AN ECONOMIC SUPPLY FUNCTION FOR THE DIVERSION

AN ECONOMIC SUPPLY FUNCTION FOR THE DIVERSION
AN ECONOMIC SUPPLY FUNCTION FOR THE DIVERSION
OF IRRIGATION WATER TO TUCSON
by
James Jerome Jacobs
A Thesis Submitted to the Faculty of the
DEPARTMENT OF AGRICULTURAL ECONOMICS
In
Partial Fulfillment of the Requirements
For the Degree of
MASTER OF SCIENCE
In
the Graduate College
THE UNIVERSITY OF ARIZONA
1968
STATEMENT BY AUTHOR
This thesis has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is
deposited in the University Library to be made available to borrowers
under rules of the Library.
Brief quotations from this thesis are allowable without special
permission, provided that accurate acknowledgment of source is made.
Requests for permission for extended quotation from or reproduction of
this manuscript in whole or in part may be granted by the head of the
major department or the Dean of the Graduate College when in his judgment the proposed use of the material is in the interests of scholarship.
In all other instances, however, permission must be obtained
from the author.
SIGNED:
1
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below:
N. N. KELSO
Professor of Agricultural Economics
April 30, 1968
Date
ACKNOWLE DGMENT S
The author wishes to express his sincere appreciation and
thanks to Dr. M. M. Kelso for the extensive guidance and constructive
criticism he provided throughout the preparation of this thesis.
Sincere appreciation is also extended to Drs. Robert A. Young
and William E. Martin for their suggestions and constructive comments
in preparation of this study.
The author is grateful to Mr. Wayne Clyma and Mr. R. J. Shaw
for their time, cooperation, and assistance in the early stages of this
thesis.
Also a very sincere thank you goes to them and to the Depart-
ment of Agricultural Engineering for providing data used in this thesis
Grateful acknowledgment is also extended to Mr. John F. Rausche
and to the City of Tucson Water and Sewerage Department for providing
data used in this thesis.
A special kind of appreciation goes to my wife, Carol, for her
patience, encouragement, and assistance throughout my graduate program.
111
TABLE OF CONTENTS
Page
LIST OF TABLES
vi
LIST OF ILLUSTRATIONS
x
ABSTRACT
xii
INTRODUCTION
1
Problem and Situation
Possible Legal Restraints on Diversion of
Irrigation Water
Implications of the Problem for Economic
Analysis
Objective of this Analysis
Theoretical Framework of Analysis
The Direct Costs of Supplying Additional
Water
The Indirect Cost of Supplying Additional
Water
The Total Economic Cost of Supplying
Additional Water
1
8
10
16
17
17
31
32
ANALYTICAL TECHNIQUE
33
Analytical Model
Assumptions
Supply Function
Use of the Imported Water
33
35
41
43
ANALYSIS OF THE DIRECT COST OF DIVERSION OF IRRIGATION
WATER TO TUCSON IN TEN MILLION GALLONS PER DAY
INCREMENTS
Cropland Acreage and Irrigation Use
Present Groundwater Table Conditions
Irrigation Water Diversion Units
Direct Cost of the Diversion of Irrigation Water
to Tucson in 10 mgd Increments
Land Costs
Construction Costs:
Pumping and Delivery Systems
Well Field Costs
Pipeline Costs
iv
46
46
47
52
.
.
54
57
58
58
60
V
TABLE OF CONTENTS--Continued
Page
Annual Invest:rnent Costs
Annual Operating Costs
ANALYSIS OF THE DIRECT COST OF DIVERSION OF IRRIGATION
WATER TO TUCSON IN TWENTY MILLION GALLONS PER
DAY INCREMENTS
Cropland Acreage, Water Use and Diversion Units
Groundwater Table
Irrigation Water Diversion Units
Cost Analysis of the Diversion of Irrigation
Water to Tucson in 20 mgd Increments
10 and 20 mgd Diversion Units
64
64
72
72
72
72
73
82
ECONOMIC EXTERNALITIES ASSOCIATED WITH DIVERTING
IRRIGATION WATER TO URBAN USE IN THE TUCSON
REGION
85
Multiplier Effects
Measuring Direct and Indirect Income Effects
85
86
SUMMARY AND APPRAISAL
Summary
Appraisal
APPENDIX:
BASIC DATA AND COST ANALYSIS FOR AREAS
I-XVIII
LIST OF REFERENCES
102
102
105
109
146
LIST OF TABLES
Page
Table
(Average Annual) Crop Acreage and Irrigation Water
Use by Water Diversion Units (1960-65)
56
Summary of Annual (Amortized) Direct Costs for
Diversion of Irrigation Water to Tucson by
Diversion Units (10 mgd)
68
The Supply Schedule: Annual (Amortized) Direct
Costs per Acre-Foot for Diverting Irrigation
Water to Tucson in 10 mgd Increments, Ranked
in Order of Ascending Costs
69
Summary of Annual (Amortized) Direct Costs for
Diversion of Irrigation Water to Tucson in
Increments of 20 mgd
79
The Supply Schedule: Annual (Amortized) Direct
Costs per Acre-Foot for Diverting Irrigation
Water to Tucson in 20 mgd Increments, Ranked
in Order of Ascending Costs
80
Direct Cost per Acre-Foot of
The Supply Schedule:
Diversion of Irrigation Water to Tucson in 10 and
20 mgd Increments
83
1967 Prices and Yields of Irrigated Crops in the
Tucson Region
89
Direct, Indirect, and Total Personal Income
Generated by Irrigated Agriculture in the
Tucson Region (Based on Tables 1 and 7)
90
Farm Real Estate Investment Incomes (Rent) Generated
in Irrigated Agriculture in the Tucson Region
.
Total Community Economic Cost per Acre-Foot (Direct
and Indirect) for Diverting Irrigation Water
to Tucson from Various Diversion Units in
Increments of 10 mgd (1967)
vi
.
.
.
92
96
vii
LIST OF TABLES-Continued
Table
11.
Page
Economic Penalty Imposed on the Tucson Economy by
Obtaining the Indicated Quantities of Additional
Water from the CAP in Place of Diversion from
Local Irrigation
101
&pendix Tables
Location and Pumping Conditions of Area I
110
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area I, 1967
111
Location and Pumping Conditions of Area II
112
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area II, 1967
113
Location and Pumping Conditions of Area III
114
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area III, 1967
115
Location and Pumping Conditions of Area IV
116
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area IV, 1967
117
Location and Pumping Conditions of Area V
118
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area V, 1967
119
Location and Pumping Conditions of Area VI
120
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area VI, 1967
121
viii
LIST OF TABLES--Continued
Table
14-A.
Page
Location and Pumping Conditions of Area VII
122
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area VII, 1967
123
Location and Pumping Conditions of Area VIII
124
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area VIII, 1967
125
Location and Pumping Conditions of Area IX
126
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area IX, 1967
127
Location and Pumping Conditions of Area X
128
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 rngd
from Area X, 1967
129
Location and Pumping Conditions of Area XI
130
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area XI, 1967
131
Location and Pumping Conditions of Area XII
132
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 7 mgd and at 14 mgd
from Area XII, 1967
133
Location and Pumping Conditions of Area XIII
134
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 4 mgd and at 8 mgd
from Area XIII, 1967
135.
Location and Pumping Conditions of Area XIV
136
ix
LIST OF TABLES-'Contjnued
Table
14-B.
Page
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area XIV, 1967
137
Location and Pumping Conditions of Area XV
138
Estimated Costs for the. Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area XV, 1967
139
Location and Pumping Conditions of Area XVI
140
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area XVI, 1967
141
Location and Pumping Conditions of Area XVII
142
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 10 mgd and at 20 mgd
from Area XVII, 1967
143
Location and Pumping Conditions of Area XVIII
144
Estimated Costs for the Diversion of Irrigation
Water to Tucson at 5 mgd and at 10 mgd
from Area XVIII, 1967
145
LIST OF ILLUSTRATIONS
Page
Figure
The Tucson Region
6
Per Unit Variable Cost of Pumped Water Over Time at
Any Given Location (Hypothetical Data)
12
Water Cost per Acre-Foot from Alternative Sources
(Hypothetical Data)
14
Short-Run Cost Curves for a Given Scale of Plant
for Production of Water from a Given Aquifer
(Hypothetical Data)
19
Long-Run Average Total Cost
21
Expansion Path
23
Average Total Cost per Acre-Foot Over Time, Scale of
Plant Given, Groundwater Declining (Hypothetical
25
Data)
Level of and Increase Over Time in Average Total Cost
per Unit of Water Relative to Plant Size (Rate
of Withdrawal), Initial Pumping Lift Equal Among
All Plant Sizes (Hypothetical Data)
26
Supply Function for Water from Alternative Subareas
for Two Given Plant Sizes (Hypothetical Data)
29
Water Level Contours, Spring 1965, in Santa Cruz
Valley, Arizona, Depth Below the Surface
50
Water Level Contours, Spring 1965, Avra Valley,
Arizona, Depth Below the Surface
51
Irrigation Water Diversion Units in the Tucson
Region
55
x
xi
LIST OF ILLUSTRATIONS-Continued
Page
Figure
Supply Function (Direct Production and Delivery Costs)
for the Diversion of Irrigation Water to Tucson
in 10 mgd Increments
71
Supply Function for Diversion of Irrigation Water
to Tucson in 20 mgd Increments
81
Expected Minimum and Maximum (Total Cost) Supply
Function for the Diversion of Irrigation Water
to Tucson in 10 mgd Increments
98
ABSTRACT
Water is a severely limited resource to the City of Tucson.
Additional water imported from outside the city is one way to mitigate
One alternative source of such water is the diversion
the shortage.
of irrigation water to the city from nearby farming areas.
The direct
cost of such water includes buying the land on which it is now used
and installing the necessary works to develop and deliver it.
Budgets
of such costs were developed in units of 10 and 20 million gallons
per day and the direct cost per acre-foot determined.
Irrigated agriculture is part of the economic base of the
Tucson economy.
Its elimination by diversion of the water upon which
it depends will reduce the city's economy and is an indirect cost of
such water.
Estimates were made of the magnitude of such indirect
economic costs and were added to the direct pumping and delivery costs.
These two costs constitute the total economic cost of diverting irrigation water to municipal use.
The increase in this cost as increasing
quantities of water are acquired constitutes the supply schedule for
increments of water diverted from irrigation to municipal and industrial
use in Tucson.
xii
CHAPTER 1
INTRODUCTION
Problem and Situation
The City of Tucson and the adjacent urban, industrial, and
farming areas are completely dependent upon underground aquifers for
their water supplies.
TUCSOfltS continual growth in population and
the consequent increased pumping of water from the Tucson Basin which
underlies the city, causes an increasing decline of the iater table in
the Basin.
Intensive study is being directed to alternative sources
of supplemental water sources for the city.
This increasing pumpage of groundwater in the Tucson urban
area cannot continue indefinitely if the recent growth and prosperity
of the city are to continue.
Since a groundwater reservoir, like a
mineral deposit, is a stock resource, continuous water withdrawal in
excess of recharge will at some point in time totally exhaust the
groundwater reservoir.
The declining groundwater table in the Basin poses a threat not
only that the water it contains may be exhausted, but also the threat
that at some depth the quality of the groundwater will become unsuitable
for urban use.
However, this problem of water quality will not be in
vestigated in this study.
Thus in the face of an increasing decline of
Basin, there is need for research
the groundwater table in the Tucson
on alternative sources of water for the city from outside the Tucson
1
2
Basin in order to diminish if not arrest the rate of decline of the
groundwater table underlying the city and to provide at minimum cost
a sufficient supply of water to meet the increasing quantity demanded
incident to urban growth.
There are several alternative sources of water available to
Tucson (Prospectus, City of Tucson, 1962) including:
Reclamation of floodwater of the Santa Cruz River and
Rillito Creek will require the construction of facilities
for the diversion, storage, and treatment of floodwater
and the development of recharge and extraction wells along
both streams.
The Rillito as a source of additional water
is not included in this analysis in that this study concerns
only the transfers of water from commercial agriculture of
which there is little along the Rillito.
An estimated 15 million gallons per day can be developed and
imported to Tucson from lands owned by the city on the San
Pedro River.
However, there are uncertainties with respect
to water rights; and the delivering of water through the
Rincon Mountains from this distant source will be quite
costly.
Additional well fields can be developed in the Sahuarita
Bombing Range south of the city, but obtaining more than
five million gallons per day from that area is not considered feasible by the city until deep test wells are completed to determine water quality.
3
Development of the groundwater knoun to underlie the desert
area southeast of Tucson is a further possibility.
However,
the drilling of test wells in this area to determine its
feasibility as a possible source of additional water has
not yet been accomplished.
The Santa Cruz River Basin can be further developed near
Tucson and north of the Sahuarita Bombing Range.
Increased
development of water from this area will tend to increase
the rate of decline of the water table in the Tucson Basin.
Importation of Colorado River water, either by the proposed
Central Arizona Project or by direct aqueduct is another
possible source.
The former requires approval by Congress;
both possibilities raise questions relative to their cost
as sources of imported water.
The diversion of irrigation water now used in the Santa
Cruz Valley south and north of Tucson and in the Avra Valley
west of the city is the possible source examined in this
study.
It could provide Tucson with approximately 161,000
acre-feet of water per annum, which is the estimated quan-
tity now being consumed annually on about 60,600 cropland
acres including fallow lands in these areas.1
Such diver-
sion of irrigation water, in addition to the question of
its costs, presents some institutional problems of water
1.
Estimated acreage and its water use were determined from
unpublished reports of the Department of Agricultural Engineering, The
University of Arizona, Tucson.
4
law and will have indirect effects on the Tucson economy;
both of these questions are considered herein in evaluating
this alternative source of supply.
The Tucson urban area, as designated here, is located in the
center of the broad central part of the Santa Cruz Valley.
It extends
from the Catalina Mountains on the north to Sahuarita Butte on the
south, and from the Rincon Mountains on the east to the Tucson Mountains
on the west.
The population of the Tucson urban area in 1966 was about
284,000 (Population Study 1966, Tucson), and its estimated water use
was about 82,30a acre-feet per year for all purposes.2
Of this quantity,
all but about 10,000 acre-feet per year imported from the Bombing Range
just east of Sahuarita was pumped from aquifers underlying the city and
its immediate environment, hereafter referred to as the Tucson Basin.
Of the 82,300 acrefeet of water estimated as used in the Tucson urban
area in 1966, municipal use accounted for about 53,700 acre-feet; irri-
gation use around 14,800 acre-feet; and miscellaneous uses such as
industrial uses, irrigation of parks, recreation areas, etc., for the
balance of 13,600 acre-feet.
In the Tucson Basin the level of the
groundwater table declined 10 to 25 feet between 1961 and 1965 or at
an average rate of 2 to 6 feet per year
(Matlock, Schwalen, Shaw, l965)
The groundwater table is declining not only in the immediate
Tucson urban area, but also in the urban, industrial, and agricultural
areas surrounding Tucson.
This entire area is designated herein as the
Based on 1966 population consuming an estimated 170 gallons per
2.
Data from unpublished sources in the Department of
capita per day.
Agricultural Engineering, The University of Arizona, Tucson.
5
Tucson Region and includes the subareas of Sahuarita-Continental, Tucson,
Cortaro-Canada Del Oro, and Avra-Marana.
This area is shown on the map
in Figure 1.
As the groundwater table in the Tucson Region continues to decline and as water demands by urban and industrial users increase, it is
likely that the long-run relative importance of agriculture in the Tucson
Region will decline.
Davis and Schwalen (1964) predict that municipal
and domestic use in the Tucson Region will increase from the 1963 quan-
tity of 56,300 acre-feet to 119,560 acre-feet by 1980 and to 294,000
acre-feet by the year 2000.
They further predict that groundwater used
for irrigation in the Region will decrease from the 1963 quantity of
165,565 acre-feet to 112,500 acre-feet by the year 2000.
They expect
that total groundwater pumpage will increase from the 257,045 acre-feet
in 1963 to 277,260 acre-feet by the year 1980 and to 413,031 acre-feet
by the year 2000.
The decline in the use of water for agricultural irrigation
which will accompany a decline in the importance of agriculture in the
Tucson Region will occur for two reasons.
First, the continued decline in the groundwater table will cause
pumping costs to rise which in turn will decrease the net revenue of the
industries using groundwater.
This increasing cost of pumping will have
its greatest effect on heavy water users of which agriculture is the
only one of significance in the Region.
