
unnecessary reactionary
management, and also
forces managers to spend
an inordinate amount of
time correcting public
perception, rather than
managing their water
system.
almost all aspects of municipal water systems. In response to this, it is
important for management personnel to create, in advance, a detailed
communications plan as part of their overall operations plan.
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A key to successful public relations is training in customer service and media
relations. Many public relations hurdles can be overcome merely by answering
questions promptly, factually, and courteously.
Public utilities have an
obligation to be transparent in their reporting. Any attempt to be otherwise will
not only result in public relations problems, but may very well result in
regulatory and legal infractions as well.
Communities may find that public information sessions and consultation forums
provide excellent opportunities for communicating the benefits, as well as the
constraints, of a water system to residents and industrial users alike. Prior to
requesting a council allocate funds for capital infrastructure, input from a public
information session may provide the necessary public support for appropriation.
Public information sessions are also a valuable part of the process for
developing new guidelines and regulations.
Community buy-in and
participation prior to regulations taking effect show that questions and concerns
were addressed as part of the decision-making process.
Drinking water programs can involve the public and increase awareness of
drinking water quality issues by:
•
Informing the public about its impact on source water quality
and about available pollution mitigation measures.
•
Informing the public about health risks and by providing
educational materials on issues such as water disinfection,
guidelines, conservation issues, and costs of providing service.
•
Making monitoring results or summaries available and relaying
information about what the authority is doing to address the
risks.
•
Issuing regular reports about drinking water systems, including
improvements and areas that need further attention.
•
Incorporating
public
consultations
into
decision-making
processes that have an effect on public health, such as the
development of new guidelines and regulations.
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It is generally accepted that pro-active community communication, on a regular
basis, can assist in the long term accomplishment of a water system’s goals.
Through on-going, pro-active communications, a community better understands
the system. In being better informed, the community is also better prepared to
accept future capital costs to improve, expand, and eventually replace the
current system.
9.1
Components of Successful Public Awareness and Involvement
Public participation is the process by which all interest groups (stakeholders and
the general public) in a community are provided the opportunity to make their
views known on drinking water issues and protection, and to contribute to
designing initiatives to improve water quality and quantity. It is important to
make an effort to include the full range of community opinion in the discussion
of possible approaches (adapted from US EPA 2002d).
Provinces may have a legislated public consultation process for informing and
discussing important initiatives with the public. For example, in Ontario, the
Environmental Bill of Rights establishes a formal framework for notifying the
public about proposed legislation, policies, regulations and other legal
instruments that could have a significant effect on the environment and then
considering the public's input before the government makes a final decision. In
addition, mandatory public consultation is required of a proponent of a
proposed municipal water undertaking under the Environmental Assessment
Act.
Public participation has many components, all of which should be considered.
These components may include direct involvement of stakeholders in planning
committees, involvement in general public informational meetings through
submission of written and oral comments, and participation in community
events such as art contests and demonstration projects. Additional components
include development and distribution of educational products that target the
public at large, such as fact sheets, posters, radio ads, brochures, and artwork.
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Education and Community Awareness
Educational activities are those that use information and instruction to
encourage awareness, understanding, and more informed decision-making.
These types of activities tend to be one-way, in that the drinking water program
will provide information to the public through resource materials, seminars,
workshops and speakers.
Municipalities have opportunities to provide information and education
campaigns to wide cross-section of their communities. The concept of the
watershed/aquifer is an excellent model for making connections, since
everybody lives in a watershed. This fact can form the basis of messages about
how everyone has an impact on the watershed/aquifer and the health of a water
source.
The watershed/aquifer management concept is also a useful way to encourage to
take ownership of issues and make a positive impact on the environment. For
example, householders make choices about the products they purchase and the
methods of disposal. Linking what goes down the sink to what the downstream
neighbor drinks is a helpful model to increase awareness and change behaviors.
Likewise, the concept of pollution prevention or cleaner production is
particularly helpful in source water management, and may help reduce the level
of disinfection need to ensure safe drinking water. This is part of the old
fashioned concept that it is better to prevent a problem than to clean up
afterwards. This can be part of community education messages, as well as
active programs undertaken by municipalities.
Excellent community education programs have been developed for both general
use and targeted groups such as schools.
It is highly recommended that
municipalities examine these existing programs and check if they can be
adapted and adopted. In some cases, municipalities may be able to use existing
brochures or poster artwork at considerable savings.
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Working with the community and industry through education, and partnerships
with stakeholders, including private landholders, and stakeholder groups, can be
very powerful in changing behaviour over the long term and protecting source
water. For instance, the call for a by-law could come from members of an
industry or association that is concerned that some members are not undertaking
best management practices and have an unfair advantage by being poor
corporate citizens. In these cases, a by-law can be a useful tool for leveling the
playing field and ensuring all industry players get treated equally. If a
municipality does decide to establish a by-law, then it must be prepared to
provide the resources and the time to enforce it.
Public consultations
Consultations are a form of structured dialogue between the government or
utility and the public or other stakeholders. The goal of consultations is to
receive input and achieve a common understanding of an issue or policy in
order to develop acceptable solutions (SERM 1995). It is imperative when
running a consultation process to be open to receiving and considering opinions
that are different than the status quo or a pre-determined outcome. There is little
point holding consultations if a desired outcome has already been selected,
since building trust in the process is key to the success of future consultations.
That said, the government or utility running the consultation process owns the
right to make final decisions. Participants need to be made aware that while the
organisation is committed to listening to all opinions, it will make the final
decision based on its criteria. These criteria should be set out clearly prior to the
start of the process.
Consultations can be done in person through steering committees, advisory
groups, and task groups, or more informally through the solicitation of
comments or feedback on documents provided to interested parties. It should be
noted that while making materials available to stakeholders on-line (i.e. by
posting documents on a website), some stakeholders do not have access to
email and the Internet. Some effort will need to be made to ensure these people
know about the consultation process and have a means to access and respond to
any required documents.
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Public meetings
A general public meeting can be a very effective way to introduce the issues
relating to local drinking water issues, such as existing and potential problems
with contamination of source waters and the impacts that contamination may be
having on public health and the need for enhanced treatment.
Public
participation via meetings is the primary mechanism to involve all stakeholders
and members of the public. It is critical to clearly invite public and stakeholder
comment, emphasize the openness of the process, and assure that all public and
stakeholder input will be given careful consideration.
Effective ways to publicize meetings and to solicit input on plan components
are newspaper and radio announcements, posters, fliers, and word of mouth.
Access to the public participation process is an important element to include
when planning for public input. The lead person or agency needs to consider
how it will reach people and organizations in remote areas of the community, as
well as people with mobility, hearing, or literacy challenges.
Working with neighbouring communities
Coordination within a community, and between communities, can greatly
increase the success of initiatives on source water protection. The boundaries
and extent of water resources, such as a river or ground water aquifer, usually
do not coincide with the borders of a single community or town. Therefore, for
example, the effectiveness of actions taken in one community to protect its
water source may be somewhat limited if similar actions are not taken by other
communities sharing a given water source.
Developing drinking water
management plans that are compatible with, and supportive of, the plans of
other communities sharing the same water source increases the overall
effectiveness of individual community initiatives.
Working with the media
Involving the media during the development of initiatives can assist the process
in a variety of ways. In addition to helping inform stakeholders and the public
and increasing public involvement, the media can play a role in encouraging
community support and communicating the value of source water protection
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and operation and maintenance programs. Visibility in the media can also
communicate the need for financial and technical assistance to government
bodies, national and international NGOs, and lending institutions. Figure 9.1
shows a sample media release.
Figure 9.1
Sample Media Release
12345 Main Street
Any City, ON 1A1 1A1
Phone 123-456-7890
Fax 123-456-7890
Press Release
Contact: [Name]
Phone: (123) 456-7890
FOR IMMEDIATE RELEASE
[Date]
Protect Your Drinking Water… Protect the Source!
[City], [Province]—Have you ever thought about where your drinking water comes from, beyond
the faucet? Did you know that what you do in and around your home can affect not only the
quality of your water but also the quality of your neighbor’s water? Find out where your drinking
water really comes from and learn about how you can help protect it during a [Duration of
campaign]-month-long drinking water source awareness campaign, starting [Start date],
sponsored by [Name of sponsor]. The campaign will provide information on
•
•
•
•
•
The source of your local drinking water
The value of safe drinking water
Potential threats to your local drinking water
Steps you can take to protect your drinking water
Contact information for additional resources on drinking water protection.
Safe drinking water is essential to a community’s quality of life and continued economic growth.
Yet citizens may not always be aware of safe drinking water issues in their community and may
not realize what needs to be done to protect drinking water and keep it safe for their families
and businesses. Drinking water wells across the country are being contaminated daily by
common activities, such as pouring motor oil and household chemicals down drains, using too
much pesticides and fertilizers, and littering streets with refuse that will eventually run off into
rivers and streams. When water supplies are not safe, the health of the community —
especially of the young, the old, and the sick — is jeopardized. In addition, communities may
experience a loss of tax revenues from real estate and new jobs as businesses refuse to locate
to or remain in communities with known or suspected water contamination problems.
[Contact name and phone number]. [Acknowledgment]
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Education of private land-owners
Private land-owners who draw their drinking water from sources on their own
property are generally responsible for ensuring its quality. This responsibility
includes having the water tested and implementing any remedial actions
necessary to improve quality should it become degraded.
Where privately owned septic tanks may impact on public water sources,
municipalities may be wise to ensuring these are being installed and managed
appropriately. Remedial actions can be costly for the municipality in terms of
staff time, and expensive for community members to comply with.
It is,
however, an area where cumulative impacts can cause major degradation
problems.
As a minimum, municipalities can ensure their staff are well trained and able to
evaluate septic system applications and their impacts. In locations where
municipalities are not responsible for septic systems they should work with the
authority to ensure that the safety of drinking water is protected. Likewise,
owners of septic systems should be made aware of their responsibilities to
properly locate and maintain their systems (AMO/MEA/OGRA, 2001).
Abandoned wells are another concern which can impact both private and public
water supplies. While some provinces have established programs that require
wellhead protection, municipalities do not have to wait to protect their
groundwater resources.
Programs to identify and seal abandoned wells can be immediately instigated by
the local authority. Abandoned wells provide an easy route of contamination
into groundwater. This is particularly important when groundwater is the source
of drinking water.
Municipalities can work with the public to highlight the relationships between
wells and groundwater quality, and encourage community members to identify
wells that can be sealed. While formal well protection programs may require
the engagement of a hydro-geologist, considerable advanced work could be
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undertaken through engaging the community. If formal records are not accurate,
requesting community input to identify old and abandoned wells can be a way
of making connections for groundwater and surface water protection.
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Appendix A: Municipal Drinking
Water Policy
Example of a Municipal Drinking Water Quality Policy
” understand
We, “the name of the owner / operator of the drinking water system servicing
that supplying good quality drinking water is essential to the continued growth, prosperity, and well being of our
citizens. We are committed to managing all aspects of our water system effectively to provide safe and aesthetically
appealing water that tastes good and is free from objectionable colour or odour. It is our policy that the drinking water
we provide will meet or exceed the quality provided by the Guidelines for Canadian Drinking Water Quality (or
provincial / territorial drinking water quality guidelines or standards).
To achieve our goals we will:
•
Cooperate with the provincial government to protect our water source from contamination.
•
Ensure the potential risks associated with water quality are identified and assessed.
•
Ensure that our water supply, treatment, storage, and distribution infrastructure is properly designed,
constantly maintained, and regularly evaluated and improved.
•
Include the drinking water quality and quantity priorities, needs, and expectations of our citizens, the
provincial authorities, and our water system employees into our planning.
•
Develop a mechanism to ensure adequate funds are available for the water utility to maintain and improve the
infrastructure, implement best practices, and ensure our water treatment employees are educated about their
responsibilities and adequately trained and certified.
•
Establish regular verification of the quality of drinking water provided to our citizens and monitoring of the
water treatment process that produce the water.
•
Provide community awareness about the water supply and its management by establishing and maintaining
effective reporting of the water quality and timely information about the water system to our citizens.
•
Develop contingency plans and incident response capabilities in cooperation with provincial health authorities.
•
Participate in appropriate research and development activities to ensure continued understanding or drinking
water quality issues and performance.
•
Participate in the drinking water guideline development and review process.
•
Regularly assess our performance and continually improve our practices to produce good quality water.
We will develop a Drinking Water Quality Management System including an implementation plan to achieve these
goals and adequately manage the risks to our drinking water quality.
All of our officials, managers, and employees involved with the supply of drinking water are responsible for
understanding, implementing, maintaining, and continuously improving the Drinking Water Quality Management
System.
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Appendix B: Summary of Canadian
Source Water Protection Measures
British Columbia
The provincial Drinking Water Protection Act was brought into force in May
2003. The Act protects drinking water through increased source and system
protection, monitoring, assessments, infrastructure and certifications. In June
2002, the BC government established the Drinking Water Action Plan to
ensure the delivery of safe drinking water. This plan includes a ‘source to tap’
approach to water protection in BC.
Existing groundwater monitoring measures include a network of 150
observation wells located throughout the province, as well as existing codes of
practice for the testing, construction, maintenance, alteration and closure of
wells. BC supports the use of GIS technology to map watersheds and
groundwater supplies for current and future monitoring purposes.
Alberta
In 1948 Alberta adopted the use of the Green Area project. This policy directed
the management of forested Crown lands in Alberta, an area encompassing
about 52 percent of the province, and focused on a multiple-use management
plan including: watershed protection, timber production, recreation, fish and
wildlife protection, domestic grazing and mineral production. The most
important lands of the Green Area, in terms of watershed protection, were the
eastern slopes of the Rocky Mountains because they are the critical headwaters
of the Prairie Provinces. The Rocky Mountain Forest Reserve was established
in 1964 for the conservation of forests, and to maintain a clean, safe and secure
water supply.