Research at The University of
Arizona has determined the quantities of water used by each of the sev-
eral Arizona economic sectors per $1,000 of output produced in 1958
(Martin and Bower, 1966).
These data show that agricultural irrigation
6
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L
Ma ra no
Silver Bell
0N0NA0O
rk
L
Redington
L
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jTUGSONI
AT I ONAL
MTN.J
E
1J
i
AT I ON A Lj
IN
M0NUMENT
-- ThL1
IF OREST
-.
ISahuarilo
j
Con ifleflt
/
RONIGE [
/RESERVJJ
FrCORONADO
NAT I ONAL
Arnado
Sonoita
FOREST
4
I
10
lI1
Figure 1.
2L
13
I--
The Tucson Region
15
-
17
-
18
7
required from 5.13 acre-feet of water per $1,000 of output for vegetables
to 50.434 acre-feet per $1,000 of output for food and feed grains, while
in all other of the state's economic sectors water required was less than
.5 acre-foot per $1,000 of output.
These data reveal dramatically the
relatively small quantity of water required per $1,000 of output in
urban uses compared to that required in crop irrigation and the consequent ability of the former uses to pay increasing pumping costs compared to low-valued agricultural uses.
Another recent study at The University of Arizona reveals that
the various agricultural sectors of the state's economy generated personal incomes of $14 to $80 per acre-foot of water consumed by them,
while the various nonagricultural sectors generated incomes of $1,685
to $82,301 per acre-foot of water consumed
(Young and Martin, 1967).
Thus, average productivity per unit of water in high waterusing activities, such as agriculture, is low relative to other water
uses in the area because of the large quantities of water required in
the former per dollar unit of output.
These high water-using activities
thus tend to be the marginal users of water; as a result, they will be
the first sectors to lose their positions in the economy as water costs
increase insofar as anything resembling a true or simulated market for
transfer of water use is permitted to operate.
The second reason why future agricultural use of water in the
Region will decline is the expectation of continual expansion of urban
and industrial areas in the Region accompanying economic growth and
expansion.
The expansion of industrial and urban areas will tend to
force agriculture off some presently irrigated lands because of the
8
higher site value the lands will have for nonagricultural uses.
Land
located in areas of municipal and industrial expansion will take on
added value as a result of the willingness of urban users to pay more
for it than its agricultural users can afford to pay, thus purchasing
it away from agricultural uses.
Possible Legal Restraints on Diversion
of Irrigation Water
The purchase of agricultural land by the city and diversion of
irrigation water to urban use may be restrained by barriers in water
law.
Although it is clearly established that landowners have the right
to use the underlying groundwater for beneficial use on their overlying
lands, there is some question whether the groundwater can be exporte,d
by its owner to some other location for such beneficial use.
Thus,
there are possible legal complications confronting the city were it to
undertake transportation of groundwater from presently irrigated lands
lying above the underground water basin from which the supply may be
pumped.
In Bristor v. Cheatham, 75 Arizona 227 (1953), the Arizona
Supreme Court followed Howard v. Perrin and held that the coiniion law
rule created a vested property right in the owner of the land to the
underlying groundwater.
The Court further held that the owner's use
of such water had to be reasonable, and explained the rule of reason
able use as follows:
A majority of the states faced with this problem in recent
years adhere to the principle that the owner of lands overiyjug groundwater may freely, without liability to an adjoining
user, use the same groundwater without limitation and without
liability to another landowner, provided his use is for the
9
purpose of reasonably putting the land from which the water
(Fourth Arizona Town Hall, 1964,
1edto beneficial use
p. 56).
The Court qualified the rule of reasonable use by limiting the use of
groundwater only to those uses which permit beneficial use or enjoyment
of the land from which the groundwater is pumped.
Thus, if the diver
sion or sale of groundwater to others away from the land impairs the
supply of groundwater underlying the property of an adjoining land
holder, such action may be illegal and damages may be recoverable.
The legal restriction that groundwater must be used on the
owner's overlying land may adversely affect municipalities, such as
Tucson, which may find it necessary to transport some or all of their
water from basins located outside their boundaries.
If the transpor-
tation of such water away from the Basin adversely affects the water
supply of other overlying landowners, the city may, at worst, be stopped
entirely from so doing or, at best, be compelled to buy the water rights
of some or all of the overlying landowners or pay them damages.
In this analysis it is assumed that the city must buy the agricultural land to obtain the right to the underlying groundwater.
It is
further assumed in the 10 million gallons per day case analyzed in
this study that the city's diversion of groundwater from lands it may
purchase will be limited to the quantity of water presently consumed
by irrigators on that land.
By so restraining its water withdrawals
the city will not be increasing the consumption of groundwater in any
area it acquires compared to present agricultural use of water in that
area, and thus the city will not adversely affect the water supply of
surrounding landowners any more than does present agricultural use.
10
These two assumptions are presumed, for purposes of this analysis, to
eliminate or diminish any legal problems the city might face were it to
divert 10 mgd of groundwater from each of the several diversion units
it might develop in the surrounding agricultural areas.
These assurap-
tions do not, however, eliminate the legal problem which may face the
20 mgd model developed below which may, in fact, prove to be the principal restraint on that model.
Assuming the export of groundwater to Tucson from surrounding
groundwater basins to be permissible, the city should obtain additional
water supplies as needed from among irrigated cropland areas and/or
from other alternative sources in order of their ascending cost.
Confronted by a continuously declining underground water table,
Tucson must find additional sources of water to meet its long-run needs.
With decreasing future agricultural use of water in the Region and with
the willingness of urban and industrial users of water to pay more for
it than can agricultural users, Tucson should consider the diversion of
groundwater from irrigation to urban uses in the Region as one of the
possible alternative sources of additional water open to it.
This study
explores this problem in a preliminary and unsophisticated manner.
plications of the Problem for
Economic Anal\rs
A declining groundwater table, with stable prices and technology, causes pumping costs to increase over time, thus being of some
time-related consequence to any activity using groundwater.
Rising
pumping costs per unit of water withdrawn cause total variable costs
11
per unit of such water to increase over time.
Ceteris paribus, as illus'-
trated in Figure 2, the total variable cost per unit of grounduater in
time period T3 will be greater than the per unit variable cost in time
period T2, which in turn will be greater than in time period T1.
If the groundwater table were not declining, with prices and
technology constant, the per unit variable cost of groundwater would
remain constant over time as illustrated by the straightline function
in Figure 2.
Were this the case, any user of pumped water, such as the
City of Tucson, could continue to fill its continuing and even its
increasing demands for water by continued or increased pumping from the
underlying aquifer and would not need to consider alternative sources of
water supply.
A declining groundwater table with its attendant increase in
pumping costs, possibly accompanied by decreasing water quality as well,
will cause per unit variable cost of water of suitable quality
crease over time.
to in-
Such increasing costs of water will make it economi-
cally desirable at some point in time for a city like Tucson to obtain
its further supplies of water, continuing and increasing alike, from
some alternative source or sources assuming such alternative supplies
exist.
There are several possible sources of additional water supply
for Tucson, as described on pages 2-4 above.
In determining, from a
purely economic standpoint, which of the alternative sources of water
to develop, the city should choose to develop additional water as needed
from that alternative source having the lowest prospective per unit cost
12
$5.0
0
4.80
j
4.60
4.20
j
4.00
Cd
I
T
I
I
T2
T3
1
Time
Figure 2.
Per Unit Variable Cost of Pumped Water Over
Time at Any Given Location (Hypothetical Data).
13
of water at each point in time when decision to expand must be made.
If
the new supplies are imported into the city from a distance, they can be
used to meet stable year-round or seasonal base demands for water, thus
tnaking it possible to operate the relatively expensive importation
facilities at capacity almost continuously and to draw on the declining
aquifer underlying the city only to meet peaking demands.
By so doing,
the city may reduce overdraft on the Tucson Basin, possibly stabilizing
it.
When the prospective pumping cost per unit of water pumped at
a given location under conditions of overdraft is expected to rise over
time at some determinable rate, such as illustrated in Figure 2, but
decision must be made now as between two or more alternative areas of
different initial pumping levels and different rates of future decline,
it is necessary to convert the prospective rising cost of pumping for
each alternative area into its average annual annuity equivalent value
as viewed at the point in time (T0) when decision between the areas
must be made and which, once made, will be irrevocable for a lengthy
period while sunk investments are depreciated.
However, by so doing,
the cost stream over time for any single location is transformed into
a single-valued definitive figure thus making it possible directly to
compare the present worth of the pumping cost stream of alternative A
with that of alternatives B, C,
.
.
.
N.
Figure 3 illustrates the comparison of average per unit cost of,
water when secured from alternative sources that differ one from another
in distance from the city, in depth to groundwater, and in rate of
14
4I
0
0
40
ci)
.lJ
cci
30
0
00
Alternative Sources
Figure 3.
Water Cost per Acre-Foot from Alternative
Sources (Hypothetical Data).
15
decline in the groundwater level.
Though the water cost at each source
includes an amount to cover future increases in cost due to expected
declines in the water tables, the analysis is nevertheless static in
that it offers no information other than as to which sources should be
chosen for development if decision were made now.
It does not forecast
the order in time nor the dates when each source should be developed.
All parameters bearing on water cost in this study are held constant as
between sources except land prices, distance from Tucson, and the rate
of decline of each aquifer.
Future choices among water sources must
repeat the analysis at each time of decision to make the then preferred
choice under the conditions then prevailing.
If Figure 3 were truly
dynamic, all parameters would be variable including future prices,
preferences, and technologies such that it would specify not only the
best choices to make now among alternative water sources but the timing
and order of development of all sources over the indefinite future.
Such an analysis requires omniscience on a vast quantity of data and
knowledge of the relations involved and thus is quite unworkable within
the constraints of time and data available for this study.
when determining the per unit cost of water from each of the
alternative sources, such as illustrated in Figure 3, there are several
factors some or all of which will affect the per unit cost of water as
between the several sources. 'These factors include declining ground.
water table, engineering costs (installation and operation, for both
extraction and delivery to the city's distribution center), quality of
the water, institutional problems (legaland political), scale of
16
operations, and the time horizon as to expected life of each unit system
and as to when the additional water units will be needed.
These factors
will, be mentioned in greater detail in the analysis to be reported herein,
but are mentioned here because they will tend to differ as between the
alternative sources considered, thus explaining increasing per unit cost
of obtaining water from alternative sources, as illustrated in Figure 3.
Oblective of this Analysis
As municipal and industrial demands for water in and about the
City of Tucson increase over time and as the groundwater table beneath
the city declines and pumping costs increase, an economic choice must
be made by the city relative to expanding its water supplying sources
in the face of such rising demands for and costs of water.
A rational
economic decision requires that the additional quantities of water
required from time to time be obtained from those sources which at the
point in time when the decision to expand must be made, add the least
to per unit cost of water.
The objective of this analysis is restricted to determination
of the supply (cost) function for additional municipal and industrial
water for the City of Tucson obtained from one of the alternative
sources available to it--the diversion of groundwater in the immediate
vicinity of Tucson from commercial irrigation to urban use.3
The supply
3.
A companion or substitute choice might be to increase the
water rates charged to water consumers in the city, thus tending to decrease the quantity of water taken by municipal consumers. The economic
implications of this alternative for meeting the cityts water poblem
are not analyzed in this study.
17
functions will be developed at two levels or scales--at the present
volume of use by agriculture and at twice this volume.
These suppiy
functions are "partial functions" because they reveal only the addi-
tional quantities of water that the city might obtain at increasing
costs by the diversion of increasing quantities of water from irrigation use.
That is, these supply functions do not reveal the additional
quantities of water that might be obtained from other sources at these
increasing costs of water.
They permit, nevertheless, comparing the
cost of transferring water from irrigation to urban use with the cost
of obtaining additional water from other sources, such as from the
Colorado River through the Central Arizona Project.
Theoretical Framework of Anal sis
The Direct Costs of Supplying
Additional Water
A resource, such as water, may be regarded as an input or as
an output; which it is depends on the focus of the analysis.
For
example, viewed by the consumer, water (resource) is an input, however,
to a municipal water company, water (resource) is an output.
Hence,
the City of Tucson's Water and Sewerage Department may be regarded as a
firm attempting to minimize the costs of producing water.
As municipal and industrial demands for water increase over time
and as the groundwater table declines causing pumping costs to rise, the
City of Tucson must make an economic choice.
Such choice to be rational
requires that the additional water expected to be needed over time
be developed from that source or sources which at that point in
18
time when the decision and irrevocable invCstments must be made will add
the least to the prospective per unit cost of water.
A theoretical model pertinent to the economic analysis of this
choice is developed below.
Let us consider first a static framework in the short run relative to costs of water development from a single source as is illustrated
in Figure 4.
In this short-run static single-source framework, the
scale of water production; the location of the well field; the condition
of the aquifer; time; size and location of the area; the market price
of land; and all other exogenous variables are assumed to be constant.
The short-run cost curves in Figure 4 show the cost per unit of
producing different quantities of water outputs with a given scale of
plant from a single aquifer; they are expected to exhibit the usual
U-shaped curvature.
The output from this aquifer at which the average
total cost per unit is the least quantity
outputt' for the given scale of plant.
is the "optimum rate of
At this optimum volume of out-
put, the value of resources sacrificed per unit output of water gained
is a minimum in the short run.
Each point on the average total cost curve represents the lowest
attainable per unit cost of producing from that source in the short
run the output associated with that point and the given scale of plant;
each output-cost point on the average total cost curve can be reached
only if the firm combines variable resources with the given scale of
plant in the proper proportions for each and every volume of output at
which those points are located.
Thus, if a firm's output is to be 10
19
AcreFeet of Water Produced per Day
Figure 4.
Short-Run Cost Curves for a Given Scale of
Plant for Production of Water from a Given
Aquifer (Hypothetical Data).
20
million gallons per day and if its average total cost is to be as low
as possible for that output, the resources to produce it must be com
bined in such proportions that the marginal physical product of an
additional dollar's worth of one resource is equal to the marginal
physical product of an additional dollars worth of each other resource.
Failure to do so will result in higher costs.
The least-cost
point on the average total cost curve for a given scale of plant thus
represents the cheapest possible
ay to produce with that scale of
plant and shows the volume of output produced at this cheapest level
of cost.
Now we shall turn to the long run, in which the firm is free
to build any desired scale of plant again on a given source.
Now, even
the scale of the plant and its complements are variables though all
other exogenous influences, as in the short run, are assumed to remain
Constant.
The long-run average cost, as illustrated in Figure 5, can be
thought of as a series of alternative short-run situations, each with
its short-run average cost curve and its particular scale of plant,
into any one of which the firm is free to move.
The long-run cost
function shows the least possible cost per unit of producing various
outputs from the given source so long as the firm is yet free to build
any desired scale of plant.
Thus, the optimum scale choice from among the possible alterna-
tive scales at T0 is plant (scale) A, assuming that the future cost
flows are similar as between the alternative plants or, if not,
21
A10
A20
Acre-Feet of Water Produced per Day
Figure 5.
Long-Run Average Total Cost
22
assuming a zero discount rate.
Under these conditions, the firm could
expand production in incremental units of plant (scale) A each produc
ing
a
output of water, as is illustrated by the expansion path in
Figure 6.
The City of Tucson chooses to expand water production in incre
mental units of plant (scale A10) of 10 mgd average capacity (plant
A10 in Figure 5) with maximum capacity of 15 mgd.
Thus, the city's
expansion is in lumpy units of 10 mgd each unit presumably designed to
produce at the minimum cost for that scale.
In this analysis, it is
assumed that the city's judgments as to scale increments and design
for each scale are valid and rational and represent the most efficient
scales for long.run decision making.
These judgments were not subjected
to scrutiny in this study.
For purposes of this analysis increments of plant (scale) of
20 mgd (plant A20 in Figure 5), double the capacity of the above 10 mgd
plants, with a maximum capacity of 30 mgd
ere also assumed.
The
hypothesis is that possible cost savings may exist if water production
were expanded in larger increments.
However, offsetting such savings
may be the added cost of more unused capacity in the early years of
life of the larger plants, a cost problem that is not explored in this
analysis; as stated earlier, legal restraints may also arise to bedevil
this alternative.
To this point the only variables have been scale of plant and
its complements; all other parameters have been assumed constant.
How-
ever, the level of the groundwater declines over time at these pumping
23
2Q
Acre-Feet of Water Produced per Day
Figure 6.