The current Alberta framework for water management planning includes
regulations for drinking water quality standards, and guidelines for surface
water quality. The recent updating of the provincial Water Act addresses many
issues related to the protection and use of Alberta’s water resources. The Water
Act includes water licenses, protection of aquatic environments and deals with
watercourse alterations and bulk water removal guidelines. In addition, the
Environmental Protection and Enhancement Act includes areas of groundwater
in its integrated approach to the protection of air, land and water. The use of
GIS mapping has been implemented to catalogue and monitor groundwater
resources.
Saskatchewan
As a result of the North Battleford inquiry, Saskatchewan has drafted a Water
Management Framework to address measures for the protection of provincial
water resources. This framework emphasizes the protection of water and
wetlands, the management and development of water resources, and the
inclusion of public involvement in decision-making processes. The planned
Saskatchewan Watershed Authority Act will govern the Saskatchewan
Watershed Authority in watershed planning, aquifer protection measures,
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management of surface and groundwater supplies and monitoring. Existing
legislation includes the Environmental Management and Protection Act, which
regulates water pollution control measures, industrial effluent, and reservoir
land use, and the Environmental Assessment Act, which requires proponents of
development projects to receive Ministerial approval before proceeding with a
development.
Saskatchewan's Rural Water Quality Advisory Program provides information
and services to people in rural areas regarding water quality collection and
testing, and surface and groundwater protection. The Prairie Farm
Rehabilitation Association uses its expertise in the biological, geological, and
engineering disciplines to develop secure water supplies, high water quality,
and wastewater infrastructure in the prairies through programs such as the Rural
Water Development Program and the Sustainable Well Water Initiative (PFRA
2001).
Manitoba
The Manitoba Water Quality Standards, Objectives and Guidelines were drafted
in 2001, outlining recommended surface and groundwater criteria for various
levels of legislative protection. Water quality standards are currently under
development. A strategic planning framework for the protection of water
resources in Manitoba includes a groundwater quality initiative for sampling
and monitoring, a drinking water advisory committee, the development of
drainage guidelines and water supply management. The Manitoba government
is also in the process of developing a Nutrient Management Strategy for the
derivation and implementation of nutrient limits in waters. Existing legislation
pertaining to water protection and management in Manitoba include: the
Environment Act, the Groundwater and Water Well Act, the Water Commission
Act, the Water Resources Administration Act and the Water Rights Act.
Ontario
The Ontario government is in the process of implementing recommendations
resulting from the Walkerton inquiry. In April 2003, the Advisory Committee
on Watershed-based Source Protection Planning released its report - Protecting
Ontario’s Drinking Water: Toward a Watershed-based Source Protection
Planning Framework. Its 55 recommendations set out a comprehensive
framework that addresses: roles and responsibilities, the planning process,
resources, timing and legislation. Guidelines for surface and groundwater Water
Quality Objectives are also in place. There is an ongoing process of mapping
surface and groundwater resources with the use of GIS technology.
Groundwater monitoring programs are underway. The Environmental
Protection Act prohibits contaminant discharges into the natural environment.
Development of a Nutrient Management Act is also in progress which includes
regulations for the protection of areas surrounding wellheads.
In Ontario, watershed management is supported by the Provincial Policy
Statement and the Planning Act which supports a coordinated approach to
address issues that cross municipal jurisdictions such as ecosystem and
watershed related issues.
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Quebec
Watershed management policies have been adopted and some regulations have
been established. Groundwater protection has been addressed through the
Regulation Respecting Groundwater Catchment, which is directed at
groundwater resources intended for human consumption. The Regulation
prevents excessive pumping by different users, and minimizes negative impacts
from land use practices within the catchment on water plans and ecosystems.
The Regulation Respecting the Quality of Drinking Water sets guidelines for
the control of water quality monitoring and management. The Regulation
combines a strict monitoring plan with high water quality standards
(bacteriological and physico-chemical), and requires operator certification at
water treatment facilities to ensure high quality drinking water is provided to
consumers.
In 2002, Quebec adopted a new water management policy in order to ensure the
protection of its water resources and manage them sustainably, while protecting
both public health and ecosystems. The province has also adopted a series of
guidelines for water quality criteria of surface waters (MENVQ 2002).
For information on Quebec’s Water Policy, see
http://www.menv.gouv.qc.ca/eau/politique/index-en.htm
Nova Scotia
In October 2002, Nova Scotia released a Drinking Water Strategy which
provides a comprehensive approach to the management of the province's
drinking water. The strategy formally adopted the multi-barrier approach and
forms a strong basis for protecting drinking water supplies. Under the strategy,
source water protection plans are required for all municipal water supplies by
2005. The Environment Act provides for designating Protected Water Areas as
one means of protection, and regulating activities which may impair water
quality. Currently there are 24 designated Protected Water Areas. Several
more designation requests are being processed as part of comprehensive water
supply area management strategies. Municipalities are also able to protect
water supply areas through municipal planning strategies and land use by-laws
under the Municipal Government Act. In addition, the province has adopted a
Statement of Provincial Interest on Drinking Water under the Municipal
Government Act which requires municipalities to identify water supply
watersheds in their municipal planning process and include strategies for their
protection. Well Construction Regulations under the Environment Act are also
in place to protect well water supplies and their surrounding aquifers. A
number of guidance documents are available, including Designing Strategies for
Water Supply Watershed Management in Nova Scotia. A detailed guide to
developing a source water protection plan is currently in preparation.
New Brunswick
The province has adopted a comprehensive program for managing drinking
water supplies from source to tap. In the area of source water protection, several
orders and regulations exist under the provincial Clean Water Act. The
Protected Area Designation Orders for watersheds and wellfields specify land
uses in delineated areas surrounding these resources. At present, 21 watersheds
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and 11 well fields are protected under these measures. The Water Classification
regulation sets some raw water guidelines for all watersheds. Source water and
raw water guidelines include the use of environmental and health-based
standards. In addition, regulations require routine testing of source water
intended for drinking and guidelines for well construction and watercourse
alteration. Inventory and assessment of watersheds, wells and protected areas
use GIS and other databases that integrate environmental, geographic and
licensing information.
Newfoundland and Labrador
The province drafted a report in May 2001 outlining the current state of public
water supplies and provided a framework for protection of public water supplies
taking a multi-barrier approach. Several steps have been taken towards
implementing these measures. In May 2002 the provincial government passed
new legislation: the Water Resources Act and the Environmental Protection
Act. The Water Resources Act addresses water protection and management
largely through licensing procedures but also allows for specific designation of
surface and groundwater supply areas. Water supply areas are monitored and
evaluated through land use inventories, risk assessments and sampling, using
diagnostic tools such as GIS. Approximately 250 water supply sources are
currently protected. Use and activity within and around these areas is limited.
Site-specific management plans have been developed for many watersheds.
The Water Resources Act allocates the designation of an area encompassing a
source of public water supply as a Protected Water Supply Area. Most
activities that could impair a water body are prohibited. Under the
Municipalities Act cities can regulate some activities in watersheds such as
sewage and sanitation. The Well Drilling Act requires that licensed operators
drill all wells; ensuring proper wellhead protection measures are followed
(Government of Newfoundland and Labrador 2001).
Prince Edward Island
Prince Edward Island relies exclusively on groundwater sources for drinking
water. A drinking water strategy has been developed using a multi-barrier
approach to safeguard the water supplies on the island. PEI has existing
guidelines for the use of surface and groundwater supplies for agricultural
irrigation purposes. A permitting process is employed for groundwater
extraction and watercourse alteration. The Environmental Protection Act
provides regulations on the construction, use and maintenance of wells, the
discharge of contaminants, and requires the establishment of buffer zones
adjacent to surface water systems. Long term water quality monitoring
continues to be carried out in PEI in conjunction with the federal government
under the Canada-PEI Water Annex to the Federal Provincial Framework
Agreement for Environmental Cooperation in Atlantic Canada. Under this
arrangement water quality is continuously monitored in 5 watersheds
throughout the province. Groundwater levels are monitored continuously at 12
locations throughout PEI.
Territories
Management of water in the Yukon, NWT and Nunavut is currently under
federal jurisdiction through the Department of Indian Affairs and Northern
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Development (DIAND). However, territorial governments are responsible for
providing safe and reliable drinking water. The Northwest Territories Waters
Act and Regulations Act (1992) provides for the conservation and use of water
that benefits the residents of the Northwest Territories (Department of Justice
Canada 2001). The Mackenzie Valley Resource Management Act (1998)
provides for an integrated system of land and water management in the
Mackenzie Valley (Parliament of Canada 1998); this fulfills clauses of the
Gwich'in and Sahtu land claims. It establishes Gwich'in and Sahtu Land and
Water Boards in the Mackenzie Valley and a Mackenzie Valley Land and
Water Board. The Mackenzie Valley includes all of the Northwest Territories,
with the exception of the Inuvialuit Settlement Region and Wood Buffalo
National Park. The NWT Public Health Act makes some provisions for the
assurance of safe drinking water. Other indirect protection of water resources is
provided by federal acts such as the Canadian Environmental Protection Act
and the Fisheries Act.
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Appendix C: Inventory of Potential
Contaminants in Canadian Drinking
Water Sources and their Origins
CATEGORY
CONTAMINANT
REASON FOR CONCERN
TYPICAL SOURCES
Colour
can be an indication of other contaminants
presence of coloured organic chemicals,
metals or other contaminants
Hardness - dissolved
polyvalent metallic
ions
aesthetic concerns
dissolution of metallic ions from minerals
total dissolved solids
indication of the presence of other chemicals and
contaminants
inorganic substances dissolved in water
Turbidity
can be a source of nutrients for waterborne microorganisms and can make disinfection of water
more difficult
suspension of matter in water including,
mineral particles, organic matter, organic
compounds and microscopic organisms
Benzene
Human carcinogen
used to manufacture other organic
chemicals, present in gasoline, main source
is vehicle emissions
Benzo(a)pyrene
classified as probably carcinogenic to humans
formed during the combustion of fossil
fuels and other organic matter
Carbon tetrachloride
liver and kidney damage in humans, classified as
probably carcinogenic to humans
used in the manufacture of other chlorinated
hydrocarbons
Monochloramines
classified as possibly carcinogenic to humans
by-product of chlorination of drinking water
Chlorophenols
certain chlorophenols are classified as “probably
carcinogenic to humans”
used in pesticide products or as wood
preservatives
Dichlorobenzene
classified as “probably carcinogenic to humans”
used in degreasing and paint removal
formulations and deodorants
1,2 – dichloroethane
classified as “probably carcinogenic to humans”
used in the production of vinyl chloride,
used as a solvent, releases into water
sources are from waste effluents and
disposal of wastes
1,1 dichlorethylene
classified as “possibly carcinogenic to humans”
used in food packaging industry,
degradation product of tetrachloroethylene
and 1,1,1 - trichloroethane
Dichloromethane
classified as “possibly carcinogenic to humans”
used as an industrial solvent for paint
stripping, as a degreasing agent and as an
aerosol propellant
Monochlorobenzene
classified as “possibly carcinogenic to humans”
solvent in adhesives
Tetrachloroethylene
classified as “possibly carcinogenic to humans”
used as a solvent in dry cleaning and metal
cleaning
Toluene
effects on the central nervous system
used as solvents, gasoline additives, used in
the manufacture of other chemicals
Physical
Chemical - Organic
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CONTAMINANT
REASON FOR CONCERN
TYPICAL SOURCES
Ethylbenzene
effects on the central nervous system
used as solvents, gasoline additives, used in
the manufacture of other chemicals
Xylene
effects on the central nervous system
used as solvents, gasoline additives, used in
the manufacture of other chemicals
Trichlorethylene
acute exposure has effects on the central nervous
system
used for metal degreasing
Trihalomethanes
one of the trihalomethanes, chloroform has been
classified as “probably carcinogenic to humans”
formed from the chlorination of dissolved
organic matter
vinyl chloride
carcinogenic to humans and animals
used in the manufacture of polyvinyl
chloride, releases are from industrial
discharges
Ammonia
indication of a potential source of nitrates
degradation of nitrogenous organic matter,
industrial and municipal waste discharges
Chloride
high chloride levels result in unpleasant taste
dissolution of natural salt deposits,
dissolution of road salt
Cyanide
highly toxic to humans at high dosages
mining and industrial effluents
Fluoride
ingestion of large amounts results in mottling of
tooth enamel
manufacture of phosphate fertilizers and
bricks, dissolution of natural minerals
containing fluoride
nitrate/nitrite
leads to methaemoglobinaemia in infants
from fertilizers
nitrilotriacetic acid
has been shown to caused tumours in studies in
rats, no adverse effects on humans have been
observed
used in laundry detergents to replace
phosphates
Sulphate
ingestion of large amounts can lead to
gastrointestinal illnesses
dissolution of sulphate containing minerals,
used in chemical, dye and fertilizer
manufacturing, mining, pulp and paper
industry, atmospheric sulphur dioxide
Arsenic
toxic and carcinogenic to humans
used in hide tanning processes, found in
pesticides, additives and pharmaceuticals,
natural sources are the dissolution of arsenic
minerals
Barium
soluble barium salts are acutely toxic
used in industrial application including
electronics, plastics, rubbers, textiles and oil
and gas
Boron
acute boron poisoning can result in nausea,
diarrhoea, vomiting, headaches, skin rashes and
central nervous system effects