Expansion Path
24
volumes, thus introducing an implicit endogenous time-related variable
into the analysis.
The analysis is, however, dynamic only with respect
to dated aquifer depths predicted directly and solely from pumping volumes; all other exogenous influences, including prices and technology
and even specific yield and quality of the aquifers,
are assumed to
remain Constant.
The presence of a declining groundwater table causes pumping
costs per acre-foot to increase over time, in turn causing the average
total cost per acre-foot for each plant size to increase over time.
This is illustrated in Figure 7 which shows the minimum average total
cost per acre-foot for a given plant size, such as plant A10, in each
time period with output held constant.
Since the rate of decline in
water level and thus the average pumping cost per acre-foot over time
depends on the rate as well as the volume of groundwater withdrawal,
choice by the firm at T0 as between alternative plant sizes depends in
part on the length of life of plant investment to which the city commits
itself.
The city assumes a 30-year life for all well, pump, and pipe-
line installations; this study adopts this planning horizon without
critical appraisal.
Figure 8 illustrates the differing levels of and
increases in the average cost per acre-foot of water for plants of
different sizes.
The differing levels and increases in cost for plants
of different sizes result from the differing rates of decline of the
groundwater table due to differing pumping volumes and to differing
levels of economic efficiency with which plants of different sizes
extract water from the aquifer.
25
/
T1
T2
T4
T3
T5
T6
Time
Figure 7.
Avera.ge Total Cost per Acre-Foot Over Time,
Scale of Plant Given, Groundwater Declining
(Hypothetical Data).
26
T30
T13
Time
Figure 8.
Level of and Increase Over Time in Average
Total Cost per Unit of Water Relative to
Plant Size (Rate of Withdrawal), Initial
Pumping Lift Equal Among All Plant Sizes
(}Iypothetical Data).
27
In this analysis the projected annual rate of decline of the
water level in any location is assumed to be a linear function of the
annual volume of water withdrawn; since all pumping units are presumed
to operate constantly (except for maintenance shutdowns), the annual
volume of water withdram at each location is projected as constant from
year to year; as a result the annual increase in pumping costs is
stant and a straight-line function.
con-
A uniform average annual annuity
value of this increasing pumping cost determined at
and extending
over the 30-year life of plant at three and one-half percent interest
(the city's borrowing rate) is used in this study.
Such an amortized
average annual cost under the conditions of this problem turns out to
be the same as the level of pumping cost reached in the 13th year of
plant operation.
(For derivation of this assertion, see pages 36-38.)
Thus, the hypothetical data of Figure 8 show that plant A20 has the
minimum amortized average annual cost (valued at T0) over the 30-year
period when discounted at three and one-half percent because it has the
lowest level of pumping cost in T13.
Other plant sizes may have a
lower cost (hypothetical) than A20 in T0 (A30, for example) or in T30
(A5, A10, A15, for example), but none of them have a lower amortized
average annual cost than A20 over the 30-year period when valued at TO
at three and one-half percent interest.
The next element in the analysis will be to allow alternative
subarea sources of water within the total irrigated area surrounding
Tucson to vary with regard to distance from Tucson, number of areas of
cropiand that must be purchased in each subarea, and market price that
28
must be paid for this cropland; but all other exogenous variables except
plant size will be assumed to remain constant throughout.
Plant size
(scale) will be at two levels, 10 mgd and 20 mgd each in each water
source subarea.
That is, water extraction per subarea will be twice
as rapid in the 20 mgd scale assumption as in the 10 mgd assumption.
Figure 9 illustrates the amortized average annual per acre-foot
total cost, (extended over a 30-year period valued at T0 at three and
one-half percent), for obtaining additional increments of water in lump
units of two scales from alternative subareas.
The increase in the
amortized average annual per acre-foot cost of water as between the
alternative subareas is represented by the step supply function in
Figure 9.
The vertical heights of the steps are due to variation be-
tween subareas in the depth of the groundwater table at T0 as between
areas, the expected rate of decline of the groundwater table over the
life of the investment in each area, the distance of the subareas from
the city, and the purchase price of the irrigated land in each area.
The preferred choices at T0 among the possible subarea alter-
natives available at T0 are those that provide the additional water
needed at T0 and subsequently for 30 years which will add the least to
the amortized average annual per acre-foot cost of water.
This goal
is achieved if those area sources are chosen for development at T0 in
the order of their ascending amortized average annual cost per acrefoot.
That is, area A first, then area B, then area C, etc., until the
required increment in volume of water to be supplied equates with the
demand for additional increments.
29
Increments of 10 mgd
Increments of 20 mgd
20
40
I
I
I
60
80
100
I
120
I
140
160
Acre-Feet Produced per Day
I
I
A
B
I
I
C
D
Alternative Subarea Sources (10 mgd)
B
A
Alternative Subarea Sources (20 mgd)
Figure 9.
Supply Function for Water from Alternative
Subareas for Two Given Plant Sizes (Hypothetical
Data).
30
In a fully dynamic analysis of the economics of Tucson's water
problem, both the city's demand for and supply of water would need to
be considered with regard to time.
The increments in quantity of water
demanded would be dated as to when supplies to fill them would be
needed.
The inputs used in the production of these dated quantities
of water would be valued at their anticipated opportunity costs for
each date.
These dated opportunity costs would be affected by antici-
pations as to changes in technology, institutions, water quality and
other parameters, all of which must be allowed to vary in a fully dynamic model.
The
optimorum choice at T0 as to scale and timing of
water development from all alternative sources and with reference to
all future dates would be that program that maximizes the present value
of the stream of net gains over time which it generates, with future
values discounted to T0-at the social rate of time preference.
This study does not attempt such a fully dynamic analysis,
hence, does provide the basis for such an optimum
choice.
The static model used in this study in which all parameters
are constant except volumes of withdrawal, depth of the aquifers,
their rates of decline, distances of the sources from Tucson, and land
prices permits one to make preferred (static) choice at T0 as between
alternative developments though not the optimum optirnorum choice in
which all parameters are variable and dated as to time of their occurrence.
After having made the T0 (static) choice, to make the next
preferred choice, say in T1, this analysis would need to be repeated
31
to determine the preferred choice under the conditions then prevailing.
This is the process of
mm incremental choice moving us in the
presently preferred direction at the presently preferred speed based
on knowledge presently available.
The process conceptualized in the analysis described above per
mits development of (direct cost) supply functions for the diversion
of irrigation water to urban use in the immediate Tucson Region.
These supply functions reveal the per acrefoot direct costs of sup
plying water in discrete quantities valued at T0 from the various
agricultural subarea sources hereafter described.
The Indirect Cost of Supplying
Additional Water
The direct costs of supplying additional increments of water
to Tucson by diverting irrigation water to municipal use as described
above include only the costs of land purchase, pumping, and delivering
the water to the city.
In addition, removal of agriculture in whole or
in part from the Region removes some of the economic base from the
Tucson economy.
In order to derive a full economic cost of additional
water from this source, it is necessary to estimate the indirect cost
to the city's economy occasioned by this curtailment of commercial
agriculture.
The conceptualization of the facet of water cost to the city
is described in Chapter 5 and will not be repeated here.
32
The Total Economic Cost of Supplying
Additional Water
The total economic cost of supplying additional water for
municipal use by this diversion from coimercial agriculture consists
of the direct costs of so doing plus the indirect costs associated
therewith.
The total economic costs of this alternative as
source
of additional water for Tucson are analyzed and described in Chapter 5.
CHAPTER 2
ANALYTICAL TECHNIQUE
Analytical Model
The analytical method used in this analysis to determine the
diversion per acre-foot to divert irrigation water to municipal use
will be the sum of (1) the amortization of depreciable capital in
wells, pumps and pipelines over 30 years at three and one-half percent,
(2) the annual operating costs of the pumps and pipelines, (3) the
interest at three and one-half percent on land purchase costs, and
(4) the amortized average annual cost of the increasing pumping costs
due to decline of the groundwater level with interest at three and
one-half percent over the 30-year period considered.
Budgeting is used to arrive at the direct cost per acre-foot
of diverting irrigation water to urban use in the Tucson Region.
Costs
of water budgets are developed for each of the several water diversion
units into which the Region is divided.
(See Figure 12 on page 55 and
the discussion on pages 53 and 54 where the water diversion units are
illustrated and discussed.)
Each diversion unit is arbitrarily bounded
to include an area of reasonably contiguous cropland from which approxiniately 9,200 acre-feet of water per year (10 mgd for 300 days)4
4.
The Tucson Water Department in its advance planning assumes
well fields will operate at design capacity for 300 days per year.
33
34
presently consumed in irrigation annually within the unit can be diverted to Tucson for use as municipal and industrial water.
The crop-
land included in these units lies north and west of Tucson along the
Santa Cruz River from Jaynes Station to Marana and in Avra Valley from
Narana to Three Points, together with that which lies along the Santa
Cruz River south of Tucson to the Santa Cruz County line.
The acreage of cropland required to make up each diversion unit
is derived from data as to the average volume of consumptive use of
irrigation water on each section of the Region from 1960-65.
5
Each
diversion unit is bounded so as to enclose an area that will supply
approximately 9,200 acre-feet of irrigation water per year except for
three isolated agricultural areas which were considered as separate
diversion units, although each used less than the 9,200 acre-feet of
water taken as the generally standard unit.
For each diversion unit costs are estimated for the production
and delivery of water from that unit to the City of Tucson at the present rate of irrigation use in the unit (the 10 mgd assumption) and
at twice the present rate of use (the 20 mgd assumption).
These
diversion units are so structured and will be brought into use in such
order that the costs of diverting irrigation water to Tucson will be
minimized subject to the selected constraints later described.
5.
Acreage and water-use data from 1960-65 were obtained from
the Department of Agricultural Engineering, The University of Arizona,
Tucson.
Water use was based on a six-year average of the following
crops:
cotton, maize, grain, safflower, alfalfa, pasture and miscel-
laneouswithawateruseof3.5, 2.5, 2.5, 3.5, 4.5, 4.0 and3.Oacrefeet per acre per year, respectively, which is considered to be their
consumptive use.
35
Assumptions
For purposes of this study, it is assumed that the price of
factor inputs will be constant over time and that there will be no
changes in technology.
It is also assumed that the quality of the
water remains constant as the water level falls.
There is, however,
evidence from present deep wells of 1,000 feet or more that the quality
of water decreases at these depths.
Whether this decrease in water
quality at these depths occurs only in isolated areas or is generally
true for all aquifers in the Tucson Region remains to be determined.
In this analysis practically all "iells are projected to be less than
600 feet deep even at the end of the 30-year period (1997) on which
cost budgets are based, with the deepest well reaching about 760 feet.
Thus, for purposes of this analysis, it is assumed that water quality
will not deteriorate significantly within the relevant time horizon
of current water supply planning for Tucson,
It is further assumed
that all legal and political barriers to groundwater diversion from
use on overlying lands have been resolved.
These assumptions have the
effect of holding constant all exogenous parameters of the budgets for
the diversion units throughout the period of analysis and of permitting
the projected diversions legally to take place.
The analysis also assumes that the rate of decline of the
groundwater table in each diversion unit will be equal to the rate
experienced under present irrigation use when water is diverted at the
present rate of irrigation use (9,200 acre-feet per year) and that the
rate of decline will double in each diversion unit when water is
36
diverted at twice the present rate of irrigation use (18,400 acre-feet
per year).
The effect of these assumptions is that the rate of decline
in the water table is assumed to be a linear function, the slope of
which is directly proportional to the rate of use or that the rate of
decline is directly related to the quantity of water pumped.
Although
it may be argued that the groundwater reservoir is similar to a bowl
with sloping sides and that, with a constant volume of extraction, the
rate of decline will tend to increase, for purposes of this analysis
the rate of decline is assumed to be linear arid directly proportional
to the rate of use.
This assumption has the effect of holding the
efficiency of the aquifer constant at the increased depths.
The de-
cline of the groundwater table in each of the diversion units is projected at the rate of decline experienced on the average over the
period 1956-65.
6
The presence of a declining groundwater table has the effect
of increasing pumping costs over time.
In this analysis, the increas-
ing pumping costs are converted into an amortized average annual cost
at three and one-half percent interest over the 30-year planning period?
Data to determine the present rate of decline in each area
was obtained from unpublished well test data on file in the Department
of Agricultural Engineering, The University of Arizona, Tucson.
The three and one-half percent interest rate and the 30years planning horizon were obtained from the City of Tucson's Water
and Sewerage Department plans for diverting water to Tucson.
37
This amortized average annual cost is determined by the following
formula:
8
flmax
A =P
n=l
1
s-
S
fl max
+ K in which
A = amortized average annual cost of regularly increasing
pumping costs.
LP = average annual increase in pumping costs over the
planning period.
n = years included within the planning period.
n max
S
last year of the planning period.
= factor representing the end-of-period (after a term
of n years) amount of an annuity of $1 per year received
at the end of each year (n) at rate of interest (i)
per year (the value of which can be found in any
standard Set of annuity tables).
K = pumping cost at beginning of year one (n = 0).
For purposes of this analysis, this formula becomes:
n = 30
A=LP
1
s-.-.
n= 1
S
1.035
+ K where
30 1.035
the years (n) in the planning period extend from 1 to 30 and the
interest rate (1) is three and one-half percent.
Solving we get:
A =P (669.41274) (.01937) + K
=P (12.9665) + K
or, approximately
=1sP (13.0) + K
8.
Formula was developed by Professor M. M. Kelso, Department
of Agricultural Economics, The University of Arizona, Tucson.
38
Since LP is the average annual increase in pumping
cost, the multiplier
(13.0) can be taken to be that year (the 13th) in which the pumping
cost equals the amortized average annual cost of the stream of
increasing pumping costs over the entire planning period or the "discounted
time average" level of the water table in that well (over
its 30-year
life).
Consequently, it becomes possible to determine the amortized
average annual cost of pumping from any given well or wells by calculating simply the cost of pumping therefrom in the 13th year (n = 13).
Knowing the average annual increase in pumping cost and the pumping
cost at the beginning of the period (the initial pumping life at n =
0), the calculation is simply:
average annual increase in pumping
cost multiplied by 13 plus beginning pumping cost.
The analysis further assumes, with respect to the organization
and operation of the diversion units, that:9
The well field in each diversion unit operates 300 days per
year.
All new wells and pumping units are installed at $50,000
each, although, in practice, some existing irrigation
wells might be used.
This assumption is conservative in
that it errs on the high side tending to make costs higher
than might actually occur in establishing the well fields.
Well output is 1,500 gallons per minute.
With an output
of 1,500 gpm, 7 and 14 wells would be required to pump
9.
Personal conversation with Mr. J. F. Rauscher, Chief
Engineer, City of Tucson Water and Sewerage Department and a study conducted by City of Tucson Water and Sewerage Department, unpublished.
39
a maximum of 15 and 30 mgd, respectively, which are the
two design standards to which well and pipeline capacities
are planned in this study.
These wells plus one emergency
well are a total of 8 or 15 wells planned for each diversion unit for the production and delivery of 10 mgd and
20 mgd, respectively.
The pumping cost per acre-foot per foot of lift is held
constant at $.0l663 throughout the analysis.
The pumping
units are powered with natural gas, pumping costs are
based on a price of 52.2 cents per 1,000 cubic feet of gas
plus an existing contract maintenance cost of 18 cents
per 1,000 cubic feet of gas
or a total of 70.2 cents per
1,000 cubic feet of gas, with an overall plant efficiency
of 13.4 percent.
Wells are located in a single well field within each diversion unit and are spaced approximately three-fourths of a
mile apart in an X pattern over the necessary sections
thus tending to minimize costs of collection into the
transmission pipeline from the several wells in a single
well field.
The eight wells composing a 10 mgd well field
are assumed to be distributed thusly over a two square
mile area:
The fifteen wells composing a 20
mgd field are distributed similarly over somewhat more than
twice the area.
40
The investment cost per foot of. each pipeline size
installed
is held constant throughout the analysis.
Friction loss within each pipeline is held between three
and
four feet per mile by using the appropriate pipeline size
for the volume of water to be transported, as suggested by
the Tucson Water and Seierage Department.
The relevant
factors can be obtained from Williams and Hazen (1945).
The delivery system is constructed to deliver a maximum of
one and one-half times the average rate of delivery; that
is, if the system is to deliver an average of 10 mgd, it
is developed to deliver 10 mgd (1.5) or 15 mgd.