used as an insecticide and disinfectant, and
as an anti-oxidant in soldering
Cadmium
ingestion causes vomiting and gastrointestinal
illnesses, chronic ingestion leads to renal disease
and softening of the bones
effluent releases from industrial operations
using cadmium
Chromium
trivalent chromium is non-toxic however it can be
oxidized to hexavalent chromium, studies on
animals have shown toxic effects on the kidneys,
liver and gastrointestinal tract
effluents from industries where chromium is
used in processes (i.e., metal plating)
Copper
adverse health effects at high doses
used in the production of electrical wire,
manufacture of alloys, and in pesticide
formulations
Chemical - Inorganic
Chemical - Metals
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CONTAMINANT
REASON FOR CONCERN
TYPICAL SOURCES
Lead
classified as “possibly carcinogenic to humans”,
has been shown to have effects on the central
nervous system
used in manufacture of lead acid batteries,
pigments, chemicals and solder
Mercury
mercury poisoning results in renal and
neurological disturbances
dental amalgam
Uranium
causes nephritis in humans and animals
dissolution of natural uranium deposits,
release from mill tailings and phosphate
fertilizer
Aldicarb and
metabolites
can cause dizziness, weakness, nausea and
diarrhoea in humans
used as an insecticide on agricultural crops
Aldrin and dieldrin
shown to have effects on the central nervous
system and liver in experimental animals
used as an insecticide on agricultural crops
atrazine and
metabolites
classified as possibly carcinogenic to humans
used as a herbicide for corn and rapeseed
crops
azinphos-methyl
studies on rats and dogs have shown effects on
cholinesterase activity
insecticide used for fruit, forage, vegetable
and grain crops
Bendiocarb
studies of bendiocarb in rats showed effects on
white blood cells, serum cholesterol levels and
brain cholinesterase levels
used as an insecticide in food storage and
handling and in agriculture
Bromoxynil
studies in rodents showed effects of increased
liver and kidney weights, thyroid enlargement and
reduced liver/body weight ratios
used to control broad-leaved weeds in grain
crops
Carbaryl
inhibits cholinesterase activity
insecticide used on fruit, vegetable and
cotton crops
Carbofuran
cholinesterase inhibitor
insecticide and nematocide used on fruit
and vegetable crops
Chlorpyrifos
cholinesterase inhibitor
insecticide use to control mosquitoes, flies,
household pests and aquatic larvae
Cyanazine
studies of the health effects on rats showed
reduces kidney weight and increased liver rates
herbicide used for weed control of corn,
rapeseed and mixed grain crops
Diazinon
cholinesterase inhibitor
insecticide used to control household and
soil insect pests
Dicamba
studies on animals have shown toxic effects on the
liver
herbicide used for weed control on grain
crops and pastures
2,4 –
dichlorophenoxyacetic
acid
classified as “possibly carcinogenic to humans”
herbicide used to control broadleaf weeds
on cereal cropland and on other
noncropland areas (i.e., lawns, pastures,
industrial properties)
Diclofop-methyl
studies on animals have shown toxic effects on the
liver
used to control grasses in grain and
vegetable crops
Dimethoate
cholinesterase inhibitor
insecticide used on fruit, vegetable, field
and forestry crops
Dinoseb
very toxic to humans, has teratogenic and
phototoxic effects
herbicide used to control weeds in cereals,
peas, bean and strawberry crops
Diquat
toxic effects to humans include damage to the
gastrointestinal tract, brain, liver, kidneys and
lungs
desiccant for seed crops
Chemical - Pesticides
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CONTAMINANT
REASON FOR CONCERN
TYPICAL SOURCES
Diuron
toxic effects include weight loss and abnormalities
of the blood, liver and spleen
used to control weeds in non-crop areas
Glyphosphate
studies on rodents have shown liver and kidney
effects
herbicide for non-selective weed control
Malathion
acetylchlorinesterase inhibitor
insecticide used to control mosquitoes and
flies
Methoxychlor
studies on rats showed reduced growth but no
other effects, studies on humans have not shown
any other adverse effects
insecticide used on fruits and vegetables
Metolachlor
some reports of skin allergies, no other adverse
effects identified
herbicide used on corn, bean and soybean
crops
Metribuzin
studies of dogs showed reduction in weight gain
and increase in thyroid, kidney, spleen and liver
weights
weed control on agricultural crops
Paraquat
can case respiratory effects and effects on the
kidneys and nervous system in humans
herbicides used on aquatic weeds, seed crop
and orchids and on
Parathion
cholinesterase inhibitor
insecticides used to control insects on
agricultural crops
Phorate
cholinesterase inhibitor
insecticide used on agricultural crops
Picloram
studies on rats showed effects on the kidneys and
liver
herbicide used on non-crop land, rights-ofway, pastures,
Simazine
no studies have been done on the effects on
humans, studies on dogs showed high levels of
simazine ingestion resulted in lower body weights
herbicide used for weed control on
agricultural crops
Terbufos
acetylcholinesterase inhibition
insecticide used on corn, sugarbeet and
rutabagas crops
Trifluralin
effects on studies of rodents were decreased body
weights, increased liver weights and renal toxicity
herbicide used in cereal, grain and vegetable
crops
Escherichia coli
the O157:H7 strain of E. coli results in
gastrointestinal illness in humans, infection can be
life-threatening to sensitive populations
human and animal wastes
Cryptosporidium
pathogen that infects the small intestine of humans
and other mammals and causes gastrointestinal
illness
wastes from wild and domestic animals
Giardia lamblia
‘beaver fever’ causes gastrointestinal illness,
headaches and fever and can be fatal to those with
compromised immune systems
wastes from wild and domestic animals
Toxoplasma gondii
toxoplasmosis causes flu-like illness, congenital
damage in the fetuses of pregnant women
domestic and wild cat feces
Biological - Bacteria
Biological – Protozoan parasite
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Appendix D: Case Studies of Water
Management Approaches in Canada
Case Study 1: Vancouver, British Columbia
Subject: WATERSHED ASSESSMENT (With GIS Technology)
The Greater Vancouver Regional District (GVRD), a partnership of twenty-one
municipalities and other communities in the Greater Vancouver area, provides
community water supplies its member municipalities. The water supply is
obtained from three watersheds, the Coquitlam, Seymour and Capilano
Watersheds, located to the north of the GVRD area. Watershed management, in
conjunction with water treatment, is an important aspect of drinking water
protection.
In the early 1990’s the GVRD began using GIS technology to map the
characteristics of the three watersheds. GIS data on the topography, surficial
geology, and soils can be obtained from the GVRD website. This data is used to
identify and assess potential threats to water, as well as to forecast water supply
and availability. This assessment will subsequently be used to develop
watershed management plans for the protection of water resources.
For more information on the Greater Vancouver Regional District Watershed
Management Plan, please visit the following website:
http://www.gvrd.bc.ca/services/water/sheds/default.html
Case Study 2: Kelowna, British Columbia
Theme: CREATING WATERSHED PARTNERSHIPS
The City of Kelowna case study illustrates a few innovative approaches at
establishing various levels of partnerships within a watershed.
The City of Kelowna is serviced by five different water utilities, each water
utility obtains water from a different source within the regional watershed. Two
of the water sources are primarily used for domestic purposes and the remaining
three sources are primarily used for agriculture. In 1991, the Kelowna Joint
Water Committee was formed to establish co-operation between the five
utilities. The City of Kelowna, the Rutland Water District and the Kelowna
Joint Water Committee have all been involved in water protection activities.
The City of Kelowna, and to a lesser extent, the Kelowna Joint Water
Committee have been involved in watershed assessment activities.
In 1995, the City of Kelowna’s adopted planning policies that have both direct
and indirect impacts on watershed protection. These policies include general
environmental policies and stream protection corridor policies. To facilitate the
implementation of the planning policies, the Council of the City of Kelowna
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established a Watershed Committee for development of a watershed
management and action plan for the creeks flowing through the City of
Kelowna in 1997. Under the direction of this committee, the City of Kelowna
has engaged in a number of watershed assessment and protection activities that
involve a number of stakeholders.
For more information on Kelowna’s Watershed Stewardship Program, please
contact the City of Kelowna: http://www.city.kelowna.bc.ca/
Case Study 3: Kamloops, British Columbia
Theme: LAND USE PLANNING TO PROTECT WATER QUALITY
The Region of Kamloops case study demonstrates the use of land use planning
for the protection of the South Thompson River, the drinking water source for
the City of Kamloops.
In 1992 the Province of British Columbia issued a Provincial Land Use Charter.
This charter outlined two commitments: 1) protecting and restoring the quality
and integrity of the environment, and 2) securing a sound and prosperous
economy for present and future generations. The charter outlined principles in
the areas of sustainable environment, sustainable economy, decision-making
processes, aboriginal peoples, and shared responsibility.
The Region of Kamloops was the first region within the Province of British
Columbia to develop and implement a Regional Land and Resource
Management Plan. The framework for the plan was begun in 1989 and the plan
was implemented in 1995. The plan is a regional plan that assesses and provides
for land use planning, and by extension watershed protection, within the
Regional watershed area, including the City of Kamloops. The Regional Land
and Resource Management Plan provides for the development of local land use
planning by local governments within the region.
The regional plan included an examination of the physical, social and economic
characteristics within the region, followed by an assessment of the land use
within the regional area. These areas were then categorized into designated
Resource Management Zones within the region. Several categories of Resource
Management Zones exist, each carrying their own specific management
principles based on protective objectives.
The City of Kamloops, whose drinking water supply is managed separately
from the LRMP, implemented a local land use plan in 1997. One of the goals
of this plan is to “protect/enhance the natural environment”. The plan identifies
significant environmental areas within the City of Kamloops including riparian
habitat and ponds, lakes or streams. Various protective mechanisms for
significant areas are identified in the plan. These include legal (i.e.,
environmental protection laws, and permits) and other mechanisms (acquisition
of significant lands, provision of buffering areas), all of which have had the
indirect effect of protecting their drinking water source, and improving their
drinking water quality.
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For more information on the region’s land use program, see the webpage of
Kamloops’ LRMP: http://srmwww.gov.bc.ca/sir/lrmp/kam/
Case Study 4: Shoal Lake, Manitoba
Theme: USING THE WATERSHED PROTECTION APPROACH TO
PROTECT SOURCE WATER
The Shoal Lake case study demonstrates an unusual case where the source
water for a city is obtained from another watershed, the majority of which is
located in another province. Cooperation between provincial and municipal
governments allowed for the development of a watershed plan from multiple
users in different jurisdictions (federal, provincial and First Nations). The Shoal
Lake Watershed Working Group (SLWWG) was formed to develop and address
the recommendations in the watershed plan. The plan allowed for the continued
use of the water resource, which includes a safe drinking water supply.
Based on the watershed assessment, the SLWWG developed a watershed
management plan over a two-year period. Source water protection was a focal
point of the overall watershed management plan because the city of Winnipeg,
as well as many First Nations tribes, draw their drinking water from Shoal
Lake. The stakeholders and the Working Group developed goals, objectives,
and water quality protection strategies that included pollution prevention, best
management practices plan, wastewater treatment upgrades, solid waste
reduction and management, and enhanced monitoring. Based on a thorough
ranking of the threats to Shoal Lake, they were able to prioritized their actions
For more information on the Shoal Lake Management Plan, please visit the
following website: http://www.gov.mb.ca/conservation/ShoalLakeWMP/
Case Study 5: Quebec City, Quebec
Theme: ASSESSING POTENTIAL THREATS
In January 2002, Quebec City and thirteen surrounding municipalities were
amalgamated into one city. One of the problems faced by the new city is the
provision of a steady supply of good quality drinking water to meet the needs of
the residents.
An assessment the current water supplies for the new city was conducted
(Problématique de l’approvisionnement et de l’utilisation de l’eau potable dans
la nouvelle ville de Québec January 2002). The assessment noted most of the
drinking water supply in the area were from surface water sources with a small
portion being supplied by groundwater. The study noted two significant threats
to source waters: 1) certain water supply systems were not able to meet
demands at peak periods, and 2) various localized chemical threats to source
waters, such as TCE.
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As a result, municipalities within the Quebec City region have implemented an
integrated watershed management plan. This plan conceived a number of
watershed protection initiatives such as the adoption of a policy for sustainable
use of drinking water resources, land-use planning (i.e. zoning to protect water
quality), water quality regulations and public education to encourage low
impact activities to minimize water consumption.
For more information on the integrated watershed management plan for the
Québec City region, please visit the following website:
www.inrs-eau.uquebec.ca/publications/r610.htm
Case Study 6: Pockwock-Bowater Watershed, Nova Scotia
Theme: INDUSTRIAL PARTNERSHIPS / WATERSHED
MANAGEMENT
The Pockwock-Bowater Watershed Project (PWP) is an on-going forestrybased ecosystem research project. The primary objective of the PWP is to
generate data on the response of stream water (quality and quantity) to varying
forestry management activities. This is of particular importance since the
Pockwock watershed serves as the primary drinking water supply for Halifax.
The study will also examine the effect of these forestry practices on nutrient
export to the watershed.
Analysis and results of the project are still forthcoming, but the information
gathered will be utilised to evaluate the effectiveness of forestry management
activities alongside water bodies within watersheds. It is hoped that the
information will be applied to future watershed management practices, as well
as providing insight into factors affecting source water quality of a municipal
water supply.
For more information on the Pockwock-Bowater Watershed Project, please visit
the following website: http://www.novaforestalliance.com/pbws/
Case Study 7: Development of Well-Field Protection Plans on Prince
Edward Island
The Province of Prince Edward Island (PEI) depends completely on
groundwater as a source for drinking water, and approximately 45% of the
population is serviced by municipal water supply systems. The Province has
long recognized the need for source water protection for these systems. Because
of the relatively uniform hydrogeological and land use conditions in PEI, it is
believed that the development of a generic approach to the protection of
municipal well-fields in the Province as a whole would assist in the
implementation of better source water protection.
In June 2001, the Government of PEI announced a ten-point strategy for the
protection of drinking water quality for private and public water supplies across
the Island. A central theme in this strategy was the adoption of a multi-barrier
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approach to drinking water protection. One of the key elements for the
protection of municipal drinking water supplies was the development of a new
set of Regulations governing the operation of municipal water supply and
wastewater treatment systems.
These new Regulations will set out mandatory requirements for water quality
monitoring, operator certification and well field protection. Under these
Regulations, municipalities will be required to develop well field protection
plans, submit them for provincial approval, and implement them by the spring
of 2004. While each municipality will have some flexibility in how it designs
and implements its well field protection plan, the intention is that plans will be
based on the approach outlined in the drinking water strategy with respect to
how protection zones will be delineated and what types of land use issues will
be addressed. The Province intends to work cooperatively with communities on
this initiative. Communities will be responsible for land use inventories within
protection zones and in collaboration with the province, identify nonconforming land uses, and suitable mitigative measures.
For more information on PEI Well Field Protection plans, please contact the
PEI local authorities. Contact information and general information on their
drinking water strategy can be accessed through their website:
http://www.gov.pe.ca/infopei/onelisting.php3?number=50234
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Appendix E: Municipal Governments
and the Protection of Source Waters
The Federation of Canadian Municipalities (FCM) has produced a document
entitled Municipal Governments and the Protection of Water Sources. The
document explicitly focuses on municipal government and is written for
municipalities. It includes resources so municipalities can obtain additional
information. This appendix summarizes the content of the FCM document.
Throughout the Source to Tap document, guidance on how to protect water
sources as part of a multi-barrier approach to providing safe drinking water
is given and special reference is made to the role of municipalities. They are
listed as partners in source protection, sources of information, potentially
sources of funding, and active players in watershed protection.
Municipal government has made a significant investment throughout
Canada in the delivery of water to communities. This document outlines the
type of actions that municipal governments can take immediately to protect
watersheds and water sources. It is directed to both elected representatives
and staff. It draws on initiatives already taken by municipal governments
throughout Canada. While provincial and federal frameworks are important
and their respective roles have been identified in some detail elsewhere in
this document, it is at the municipal level that significant improvement can
be made. Municipalities know their local area and issues. They can act as a
catalyst to engage their community, and can identify significant
opportunities and act to protect their water sources.
The maintenance and improvement of source water quality is an investment
that more municipalities will be taking in the future. This will be particularly
important as the onus on municipal politicians and staff increases under the
legal changes foreshadowed, for example in Ontario. The concept of
‘statutory standard of care’ increases the obligations of municipal
councillors to ensure effective oversight of the operation of municipal
waterworks. This is likely to include all elements of the provision of
drinking water, including source protection.
Source water protection can include difficult political decisions that may
well restrict individual activities and the ‘right’ to use land (or water) as
people have been used to. In addition there can be well-entrenched industrial
activities (including agriculture) that have traditionally had precedence. A
challenge for some municipalities will be to provide a high priority to water
quality protection.
A number of municipalities have already undertaken the full range of
activities described here. Not all of the options will be suitable for every
municipality, but are offered as starting points for selecting different
options.
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The suggestions in this document have drawn from individual
municipalities, municipal websites and publications, water authority
websites and newsletters, as well as submissions and commissioned papers
to the Walkerton Inquiry and other water investigations. In addition, papers
from recent water quality conferences were identified, with additional
assistance provided by the Federation of Canadian Municipalities, individual
municipalities and organizations such as the Association of Ontario
Municipalities and Conservation Ontario.
For more information on the contributed document from FCM, please
contact the National Guidelines and Standards Office, Environment Canada.
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Appendix F: Municipal Waste Water
Treatment and the Multi-Barrier
Approach
The Canadian Water and Wastewater Association has written a document titled:
Municipal WasteWater Treatment – Its Role in the Source to Tap Framework.
This appendix summarizes the content of that document.
Generally, wastewater management and wastewater treatment levels
achieved in Canada require improvement. Notwithstanding the fact that
municipal wastewater effluent impacts on the environment are well
documented, direct impacts on drinking water needs to be further
investigated (e.g., pharmaceutical effects). Environmental water quality
management, however, must also weight in other land use practices that
have point source discharges such as the mining and pulp and paper sectors
which can tax the receiving environment. Land use practices with non-point
source discharges cause a greater challenge and include, for example,
forestry and agriculture.
Wastewater total quality management is implicit in the source to tap
approach and addresses management and treatment of public wastewater
“back to the source”. As such, municipal wastewater treatment is
traditionally considered to be the final phase of municipal management of
water services. These services commence with the removal of water from a
source, then this water passes through a treatment system to remove
contaminants and render it potable, is then distributed to customers through
a network of water mains and subsidiary distribution systems for delivery to
the point of consumption, where it is then used by the customers and the
waste water discharged to waste water collection systems for and return to a
wastewater treatment plant where it is treated prior to discharge back to the
environment. In many areas, there are similar but private systems involving
a well, some point-of-entry treatment systems, use and collection and return
to the environment following on-site treatment.
Approximately 24 million Canadians are connected to central (municipal) water
and waste water services while the remaining 7 millions are on private systems.
Millions of Canadians also use from time to time, community and other private
water and waste water systems outside municipal service areas. The municipal
collection of waste waters may also involve the collection of storm water
through a collection system which is often linked with or part of the sanitary
wastewater collection system of the municipality. Municipal systems will also
collect non-sanitary wastewaters from industry and commercial activities
resident within their jurisdictions, often containing chemical wastes. The two
systems (municipal and private) are linked in that the solids accumulating in the
private on-site treatment systems are removed periodically and delivered to a
municipal wastewater treatment plant for further treatment prior to discharge to
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the environment. Industrial wastewaters may also be generated and discharged
to the environment on private systems not connected to municipal systems,
whether or not located within a municipality. Additional information on
municipal waste water treatment, residential on-site waste water treatment and
storm water management is given in the CWWA document
For more information on the contributed document from CWWA, please
contact the National Guidelines and Standards Office, Environment Canada.
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Appendix G: Descriptions of Backflow
Prevention Devices
There are five distinct types of backflow prevention devices and a number of
subtypes which are designed to protect against specific types of hazards. The
degree of hazard must be assessed along with the type of cross-connection
present to determine which type of backflow prevention device is suitable for
the situation.
Air Gap (AG)
An AG is a physical separation of the supply pipe by at least two pipe diameters
vertically above the flood rim of the basin to protect against both backsiphonage
and backpressure. An AG device is suitable in non-pressurized plumbing
settings.
Atmospheric (non-pressure) Type Vacuum Breaker (AVB)
The AVB is always placed downstream from all shut-off valves and must
always be installed at least 15 cm (6 inches) above all downstream piping and
outlets to prevent backsiphonage only, not backpressure. An AVB must not be
used for more than twelve (12) out of any twenty-four (24) hour period.
Pressure Vacuum Breaker (PVB)
The PVB includes a check valve which is designed to close with the aid of a
spring when flow stops. It also has an air inlet valve which is designed to open
when the internal pressure is 7 kPa (1 psi) above atmospheric pressure to
prevent so no contaminant can be siphoned back into the potable water system.
The PVB must be installed at least 30 cm (12 inches) above all downstream
piping and outlets. It may only be used to protect against backsiphonage. It is
not acceptable protection against backpressure.
Double Check Valve Assembly (DCVA)
The Double Check Valve Assembly comprises two internally loaded,
independently operating check valves together with tightly closing resilient
seated shut-off valves upstream and downstream of the check valves. This
device assembly is suitable for protection against either backsiphonage or
backpressure.
Reduced Pressure Principle Assembly (RP)
This assembly comprises two internally loaded independently operating check
valves and a mechanically independent, hydraulically dependent relief valve
located between the check valves. This is to be installed horizontally and used
to protect against either backsiphonage or backpressure.
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Double Check Detector Assembly (DCDA)
The DCDA comprises a line-sized double check valve assembly with a specific
bypass meter and meter-sized double check valve assembly. This assembly is
used when the protection of a double check valve assembly is required, yet
where the added requirement of detecting any leakage or unauthorized use of
water exists.
Reduced Pressure Principle Detector Assembly (RPDA)
The RPDA is very similar to the double check detector assembly except that the
RPDA is designed for situations requiring the protection of a reduced pressure
principle assembly and detection of unauthorized use of water or leaks. This
assembly is normally used on fire lines which may contain contaminants, such
as anti-freeze additives.
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Appendix H: Procedures for Flushing
and Pipe Cleaning
The following procedures are recommended for flushing operations.
•
Pre-plan an entire day's flushing using the available distribution
system maps. Consider flushing at night between midnight and
5:00 a.m. to minimize completing water demand and any
inconvenience to customers.
•
Determine where sections of mains are to be flushed at one
time, the valves to be used, and the order in which the pipelines
will be flushed.
•
Start at or near a source of supply and work outward into the
distribution system. Progress from large mains to small mains.
Generally it is not practical to flush mains larger than 60 cm or
24 inches. Record which wells are on-line or isolated.
•
Assure that an adequate amount of flushing water is available at
sufficiently high pressures, that is, ensure the reservoir(s) are
full. A minimum flushing velocity of 2.5 ft/sec (5 ft/sec
preferred) (0.75 and 1.50 m/sec) should be used.
•
Prior to flushing the mains, notify all customers who will be
affected of the dates and times of the flushing through billing,
newspapers, and local radio and TV announcements.
Individually notify people who might be on dialysis machines
and also hospitals, restaurants, laundromats, and others who
might be affected while the mains are being flushed.
•
Isolate the section to be flushed from the rest of the system.
Close the valves slowly to prevent water hammer.
•
Open the fire hydrant or blowoff valve slowly.
•
Direct flushing water away from traffic, pedestrians, and
private lots.
•
Open hydrant fully for a period long enough (5 to 10 minutes)
to stir up the deposits inside the water main.
•
Assure that system pressures in nearby areas do not drop below
138 kPa (20 psi).
•
Record all pertinent data (such as valve and hydrant condition)
regarding the flushing operation as well as a description of the
appearance and odour of the water flushed.
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•
Collect two water samples from each flowing hydrant, one
about 2 to 3 minutes after the hydrant was opened and the
second sample just before closing the hydrant. These samples
allow a check on the water quality for certain basic water
quality indicators (iron, chlorine residual, turbidity).
•
After the flushing water becomes clear, slowly close the
hydrant or blowoff valves.
•
In areas where the water does not become completely clear, the
operator should use judgment as to the relative colour and
turbidity and decide when to shut down.
•
Mark closed valves on a map or flushing sheet (see Flushing
Procedures) when they are closed and erase marks after the
valves are reopened.
•
After one section of pipe has been flushed, move onto the next
section to be flushed and repeat the same procedures.
Pipe Cleaning
Mechanical cleaning devices are often used to clean pipes if flushing does not
provide relief from water quality problems or from problems in maintaining the
carrying capacity. Foam swabs, pigs, and air can be used to remove loose
sediments and soft scales from mains. Pigs can be used to flush new mains
prior to disinfection. Scrapers or brushes can be used in mains with hardened
scales or extensive tuberculation, but are usually used prior to relining. Of the
available devices, foam swabs and pigs are the easiest and most effective to use.
Pipe cleaning projects should produce improved pipe carrying capacity and a
reduction of power (and cost) to pump the water.
Swabs are typically made of polyurethane foam; both soft and hard grade forms
are available. All swabs inserted in mains must be retrieved. Pigs are also
made of polyurethane foam, but are much heavier in weight, harder, and less
flexible than swabs. They are bullet-shaped and come in various grades of
flexibility and roughness.
Generally, if loose sediments and soft scales in the pipe are to be removed
without disturbing hardened incrustations, swabs are use. To improve the
carrying capacity of the main, then pigs should be used. The use of pigs is more
likely to result in leaks at a later date.
A mixture of air and water can effectively clean small mains up to 100 mm (4
inches) in diameter. Air is introduced into the upstream end of the pipe from a
compressor of the same type used for pneumatic tools. Spurts of water mixed
with the air can remove all but the toughest scale.
The use of compressible foam swabs and pigs provides flexibility in their
insertion and removal. The entry and exit points used for smaller size mains are
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fire hydrants, air valves, blowoffs, wyes, and tees. In larger mains, a section of
pipe may be removed and a wye inserted in its place as the entry and exit points
to allow insertion, launching and exiting of the swabs and pigs.
The routine procedures used for cleaning pipe are very similar to those used for
flushing except that services to customers will have to be shut off during
cleaning. A typical main cleaning includes both flushing and swabbing
operations which usually start near the beginning of the system and move
outward toward the ends of the system.
The swab should pass through the main at a speed of 0.6 to 1.2 m/sec (2 to 4
ft/sec). Using velocities in this range, up to 1,200 m (4,000 feet) of pipe can be
effectively cleaned before the swab wears down to a size smaller than the main.
The entire operation may require 10 to 20 swabs. Typically, 2 to 3 runs are
made using 4 to 5 swabs in each run. The cleaning should continue until the
water behind the swabs emerging at the exit clears up within one minute. All
swabs inserted into and ejected from the main must be accounted for.
Before starting any cleaning job, determine how to dispose of or remove the
water and deposits discharged from the cleaned water main. If the water is
discharged onto a street or the ground, be certain the drainage is proper and
adequate.
The procedures to follow for cleaning a water main using pigs or swabs are as
follows:
•
Isolate the line to be cleaned. Be sure that those customers
requiring temporary services have enough water.
•
Be sure that all valves in the section to be cleaned are fully
opened.
•
Turn on the water and verify the direction of flow.
•
Run a full-sized bare swab through the main to prove the
direction of flow.
•
Run a swab unit through the main. Measure the diameter of the
unit upon exiting and introduce a crisscross type unit into the
main that will just fit the "true" opening. Run a full-sized bare
swab behind the crisscross unit to assure a tight seal. Continue
this process until a unit is discharged from the main in reusable
condition.