Capital costs are amortized at three and onc-half percent
over 30 years; the annual charge for capital invested thus
amounts to initial capital cost times .05437.
Average pumping lifts for the purpose of determining the
variable costs of pumping over the 30-year life of each
well field are taken to be the pumping lift of the wells
in each diversion unit in the 13th year of operation (see
pages 36-38) plus the lift to deliver water from the well
field in each unit to the Twenty-Second Street Reservoir
in the City of Tucson.
The well fields are located in each diversion unit so as
to minimize costs of pumping lift plus transportation which
in this analysis turns out to be that point in each unit
closest to Tucson.
41
Diversion units are based on acres of cropland which, at
their present rate of consumptive use for irrigation,
could supply 9,200 acre-feet of water per year, except
for three isolated areas which are considered as separate
diversion units although smaller than this standard.
It is assumed that the city will purchase all the agricultural real estate (land plus nonsalvageable improvements) in each diversion unit at the going market price
in each area,
10
The value of cotton allotments is in-
cluded in the market prices assumed.
t ion
The direct cost per acre-foot of diverting irrigation water to
Tucson will vary as between diversion units because of differences in
initial depth of the groundwater table and its rate of decline over
time, price of land, elevation relative to the point of delivery in
Tucson and the distance from the Tucson delivery point.
The estimation
of water production and delivery costs for each diversion unit, under
the assumptions listed above, permits determination of the cost per
acre-foot of diverting increasing quantities of irrigation water by
acquiring and developing an increasing number of diversion units at
one point in time (1967), producing the water therefrom at a constant
The market price for irrigated cropland in each diversion
unit was supplied in a personal conversation with Mr. Daniel W. Clarke,
Vice President, Southern Arizona Bank and Trust Company; Mr. William
0. Fraesdorf, Jr., Real Estate Broker, Canyon State Land Company; and
Mr. Andrew W. Hodge, Assistant Vice President, Bank of Tucson.
10.
42
rate over 30 years and transporting it to a single delivery point in
Tucson.
From this analysis one can derive the (direct cost) supply
function for the diversion to Tucson of irrigation water from within
the Tucson Region by ordering horizontally the several diversion units
and the cumulative quantities of water they could deliver annually in
ascending order of their costs per acre-foot for supplying such water.
The (direct cost) supply function reveals the increased direct
cost per acre-foot confronting the city were it to divert additional
increments of irrigation water to meet its needs for municipal and
industrial water; thus, it represents the marginal cost to the city
for obtaining additional units of water by diversion from nearby
irrigation.
The quantity of irrigation water that could be actually
diverted to Tucson, from a standpoint of direct economic costs only,
would be that quantity for which marginal costs of delivery to Tucson
are lower than the marginal cost of water from possible alternative
sources.
The development of the analysis as presented in this section
will provide the structural framework within which the answer to the
major question posed in this study will be found.
The answer is devel-
oped from data obtained from the Department of Agricultural Engineering,
The University of Arizona, and from the City of Tucson Water and
Sewerage Department.
This answer, when found, will be in the form of
a (direct cost) supply function for the diversion of irrigation water
to municipal use from
within
the Tucson Region; it will be composed of
43
discrete stepwise increments in number and location of diversion units
with estimates of the direct cost per acre-foot to extract and deliver
groundwater to Tucson from each.
Use of the Imported Water
A significant question has to do with extent to which ádditional water imported into the Tucson Basin will add to or substitute
for water currently withdrawn by the city from its presently diminishing sources.
Insofar as substituted for present water supplies, the
imported water will prolong the life of the city's present sources
but at the expense of aggregate volume available for short-run municipal
growth; if added to present supplies, the reverse consequences will
result.
During the period since 1960, annual deliveries by the city
have grown from 13 billion 238 million gallons per year to 15 billion
gallons.
The average monthly distribution of these deliveries during
this period has been as follows:
Month
Portion of
Annual Delivery
(percent)
January
February
March
April
May
June
July
August
September
October
November
December
4.6
4.9
6.4
8.6
11.5
13.0
12.4
10.3
93
8.0
5.8
4.9
99.7
44
If we assume a current annual delivery by the city of 15 billion
gallons per year, it may be assumed to be delivered by months on the
average as follows:
Deliveries
per Month
Month
(millions of gallons)
January
February
March
April
May
June
July
August
September
October
November
December
690
735
960
1,290
1,725
1,950
1,860
1,545
1,395
1,200
870
735
14,955
If it is. assumed that the city will operate the sources of
imported water in such manner as to keep them supplying a constant
amount throughout the year, using its existing water sources to meet
seasonal peaking demands, it can be expected to use the demands of the
four lowest months (November, December, January and February) as the
constant base demand to be supplied throughout the year.
These four
months demand an average of 758 million gallons or 2,318 acre-feet
each.
Over 12 months, this base demand therefore will be (2,318 acre-
feet x 12) approximately 27,800 acre-feet.
Total annual demand is
15 billion gallons or approximately 45,900 acre-feet.
Hence, if base
demand of 27,800 acre-feet is met from imported sources, the present
sources of water dram upon by the city will supply about 18,100
45
acre-feet, a net saving in withdrawal from the city's present sources
of 27,800 acrefeet or 60 percent of present withdrawals.
From these estimates, it may be concluded that 60 percent of the
water drawn by the city from outside its present sources can be assumed
to be a replacement supply and 40 percent can be called additional
Another way of putting it is that each unit of water imported
supply.
will be divided 60.40 between replacement of and addition to present
supplies.
These calculations include nothing as to the possibilities of
judicious mixing of waters of different qualities which might extend
the efficiency with which present municipal supplies could be used.
Neither do they include any reference to that rate of withdrawal from
present municipal supplies that would stabilize present supplies nor
to any other rate that might be considered to be a judicious quantity
in reference to the rate of decline in present supplies
low therefrom.
that would fol-
Incorporating into this demand analysis estimates on
these two points might increase or decrease the proportion of imported
water that would be available to increase total available supplies,
hence be available to meet increasing future municipal demands.
On
the basis of these simplified estimates, one may conclude that ilLauediate diversion of water from irrigated agriculture in the Tucson
Region in the amount of 27,800 acre-feet per year
(or from about three
diversion units) will take most if not all of the excess pressure off
the city's present supplies, and that as the city's future demands increase it can obtain additional supplies from this source of which about
40 percent will be available to meet expanded water demands.
CHAPTER 3
ANALYSIS OF THE DIRECT COST OF DIVERSION
OF IRRIGATION WATER TO TUCSON IN TEN
MILLION GALLONS PER DAY INCREMENTS
Cropland Acreage and
Irrigation Use
The determination of cropland acreage surrounding Tucson and
the quantity of irrigation water used by it was the starting point of
this analysis.
Data as to crop including fallow acreage by sections
in the Tucson Region were obtained from annual surveys conducted by
the Department of Agricultural Engineering, The University of Arizona,
Tucson.
Irrigation water use by sections was computed from these
crop acreages and consumptive use in acre-feet per acre for the various
crops as follows:-Cotton 3.5
Safflower 3.5
Maize 2.5
Alfalfa 4.5
Grain 2.5
Miscellaneous 3.0
Inasmuch as these are consumptive use figures, they represent
net withdrawal rather than gross pumpage of groundwater for irrigation
purposes.
Experiments in the Santa Cruz Basin (Halpenny, et al., 1952)
have shown that 10 to 33 percent of the gross water applied for irrigation recharges the groundwater basin and that consumptive use approximates net disappearance of water applied for irrigation purposes.
The
acreage of each crop in each section was estimated for purposes of this
11.
Consumptive use figures were supplied by the Department of
Agricultural Engineering, The University of Arizona, Tucson.
46
47
study by taking the average of the acreage of each crop in each section
for the period 1960-65, as shown in the crop acreage surveys referred
to above.
Multiplying this estimate of the acreage of each crop on
each section by the consumptive use of irrigation water by each crop
and summing by sections gave an estimate of the average annual net
use of irrigation water on each section in the Tucson Region over
the same period.
The estimatEs of crop acres per section, consumptive
use of irrigation water by each crop, and the resulting estimate of
use of irrigation water on each section are assumed to remain constant over the time period of this analysis.
From these data it was estimated that 153,000 acre-feet of
groundwater is the net withdrawal for irrigation in the Tucson Region
and is used on about 61,000 acres of cropland.
This is almost 65
percent of the estimated total annual pumping draft of about 248,000
acre-feet12 in the same Region.
Present Groundwater
Table Conditions
The continued population growth in the Tucson Region, the consequent increased pumping of groundwater and decline in groundwater
levels underscore the importance of a detailed study of the groundwater system.
Figures for estimating the total annual pumping draft
12.
were supplied by the Department of Agricultural Engineering, The
University of Arizona, Tucson.
48
The United States Geological Survey has been collecting hydro-
logic and geologic data in the major irrigated basins of Arizona for
many years as part of a continuous program of statewide groundwater
surveys (White, Matlock and Schwalen, 1966).
The Department of
Agricultural Engineering, The University of Arizona, has also been
collecting groundwater data in parts of the state with concentration
on the immediate Tucson Region for nearly an. equal period of time.
The work of the Geological Survey is conducted mainly in cooperation
with the Arizona State Land Department, while that of the Agricultural
Engineering Department is mainly in cooperation with the City of Tucson
and Pima County.
The volume of data collected has increased in recent years.
With the growing demand for water, there is an increased need for a
more comprehensive analysis of these data to provide the necessary
quantitative solutions to the problems of water quality, water availa-
bility, and the effects of increasing withdrawals.
In the study reported herein the level of the groundwater table
in 1965 and its average annual rate of decline during the period 195665 were determined for each township in the Tucson Region from well
information on open file in the Department of Agricultural Engineering,
The University of Arizona, Tucson.
The Agricultural Engineering
Department measures annually the depth below the surface in over 1,500
wells to deteLluine changes in water level from the previous year
(Natlock, Schwalen and Shaw, 1965).
These well measurements are made
on approximately the same date each year, winter or spring measurements
49
being preferred since at that time of year the drawdown coning of the
groundwater level is at a minimum because pumping is least active.
Drawdown coning occurs when the pump is in operation and is equal to
the gallons pumped per minute divided by the estimated specific
capacity of the aquifer.'3
Such drawdown coning will be computed for
each well field and added to the static pumping lift for purposes of
computing dynamic pumping lift and, hence pumping costs.
However,
the initial and groundwater levels shown in this study are static
levels taken directly from the measurements made during periods of
reduced pumping activity.
The levels of the groundwater table in the spring of 1965,
the Tucson Region, are shown in Figures 10 and 11.
for
These depths to
water were determined also for the springs of 1956 and 1961.
The rate of decline of the water table for each township in
the Tucson Region was determined by calculating the decline between
the 1956 and 1965 water levels for each well measured in each township,
and determining its average annual rate of decline during that period.
The same procedure was used to determine the average annual rate of
decline of each well for the 1956 to 1961 period and for the 1961 to
1965 period.
Since, in almost all cases, the rate of decline did not
change significantly during the 1961-1965 period, from what it was
during the 1956-1961 period, the rate of decline in groundwater
The estimated specific capacities were obtained from the
13.
Department of Agricultural Engineering, The University of Arizona,
Tucson.
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Figure 10.
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'' SANTA CRUZ COUNTY
Water Level Contours, Spring 1965, in Saxta Cruz Valley, Arizona, Depth Below the Surface.
Jy
aI*ca
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ILJuJ;hAJ1
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Figure 11.
Valley, Arizona,
Water Level Contours, Spring 1965, Avra
Depth Below the Surface.
52
level in all areas of the Region is estitnated to be the
average annual
change in groundwater level between 1956 and 1965.
This rate of
decline is assumed to remain constant throughout the time period covered by this analysis.
The computed level of the groundwater table
in 1965 and the rate of decline used for each diversion unit
are found
in Tables 1-A through l8A in the Appendix.
It is assumed that the groundwater table is at a uniform
depth everywhere in the well field located in each diversion unit.
Although the level of the groundwater table and its rate of decline
vary continuously over the area of each diversion unit, for purposes
of this analysis a single but separate groundwater level and rate of
decline representative of each well field location is assumed for
each diversion unit.
Thus, the groundwater level and its decline
rate for each well field will be taken to be the average level and
decline rate of each particular well field location.
The importance to this analysis of the level of the ground-.
water table and its rate of decline will be discussed more thoroughly
in connection with the analysis of pumping costs later in the chapter.
Irrigation Water
Diversion Units
It is assumed that the City of Tucson in order to obtain irri-
gation water for its use must buy the agricultural land previously
using the water to obtain the right to the underlying groundwater.
is also assumed that the city will not be permitted by choice or by
regulation to withdraw water from any point at a rate greater than
it
53
present irrigation use in each area.
In unpublished studies of pro-
spective water supply developments by the City of Tucson Water and
Sewerage Department, delivery systems were planned that would deliver
increments of an average of 10 million gallons per day, with maximum
capacity of 15 mgd.
Hence, in this study irrigation water diversion
units and water delivery systems were developed that would produce
and deliver an average of 10 mgd (15 mgd capacity) for 300 days per
year, or approximately 9,200 acre-feet per year.
Planning water pro-
duction and delivery systems in units of 10 mgd (average) and 15 mgd
(capacity) implicitly assumes that a unit of this size is the most
economical size system, an assumption which will be discussed more
thoroughly later in this chapter.
Since each diversion unit and its delivery system is to
supply an average of 10 mgd and operate 300 days per year, it will
produce about 3,000 million gallons of water per year or about 9,200
acre-feet.
Knowing the number of cropland acres and their water use
for each section in the Region, and since withdrawal by the city is
assumed to be restricted to present net irrigation water use in each
diversion unit, we can determine the acres of cropland the city would
have to purchase to compare each diversion unit in order that it may
supply 9,200 acre-feet of water per year.
Thus, for this analysis
the agricultural land surrounding Tucson was divided into diversion
units, each of which could supply about 9,200 acre-feet per year without exceeding the present rate of irrigation water use in each.
were three exceptions to this standard.
There
Because they were isolated
54
from other areas of irrigation land, three small isolated areas (nun-
bers XII, XIII, and XVIII in Figure 12) were considered as individual
units which supply 6,700; 3,490; and 4,150 acre-feet of water per
year, respectively.
These small, separate units were developed at a
delivery rate (mgd) which would exhaust, in the 300-day period, the
average annual irrigation water used in each unit.
The agricultural diversion units thus determined for use in
this study, based on the assumptions above, are shown in Figure 12.
Table I summarizes the crop acreage and water use for each
agricultural diversion unit shown in Figure 12.
Direct Cost of the Diversion of
Irrigation WatSOn
in 10 mgd Increments
The location of the water diversion units, the groundwater
level and its rate of decline in each, and the rate of delivery outlined in the first part of this chapter are used to determine the
direct cost per acre-foot of diverting irrigation water to Tucson from
each diversion unit.
The computation of costs for each of the component parts of a
and can
10 mgd diversion system will be discussed individually below
1-B through 18-B
be found for each of the 18 diversion units in Tables
in the Appendix.
55
RIlE. PIN AL COUNTY
PIMA COUNTY
1.
IS
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1.13 S.
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1. IS S.
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PIMA COUNTY
J5ANTA CRUZ COUNTY
Figure 12.
Irrigation Water Diversion Units in the Tucson
Region.
56
Table 1.
(Average Annual) Crop Acreage and Irrigation Water Use by
(196065)a
Water Diversion Units
Water
Divers ion
Cro sland
Unit
(acres)
Irrigation
Water Use
per Year
(acre-feet)
I
3,636
9,190
II
3,283
9,170
III
3,367
9,270
IV
3,550
9,260
V
3,739
9,380
VI
4,042
9,220
VII
3,657
9,240
VIII
3,860
9,310
IX
4,161
9,320
X
4,019
9,290
XI
3,371
9,100
XII
3,042
6,700
XIII
1,219
3,490
XIV
3,634
9,270
XV
3,291
9,240
XVI
3,382
9,080
3,636
9,170
XVI I
1,748
4,150
60,627
153,050
XVIII
Totals
For a legal description of each water diversion unit, see
Appendix.
footnote a of Tables 1-A through 18-A in the
a.
57
Land Costs
We begin our discussion of costs with the computation of land
costs.
The acres of cropland in each diversion unit are determined as
described above and are shown in Table 1.
The current market value of
cropland was estimated for each of these diversion units (see footnote
10, page 41).
Thus, the total cost of land in each diversion unit
were the city to buy it now is determined by the number of cropland
acres and the estimated price per acre.