•
Increase the size of the crisscross pigs in one-inch increments
until the units that measure the same as the pipe inside diameter
are being used. For pipes with a build-up of hard scale, such as
carbonates, crisscross wire pigs can be used on the final pass.
•
Run a full-sized bare swab to sweep out any loose debris.
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To obtain the best possible cleaning results, be sure to:
•
Flush thoroughly after each pig run.
•
Avoid applying more than two wire-brush pigs on the final pass
(this prevents overcleaning).
•
Launch the pigs from fire hydrants for mains of 8 inches (200
mm) or smaller, or from concentric reducers, pipe couplings,
spools, eccentric reducers, in-line launchers, or by hand.
•
Have an operator with experience in proper main cleaning
procedures help you the first time you attempt to clean a main.
This is a good practice to avoid stuck, lost or damaged pigs or
swabs.
•
After the cleaning operation is completed, flush and disinfect
(chlorinate) the main. When the main is reactivated, flush
service lines and remove any temporary services.
For more information on flushing and pipe cleaning, see "Guidance Manual
for Maintaining Distribution System Water Quality", AWWARF (2000),
Report Number ISBN 1-58321-074-1
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Appendix I: Procedures for Inspecting
and Maintaining Valves and Hydrants
Procedures for valves
Routine valve inspections should be conducted by performing the following
tasks:
•
Verify the accuracy of the location of the valve boxes on the
system map (if incorrect, change the map and update the Master
Copy).
•
After removing the valve box cover, inspect the stem and nut
for damage or obvious leakage.
•
Close the valve fully and record the number of turns to the fully
closed position. Always close a valve slowly to prevent water
hammer.
•
Reopen the valve to re-establish system flows.
•
Clean valve box cover seat. Sometimes covers on valve boxes
will come off when traffic passes over them due to dirt in the
seat.
Exercising (opening and closing a valve) should be done at the same time the
valve inspection is made. Some manufacturers recommend that a valve stem
never be left in a fully open or closed position. They recommend that after fully
opening or closing a valve, back off the stem by one turn.
Conditions of each system will determine how often the valves should be
exercised, in general, it is recommended that all valves be exercised at least
once a year. Planned exercising of valves verifies valve location, determines
whether or not the valve works, and extends valve life by helping to clean
incrustations from the valve seats and gates. Any valves which do not
completely close or open should be replaced. Valves which leak around the
stems should be repacked. To determine that a valve is closed, an aquaphone or
other listening device can be used. Valves should be exercised in both
directions (fully closed and fully opened) and the number of turns and direction
of operation recorded. Valves operating in a direction opposite to that which is
standard for the system need to be identified and this fact recorded. The
condition of the valve packing, stem, stem nut, and gearing should be noted. A
timely maintenance program should be initiated to correct any problems found
during the inspection and exercising.
An important factor in maintaining distribution system valves are the
availability of current and correct maps of the distribution system. Each utility
should verify their maps often so that it is accurate, and keep the map up to date
by immediately recording any changes such as replacements or additions.
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Some water purveyors equip their service trucks with "gate books" which carry
all of the pertinent valve information including location, direction of turning to
close, and number of turns required.
Maintaining current records is as important as maintaining current maps. A
purveyor should develop a valve form to track important information. The
location of a valve is obtained from a controlled survey bench mark or
permanent reference point. The make of valve is important because different
makes have different operating characteristics. The use of a simple valve
numbering system keyed to up-to-date drawings is recommended. This
procedure has proven to be quite helpful in locating valves rapidly and in
communicating with others about particular valves.
Road improvements require constant attention from water distribution system
operators to ensure that valves are not lost. Valve boxes can be graded out or
covered with pavement. The centre lines of roads, curb lines, and right-of-way
lines are not to be used as reference points for locating valves, because they can
change over time.
Valves left closed in error can cause severe problems in a distribution system.
Construction and maintenance crews operate valves as they do their work, and
contractors and plumbers may operate valves without permission. Separate
pressure zones in distribution systems may be established by closing valves,
thus increasing the possibility of problems related to the incorrect use of valves.
Unexplained problems with pressure and excessive operation of pumps in a
given area have been traced to valves left closed or open in error. When crews
change shifts during a project, valve closure and opening information must be
exchanged. Crew chiefs must be certain all valves are restored to proper
positions.
Proper advance planning is important. The valves that will be used to isolate a
damaged valve must be in good operating condition. When ordering repair
parts, include the size, make, direction of opening, year of manufacture, and
other pertinent information in order to assure that the correct repair parts will be
received.
Until the valve is isolated and opened up, it is difficult to determine what part of
the valve is damaged. Therefore, have all replacement parts available before
isolating the necessary section of the water main, excavating the valve, and
making the repairs.
Procedures for Fire Hydrants
Operators responsible for hydrant inspections should be familiar with the
various types of hydrants used in their system. There are two basic types of fire
hydrants, the dry barrel and wet barrel. A hydrant has four principal parts: the
inlet pipe which is connected to the main water supply, the main valve, the
barrel and the head. The supplier should be contacted whenever necessary to
obtain descriptive literature, operation and maintenance instructions, parts
manuals or assistance on particular problems.
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In general, fire hydrants should be inspected and maintained twice a year.
These operations are often done in the spring and the fall. However, each
hydrant should also be inspected after each use. Inspect dry-barrel hydrants
after use, especially during freezing weather, to assure that the drain remains
open when the hydrant is not in use.
An additional source of information on fire hydrants is AWWA's Manual M17,
Installation, Field Testing, and Maintenance of Fire Hydrants. Some general
inspection and maintenance procedures used for hydrants include:
•
Inspect for leakage and make corrections when necessary.
•
Open hydrant fully, checking for ease of operation.
•
Flush hydrant to waste (take care to direct flow).
•
Remove all nozzle caps and inspect for thread nozzle and cap
threads. Clean and lubricate outlet nozzle threads.
•
Replace caps, tighten with a spanner wrench, then back off on
the threads slightly so that the caps will not be excessively tight
but will leave sufficient frictional resistance to prevent removal
by hand.
•
Check for any exterior obstruction that could interfere with
hydrant operation during an emergency.
•
Check dry-barrel hydrants for proper drainage.
•
Clean exterior of hydrant and repaint if necessary.
•
Be sure that the auxiliary valve is in the fully opened position.
•
If a hydrant is inoperable, tag it with a clearly visible marking
and immediately report the condition of this fire hydrant to
your fire department.
•
Prepare a record of your inspection and maintenance operations
and any repair work.
Hydrants can be partially protected against freezing by covering them with a
box which can be quickly removed when the hydrant must be used. To keep
hydrants from freezing (those that won't drain in the winter due to frozen
conditions), insert in the hydrant propylene glycol or some other non toxic NSF
approved substance that won't freeze or cause water quality problems. Frozen
hydrants may be thawed using electric current thawing or live steam injected
through a hose into the hydrant barrel.
Standardization of hydrants minimizes the requirement for stocking parts,
simplifies repair procedures, and allows replacing only defective parts. Every
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water purveyor should keep a basic stock of repair parts on hand for immediate
use.
Fire hydrants are usually the only part of the distribution system regularly seen
by the general public. Frequent painting of hydrants creates a favourable
impression and is, therefore, a public relations tool. Fire hydrant caps or guards
can be installed on the tops of fire hydrants to eliminate fire hydrant vandalism.
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Appendix J: Locating and
Remediating Line Breaks
Breaks in water mains can occur at any time and every purveyor must have an
established, written response plan. After a break has been located, determine
which valves must be closed to isolate the break. A good policy before shutting
off any valves is to notify every consumer involved that they will be out of
water for an estimated length of time. The purpose of this advance notification
is to allow consumers to make any necessary preparations. If extensive damage
is caused by the break (flooding and/or washouts), close the valves and isolate
the section as soon as possible, even before notifying all consumers.
After the valves are closed, a trash pump can be used to drain the hole. A
backhoe or other equipment can be used to dig down to the break. Before
entering the hole, determine the necessary shoring needed. Use the appropriate
shoring. Remove the damaged section of pipe and as much silt and debris as
possible from the remaining sections of the main by flushing or other methods.
Replace the damaged section of pipe and/or valves using clamps and other
fittings. Flush the entire section which was isolated using hydrants or drains.
Disinfect the system by following the recommended standards for disinfecting
mains.
All new or repaired watermains should be disinfected according to the current
edition of the AWWA Standard for Disinfecting Water Mains Standard
C651-92. New lines shall be thoroughly flushed and chlorinated at a dosage of
50 mg/L for 12 hours. In short lines, and if portable chlorination equipment is
not available, thorough flushing and maintenance of a free chlorine residual of
1.0 mg/L after 24 hours shall be carried out, with a test for residual chlorine
being made at the end of the test period.
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Appendix K: Processes for Detecting
Leaks
Leaks may originate from any weakened joint or fitting connection or from a
damaged or corroded part of the pipe. Leaks are undesirable not only because
they waste water, but because they can undermine pavements and other
structures. Another undesirable effect of leaks is that the leak soaks the ground
surrounding the pipe and in the event that pressure is lost in the pipe, the water,
combined now with dirt and other contaminants, may backflow into the pipe.
The total amount of leakage is also affected by the type of soil surrounding the
leaking pipes. In coarse soils (sands) the leakage may continue for an extended
period without detection, whereas in finer soils (clays) leaks are detected sooner
on the surface.
The process of locating a leak can be difficult and can become a troublesome
and frustrating experience. Methods used to locate leaks include direct
observation as well as use of sounding rods, listening devices, and data from a
waste control study.
The simplest method of leak detection is to search for and locate wet spots
which might indicate the presence of a leak. Sometimes these are reported by
the system's customers. However, even if a damp spot is found, it does not
necessarily mean the leak can be easily found. The leak may be located
directly below the damp area or it may be metres away. Often the leak is not
located where it would be expected because water follows the path of least
resistance to the ground surface.
After the general location of the leak has been determined, a probe may be used
to find the exact location. This probe is a sharp-pointed metal rod that is thrust
into the ground and pulled up for inspection. If the rod is moist or muddy, the
line of the leak is being followed. Do not probe into an area that has an
electrical cable.
Listening devices are sound-intensifying equipment that is used in a systematic
fashion to locate leaks. The simplest listening device is a steel bar held against
the pipe or valve. The device is moved in the direction of increasing sound
until the leak is found. Patented leak detectors use audiophones to pick up the
sound of escaping water.
Another method for locating leaks is the use of a leak noise correlator. This
instrument locates leaks by noise intensity and the time it takes for the leak
sound to travel to a pair of microphones placed on fittings (fire hydrants or stop
valves) on each side of a suspected leak. Leak correlators are fairly accurate in
locating a leak.
The amount of water lost from the distribution system through leakage is only
one component of the system's total water losses. The total amount of water
lost from a distribution system from all sources is often referred to as
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"unaccounted for water" or non-revenue water (NRW). The NRW is the
difference between the total amount of water produced and the total amount of
water consumed. The amount of unaccounted for water lost by a distribution
system is usually determined by conducting a water audit.
Waste control or water audit studies are usually conducted when no specific
reason can be found for a significant water loss in the system. Routine
comparisons of water production and use should be made to determine the
amount of NRW or unaccounted for water. When the loss exceeds 10 percent
of the water produced corrective actions should be taken.
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Appendix L: List of Measurement
Instruments, Alarms, Status
Indicators, etc
Measurement Instruments
For plants of 1 ML/d (220,000 igpd) capacity and greater, the following
instruments should be provided as a minimum for the relevant processes listed.
Raw Water Instrumentation
•
Low-level switches to shut down the raw water pumps. These
should be hard-wired to the starters.
•
Running and trip indication for raw water pumps.
•
Raw water turbidity, pH, pressure, flow rate, and flow volume.
Rapid Mixer
•
Running and trip indication.
Flocculators
•
•
Running and trip indication.
Speed (if variable speed type).
Solids Contact Clarifiers
•
Recirculator speed indication.
•
Running and trip indication.
•
Level indication.
•
Blow down valve status.
•
Turbidity and pH following clarification.
Softening
•
•
If lime softening is used, pH following recarbonation.
Recarbonation CO2 feed status.
Filter Instrumentation
•
Turbidity on each individual filter effluent and filter to waste.
This can be a single instrument for each filter if piping
arrangement permits.
•
For constant rate filters: differential head loss across the filter
media.
•
Filter flow rate.
•
Where the backwash sequence is automated, provide open and
close limit switches or position on all filter valves and status on
backwash equipment.
•
Filter run time.
Backwash Instrumentation
•
Running and trip indication for backwash pump(s).
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Running and trip indication for air blowers (if air scour is
used).
Backwash flow rate and flow total.
Elapsed time since last backwash.
Clearwell and Distribution Pump Instrumentation
•
Level indication for clearwell and other tanks.
•
Running and trip indication for the distribution pumps.
•
Low-level switches to shut down the distribution pumps. These
should be hard-wired to the motor starters.
•
Turbidity, chlorine residual, fluoride residual (if fluoridation is
practised), pH, pressure, flow rate, and flow total on plant
discharge.
•
For variable speed pumps, indicate the pump speed.
Chemical Systems
•
Running and trip indication for chemical loading, batching and
pumping equipment.
•
Low and high level alarms in storage bins, silos or tanks.
•
Level indication for tanks.
•
Weigh scales for hydrofluosilicic acid day tanks or storage if no
day tank is used.
•
Weigh scales for gaseous feed chemicals such as chlorine or
sulphur dioxide.
•
Speed indication on variable speed pumps.
•
Rotameters (or other flow monitoring device) for carrier water
feed systems.
•
Chemical feed flow rate is desirable but not mandatory.
Miscellaneous Instrumentation
•
Run time meters on all pumps and major electrically driven
equipment.
•
Speed, run time, oil pressure and temperature gauges, fault
signal switches and manual start and shut down on engines.
•
Where the plant is automated or operated remotely from either
within the plant or outside, provide open and close limit
switches or position indicators on all major valves, status on all
major equipment and security instruments including door
switches, building temperature switches and smoke alarms.
•
Any additional instrumentation recommended by equipment
manufacturers.
Alarms and Status Indication
As a minimum, the following alarms should be provided:
•
High turbidity on the raw water, clarifier effluent (if
applicable), filter effluent, and plant discharge.
•
High and low pressure on the raw water line.
•
High flow rate on the raw water line.
•
High and low level in clarifiers or flocculators.
•
High torque on solids contact clarifier recirculator and rake.
•
High torque on flocculators.
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•
•
•
•
•
•
•
•
•
•
•
•
•
•
TO
SAFE DRINKING WATER
High level in filters.
High and low level in chemical storage tanks.
High and low chemical feed rates (if measurement is provided).
High flow rate on each filter individually (also low flow rate on
declining rate filters).
High and low levels in each clearwell, pumpwell, and reservoir.
High and low pH on the raw and treated water (if on-line
measurements are provided).
High and low chlorine residual on the plant discharge (where
online measurements are provided).
High head loss on the filters (if constant rate type).
Trip or failure to run on each pump.
High and low pressure on the plant discharge line.
High flow rate on the plant discharge line.
Chlorine gas detection in the chlorine storage rooms.
Chlorine scale low weight (where scales are equipped with
transmitters).
Valve operation failure (where valves are provided with limit
switches.
Field Instruments
Level Instruments
Where access to the top of the reservoir is convenient (such as in a clearwell),
an ultrasonic level transmitter should be used. Where access to the bottom of
the reservoir is convenient (such as at a tower or above-ground reservoir), a
pressure transmitter can be used.
Flow Instruments
On-line flow meters should generally be one of the following types:
•
•
•
Turbine (or nutating disk)
Magnetic
Ultrasonic (either transit-time or Doppler)
All of these types of instruments can be equipped to provide both flow rate and
flow total measurements.
Price, line size, flow rate, flow range, pipe material, required accuracy, and
water quality will dictate the selection of the type of instrument.
Water Quality Instruments
The most frequently used water quality measurements are turbidity, pH, and
chlorine residual. On-line turbidity measurement is relatively inexpensive and
should be provided in any plant, on the raw water, flocculator or clarifier
effluent (if applicable), each filter effluent, and final plant discharge lines. In
larger plants, on-line pH and chlorine residual are generally used, but manual
testing can be done in smaller plants.
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Process Controls
Pumping Systems
Regardless of the function of the pumping system, its control will normally be
achieved through monitoring level, flow and/or pressure. The choice of control
parameter(s) will depend on the system's function and features. Controls and
monitoring for raw water pumping and finished water pumping are normally
required.
Treatment Processes
Travelling Screens
Two methods may be used to control the operation of travelling screens:
•
Simple manual start/stop which requires the presence of the
operator to start and stop the screen. This method is not
recommended where sudden changes in raw water quality
could result in heavy debris accumulation on the screens.
•
Automatic activation by differential level or time. This method
uses the differential level across the screen to provide the start
condition. Once started, the screen should run at least one
"cycle" and stop automatically when the differential level is
returned to the clean screen value.
Chemical Feed Systems
Liquid/Gas Chemical Feed
Basic chemical dose rate control can be achieved by flow pacing (i.e., adjusting
chemical feed rate based on the flow of the stream it is to be injected into). This
can be achieved using a variable speed metering pump (liquid) or flow control
valve (gas) linked to a flowmeter on the receiving stream. For finer dosage
adjustment, feed rate can also be controlled based on downstream
instrumentation (e.g., residual chlorine analyzer providing feedback signal to
chlorine dosing pump).
Dry Chemical Feed
Dry chemical feed systems typically include a packaged bulk storage
combination feeder and mixer. The feeder can be gravimetric or volumetric,
and will be controlled by a 4-20 mA signal from the flow transmitter on the
plant flowmeter.
Rapid Mixing
Control of the rapid mixer will be simply on or off; the unit should operate
continuously whenever the plant is in operation.
Flocculation
Flocculation requirements should be addressed in terms of the unit process
parameters.
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Clarification
Careful monitoring and control is most important to successful clarification.
Adequate instrumentation to measure water quality parameters (e.g., turbidity)
prior to and after clarification is essential.
Dissolved Air Flotation (DAF)
The process variables in DAF are:
•
•
•
Flowrate
Recycle rate
Float removal cycle
Filtration
Two types of filtration are used for water treatment:
•
•
Rapid gravity filtration.
Slow sand filtration.
Rapid Gravity Filtration (RGF)
Constant Rate - Flow through a constant rate RGF is controlled by a flow
control valve on the filter effluent or by influent flow splitting and filter level
control. For the flow control type, the effluent valve position is controlled by a
flowrate signal from a flow meter, usually located on the filter effluent. For the
level control type, the effluent valve position is controlled by the water level in
the filter.
A filter run will be terminated, and the bed backwashed, based on one or any of
the following:
•
Run time.
•
Headloss across the bed.
•
Effluent turbidity.
•
Effluent particle count (optional).
Declining Rate - Flow through a declining rate RGF is not directly controlled as
is the case with constant rate RGF. The rate simply decreases as the filter plugs.
An effluent valve with manually adjustable stops is set to ensure the flowrate
through a clean bed is not excessive. Once set, this valve will return to the set
position after backwash (or after being closed for maintenance, etc.).
A filter run will be terminated based on one or any of the following:
•
Run time.
•
Effluent flowrate.
•
Effluent turbidity.
•
Effluent particle count (optional).
A time initiated backwash can be automatic. Smaller plants feeding smaller
systems may benefit from backwashing overnight when demand is low - and the
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operator is not present. In such cases, a timer can be hard-wired into the filter
control panel to initiate the backwash, or alternatively, the time control can be
programmed into the plant's programmable logic controller (PLC).
Slow Sand Filtration
Because of the very slow flow rate through SSF, headloss, flow rate, and
effluent quality can remain very stable for many weeks. Adjustments to the
flow rate can be made manually by the operator.
Instrumentation should be provided to routinely monitor raw and treated water
quality. A sudden increase in headloss accompanied by a reduction in flow rate
signals that the filter is plugged.
Disinfection
The dosage is controlled on the basis of the measured residual; an analyzer/
controller measures the residual downstream of the point of injection and
adjusts the rate of injection accordingly via a control signal to the metering
pump (liquid feed) or gas flow control valve (gas feed).
Control System Documentation
The following documents should be provided following completion of the
control system:
•
Record drawings to show any changes to the original design
and including any drawings produced during construction.
•
Annotated listings of control system programs and packaged
system configuration.
•
Manufacturer's literature for all control and instrumentation
components.
•
Final wiring diagrams complete with wire and terminal coding.
•
Motor control schematics.
•
Instrument loop diagrams.
•
Panel wiring and layout details.
•
PLC or DCS wiring schematics.
•
Instrument calibration sheets.
•
Operating instructions.
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Appendix M: Facility Classifications
Most jurisdictions in Canada classify water and wastewater facilities based on a
point rating classification system developed by the Association of Boards of
Certification (ABC), Ames, Iowa. Examples of the rating system are shown
below.
Facility Classification System for Class I to IV
Type of
Works
Classification
I
II
III
WT
Range of pointsa
< =30
31-55
56-75 >=76
WD*
Population served
<=1500 1,501 15,00
-15,000
WWT
Range of points
<=30
WWC*
Population served
<=1500 1,501 15,001 >=50,001
-15,000
-50,000
*
31-55
IV
>=50,001
-50,000
56-75 >=76
Simple in-line treatment (booster pumping, chlorination or odour
control) is considered to be a part of a distribution or collection system.
Notes:
WW WWW WT
-
Waterworks
Wastewater works
Water Treatment Facility
WD
Water Distribution Facility
-
WWT WWC -
Wastewater Treatment Facility
Wastewater Collection Facility
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Appendix N: Operator Certification
Day-to-day operations of waterworks systems should be supervised by one or
more persons who hold a valid certification for the type and class of facility
concerned. This or these persons should be fully responsible for operation and
maintenance of the facility. Typically, the approval for each facility should
state the required number of certified operators and their required level of
certification. The level of operator certification is to match or exceed the
classification of the water treatment/distribution facilities. Various certification
criteria have been developed through Canada based on ABC model. These
criteria are shown below.
Summary of Operator Certification Criteria
Certification
Class
Small System
Years of
Education
10
Level I
12
Level II
12
Level III
14
Level IV
16
Facility Experience
6 months in a Small
System or higher facility
1 year in a Class I or
higher facility
3 years in a Class I or
higher facility
4 years in a Class II or
higher facility
4 years in a Class III or
Class IV facility
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Other
Complete a small system
Complete a Level I certification
exam
Complete a Level II certification
exam
WT and WWT certificates
require 2 yrs of DRC at Class II
or higher facility.
WT and WWT certificates
require 2 yrs of DRC at Class III
or Class IV facility. Complete a
Level IV certification exam
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Appendix O: Auditing Processes
Auditing can be done for a number of processes common to drinking water
programs, including treatment systems, filtration systems, distribution systems
and administrative systems. Below are some of the questions that may be asked
during such audits.
Treatment System Audit
Suggested features and points of the water disinfection process to review are:
•
Is the disinfection equipment and disinfectant appropriate for
the application?
•
Are there back-up disinfection units on line in case of failure,
and are they operational?
•
Is there auxiliary power with automatic start-up in case of
power outage? Is it tested and operated on a regular basis, both
with and without load?
•
Is there an adequate quantity of disinfectant on hand and is it
properly stored (e.g., are chlorine cylinders properly labelled
and chained)?
•
What is the production and expiry date on sodium and calcium
hypochlorite containers?
•
In the case of gaseous chlorine, is there automatic switch over
equipment when cylinders expire?
•
Are critical spare parts on hand to repair disinfection
equipment?
•
Is disinfectant feed proportional to water flow?
•
Are daily records kept of disinfectant residual near the first
customer from which to calculate CTs?
•
Are production records kept from which to determine CTs?
•
Is a disinfectant residual maintained in the distribution system,
and are records kept of daily measurements?
•
If gas chlorine is used, are adequate safety precautions being
followed. Is the system adequate to ensure the safety of both
the public and the employees in the event of a chlorine leak?
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•
Are other treatment processes appropriate and are they operated
to produce consistently high water quality?
•
Are pumps, chemical feeders, and other mechanical equipment
in good condition and properly maintained?
•
Are controls and instrumentation adequate for the process,
operational, well maintained and calibrated?
•
Are accurate records maintained (volume of water treated,
amount of chemical used, etc.)?
•
Are adequate supplies of chemical on hand and properly
stored?
•
Are adequate safety devices available and precautions
observed?
Filtration System Audit
The type of treatment processes and facilities used to provide safe drinking
water are determined by the type and quality of the source water plus regulatory
requirements. In general, most surface water sources and some GWUDI require
complete conventional treatment which includes coagulation/flocculation,
sedimentation/clarification, and filtration processes to physically remove
pathogens and other particulates, and disinfection to inactivate any pathogens
that are not physically removed. The physical facilities at a conventional
surface water treatment plant normally include chemical feed equipment, rapid
mixing basins, flocculation basins, sedimentation/clarification basins, filters,
and treated water storage facilities.
An auditor should evaluate all water treatment processes in use at the water
system. This evaluation should consider the design, operation, maintenance,
and management of the water treatment plant to identify existing or potential
risks. The treatment and processes should be evaluated to assess the ability to
meet intended purpose regulatory requirements at all times. An audit of a
treatment plant should:
•
Analyze all the parts of the treatment process, including but not
limited to coagulation/flocculation, sedimentation, filtration,
disinfection, chemical feed systems, hydraulics, controls, and
wastewater management.
•
Review source water quality data that may impact the treatment
process, such as turbidity, pH, alkalinity, and water
temperature.
•
Identify features that may pose a risk, such as cross connections
in the plant.
•
Review the criteria, procedures, and documentation used to
comply with regulatory requirements, for example, adequate
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disinfection based on CT values, individual filter turbidities,
finished turbidities, post backwash turbidity profiles, etc.
•
Is the treatment plant located at a level below the 100-year
flood line?
•
Are there any sources of contamination in the vicinity of the
treatment plant which affect the quality of water produced?
•
Do the plant drawing(s) shows the name of the facility and date
of the last modification made to the drawing(s)? Are the
drawings up-to-date?
•
Are the schematic or layout plans complete with the proper
information (e.g., a legend that explains key symbols used)?
•
Do the schematics or plan(s) identify treatment type(s)?
•
What is the design capacity of the treatment facilities? What is
the historical maximum daily demand of the water system?
What is the storage capacity of the system? Given service
connections or population, are treatment facilities reasonable?
•
Does the system meet regulatory requirements?
•
Is the plant capable of meeting the required capacity with the
largest unit out of service?
•
What backup or standby provisions are available? If a
generator is provided for emergency power, how often is the
generator used? Can the operator demonstrate that the backup
systems are operational?
•
What protective storage measures are in place for fuel used in
the standby generators?
•
Can the operating characteristics of the existing units be
checked? If so, does the purveyor check them periodically?
How does the existing operational point compare to the original
operational characteristics of the unit?
•
Is the total capacity of the presedimentation basins large
enough to accomplish the purpose of reducing turbidity?
•
Check the turbidity levels of water drawn from the inlet and the
outlet of the presettlement basin(s) to determine if it is
functioning properly.
•
How often are the presedimentation basins cleaned?
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•
Are flow measurement devices installed at source water inlet
and finished water outlet? Are they functioning? Are they
calibrated to assure accuracy?