For this study, it is assumed
that land is an investment that is neither appreciable nor depreciable;
hence, the annual land cost charged to the cost of water is only the
interest cost of the funds borrowed or the opportunity cost of nonborrowed funds used by the city to purchase the land.
The interest
rate used was three and one-half percent, which is what the city con-
siders to be its long-term borrowing rate.14
After determining the
acres of croplanci and the market price of land in each unit and the
interest rate, we can calculate the annual land cost in each diversion
unit with the following formula:
(See Tables 1-B through 18-B in the
Appendix.)
Acres
X
Price per acre
X
.035
The three and one-half percent interest rate used in this
14.
analysis is the expected long-term borrowing rate of the city. However, the opportunity cost to the taxpayer and the water rate payer is
surely considerably higher than this. Thus, perhaps a higher interest
rate may be appropriate. But, since the city's borrowing rate is more
surely known than are these opportunity costs, the city's rate has been
used here.
58
Construction Costs:
Pumping
and Delivery Systems
Given the locations and characteristics of the various
diversion units (Tables 1-A through l8A of the Appendix),
one can determine
the capital cost of constructing a water pumping and delivery
system
for each diversion unit capable of delivering an average of 10
mgd
with a maximum capacity of 15 mgd, or at that rate (mgd) which will
divert the present annual irrigation use in that unit to Tucson in a
300-day period.
Well Field Costs
The first part of the system to be discussed is the location
of and installation of the wells and pumping units.
Because pumping
costs due to pumping lift and transportation costs due to distance from
the city will vary with the location of the well field within a diversion unit, the well field should be located within each unit where the
sum of pumping cost an
unit.
transportation cost is a minimum within that
A comparisonof pumping cost with transportation cost revealed
that the cost per acre-foot of installing one mile of 36-inch pipeline
(15 mgd capacity) is equal to a pumping lift of 51 feet.15
Thus, it
would be economical to locate the well an additional mile further from
15.
Pumping versus transportation cost:
36-inch pipeline @
$27 per foot costs $142,560 per mile which on an annual delivery capacity of 9,200 acre-feet equals $15.50 per acre-foot-year; this cost amortized at three and one-half percent over 30 years equals $.84, which is
the annual cost per acre-foot. With a pumping cost of $.0l663 per acrefoot per foot of lift, one additional mile of pipeline ($.84 per acrefoot) is equivalent in cost to 51 additional feet of pumping lift (51 x
$.0l663 = $.84).
59
Tucson only if the pumping lift were less by more than 51 feet in that
mile.
In this analysis, the most economical well field location in
each diversion unit turned out to be that point closest to Tucson
within each unit.
At this point particular reference must be made to the planned
location of the well field for Area II.
It is assumed that the well
field for Area II will be located near Cortaro, which is in Area
I,
because 12,000 to 14,000 acre.feet of the water pumped near Cortaro
presently are transported to the northwestern part of Area I and to the
Marana area each year.
Thus, the location of another well field in
Area I will not raise withdrawals in that area above present levels
and, because Cortaro is much closer to Tucson than is Area II, it is
decidedly economical to locate Area II's well field in Area 1.16
Each well and pumping unit in each well field is assumed to
have an output of 1,500 gallons per minute and an estimated capital
cost of $50,000.17
Though this standard may be generally applicable,
it may not hold for diversion units I, XIII and Xvii which for hydro..
logic reasons may not permit the development of 1,500 gpm wells.
Thus
more wells may be needed in these areas which would make the estimate
of well costs in these areas in this study somewhat on the low side.
Omitted from this study is the minor circumstance that by
so doing that part of the water formerly transported from near Cortaro
to Area I to Marana that was not consumed thus percolating to the
groundwater in those areas would be cut off by the city development
assumed here.
Assumptions are based on planning standards used by the
City of Tucson Water and Sewerage System.
60
From this we can determine the daily output of each well and from this
the number of wells needed to produce a maximum of 15 mgd or whatever
rate of delivery the diversion unit is assumed to have; to this number
of wells one additional well is added for standby use.
Thus, the
total capital cost of the wells and pumping units can be computed for
each diversion unit in the following manner:
Rate of Delivery (mgd)
Output of each well per day (mg)
+ 1
$50,000.
The cost analysis of wells and pumping units just outlined
implicitly assumes that the city will install all new wells and pumping
units.
It is quite likely that the city will be able to use some of
the existing irrigation wells, which would tend to lower the capital
cost of the well fields.
But, in this analysis, the assumption is
made that all new wells and pumping units will be installed, thus
biasing the cost estimates on the high side.
Pipeline Costs
Having determined the location of the wells for each diversion unit, the capital cost of installing collection lines from each
individual well to a collecting point within the diversion unit and
the cost of constructin
a transmission line to Tucson from each diver
sion unit can be calculated.
The estimated transmission and collection
line unit costs are shown on the following page.18
Personal conversation with Mr. John F. Rauscher, Chief
18.
Engineer, City of Tucson Water and Sewerage Department.
61
42-inch
36-inch
30-inch
24-inch
20-inch
18-inch
16-inch
14-inch
12-inch
pipeline
pipeline
pipeline
pipeline
pipeline
pipeline
pipeline
pipeline
pipeline
- $30.00 per foot installed
- 27.00 per foot installed
- 22.00 per foot installed
- 16.00 per foot installed
- 12.00 per foot installed
9.50 per foot installed
8.50 per foot installed
7.50 per foot installed
7.00 per foot installed
The computation of the collection line costs for each diversion unit was based on the unit costs above and on the assumption
that all wells would be approximately three-fourths of a mile apart
and located in an
pattern over two sections of land.
It was
also assumed that pipeline sizes that would hold friction loss between three and four feet per mile (see footnote 9, page 38) would
be used in all parts of each collection system.
Given the location and output of each well, we can determine
the length of pipeline between each well and the rngd it must transmit.
Given the mgd a pipeline must transmit and holding the assumed friction
loss within the limit specified above, the appropriate pipeline size
can be obtained from a set of hydraulic tables (Williams and Hazen
1945).
Having determined the appropriate collection line sizes and
lengths, one can calculate the capital cost of each pipeline size
by taking cost per foot x 5,280 x miles and by summing overall pipeline sizes one can obtain the total capital cost of the unit collection system.
Since the volume of available water per year and the well
field location in each diversion unit are both known, the distance
to the city's collection point and the daily volume which will be
62
delivered to Tucson from each diversion unit to exhaust in 300 days
the irrigation water used annually within it can now be computed.
Given the mgd, which in most cases is 10 with a maximum of 15 mgd,
that the transmission line must carry, the distance to Tucson, and
the above assumption on friction loss, one can calculate the appropriate pipeline size and the capital cost of the transmission line
in the same manner as outlined for the collection lines.
In this analysis it is assumed that the city will construct
an additional and independent 10 mgd delivery system for each diversion unit.
It may in reality be economically desirable to build
larger transmission lines to commingle water from two or more diversion units.
Economy of this alternative depends on the sequence in
which the several diversion units would come into development.
This
sequence would in turn depend on the cost savings made possible by
larger pipelines and on a dynamic analysis of the city's (dated)
demand for water increisents.
mining the
transmission
Since such an analysis required deter-
costs for all possible combinations of diversion
units from which the likely savings seemed minimal at best, and since
a dynamic demand analysis is required which is not possible in this
study, it was decided to consider each diversion unit and its transmission line as an independent unit.
But, by this assumption, this
study again assumes conditions that make for conservatism (on the high
side) in its cost estimates.
There is in addition another cost that must be incurred to
tie into the city system any water imported from the areas northwest
63
of Tucson, a cost which does not arise for water imported
from areas
west and south of Tucson because the tie-in facilities are already
available in the southwestern part of Tucson but are not available
to water imported from the north.
These tie-in costs were estimated
from the city's present unpublished plans for a reservoir and
booster
station north of the city and the various pipeline sizes and lengths
needed to tie an additional (single) 10 mgd into the present system.
A comparison of the tie-in cost (see Table 1-B in the Appendix) with
the cost per mile of a 36-inch pipeline shows that the tie-in cost is
equal to the cost of installing about nine miles of 36-inch pipeline.
This makes it cheaper to import the water from Areas VI and IX from
the west rather than from the north, which otherwise would have been
the case.
The cost of securing easements for the pipeline rights-of-way
across private property was estimated to be $387 per mile)9
This
cost was assumed to be the same for all areas.
The final component in the delivery system is the capital cost
of constructing a reservoir and booster station at each well field
location.
The estimated cost of the reservoir and booster station was
obtained from an unpublished study conducted by the City of Tucson Water
19.
43560
Easement cost used is based on the following formula:
x 25 x .25 x 5,280, where $500 is the estimated average land
value per acre, 25 feet is the width of the easement, and .25 is 25
percent of the average land value.
This formula was obtained from
Nr. John F. Rauscher, Chief Engineer, City of Tucson Water and Sewerage
Department.
64
and Sewerage Department and is assumed to be constant
throughout the
analysis.
The computation of costs for each component of each 10 mgd
delivery system and the total of these capital
costs is shown for
each diversion unit in Tables 1-B through 18-B in the Appendix.
Annual Investment Costs
The sum of these capital costs is amortized at three and
onehalf percent interest over 30 years, which is the estimated life of
the capital items, to determine the amortized average annual cost of
these depreciable capital items.
(See Tables 1-B through 18-B in the
Appendix.)
Annual Operating Costs
Having determined the average annual fixed costs of diverting
irrigation water to Tucson from each of the diversion units at 10 mgd
or at the volume of present irrigation use in each area, the only
direct costs remaining to be determined are operating costs.
These
operating costs are the pumping costs at the welihea.d and the pumping
costs for the delivery of water from the well to Tucson.
The unit
pumping cost used in this analysis is $.01663 per acre-foot per foot
of lift, which is based on information obtained from the City of Tucson
Water and Sewerage Department (footnote 9, page 38).
This pumping cost, together with the pumping conditions in
each diversion unit, permits the computation of the average annual
pumping cost.
For the pumping conditions that presently exist in each
65
diversion unit see Tables 1-A through 18-A in the
Appendix.
The static
water level in 1965, the annual decline (both of which
were explained
earlier in this chapter), and the drawdown 20 permit us to determine the
pumping level for 1967.
In this part of the analysis it was assumed that the city's rate
of withdrawal from each diversion unit would not exceed present irrigation use in that unit, although city pumping, compared to the agricultural pumping it would displace, would be in a more concentrated area
in each unit.
This will increase the rate of decline at the city's
wells during the first few years of the operation of each well field.
However, as the deepening cone at the wells increases, the rate of
flow into the cone will increase thus causing the rate of decline to
decrease, finally stabilizing at the earlier irrigation rate.
Thus,
the average rate of decline in each unit was assumed to be the same
after city development of the diversion unit as before under irrigation
withdrawal.
Knowing the annual average rate of decline following city
development and the assumption that the rate of decline is constant
for a given rate of withdrawal permits determination of the 13th-year
or "time weighted" average groundwater level over the life of the well
and equipment (30 years).
The 13th-year pumping cost represents the
amortized average annual cost of pumping as described more fully on
pages 36-38 in Chapter 2.
Thus, the depth to water in each well in
Drawdotvn is equal to
gpm
The estimated
Specific Capacity
specific capacity for each unit was obtained from the Department of
Agricultural Engineering, The University of Arizona, Tucson.
20,
.
66
the initial year (1967) and the additional depth reached in the ].3th
year gives the "time discounted" average annual water level or pumping
lift at the welihead for the 30.-year period.
This lift multiplied by
acre.-feet and, in turn, by $.0l663 will give presently valued amortized
average annual cost of the annually increasing pumping cost at the
welihead over the 30.-year period.
The next part of pumping cost to be considered is the lift and
friction loss in delivering the water from each well field to Tucson.
Tables 1.-A through 18.-A and 1.-B through 18.-B in the Appendix give us
the elevation of each well field and the elevation of the Twenty-Second
Street Reservoir, from which one can determine the lift in the delivery
system.
These tables also give us the rate of delivery (mgd) and
the distance to Tucson which, together with the standard friction loss
used in the analysis (see page 37) permit us to determine the appro.-
priate pipeline size and the resulting friction loss from a set of
hydraulic tables (Williams and Hazen, 1945),
The sum of the extraction lift in the 13th year, the delivery
lift, and the feet of friction loss gives us the presently valued
average annual overall pumping head for the 30.-year period.
Since
the number of years (30) and the interest (.035) remain constant in
this analysis, the overall pumping head depends on the initial water
level, its rate of decline, the elevation of the well field relative
to the Twenty-Second Street Reservoir, and the distance from Tucson.
Having computed the average annual overall pumping head, the
acre-feet of water pumped each year, and knowing the pumping cost per
67
acre-foot per foot of lift, the average annual pumping cost for each
diversion unit can be computed by multiplying number of acre-feet
pumped by feet of lift by $.0l663 per acre-foot per foot of lift.
(See
Tables 1-B through 18B of the Appendix.)
Having calculated the present average annual cost of land, the
present annual (amortized) cost of construction of an appropriate
pumping and delivery system, and the amortized average annual cost of
pumping for each diversion unit, their sum gives us the annual (amor-
tized) total direct cost for diverting irrigation water to Tucson from
each unit.
This annual (amortized) direct cost of water from each
diversion unit, when divided by the acre-feet delivered annually from
that unit, gives the annual (amortized) total direct cost per acrefoot of water diverted from that unit.
This annual (amortized) direct
cost per acre foot is the estimated direct cost that would be incurred
now and in each year for 30 years in each diversion unit if the decision were made now to develop and divert all water from that unit.
Table 2 is a summary of the annual (amortized) direct costs computed
for each diversion unit.
Table 3 reveals the annual (amortized) direct cost per acrefoot for each diversion unit when they are ranked in order of the
increasing cost of water, in other words, the supply schedule (direct
cost) for this water.
These costs do not include an estimate of costs
resulting from possible water quality problems or the indirect economic
effect that the disappearance of agriculture may have on the Tucson
economy.
These will be discussed later in the analysis.
XII
XIII
XIV
XV
XVI
XVII
XVIII
VI
VII
VIII
IX
X
XI
V
III
IV
II
I
a.
Diversion
Unit
Table 2.
(dollars)
151,519
225,353
303,074
318,618
326,390
318,161
266,156
195,302
294,845
255,953
221,011
142,917
139,037
85,000
131,632
143,290
189,923
54,377
(dollars)
222,705
89,939
91,821
93,734
93,160
84,847
76,797
76,563
72,818
70,332
58,992
53,235
21,332
127,190
115,185
118,370
127,260
152,950
85,585
78,231
170,809
171,395
168,625
163,278
161,173
173,714
162,431
153,720
133,324
82,674
23,680
37,153
49,786
46,206
43,919
27,054
(dollars)
Pumping
459,809
393,523
565,704
583,747
588,175
566,286
504,126
545,579
530,094
480,005
413,327
278,826
184,049
249,343
196,603
307,866
361,102
234,381
(dollars)
Total
9,190
9,170
9,270
9,260
9,380
9,220
9,240
9,310
9,320
9,290
9,100
6,700
3,490
9,270
9,240
9,080
9,170
4,150
(acre-feet)
For the computation of these costs see Tables 1-B through 18-B of the Appendix.
Capital
Land
Water
Quantity
50.00
42.90
61.00
63.00
62.70
61.40
54.10
58.60
56.90
51.70
45.40
41.60
52.70
26.90
32.10
33.90
39.40
56.50
(dollars)
Direct
Cost per
Acre-Foot
Summary of Annual (Amortized) Direct Costs for Diversion of Irrigation Water to Tucson
by Diversion Units (10 mgd).a
69
Table 3.
The Supply Schedule: Annual (Amortized)
Direct Costs per
Acre-Foot for Diverting Irrigation Water to Tucson
in 10
mgd Increments, Ranked in Order of Ascending
Costs,
Area
Water
Quantity
a
Direct
Cost per
Acre-Foot
(acre-feet)
XIV
9,270
$26.90
Xv
9,240
32.10
Xvi
9,080
33.90
XVII
9,170
39.40
XII
6,700
41.60
II
9,170
42.90
XI
9,100
45.40
I
9,190
50.00
X
9,290
51.70
XIII
3,490
52.70
VII
9,240
54.10
XVIII
4,150
56.50
IX
9,320
56.90
VIII
9,310
58.60
III
9,270
61.00
VI
9,220
61.40
V
9,380
62,70
Iv
9,260
63.00
a.