•
Are there adequate flow measurement devices throughout the
treatment process?
•
Does the rapid mix unit visually appear adequate?
•
The auditor should look at the general sanitary condition of the
housing of the rapid mix unit. Mouldy, dusty, and dirty walls
and floors are signs of unsanitary conditions. The auditor
should note the existence of wildlife taking shelter inside and
even outside the housing unit and should note if there is a
possibility that a wild animal or its feathers, fur, or droppings
may end up inside the rapid mixing unit.
•
Are coagulant chemicals being fed continuously during
treatment plant operations?
•
Does the plant have multiple mix units? How often is
maintenance done?
•
Is the mechanical equipment working and maintained? Are
there any hydraulic inadequacies?
•
Is the rate of mixing adjustable, so that the correct mixing can
be provided at all flows? If so, can the operator adjust the rate
of mixing?
•
What is the detention time? Is it within the generally accepted
range?
•
What chemicals are used? Are the chemicals approved for use
in drinking water? (e.g., NSF60)
•
What chemical amounts are used - average and maximum? Are
the various systems sized to feed more than the maximum
amount required?
•
Where are various chemicals applied?
•
What type of chemical feed equipment is used? Are the
materials used for each chemical feed system compatible with
the chemical? What is the general condition of the chemical
feed equipment?
•
How often is the feed rate checked for each chemical?
•
Is the control of the chemical feed equipment manual or
automatic?
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•
Is a standby feeder and/or metering pump provided for each
chemical?
•
Is backflow prevention provided on the water lines used for
chemical feed makeup?
•
Is the storage area for each chemical adequate and safe? Is
containment provided for a potential spill?
•
What type of flocculation facilities are being used? Does the
coagulation/flocculation process visually appear adequate?
•
Does a preventive maintenance program exist?
•
Is the rate of mixing adjustable, so that the correct mixing can
be provided at all flows? If so, can the operator adjust the rate
of mixing?
•
What type of sedimentation/clarification process and facilities
are being used? Does the sedimentation/clarification process
visually appear adequate?
•
Is the flow distributed evenly to all basins? Is the inlet flow
distributed uniformly over the full cross section?
•
Is the mechanical equipment working and maintained? Are
there any hydraulic inadequacies?
•
Does there appear to be too much sludge in the basin(s)? How
is sludge removed from the clarifier(s)? How often is sludge
removed?
•
What is the settled water turbidity? Does it meet the general
criteria?
•
What type of filtration system is being used (gravity or
pressure; constant or declining rate) and what kind of media has
been installed (mono media, dual media, or multi media)?
•
What is the maximum filtration rate at design capacity with one
filter out of service? Is it at or less than the maximum water
demand?
If a pressure filtration system is installed, then the following should be checked:
•
When was the last internal inspection of the filters performed?
Is the inspection frequency in accordance with regulatory
requirements?
•
What is the turbidity of the backwash waste?
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•
What is the turbidity level of the effluent water following the
backwash?
•
Does the first forward flow go to waste?
If a gravity filtration system is installed, then the following should be checked:
•
Is there any visible indication of problems on the surface of the
filter?
•
Are there any pressure relief vents from the underdrain through
the filter media?
•
Is the monitoring instrumentation (loss-of-head, effluent flow
rate, and filtered water turbidity) working for all filters? What
condition is the instrumentation in?
•
What criteria are used by operators to determine when a filter
requires backwashing? Are filters ever stopped, then started-up
again without backwashing them first? Are filters ever
"bumped" to extend filter runs?
•
Is there a means of measuring the backwash flow rate? What is
its condition? When was the flowmeter calibrated last? Can
the backwash flow be varied to allow for varying conditions?
•
Are newly backwashed filters brought back into service at low
rates that are gradually increased (ramped-up) in order to
minimize post-backwash turbidity spikes? Are operating filter
flow rates reduced when another filter is backwashed?
•
What is the condition of the piping in the filter gallery? Is it
colour coded for the use or service in accordance with
regulatory requirements? Are there any cross-connections?
•
Is there a floor drain to remove all leaking water from the filter
gallery floor?
•
What type of disinfection process and facilities are used at the
treatment plant? Does the operator understand the disinfection
process?
•
What is the chlorine residual leaving the treatment plant? Do
disinfectant residuals meet regulatory requirements?
•
How are wastewater from the backwash process and sludge
from the sedimentation process managed?
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•
Does the water system have a cross connection control plan for
the plant? Is the program active and effective in controlling
cross connections?
•
What are the water uses in the plant? Where does the supply
for these uses come from? Are proper backflow prevention
devices installed to protect potable water at the plant?
•
Are the appropriate backflow preventers used for all existing
cross connections? The auditor should have a copy of
CAN/CSA B64.10 Manual for the Selection, Installation,
Maintenance, and Field Testing of Backflow Prevention
Devices.
Audit Priority Criteria
The following criteria related to the water treatment element of the audit are
considered high priority based on their potential for impacting public health:
•
•
•
•
•
•
•
•
Capacity of Treatment Facilities
Rapid Mix, Chemicals and Chemical Feed Systems, and
Coagulation/ Flocculation
Sedimentation/Clarification
Filtration
Disinfection
Waste Streams
In-Plant Cross-Connection Control
Treatment Plant Schematic/Layout Map
Distribution System Audit
After water has been treated, water quality must be protected and maintained as
it flows through the distribution system to the customer's tap. The following
questions relate to the water purveyor's ability to maintain high water quality
during storage and distribution.
Storage
Gravity
•
Are storage reservoirs covered and otherwise constructed to
prevent contamination?
•
Are all overflow lines, vents, drainlines, or cleanout pipes
turned downward and screened?
•
Are all reservoirs inspected regularly?
•
Is the storage capacity adequate for the system?
•
Does the reservoir (or reservoirs) provide sufficient pressure
throughout the system?
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•
Are surface coatings within the reservoir in good repair and
meet National Sanitation Foundation (NSF) Standard 6.1.
•
Is the hatchcover for the tank watertight and locked?
•
Can the reservoir be isolated from the system?
•
Is adequate safety equipment (caged ladder, approved safety
belts, etc.) in place for climbing the tank?
•
Is the site fenced, locked, or otherwise protected against
vandalism?
•
Is the storage reservoir disinfected after repairs are made?
What disinfection process standard is followed?
•
Is there a scheduled program for cleaning storage reservoir
sediments, slime on floor and side walls.
Hydropneumatic
•
Is the storage capacity adequate for the system?
•
Are instruments, controls, and equipment adequate, operational,
and maintained?
•
Are the interior and exterior surfaces of the pressure tank in
good condition?
•
Are tank supports structurally sound?
•
Does the low pressure cut in provide adequate pressure
throughout the entire system?
•
Is the pump cycle rate acceptable (not more than 15
cycles/hour)?
Cross Connections
•
Does the utility have a cross connection prevention program,
including annual testing of backflow prevention devices?
•
Are backflow prevention devices installed at all appropriate
locations (wastewater treatment plant, industrial locations,
hospitals, etc.)?
•
Are proper pressures and flows maintained at all times of the
year?
•
Do all construction materials meet AWWA, NSF or equivalent
standards?
•
Are all services metered and are meters read?
•
Are plans for the system available and current?
•
Does the system have an adequate maintenance program?
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•
Is there evidence of leakage in the system?
•
Is there a pressure testing program?
•
Is there a regular flushing program?
•
Are AWWA standards for disinfection followed after all
repairs?
•
Are there specific bacteriological criteria and limits prescribed
for new line acceptance or following line repairs?
•
Describe the corrosion control program.
Administrative Audit
•
Is there an organization that is responsible for providing the
operation, maintenance, and management of the water system?
•
Does the utility regularly summarize both current and longterm problems identified in their watershed, or other parts of
the system, and define how they intend to solve the problems,
i.e., is their planning mechanism effective; do they follow
through with plans?
•
Are customers charged user fees and are collections
satisfactory?
•
Are there sufficient personnel to operate and manage the
system?
•
Are personnel (including management) adequately trained,
educated, and/or certified?
•
Are operation and maintenance manuals and manufacturers
technical specifications readily available for the system?
•
Are routine preventative maintenance schedules established and
adhered to for all components of the water system?
•
Are sufficient tools, supplies, and maintenance parts on hand?
•
Are sufficient operation and maintenance records kept and
readily available?
•
Is an emergency plan available and usable, and are employees
aware of it?
•
Are all facilities free from obvious safety defects?
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When the survey is completed, it is preferable to briefly summarize the survey
with the operator(s) and management. The main findings of the survey should
be reviewed so it is clear that there are no misunderstandings about the findings.
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Acronyms
AFR
Arbitrary fixed radius
AMO/MEA/OGRA
Association of Municipalities of Ontario,
Municipal Engineers Association and the
Ontario Good Roads Association
AVI
Aquatic Vulnerability Index
AWWA
American Water Works Association
CCME
Canadian Council of Ministers of the
Environment
CCPs
Critical Control Points
CDW
Federal-Provincial-Territorial Committee on
Drinking Water which reports to the FederalProvincial-Territorial Committee on Health
and Environment
CFR
Calculated fixed radius
CT
Contact Time (of disinfectant in water)
CTIC
Conservation Technology Information Center
CWWA
Canadian Water and Wastewater Association
DBPs
Disinfection By-Products
DSS
Decision support systems
EQGs
Environmental Quality Guidelines
EQOs
Environmental Quality Objectives
FCA
Full-cost accounting
FCM
Federation of Canadian Municipalities
GIS
Geographic Information System
HACCP
Hazard Analysis and Critical Control Points
MAPAQ
Ministry of Agriculture, Fisheries and Food of
Quebec
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MF
Microfiltration (drinking water treatment
process)
MPA
Microscopic particulate analysis
NF
Nanofiltration (drinking water treatment
process)
NRC
Natural Resources Canada
OMAFRA
Ontario Ministry of Agriculture, Food and
Rural Affairs
PPCPs
Pharmaceuticals and Personal Care Products
RO
Reverse osmosis (drinking water treatment
process)
SCADA
Supervisory control and data acquisition
equipment
SSO
Site specific objective
SWP
Source water protection
TDML
Total maximum daily load
TDS
Total Dissolved Solids
TOT
Time of Travel (for streamflows)
TQM
Total Quality Management
UF
Ultrafiltration (drinking water treatment
process)
US EPA
United Stated Environmental Protection
Agency
WHMIS
Workplace Hazardous Materials Information
System
WHO
World Health Organization
WQTG
Water Quality Task Group of the Canadian
Council of Ministers of the Environment
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Glossary
Acute Health Effect
An immediate (within hours or days) effect that
may result from exposure to certain drinking
water contaminants.
Anthropogenic
Resulting from the influence of humans;
induced or altered by human presence or
activities.
Aquifer
Geological formation of permeable rock, sand,
or gravel that conducts ground water and yields
significant quantities of water to springs and
wells.
Aquitard
Geological formation of a semi-impermeable
and semi-confining nature, which transmits
water at a very slow rate. It serves mostly as a
storage unit for groundwater rather than yield
water to springs or wells.
Artesian Well
A well in which water from a confined aquifer
rises above the water table of the aquifer.
Bacteria
Simple, unicellular organisms with an average
size of 1/1,000 mm diameter.
By-product
New products or substances formed when a
chemical reaction occurs.
Catchment
A surface from which draining water is
collected.
Chloramines
Chemical compounds of chlorine and nitrogen
used in disinfection of drinking water.
Chronic Health Effect
The possible result of exposure over many
years to a drinking water contaminant.
Cistern
A water storage tank typically used for catching
and storing rainwater.
Coliform Bacteria
A group of related bacteria whose presence in
drinking water may indicate contamination by
disease-causing microorganisms.
Conductivity
The property of a body to conduct electricity.
Contaminant
Anything found in water that might be harmful
to human health.
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Cryptosporidiosis
The illness caused by Cryptosporidium.
Cryptosporidium
A protozoa commonly found in lakes and
rivers, which is highly resistant to disinfection.
May cause gastrointestinal illness.
Disinfection
A chemical or physical process that kills
microorganisms.
Disinfection by-products
Chemical compounds that result from the
reaction of disinfectants with organic matter in
the water being treated.
Erosion
Process whereby the materials of the Earth's
crust are loosened, dissolved, or worn away.
Erosion results in higher sedimentation of
particles in bottom of in water plans.
Eutrophic
Designating a water plan enriched in dissolved
nutrients that stimulate the growth of aquatic
plant life and usually resulting in the depletion
of dissolved oxygen.
Exposure
Accessibility to drinking water contaminants
that may cause harm or danger to the consumer.
Finished Water
Water that has been treated and is ready to be
delivered to consumers.
Giardia
A protozoa frequently found in rivers and lakes,
which, if not treated properly, may cause
gastrointestinal illness.
Groundwater
The water found in underground aquifers which
supplies wells and springs.
Hazard
A source of danger or harm to the drinking
water consumer.
Hydraulic
Operated, moved, or effected by a fluid under
pressure, often water.
Hydrology
Science studying properties, distribution, and
effects of water on the Earth's surface.
Local Authority
The group or organization that has the local
control over the drinking water supply, such as
a municipality or conservation authority.
Irrigation
The artificial supply and application of water to
the soil to maintain moisture in crop fields.
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Microorganisms
Living organisms that can be seen only with the
aid of a microscope.
NTU
Nephelometric Turbidity Unit – a unit that
expresses the amount of turbidity in water.
Oligotrophic
Designating a water plan with a low nutrient
content. As a result, algal growth is minimal.
Owner/operator
The organization or person(s) who own or run
the drinking water system (including treatment
plant(s) and distribution system). Examples
include public or private water utilities.
Pathogen
A disease-causing organism.
Porosity
Property of a solid containing minute channels
or open spaces, often referred as the ratio of the
volume of all the pores in the solid to the
volume of the whole.