See footnote a of Tables 1-A through 18-A in the Appendix.
70
The annual (amortized) direct costs per acre-.foot for the
diversion to Tucson of 10 mgd of irrigation water from the various
diversion units are plotted in Figure 13.
(step) supply function.
Figure 13 is an incremental
It tells us the additional (marginal) direct
cost of obtaining additional water in 10 mgd increments in 1967 by
diversion from irrigation in the Tucson Region,
71
$65
60.
55
I
50.
I
Annual (Amortized) Land Cost
U)
qj
-I
-I 45-
Total Direct Annual (Amortized) Cost
o 400
35
25
20-
Annual (Amortized) Pumping and Delivery Costs
15
10'-
I
I
I
I
I
I
I
20
10
I
I
I
40
30
I
I
I
I
I
70
6 0
50
t
I
I
I
I
I
I
110
100
90
80
I
120
I
I
130
I
I
I
I
150
140
Acre-Feet per Year (Thousands)
XIV
Figure 13.
XV
XVI
XVII
XII
II
Supply Function (Direct Production and Delivery Costs)
for the Diversion of Irrigation Water to Tucson in 10
mgd Increments.
I
I
I
XI
I
X
I
XIII
I
I
VII XVIII
I
IX
I
VIII
I
III
I
160
I
I
I
VI
V
IV
CHAPTER 4
ANALYSIS OF THE DIRECT COST OF DIVERSION OF
IRRIGATION WATER TO TUCSON IN TWENTY
MILLION GALLONS PER DAY INCRENT5
Cropland Acreage, Water Use
and Diversion Units
The cropland acreage in the Tucson Region, its water use
for irrigation, and the diversion units determined in Chapter
3 will
remain the same for this part of the analysis.
The well field loca-
tion (though larger in area) in each diversion unit, the resulting
distance to Tucson, and the size of individual wells and pumping units
are also the same as those in Chapter 3.
Groundwater Table
The present level of the groundwater table and its current
rate of decline by township under conditions of irrigation pumping were
determined in the previous chapter (see pages 48-53) and will remain
the same for the analysis in this chapter.
These data for each diver-
sion unit will be found in Tables 1-A through 18-A of the Appendix.
Irrigation Water Diversion Units
It will now be assumed that the city will withdraw water from
each diversion unit at twice the present rate of irrigation use (or at
20 mgd) in each unit.
Possible institutional constraints on withdrawal.
and exportation of groundwater at this rate relative to previous rates
72
73
under irrigation will be ignored in this analysis.
Pumping at this
higher rate may so cheapen the cost of water as to make it possible for
the city to pay damages to complaining irrigators and yet obtain water
cheaper than at the 10 mgd rate of withdrawal.
In this part of the analysis, the well fields and delivery
systems were developed to deliver to Tucson an average of 20 mgd per
diversion unit with a maximum capacity of 30 mgd.
These increased
pumping and delivery rates were assumed in order to compare the cost
per acre-foot of diverting irrigation water at two levels of scale-
one level the city prefers and the other representing a probable maxi.
mum "lumpiness" of expansion.
Since each diversion unit and its delivery system will supply
an average of 20 mgd and operates 300 days per year, it will supply
6,000 million gallons of water per year or about 18,400 acre-feet-twice the quantity assumed (9,200 acre-feet per year) in Chapter 3.
Cost Analysis of the Diversion of Irriion
Water to Tucson in 20 mgd Increments
Knowing the distance from Tucson of each diversion unit, the
rate of delivery, and the groundwater level and rate of its decline
outlined in the first part of the chapter, one can compute the cost
per acre-foot to divert irrigation water to Tucson from each of the
diversion units.
The calculation of costs for each of the component parts of a
diversion system was discussed in the preceding chapter; the method
used in the computation of these costs will remain the same in the
74
cost analysis of a 20 rngd delivery system.
puted for the various
pa1t
The costs which were com-
of the 20 mgd diversion system are found in
Tables 1-B through 18-B in the Appendix.
Since the area and location of each diversion unit for the 20
and the 10 mgd delivery system are the same, the annual land cost for
each unit will also be the same.
The computation of the annual land
cost for each of the diversion units was explained in the preceding
chapter (see page 58), and is shom for the 20 nigd systems in Tables
1-B through 18-B in the Appendix.
The next cost to be considered is the capital cost of constructing a system for each diversion unit that will deliver to Tucson
an average of 20 mgd with a maximum capacity of 30 mgd.
For three
diversion units a 20 mgd delivery system is not needed.
In these units
the delivery system was planned to deliver at that rate which would
divert twice the present annual irrigation water use in that unit to
Tucson in the 300 day per year pumping period assumed.
We begin consideration of the investment cost of the pumping
and delivery systems by taking up the location and installation of the
wells and pumping units in each diversion unit.
To determine the
economical].y efficient location of the well field in each diversion
unit, a comparison of pumping versus water transportation costs
revealed that the annual cost per acre-foot of installing one mile
of 42-inch pipeline, which is the size needed to hold the friction
loss between the values assumed in Chapter 3, is equal to a pumping
75
lift of 28 feet.
21
thus, it will be economically desirable to locate
the well another mile further from Tucson only if the pumping lift is
decreased by 28 feet or more in that mile.
The most economical loca-
tion of the well field for each diversion unit turned out to be that
point in the unit closest to Tucson (see Tables 1-A through 18-A in
the Appendix).
For an explanation of the location of the well field
for Area II see page 60.
The number of wells and pumping units needed per diversion
unit and their capital cost were computed in the same manner as in the
preceding chapter (see pages 60 and 61).
The individual wells and
pumping units are the same size as analyzed in Chapter 3; however, 15
such wells were needed
isolated
units
in
each diversion unit except for the three
previously mentioned.
Having determined the location of the well field for each diversion
unit
and the number of wells needed, the next capital
cost
to
be computed is that of installing collection lines and a transmission
line from each diversion unit to Tucson.
The calculation of the capital
costs of the collection lines and a 42-inch transmission line for each
diversion unit is based on the costs shown on pages 61 and 62.
The
size and capital cost of the collection lines and a transmission line
42-inch pipeline @
Pumping versus transportation cost:
21.
$30 per foot costs 158,400 per mile which on an annual delivery capacity of 18,400 acre-feet equals $8.60 per acre-foot-year; this cost
amortized at three and one-half percent over 30 years equals $.47 which
With a pumping cost of $.0l663 per
is the annual cost per acre-foot.
acre-foot per foot of lift one additional mile of pipeline ($.47 per
acre-foot) is equivalent in cost of 28 additional feet of purilping lift
(28 x $.0l663 = $.47).
76
were calculated in the same manner as was outlined in the preceding
chapter, pages 61-63.
In addition to the collection and transmission line costs, an
investment cost is also required to tie into the city system the water
imported from areas northwest of Tucson.
This cost is not required for
water imported from the areas west and south of Tucson because tie-in
facilities are already available for this water.
These tie-in costs
are based on unpublished plans by the city for a reservoir and booster
station north of the city and the various pipeline sizes and lengths
needed to tie an additional (single) 20 mgd increment into the city
system.
A comparison of these tie-in costs (see Table 1-B in the
Appendix) with the cost per mile of installing a 42-inch pipeline shows
that the tie-in cost is equal to about 10 miles of 42-inch pipeline.
This tie-in cost makes it cheaper to bring in the water from Areas
VI and IX from the west rather than from the north, which would otherwise be the case.
Easement, reservoir and booster station costs are assumed to
remain the same for the 20 mgd systems as for the 10 mgd systems (see
pages 64 and 65).
The computed costs for each of the component parts of the 20
mgd delivery systems (twice the present irrigation use), and the total
capital costs are shown for each diversion unit in Tables 1-B through
18-B in the Appendix.
The total capital required for each diversion unit is amortized
at three and one-half percent over 30 years to determine the annual
amortized cost of these depreciable capital items.
77
Having computed the annual (artiortized)
fixed costs (land cost
plus capital cost) of diverting irrigation water to Tucson from each
of the diversion units in 20 mgd increments, the only costs remaining
to be determined are the operating costs.
These are composed of the
pumping costs at the welihead and the pumping costs to deliver the
water to Tucson.
The operating cost of pumping used in this analysis
is $.01663 per acre-foot per foot of lift (see page 39).
This cost together with data related to pumping conditions for
each diversion units permits the computation of the average annual
pumping costs.
The pumping conditions for the 20 mgd diversion systems
are the same as for the 10 mgd diversion, except as to (1) the rate of
decline in the groundwater level after city development resulting from
the doubled volume of withdrawal and (2) the friction loss in the 42compared to the 36-inch pipeline.
Appendix.)
(See Tables 1-A through 18-A in the
Since the rate of groundwater withdrawal in the 20 mgd
diversion systems is twice that in the 10 mgd systems, it is assumed
that the rate of decline in the groundwater level after city development will be twice that when 10 million gallons per day are pumped.
This assumes that the rate of decline in the groundwater level is a
linear function directly proportional in magnitude to the rate of
withdrawal.
The pumping conditions, which include friction loss in the
42-inch pipeline, for each of 20 mgd diversion systems and the two
components of pumping costs were computed in the same manner as was
outlined in the previous chapter.
78
Given the annual (amortized) investment costs and annual operating (pumping) costs, their sum will he the annual (amortized) total
direct cost of diverting irrigation water to Tucson
in units of 20 mgd.
The annual (amortized) total direct cost for each diversion
unit was
divided by the acre-feet of water diverted from each unit
to get the
annual total direct cost per acre-foot for these diversions.
These
total direct costs per acre-foot constitute the annual (amortized)
direct cost per acre-foot of diverting irrigation water to Tucson in
20 ingd increments over a 3O-year period from each of the various diversion units.
These annual direct costs are shown in Tables 4 and 5 and
in Figure 14.
Figure 14 is a stepped incremental supply function of water
available to Tucson for urban use when obtained by the diversion of
irrigation water in 20 mgd increments from within the Tucson Region.
It tells us the additional direct (marginal) cost of obtaining additional water from irrigation in 20 mgd increments in the Tucson Region
if the decision were made now (1967).
function.
Thus it is a static supply
It tells only which and how many diversion units to acquire
and develop today to obtain whatever volume of water per day the city
might wish to procure at this time and to do so at minimum direct cost.
The supply function in Figure 14 tells nothing as to the order in time
at which additional diversion units should be retained and developed.
The annual (amortized) total direct costs shown above (Tables 4
and 5 and Figure 14) do not include any estimate of the effect that
the disappearance of agricultural production due to diversion of
XV
XVI
XVII
XVIII
XIII
XIV
IX
X
XI
XII
V
VI
VII
VIII
IV
III
I
II
Unit
a.
Diversion
Table 4.
181,867
170,492
380,159
382,213
375,310
361,549
354,440
386,754
355,861
342,974
289,046
166,240
45,270
86,946
113,095
109,324
100,343
61,285
(dollars)
Pum.jn
616,166
554,040
851,922
873,155
874,855
837,752
770,281
834,626
794,135
735,565
631,479
431,210
298,230
346,495
412,438
424,802
476,511
291,463
(dollars)
Total
18,380
18,340
18,540
18,520
18,760
18,440
18,480
18,620
18,640
18,580
18,200
13,400
6,980
18,540
18,480
18,160
18,340
8,300
(acre-feet)
For the computation of these costs see Tables 1-B through 18-B in the Appendix.
211,594
293,609
379,942
397,208
406,385
391,356
338,934
371,309
365,456
332,259
283,441
211,735
231,628
132,359
184,158
197,108
248,908
77,228
(dollars)
(dollars)
222,705
89,939
91,821
93,734
93,160
84,847
76,797
76,563
72,818
70,332
58,992
53,235
21,332
127,190
115,185
118,370
127,260
152,950
Ca.ital
Land
Water
Quantit
33.00
30.20
46.00
47.10
46.00
45.40
41.40
44.80
42.60
39.60
34.70
32.20
42.70
18.70
22.30
23.40
26.00
35.10
(dollars)
Direct
Cost per
Acre-Foot
Summary of Annual (Amortized) Direct Costs for Diversion of Irrigation Water to Tucson
in Increments of 20 rngd.a
80
Table 5.
Water
Quantit
a
Area
The Supply Schedule: Annual (Amortized) Direct
Costs per
Acre-Foot for Diverting Irrigation Water to Tucson in 20
mgd Increments, Ranked in Order of Ascending Costs.
Direct
Cost per
Acre-Foot
(acre- feet)
XIV
18,540
$18. 70
XV
18,480
22.30
XVI
18,160
23.40
XVII
18,340
26.00
II
18,340
30.20
XII
13,400
32.20
I
18,380
33.00
XI
18,200
34.70
XVIII
8,300
35.10
X
18,580
39.60
VII
18,480
41.40
IX
18,640
42.60
XIII
6,980
42.70
VIII
18,620
44.80
VI
18,440
45.40
III
18,540
46.00
V
18,760
46.00
IV
18,520
47.10
a.
See footnote a of Tables 1-A through 18-A in the Appendix.
81
$50-
45
40
Total Direct Cost per Acre-Foot
35
30
25
Direct Land Cost per Acre-Foot
20
15
Direct Pumping and Delivery Costs per Acre-Foot
10
10
20
40
30
60
50
70
80
90
iod
110
120
130
140
150
160
170
180
190
200
220
210
230
240
250
260
270
280
290
310
300
Acre-Feet per Year (Thousands)
I
XIV
XV
XVI
XVII
II
XII
I
XI
XVIII
Diversion Units
Figure 14.
Supply Function for Diversion of Irrigation Water
to Tucson in 20 mgd Increments.
X
VII
IX
XIII
I
I
VIII
VI
I
III
1
I
V
IV
82
irrigation water might have on the Tucson economy; neither does
it
include any economic costs of possible water quality
problems.
These
two problems and their possible effects on the cost of diverting
irrigation water to Tucson are discussed in Chapter 5.
10 and 20 mgd Diversion Units
The direct cost per acre-foot for diverting irrigation water to
Tucson from the various diversion units in 10 and 20 mgd increments are
shown in Table 6 in order of increasing costs.
The plots of these increasing costs per acre-foot (see Figures
13 and 14, respectively) represent the supply functions for diverting
irrigation water to Tucson from within the Tucson Region at two different scales of plant development.
These supply functions reveal the
additional (marginal) cost of diverting successive 10 or 20 mgd increments of irrigation water now (1967) thus permitting comparison of
total direct costs per acre-foot for diverting increasing amounts of
irrigation water to urban use with the cost of obtaining such increments of supply from alternative available sources.
Table 6 indicates that the direct cost per acre-foot of diverting irrigation water to Tucson in increments of 20 mgd is from $8
to $16 less than diverting it in 10 mgd increments.
This indicates a
possible cost saving if the water were to be diverted in larger incremental units.
However, offsetting such possible savings would be
possible increase in cost resulting from unused capacity in the early
years of life of the larger (20 mgd) diversion units, a cost which was
83
Table 6.
The Supply Schedule:
Direct Cost per Acre-Foot of Diversion
of Irrigation Water to Tucson in 10 and 20 mgd Increments.
2d
10 md
Acre-Feet
of Water
Direct
Cost per
Acre-Foot
XIV
9,270
$26.90
XIV
18,540
$18.70
XV
9,240
32.10
XV
18,480
22.30
XVI
9,080
33.90
XVI
18,160
23.40
XVII
9,170
39.40
XVII
18,340
26.00
XII
6,700
41.60
II
18,340
30.20
II
9,170
42.90
XII
13,400
32.20
XI
9,100
45.40
I
18,380
33.00
I
9,190
50.00
XI
18,200
34.70
X
9,290
51.70
XVIII
8,300
35.10
XIII
3,490
52.70
X
18,580
39.60
VII
9,240
54.10
VII
18,480
41.40
XVIII
4,150
56.50
IX
18,640
42.60
IX
9,320
56.90
XIII
6,980
42.70
VIII
9,310
58.60
VIII
18,620
44.80
III
9,270
61.00
VI
18,440
45.40
VI
9,220
61.40
III
18,540
46.00
V
9,380
62.70
V
18,760
46.00
IV
9,260
63.00
IV
18,520
47.10
Areaa
a.
Areaa
Acre-Feet
of Water
Direct
Cost per
Acre-Foot
See footnote a of Tables 1-A through 18-A in the Appendix.
84
unexplored here.
Thus, a cost comparison of the 10 and 20 mgd diver-
sion units would necessitate analysis of the cost of any unused capacity in the larger units in the early years after expansion, which in
turn would depend on the rate of increase in the demand for water.
Since population growth and resulting increase in demand for water were
not analyzed in this study, a complete cost comparison of the 10 and 20
mgd diversion units was not possible.
However, by assuming diversion
by the city in 10 mgd increments, a probable upper limit of cost for
increasing the supply of water to Tucson from this source was determined thus, again, emphasizing conservatism in the cost of this com-
pared to other alternatives as a source of increased supply of water
for the city.
CHAPTER 5
ECONOMIC EXTERNALITIES ASSOCIATED WITH DIVERTING IRRIGATION
WATER TO URBAN USE IN THE TUCSON REGION22
Multplier Effects
So far, this analysis has considered only the direct costs to
the City of Tucson for obtaining, constructing, and operating the 10
and 20 mgd diversion units for municipal water in the Tucson Region.
In addition to these direct costs to the city, there will be indirect
or external costs which will affect the Tucson economy.
These indirect
or external costs are the reductions in or losses of income experienced
by all those persons in the Tucson area whose incomes will be adversely
affected by any decrease in agricultural production brought about by the
diversion of irrigation water to municipal use.
The magnitude of these
costs is measured by the personal incomes that are lost directly in
agriculture, indirectly in agribusinesses, and in consumer goods and
service businesses in the Tucson Region by virtue of reduction or elimination of agricultural output.
Thus, not only are personal incomes lost
Subsequent to completion of this thesis, a largely different and in many respects more satisfactory analysis of the economic
cost of the externalities presented in this chapter was carried out.
The conclusions drawn from this substitute analysis are not greatly
different from those reached in this chapter in spite of the differing
conceptualization of the problem.
Readers of this thesis who may be
interested in the analysis of such externality costs will find the
substitute analysis of this problem in a paper by Kelso, M. M. and
James J. Jacobs (1967).
22.
85
86
directly by farmers, farm workers, and investors in farms and farming
when agriculture is curtailed, but also there are personal incomes
lost to associated nonfarm earners in the Tucson Region.
This asso-
ciated effect is called the multiplier effect.
The direct cost to the city of diverting irrigation water to
supply its residents with municipal water consists of the costs incurred
by the city to obtain, construct, and operate the water producing and
transporting facilities.
But, the full cost to the residents of the
Tucson area must also include the indirect costs incurred by them in
the form of incomes lost directly by those engaged in agriculture plus
its multiplied effects in the form of incomes lost by nonfarm earners
through reduction or elimination of agricultural output caused by diver.
sion to the city of the water on which it depends.
These income losses
in the Tucson Region must be regarded as part of the economic cost of
the water diversions, because additional municipal water imported into
Tucson from sources that would not reduce irrigation in the area of
the city would not cause a reduction in these incomes.
Thus, these
indirect costs are necessarily included in order to permit one to compare the cost of this means of increasing municipal water for Tucson,
with the full cost of obtaining the water from possible alternative
sources.
Measuring Direct and Indirect
Income Effects
The economy, be it the Tucson Region's, the state's, or the
nation's, is an interrelated structure.
Each economic sector not only
87
produces goods and services but also purchases goods
and services for
use in its production process.
This interdependence may be analyzed in two separate
components.
The first component is direct
pendence, which is the direct purchases
of one industry from another of things needed in the production
of the
first industry's product.
The second component, the more difficult to
measure, is the sum of the indirect effects generated by the direct
purchases.
These occur because any sector which supplies inputs to
another sector must also acquire inputs, thus generating incomes in
other economic sectors, ad infinitum.
The construction of analytical models and the collection of
data necessary to measure the indirect income effects, caused by the
diversion of irrigation water to urban use in the Tucson Region, are
not possible within the time limits of this study.
However, an indi-
cation of the probable order of magnitude of such indirect income
effects of irrigated agriculture on the Tucson economy can be derived
from studies which have attempted to measure these effects in other
western irrigation communities.
The indirect income multipliers de-
rived in all such studies, though differing, are similar and of the
same order of magnitude.
In this analysis, the multiplier determined for the Grand
Valley trade area of Colorado is used as an indicator of the magnitude
of indirect income losses we might expect were irrigation water di-
verted to urban use in the Tucson Region
(Struthers, 1963).
88
In this analysis of the Tucson Region, the income effects flowing from reduced output from irrigated agriculture are measured in two
components.
The first component is the income lost directly in agri-.
culture itself; the second component is the resulting indirect loss of
incomes
which occur in related nonfarm businesses.
We begin our analysis by determining the magnitude of direct
income losses we might expect in irrigated agriculture itself.
acreages of the various crops in the
Since
Tucson Region have already been
determined (page 47), one can calculate the gross sales from irrigated
agriculture that would be lost to the Region if all irrigation water
were diverted by determining the gross income per acre for the various
crops grown in the Region, multiplying by the acres of each crop in
the Region and summing the results.
The 1967 prices and yields per
acre for the crops of the Tucson Region from which these gross incomes
per acre can be determined are given in Table 7.
However, only about
75 cents of each dollbr of gross sales from irrigated agriculture
appears as personal income to the persons engaged
(Tenth Arizona Town
Hall, 1967). Thus, 75 percent of the gross sales from irrigated agri-
culture in the Region measures the direct income effects within
agriculture itself from reduction in agricultural output.
calculations are presented in columns 2,
These
3, 4 and 5 in Table 8.
Table 8, column 6, also shows the magnitude of indirect income
effects (losses) we might expect in related nonfarm businesses in the
Tucson Region resulting from
agriculture.
reduction
The multiplier determined
of
incomes within irrigated
or the Grand Valley trade area
89
Table 7.
1967 Prces and Yields of Irrigated Crops in the Tucson
Region.
Crop
Area
Yield
Price
Gross Income
'er Acre
Cotton
Avra-Marana
2 bales/acre
$.4l/lb.b
$410
S ahuar it a
1.5 bales/acre
$.41/lb.
Barley
Tucson
158 tons/acre
$46/ton
73
Sorghum
Tucson
2.02 tons/acre
$42/ton
85
Forage
Tucson
4 tons/acre
$26/ton
104
Misc.
Tucson
308
90c
Prices and yields were obtained from Mr. N. Gene Wright,
Research Associate, Department of Agricultural Economics, The University of Arizona, Tucson.
The $41/lb. includes lint receipts, support payments,
diverted acres payments on 35 percent diverted acres, and cottonseed
receipts.
The gross
estimated at $90.
return
per acre for miscellaneous crops was
49,127
1,284
3,226
90
104
80
$410
308
(3)
320,679
$35,252,090
260,010
$28,582,776
234,009
$25,724,498
173,340
$19,005,184
86,670
$9,527,592
$12,703,456
931,024
754,884
679,396
503,256
251,628
335,504
115,560
3,621,486
2,936,340
$24,871,215
5,507,687
$20,165,850
4,465,692
(7)
2.7
2,642,706
$18,149,265
4,019,123
2.0
1,957,560
(6)
2.7
Total Personal Income
(Column 5 plus Column 6)
978,780
$13,443,900
2,944,128
2.0
Indirect Personal Income
Column 5 multiplied bYc
1,305,040
$6,721,950
1,488,564
(5)
(4)
$ 8,962,600
1,984,752
(757. of Column 4)
Direct Personal
Income
Gross Sales
per Crop
These multipliers were obtained from a study of the Grand Valley trade area, Colorsdo.
Food and feed grains consist of barley and sorghum grain.
Acres are averages of crop acres from 1960-66, based on annual crop surveys conducted by the Department of Agricultural
Engineering, The University of Arizona, Tucson.
Total
Miscellaneous
alfalfa)
Forage (largely
16,313
Food and Feed Gratnsb
(2)
(1)
a
21,860
6,444
Acres
Crop
Gross Income
per Acre
Direct, Indirect, and Total Personal Income Generated by Irrigated Agriculture in the Tucson Region
(Based on Tables 1 and 7).
Cotton - Avra-Marana
Sahuarita
Table 8.
91
and used herein lies between 2.0 and 2.7
(Struthers, 1963),
In this
analysis, both figures are used, thus determining the likely minimum
and maximum magnitudes of indirect income effects.
The multipliers
2.0 and 2.7 mean that for each dollar in persona]. income lost within
irrigated agriculture there will be $2.00 to $2.70 of personal income
lost in related nonfarm businesses in the Tucson Region.
Column 7 of Table 8 shows the sum of direct and indirect or
the total of personal incomes generated in the Tucson Region by irrigated agriculture.
Table 8 gives reasonable estimates of the probable minimum and
maximum orders of magnitude of total income losses (direct and indirect)
one might expect if irrigation water in the Tucson Region were to be
diverted to urban use.
However, the incomes received directly as re
turns on investments in farm real estate in the Region have previously
been accounted for in this analysis by the sums paid by the city to
farmland owners in purchasing the agricultural lands.
Thus, the sum of
the direct and indirect income losses of $28,572,776 and $35,252,090
presented in Table 8 must be adjusted downward by the amount of farm
real estate investment income generated within agriculture and already
accounted for among the direct costs to the city of acquiring irrigation
water for municipal use as shown in Table 2.
Table 9 gives an estimate of $2,382,931 as the farm real estate
investment income generated within irrigated agriculture in the Tucson
10d
12,840
$2,382,931
49,127
22,582
212 ,069
1,284
3,226
$7
4tons
$1.60 ton
$
16,313
$13
21,860
6,444
$80
$60
1.58 tons
2.02 tons
$1,748,800
386,640
Acres
Rent per acre of mise1laneous crops is estimated at $10.
$13 is the average rent per acre of barley and sorghum.
See Table 7, page 89.
The rents generated per unit of output were estimated from Arizona Ariculture 1966,
Tables 14, 15, 16, 17 and 18, pages 26-30 by estimating returns to management at nine percent of
gross income and assuming a pumping lift of 300 feet.
Totals
Miscellaneous
Forage
Barley
Sorghum
2.0 bales
1.5 bales
perb
Acre
Total
Rental
Incomes
Rent
per
Acre
$9 ton
$6 ton
Cotton - Avra-Marana
Sahuarita
Food and Feed Grains
$40 bale
$40 bale
Crop
Output
Farm Real Estate Investment Incomes (Rent) Generated in Irrigated Agriculture in the
Tucson Region.
Rent per
Unit of
Output
Table 9.
93
Region.
This real estate income of $2,382,931 is then subtracted
from the estimate of total personal incomes of $28,252,776 and
$35,252,090 (Table 8) which gives us an estimate of $25,869,845 to
$32,869,159 as total personal income that would be lost in the Tucson
Region and not compensated by the city if it were to acquire the
Tucson Region's farmlands and divert their irrigation water to the
city.
However, this personal income loss cannot legitimately be considered to be an annually recurring loss in perpetuity.
All income
recipients deprived of these incomes can, with differing degrees of
difficulty and inflexibility, transfer their earning power (assets)
to other locations or employments.
In a full employment economy such
as now exists in the United States,
they can do so at earning levels
fully comparable (on the average) to those lost by virtue of this
agricultural curtailment and can do so with only temporary loss of
earnings due to the frictions and inflexibilities in finding and
trans ferring their earning assets to the new employments.
In this study, it is arbitrarily assumed that, on the average
over all persons and assets affected, a half year's income will be
lost due to these inflexibilitieS and frictions or between $12,934,222
and $16,434,580.
$2,382,931 real estate income from 49,127 cropped acres is
approximately $48.50 per acre. Capitalized at six to eight percent,
such annual return per acre becomes $600 to $800 as the value per acre,
the ball park of crop
an estimate of farmland values certainly within
production values for farmlands in this Region. Thus, this estimate
of farm rental income appears reasonable.
23.
94
But this loss of one-half year of income is incurred but
once,
hence, can be evaluated as if it were an investment cost attributable
to change of employment and can be converted into an average annual
cost as are the other costs of urban water
Supply
Suirifflarized in Table 3
by assuming it, like these other costs, to be amortized over 30 years
at three and one-half percent (the city's assumed borrowing terms) or
at an annual cost of $.05437 per dollar of investment.
The average
annual costs of personal incomes lost directly and indirectly in the
Tucson Region if irrigated agriculture were to be completely eliminated
would at these rates be between $703,272 and $893,548.
Knowing the minimum-maximum average annual values of personal
incomes lost in the Region by diverting irrigation water one can relate
them to the total acre-feet of water used by agriculture and diverted
to urban use (153,000 acre-feet-page 48) thus determining the average
annual indirect economic cost to the Region's residents were irrigation
water to be acquired by the city.
This average annual indirect economic
cost is, on this basis, found to be between $4.60 and $5.80 per acrefoot of irrigation water diverted.
These amounts represent the
minimum-maximum order of magnitude of the average annual indirect
loss we might expect in the Tucson economy per acre-foot of irri-
gation water diverted to urban use.24
This estimate of indirect economic cost to personal income
24.
receivers due to reduction of agricultural output is probably defensivle only in the event the city is assumed to use its credit and
borrowing power to "pay off" all injured parties in the same way it is
assumed to do respecting farmland owners thus holding all affected
95
Table 10 shows the range of probable total (direct and indirect)
average annual costs we might expect per acre-foot of irrigation water
diverted to urban use from the various diversion units in the Tucson
Region.
This range of costs is also presented in Figure 15.
The data
in Table 10 arid Figure 15 may be defined as the static (1967) total
cost supply schedule confronting the City of Tucson for additional
increments of urban water supply obtainable by the diversion of irrigation water used within the Region.
It is illustrative of how these data may be used to compare
the costs in Table 10 and Figure 15 with one of the alternative sources
of municipal water--the Central Arizona Project at $50 per acre-foot
for "raw" water (planned).
Table 10 indicates that the water from
diversion units XIV, XV, XVI, XVII, XII and II amounting to about
52,630 acre-feet per year could be diverted to Tucson municipal use
currently at a total economic coinnunity cost less than $50 per acre-foot.
income receivers free of harm. If, as is more conventional, the city
were to hold only farm property holders free of harm by buying their
assets and thus generate external economic effects on many other income
receivers in the Region, the average annual equivalent cost of this
loss would be significantly higher than shown above because many--maybe
all--of those private income receivers adversely affected would not be
able to amortize the loss nearly so favorably as could the city--the
costs of consumer credit rather than municipal credit would be relevant
to many of the injured income receivers. However, it is appropriate to
observe, though magnitudes are impossible to establish, that to some
degree even these "credit costs," whether municipal or private, are
merely transactions within the regional economy thus becoming somebody's income as well as somebody's cost and hence are not fully
chargeable as economic cost to the conmiunity, only the extra regional
leakage being so chargeable. To the extent that this circumstance
holds, the indirect income consequences of a program such as considered
herein is distributional rather than efficient, that is, a question of
"who gets it" rather than whether the "outlay"--cost-iS "worth it."
9 , 100
9,190
9,290
3,490
9,240
4,150
9,320
9,310
9,270
9,220
9,380
9,260
XI
I
IV
V
III
VI
VIII
IX
VII
XVIII
X
XIII
II
9,270
18,500
27,590
36,760
43,460
52,630
61,730
70,920
80,210
83,700
92,940
97,090
106,410
115,720
124,990
134,210
143,590
152,850
(acre-feet)
(acre-feet)
9,270
9,240
9,080
9,170
6,700
9,170
Cumulative
Water
Quantity
Water
Quantity
(1967).
$26.90
32.10
33.90
39.40
41.60
42.90
45.40
50.00
51.70
52.70
54.10
56.50
56.90
58.60
61.00
61.40
62.70
63.00
Direct Cost
per
Acre-Foot
$4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
4.60
$5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80
Indirect Cost'
per Acre-Foot
Maximumd
Minimumd
$31.50
36.70
38.50
44.00
46.20
47.50
50.00
54.60
56.30
57.30
58.70
61.10
61.50
63.20
65.60
66.00
67.30
67.60
$32.70
37.90
39.70
45.20
47.40
48.70
51.20
55.80
57.50
58.50
59.90
62.30
62.70
64.40
66.80
67.20
68.50
68.80
Total Economic Cost
per Acre-Foot
Minimumd
Maximumd
Total Community Economic Cost per Acre-Foot (Direct and Indirect) for Diverting
Irrigation Water to Tucson from Various Diversion Units in Increments of 10 mgd
XIV
XV
XVI
XVII
XII
Diversion
a
Units
-
Table 10.
See footnote a of the Appendix, Tables 1-A through 18-A.