Private Water System
Individual domestic drinking water system used
for personal or family needs only.
Protozoa
Single-celled organisms. More complex
physiology than viruses and bacteria. Average
size of 1/100 mm diameter.
Raw Water
Water in its natural state, prior to any treatment
for drinking.
Riparian
Of or on a riverbank.
Risk
The possibility of suffering, harm, or danger
from consuming drinking water.
Sanitary Survey
An on-site assessment of the water sources,
treatment facilities, equipment, operation, and
maintenance of a water system for the purpose
of evaluating the adequacy of the facilities for
producing and distributing safe drinking water.
Sedimentation
The process of settling and deposition of
suspended matter in the bottom of a water plan.
Semi-Public Water System
Drinking water system with fewer source
connections than regulated for a public system
but more than for personal or family use.
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Source Water
Water in its natural or raw state, prior to being
withdrawn for treatment and distribution as a
drinking water supply.
Stakeholder
Person or group of people affected by, or who
can influence, a decision or action.
Surface Water
The water from sources open to the atmosphere,
such as rivers, lakes, and reservoirs.
Topography
Three-dimensional graphic representation of the
elevations or inequalities of the Earth's surface.
Total Organic Carbon
A laboratory measurement that indicates the
amount of organic matter in water.
Transmissivity
A measure of the rate of movement of water
through an aquifer.
Turbidity
The cloudy appearance of water caused by the
presence of tiny organic or inorganic particles.
Vadose
Relating to an area with dry and wet periods
depending on groundwater table level.
Virus
Very simple life forms that do not multiply
outside of living host cells. Average size of
1/10,000 mm diameter.
Velocity
Rate of movement of an object past a point in a
specified direction.
Watershed
The area draining naturally from a system of
watercourses and leading to one body of water.
Wellhead
The structure built over a well to maintain
water protection. The land area surrounding a
drinking water well or well field.
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Reference List
Agriculture and Agri-Food Canada. 2002. Mapping Applications and Data.
http://www.agr.gc.ca/pfra/gis/ (accessed September 17, 2003).
Alberta Environmental Protection. 1997. Standards and Guidelines for
Municipal Waterworks, Wastewater and Storm Drainage Systems.
Edmonton, AB: Government of Alberta. Available at:
http://www3.gov.ab.ca/env/waste/muniwwater/stormdrainage.html
Association of Municipalities of Ontario, Municipal Engineers Association and
the Ontario Good Roads Association. 2002. Submission to the
Walkerton Inquiry in Preparation for Public Meeting #1 [July 2001]. In
Report of the Walkerton Inquiry, Commissioned Papers and
Submissions, Hon. D.R. O’Connor. Toronto, ON: Ontario Ministry of
the Attorney General. CD-ROM.
American Water Works Association. 2002. Workshop S6: The How, Where and
Why of Applying HACCP to Water. Workshop Manual distributed at
the AWWA Water Quality Technology Conference, Seattle.
British Columbia Provincial Health Officer. 2001. Drinking water quality in
British Columbia: The public health perspective. In A Report on the
Health of British Columbians: Provincial Health Officer’s Annual
Report 2000. Victoria, BC: Ministry of Health Planning. Available at:
http://www.healthplanning.gov.bc.ca/pho/ar/index.html
Canadian Council of Ministers of the Environment. 1996. A Framework for
Ecosystem Health Goals, Objectives, and Indicators: Tools for
Ecosystem- Based Management.
Canadian Council of Ministers of the Environment. 1999a. Canadian
Environmental Quality Guidelines. Winnipeg, MB: Canadian Council
of Ministers of the Environment.
Canadian Council of Ministers of the Environment. 1999b. Canadian water
quality guidelines for the protection of aquatic life: pH (Marine). In
Canadian Environmental Quality Guidelines. Winnipeg, MB:
Canadian Council of Ministers of the Environment.
Canadian Council of Ministers of the Environment. 1999c. Canadian water
quality guidelines for the protection of aquatic life: Temperature
(Marine). In Canadian Environmental Quality Guidelines. Winnipeg,
MB: Canadian Council of Ministers of the Environment.
Conservation Technology Information Center. 2002. Know your watershed.
http://www.ctic.purdue.edu/KYW
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SAFE DRINKING WATER
Coote, D.R., and L.J. Gregorich, eds. 2000. Incentive mechanisms. In The
Health of Our Water - Towards Sustainable Agriculture in Canada.
Ottawa, ON: Agriculture and Agri-food Canada, Research Branch.
Available at: http://res2.agr.ca/publications/hw/index_e.htm
Department of Fisheries and Oceans, Habitat and Enhancement Branch. 2002.
GIS Maps and Data. http://www-heb.pac.dfompo.gc.ca/english/maps/maps-data.htm
Dobson Engineering Ltd. 2002. City of Rossland Watershed Management
Plan.
Environment Canada. 1987. Federal Water Policy. Available at:
http://www.ec.gc.ca/water/en/info/pubs/fedpol/e_fedpol.pdf
Environment Canada. 2002a. Freshwater Website.
http://www.ec.gc.ca/water/e_main.html (accessed September 17, 2003)
Environment Canada, Prairie and Northern Region. 2002b. Prairie Provinces
Water Board Reports - Index.
http://www.mb.ec.gc.ca/water/fa01/fa01s56.en.html
Government of British Columbia. 2000. Well protection toolkit. B.C. Ministry
of Environment, Lands and Parks, B.C. Ministry of Health and Ministry
Responsible for Seniors, and Environment Canada. Available at:
http://wlapwww.gov.bc.ca/wat/gws/well_protection/wellprotect.html
Government of Newfoundland and Labrador. 2001. Source to Tap: Water
supplies in Newfoundland and Labrador. Department of the
Environment, Water Resources Management Division. Available at
http://www.gov.nf.ca/env/SourceToTap/SourceToTap/Report.asp
Health Canada. 2000. Decision-making framework for identifying, assessing,
and managing health risks.
Health Canada. 2001. Guidelines for Canadian Drinking Water Quality Supporting Documents. Available at http://www.hc-sc.gc.ca/hecssesc/water/dwgsup.htm
Livernois, J. 2002. The Economic Costs of the Walkerton Water Crisis.
Walkerton Inquiry Commissioned Paper 14. Toronto, ON: Ontario
Ministry of the Attorney General. Available at:
http://www.uoguelph.ca/~live/WICP-14-Livernois1.pdf
Lowrance, R., S. Dabney, and R. Schultz. 2002. Improving water and soil
quality with conservation buffers. Journal of Soil and Water
Conservation. 57(2): 36a-43a
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SAFE DRINKING WATER
MacDonald, D.D., D.E. Smorong, D.A. Levy, L. Swain, P.Y. Caux, and J.B.
Kemper. 2002. Guidance on the site-specific application of water
quality guidelines in Canada: Procedures for deriving numerical water
quality objectives (Draft for public review). Report prepared for the
Canadian Council of Ministers of the Environment, Winnipeg, MB.
Ministry of Environment and Energy and Ministry of Natural Resources. 1997.
Inventory of watershed management projects in Ontario 1990-1995.
Government of Ontario. Available at:
http://www.ene.gov.on.ca/programs/35460.pdf
Natural Resources Canada. 2000. Geogratis - Canada Land Inventory.
http://geogratis.cgdi.gc.ca/clf/en
Natural Resources Canada. 2002a. Geoconnections - Canadian Geospatial
Data Infrastructure. http://www.cgdi.gc.ca
Natural Resources Canada. 2002b. Atlas of Canada.
http://atlas.gc.ca/site/english/index.html
NHMRC/ARMCANZ Co-ordinating group. Framework for management of
drinking water quality: A preventive strategy from catchment to
consumer. Document for public consultation. Australia.
Saskatchewan Environment and Resources Management. 1995. A Policy
Framework. Public Involvement in the Management of Saskatchewan’s
Environment and Natural Resources. Saskatchewan Environment and
Resource Management Public Involvement Working Group.
Statistics Canada. 2002. Statistics Canada home page.
http://www.statcan.ca/start.html
United States Environmental Protection Agency. 1995. Watershed tools
directory: A collection of watershed tools. Washington DC: US EPA
Office of Water. EPA 841-B-95-005. Available at
http://www.epa.gov/OWOW/watershed/tools/index.html
United States Environmental Protection Agency. 1997a. Top 10 watershed
lessons learned. Washington, DC: U.S. EPA Office of Wetlands,
Oceans and Watersheds. EPA840-F-97-001. Available at:
http://www.epa.gov/owow/watershed/lessons/index.html
United States Environmental Protection Agency. 1997b. State methods for
delineating source water protection areas for surface water supplied
sources of drinking water. Washington, DC: U.S. EPA Office of
Water. EPA816-R-97-008.
United States Environmental Protection Agency. 1997c. Delineation of source
water protection areas, a discussion for managers, Part 1: A conjunctive
approach for ground water and surface water. Washington, DC: U.S.
EPA Office of Water. EPA816-R-97-012.
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United States Environmental Protection Agency. 1997d. Compendium of tools
for watershed assessment and TMDL development. Washington DC:
US EPA Office of Water. EPA 841-B-97-006. Available at:
http://www.epa.gov/owow/tmdl/comptool.html
Watershed Planning Implementation Project Management Committee. 1997. An
Evaluation of Watershed Management in Ontario - Final Report.
Government of Ontario. Available at:
http://www.ene.gov.on.ca/programs/3513e.pdf
Watson, S.B., M. Charlton, B. Brownlee, M. Skafel, T. Howell, L. Moore, J.
Ridal and B. Zaitlin. 2002. Aquatic odour in Lake Ontario: Tracing
origins through a complex system. Abstract. 37th Central Canadian
Symposium on Water Pollution Research, 2002. Canada Centre for
Inland Waters, Burlington, ON.
Yates, C. 2001. Applications ‘on the Ground’: The HWRC approach to
Watershed Management. Halifax Region Water Commission. Toronto,
ON: PowerPoint presentation to the Water Quality Management
Symposium, 2001.
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For Further Reading
Alberta Environment. Standards and Guidelines for Municipal Waterworks,
Wastewater and Storm Drainage Systems. 1997.
AWWA. Emergency Planning for Water Utilities - Manual of Water Supply
Practices (M19). 2001.
— Recommended Practice for Backflow Prevention and Cross-Connection
Control (M14). 1990.
— Installation, Field Testing and Maintenance of Fire Hydrants (M17). 1989.
—Distribution Valves: Selection, Installation, Field Testing, and Maintenance
(M44). 1998.
AWWA and ASCE. Water Treatment Plant Design, 3rd Edition. McGraw Hill,
1998. (pp576-604)
AWWARF. Guidance Manual for Maintaining Distribution System Water
Quality. 2002.
— Investigation of Criteria for GWUDI Determination. 2001. Report No ISBN
1-58321-116-0
— Filter Maintenance and Operations Guidance Manual. 2002. Report ISBN 158321-234-5
Canadian Standards Association. Manual for the selection, installation,
maintenance, and field testing of backflow prevention devices-Plumbing
products and materials: A National Standard of Canada. 2001.
Canadian Water and Wastewater Association. Municipal Water and Wastewater
Rates Primer. 1997.
— Municipal Water and Wastewater Rate Manual, 2nd Edition.
— Meters Made Easy: A Guide to the Economic Appraisal of Alternative
Metering Investment Strategies.
— Vulnerability Assessment Template. CD-ROM. 2003.
Fire Underwriters Survey. Water Supply for Public Fire Protection - A Guide to
Recommended Practice.
Health Canada . Guidance for Issuing and Rescinding Boil Water Advisories.
2001
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Health Canada. Guidelines for Canadian Drinking Water Quality. For the most
current guidelines and supporting documentation, see http://www.hcsc.gc.ca/waterquality
Nova Scotia Department of Environment and Labour. Protocol for Determining
Groundwater Under the Direct Influence of Surface Water. 2002.
Available at: http://www.gov.ns.ca/enla/water/pdf/munguidp.pdf
Ontario Ministry of the Environment. A Kit for Regulated Non-Municipal
Drinking-Water System Owners (Drinking Water Systems Regulation
O. Reg. 170/03). Toronto, ON: July 2003. ISBN 0-7794-4899-5
Twort, C. Alan, D. Don Ratnayaka and J. Malcom Brandt. Organization and
Financing of Public Water Supplies. In Water Supply, 5th Edition.
London: Arnold and IWA Publishing, 2000.
University of Southern California Foundation for Cross-Connection Control and
Hydraulic Research (USC-FCCHR). Manual of Cross Connection
Control.
US EPA. Technology Transfer: Optimizing Water Treatment Plant
Performance using the composite correction program. 1998. Available
at: http://www.epa.gov/ORD/NRMRL/Pubs/1991/625691027.pdf
World Health Organization. Water Quality: Guidelines, Standards and Health:
Assessment of Risk and Risk Management for Water-Related Infectious
Disease. 2001.
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Websites referenced in the document
Canadian Council of Ministers of the Environment:
http://www.ccme.ca
Health Canada’s water quality website:
http://www.hc-sc.gc.ca/waterquality
Natural Resources Conservation Service (US Department of Agriculture):
www.wcc.nrcs.usda.gov/water/quality/frame/waterqal.html
Surface Water and Water Quality Models Information Clearinghouse:
http://smig.usgs.gov/SMIC
US Army Corps of Engineers:
http://www.wes.army.mil/el/elmodels
US EPA:
http://www.epa.gov/waterscience/wqm
http://www.epa.gov/ada/csmos/models.html (Groundwater Models)
http://www.epa.gov/OGWDW/swp/sources1.html (Resource guide: creating
hazard inventory list)
http://www. epa.gov/OGWDW/filterbackwash.html (Filter Backwash Recycling
Rule)
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