(Continued).
Minimum indirect cost is obtained by using a multiplier of 2.
Indirect costs consist of direct and indirect income losses experienced in the
Tucson Region by other than the owners of farm real estate which is included in t'direct costs."
Direct costs consist of land purchase, construction, and operatIon costs for wells,
pumps, and pipelines.
Table 10.
98
Marginal Cost of Water--CAP Alternative
Total Economic Cost per Acre-Foot (at Multipliers of 2.0 and 2.7)
6
2.0
,J
IMultipliers
2.7
I
I Indirect Costs
per Acre-Foot J
C)
50
Direct Costs per Acre-Foot
El
20
10
20
30
40
50
60
70
So
90
100
110
120
130
140
150
160
Acre-Feet per Year (Thousands)
XIV
XV
XVI
XVII
XII
II
XI
Diversion Units
Figure 15.
Expected Minimum and Maximum (Total Cost) Supply
Function for the Diversion of Irrigation Water to
Tucson in 10 mgd Increments.
I
X XIII
VII
XVIII
IX
VIII
[II
VI
V
IV
99
Note that whether the value of the multiplier is 2.0 or 2.7 makes no
difference to the decision.
If, however, an expected water treatment cost of $15 per
acre-foot (wheeler, Peterson and Coffeen, 1965) is added to the $50
charge per acre-foot for CAP water, the full cost of additional
quantities of water from this alternative supply sould be $65 per
acre-foot.
This additional or marginal cost for increasing supplies
of water from this alternative source is shown in Figure 15 in relation to the supply schedule derived from this study.
Assuming the
locally pumped and diverted irrigation water will need little or no
treatment for many years at present groundwater levels and rates of
decline particularly if judicious mixing of water of different qualities is practiced, the supply schedule of Table 10 and Figure 15 shows
that, at an alternative cost of $65 per acre-foot for treated CAP
water, the water from 14 of the 18 diversion units or about 115,720
acre-feet can be diverted to Tucson more cheaply.
Note that in this
connection also it is immaterial to the decision whether the size of
the multiplier is 2.0 or 2.7.
A comparison of alternatives such as that described above
reveals that if the city were to turn to the CAP alternative for additional water or for water to replace some of that currently pumped
from existing sources, the Tucson economy would be penalized for any
quantity obtained up to 115,720 acre-feet,
The economic penalty for
any quantity obtained by the city from the Central Arizona Project up
to that quantity would be the difference between the CAP cost ($65 per
100
acre-foot) the economic cost of each additional acre-foot diverted from
agriculture (in order of the magnitude of such costs) multiplied by
the number of acre-feet of water thus secured.
For example, if 27,590
acre-feet of imported water were to be obtained by the city, the economic penalty on the City's economy by obtaining it from the CAP rather
by diversion from local irrigation could be approximately threequarters of a million dollars on $28.25 per acre-foot as shown in
Table 11.
9,080
XVI
$1,793,350
$1,013,801
Average weighted by quantity obtained at each cost per acre-foot.
At $65 per acre-foot.
$779, 549
229,724
25.30
590,200
360,476
39.70
28.
250,404
$299,421
$32.30
602,550
27.10
$
Economic Penalty
per
Total
Acre-Foot
600,600
303,129
CAPb
Cost
Total
350,196
$
Total
Diversion
Cost
37.90
$32.70
Assuming maximum indirect cost.
27,590
9,240
xv
Total
9,270
(acre-feet
per year)
Quantity
of Water
Diversion
Cost pera
Acre-Foot
Economic Penalty Imposed on the Tucson Economy by Obtaining the Indicated Quantities
of Additional Water from the CAP in Place of Diversion from Local Irrigation.
xIv
Diversion
Unit
Table 11.
CHAPTER 6
SUMMARY AND APPRAISAL
Summary
The total economic cost of obtaining additional water for Tucson
by diversion from irrigation in the Tucson Region is assumed to be the
sum of the land cost, the construction cost, the diversion (operation)
cost, and the value of the net income lost to Tucson's nonagricultural
economic sectors from curtailment of agricultural output in the Tucson
Region.
Water in the Tucson Region is scarce because sacrifices of
alternative enjoyments (costs) must be incurred to capture it for
municipal use.
It is growing progressively scarcer because withdrawals
of groundwater from beneath the city are exceeding recharge and the
water level is falling and because increasing demand for water by the
city is expected to continue.
The importation of any additional water
into the city from any source will tend to diminish the amount of water
pumped from the Tucson Basin now and in the future thus relieving the
severity of the 1oal overdraft.
to be obtained from sources
This additional water, assuming it
iith the lowest per unit costs, will per-
mit the city to maintain its present rate of growth for a longer period
of time with least economic sacrifice.
As additional supplies of water
are acquired from among the array of alternative sources, the least
per unit cost of water to the city will increase because of variation
in conditions prevailing in each source.
102
103
The level of the cost per acre-foot diverted from irrigated
agriculture will vary among the water diversion units because of differences among them in (1) initial depth of the groundwater table,
(2) rate of decline in that depth relative to rate of withdrawal, (3)
the price of land, (4) the rate of water delivery, and (5) the distance
from Tucson.
The level of this cost will increase from year to year
over time in each diversion unit as a result of the continual increase
in the depth to groundwater resulting from continuous withdrawal in
excess of annual recharge.
This increasing level of cost for each
diversion unit is in this analysis reduced to a constant cost for each
diversion unit by amortizing it over the 30-year period of the life
of wells and equipment at three and one-half percent interest.
Capital costs for wells and for pumping and pipeline equipment for each diversion unit are amortized at three and one-half percent over the 30-year life of equipment period to determine the annual
Cost against the capital account that would liquidate the investment
by the end of the 30-year period.
The land cost for each diversion
unit, since land is considered to be nondepreciable, is the annual
interest charge at three and one-half percent on the borrowed funds
used in its acquisition.
The level of the total cost per acre-foot of water diverted
from each unit is affected uniformly for all units by the amortized
value of the net incomes lost by nonlandowners in agriculture and by
all affected persons in the nonagricultural sectors of the Tucson
104
Region due to elimination of any part or all of agricultural production
and incomes from the Region.
The sum of these operating costs of pumping and transporting
the water, the amortized costs for each diversion unit and the amortized
value of incomes lost due to elimination of some or all of irrigated
agriculture is the amortized average annual total cost of diverting
irrigation water to Tucson from each of the various diversion units.
The amortized average annual total costs, divided by the acre-feet of
water available in each diversion unit, is the amortized average annual
total cost per acre-foot for irrigation water diverted to Tucson from
each of the various diversion units.
The amortized average annual total costs of diverted irrigation water at delivery rates of 10 mgd and 20 mgd are found by this
Study to vary from $31.08 to $67.18 per acre-foot and from $22.88 to
$51.28 per acre-foot, respectively.
The costs per acre-foot for the
10 mgd delivery rate represent a reasonable upper limit of costs that
the city would incur at the present time, were it to obtain its additional supply of water by the diversion of irrigation water in incre-
ments of 10 mgd or 9,200 acre-feet per year.
The increasing average annual costs per acre-foot for diverting additional irrigation water to Tucson in 10 or in 20 rngd amounts
by increasing the number of diversion units brought into production
are the marginal or incremental costs of expanded supplies.
They
represent the additional costs per acre-foot that must be paid annually
105
to obtain additional supplies of urban water from irrigation in incre-
ments of 9,200 or 18,400 acre-feet per year.
Appraisal
The costs developed herein for the diversion of irrigation water
to urban use are dependent upon the conditions and assumptions in the
analysis.
The elimination of or change in any one of these conditions
or assumptions will result in different costs than those determined in
this study.
The validity and rationale of the conditions and assump-
tions in the analysis are developed and defended in all cases.
The cost of diverting water to urban use as developed herein
relates only to the cost of diverting water from one possible source
only; namely, the diversion of irrigation water to Tucson from the
agricultural land immediately surrounding the city.
The use of simplifying assumptions where no exact information
is available, necessarily places limitations upon the analysis.
Some
of the more pertinent of these are:
1.
The budgets developed for the diversion of irrigation water
to Tucson are constant over time because the prices and
technology employed in the budgets are not permitted to
vary.
Over the period of time covered by the budgets in
this analysis, prices and technology would ordinarily be
expected to vary.
However, due to the lack of relevant
information and for purposes of simplifying the analysis,
technology and price projections are held constant.
106
The analysis uses only two scales (sizes) of diversion
units thus implicitly assuming that one of these two diversion scales is the most economical and would not change in
the time period of this analysis.
If, in fact, the costs
resulting from economies or diseconomies of scale of diversion works do change over time, the size of the economically
efficient diversion units may change.
The decline rate of the groundwater level is assumed to be
directly proportional to the rate of withdrawal.
This
assumption holds the yield of the aquifer constant with
increasing depth.
In reality, however, there is some indi-
cation that water quality and aquifer yield tend to decrease at greater depths.
If the efficiency of the aquifer
does decrease at increased depths, it will cause the pumping costs to increase more rapidly and costs to be higher
because of the increased rate of water level decline.
Since
the exact effects, if any, of the depth to groundwater on
the efficiency of the aquifer are yet to be determined, it
is assumed that the quality of water and the efficiency of
the aquifer remain constant.
In any case, over the ensuing
30 years (to 1997) the deepest well (at 10 mgd delivery)
will reach no more than 576 feet of lift.
It is doubtful
that decline in aquifers or in water quality will have
changed significantly at that depth.
107
The analysis assumes that the institutional difficulties
of diverting groundwater from the land overlying the
aquifer can be overcome.
The Supreme Court has held that
if the diversion of groundwater away from
the land im-
pairs the supply of groundwater on the property of another,
it constitutes an illegal action for which damages are
recoverable.
In this analysis, it was assumed that the
city would be required by law or public relations policy
to buy the farmland from which it might wish to divert
water; and, by restricting itself to withdrawals equal to
present withdrawals from those lands, that it would be
able to defend itself against claims that it is demaging
other overlying owners.
This, it is assumed, would di-
minish the legal problems and justly compensate land-
owners, thereby eliminating or minimizing the institutional
constraints.
The supply functions developed in this analysis for the
diversion of irrigation water to Tucson are of a tentative
nature.
A more comprehensive statistical analysis of the
data used to develop the supply function may reveal inaccuracies.
Although the general shape of the supply function
is not likely to change, the level of costs determined for
each of the various
slightly.
diversion
units may be affected
108
6.
The supply functions developed for the diversion of irrigation water to urban use relate only to Tucson and only
to decisions that might be made now.
At each succeeding
point in time at which the city might consider further
additions to its water supplies by diversion from irri-
gation as well as other alternatives, an analysis similar
to this one will be required reflecting the conditions at
that point in time for obtaining such additional supplies
of water.
APPENDIX
BASIC DATA AND COST ANALYSIS
FOR AREAS IXVIII
109
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Level over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
17
560
25
8
177
200
177
2,600
350
14
37
595
2,600
350
97
1.3
25
60
160
2.6
34
194
238
194
97
1.3
25
60
160
1.3
2,250
(feet)
(feet)
2,250
3.5
T13S-R13E
Sections 9,
14, 15 and 16
T13S-R13E
Sections
14 and 15
3.5
20 mgd
10 mgd
a.
Area I consists of cropland in T12S-R12E, T12S-R13E, Tl2SRl4E and Sections 6, 7, 8, 9,
14, 15, 16, and 17 of T13S-R13E.
15.
10.
11.
12.
13.
14.
9.
8.
7.
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 1-A.
750,000.00
799,260.00
1,354.00
250,000.00
554,400.00
1,536,720.00
$3,891,734.00
$
211,594.00
181,867.00
393,461.00
616,166.00
21.40
33.00
85,585.00
237,104.00
459,809.00
25.80
50.00
The acre-feet of water delivered per year would be 9,190 and 18,380 for the 10 and 20
mgd systems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
$222,705.00
151,519.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 1-A.
498,960.00
341,580.00
1,354.00
250,000.00
400,000.00
1,294,920.00
$2,786,814.00
$
$222,705.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20 mgd
from Area 1,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
10
mgd
20 m&
20mgd
10 mgd
Land
3,636 acres @ $1,750/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
3.5 miles - 36" pipeline @ $27/ft.
3.5 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
c
(Acre-feet x lift x $.01663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 1-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head-We11 Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
11a
2
26
121
155
121
2,600
350
51
37
559
108
2,600
350
30
25
513
95
13
108
125
12
12
95
1
1
120
93
93
120
2,250
2,250
1
(feet)
T12S-R12E
Sections 25,
26, 27, and 35
20 mgd
(feet)
25 arid 26
T12S-R12E
Sections
10 mgd
Area II consists of cropland in Sections 22, 25, 26, 27, 33, 34, 35 and 36 of TllSa.
RllE and Section 1 of T12S-R11E.
15.
13.
14.
11.
12.
10.
9.
8..
7.
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 2-A.
750,000.00
799,260.00
5,031.00
250,000.00
2,059,200.00
1,536,720.00
$5,400,211.00
$
170,492.00
464,101.00
554,040.00
25.30
30.20
78,231.00
303,584.00
393,523.00
33.10
42.90
The acre-feet of water delivered per year would be 9,170 and 18,340 for the 10 and 20
mgd systens respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
5,956.00
83,983.00
293,609.00
$
225,353.00
5,956.00
83,983.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 2-A.
1,853,280.00
341,580.00
5,031.00
250,000.00
400,000.00
1,294,920.00
$4,144,811.00
$
$
Estimated Costs
for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20 mgd
11a 1967.
from Area
Estimated Cost of
Average Annual
Depreciable Capital
Cost
10 mgd
20 mgd
10 mgd
20 mgd
Land
284 acres @ $600/acre @ .035 interest
2,999 acres @ $800/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
13 miles - 36' pipeline @ $27/ft.
13 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amcrtized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x $.0l663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 2-B.
Location and Conditions
Location and Pumping Conditions of Area
15.
11.
12.
13.
14.
9.
10.
8.
7.
4.
5.
6.
3.
2.
1.
a.
305
5.8
75
380
479
380
2,600
650
53
25
1,108
12
120
1,950
281
5.8
(feet)
23
Sections
28 and 29
Ti iS - RilE
10 mgd
12
305
11.6
151
456
653
456
2,600
650
90
37
1,233
1,950
281
5.8
120
(feet)
23
T11S-R11E
Sections 20,
21, 28 and 29
20 mgd
Area III consists of cropland in Sections 16, 19, 20, 21, 28, 29 and 30 of TllS-R11E.
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
Miles from City
Well Field Location
Table 3-A.
3,278,880.00
341,580.00
8,901.00
250,000.00
400,000.00
1,294,920.00
$5,574,281.00
$
750,000.00
799,260.00
8,901.00
250,000.00
3,643,200.00
1,536,720.00
$6,988,081.00
$
380,159.00
760,101.00
851,922.00
41.00
46.00
170,809.00
473,883.00
565,704.00
51.10
61.00
The acre-feet of water delivered per year would be 9,270 and 18,540 for the 10 and 20
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
7,365.00
84,456.00
379,942.00
$
303,074.00
7,365.00
84,456.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 3-A.
V
$
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20 mgd
from Area III,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
10 mgd
20 mgd
10 mgd
Land
351 acres @ $600/acre @ .035 interest
2,016 acres @ $800/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
23 miles - 36!! pipeline @ $27/ft.
23 miles - 42It pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and interest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 3-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
1,113
25
380
479
380
2,600
650
58
75
5.8
12
12
305
1,241
98
37
2,600
650
305
11.6
151
456
653
456
1,950
281
5.8
120
25
25
1,950
281
5.8
120
Sections 7,
8, 17, and 18
Sections
17 and 18
(feet)
Ti iS - Rl 1E
Ti iS-RilE
(feet)
20 mgd
10 mgd
a.
Area IV consists of cropland in Sections 7, 17, and 18 of T11S-RI1E and Sections 1,
2, 3, 12 and 13 of T11S-R1OE.
15.
10.
11.
12.
13.
14.
9.
8..
7.
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 4-A.
ia
1,294,920.00
$5,860,175.00
3,564,000.00
341,580.00
9,675.00
250,000.00
400,000.00
750,000.00
799,260.00
9,675.00
250,000.00
3,960,000.00
1,536,720.00
$7,305,655.00
$
397,208.00
382,213.00
779,421.00
873,155.00
42.10
47.10
171,395.00
490,013.00
583,747.00
52.90
63.00
The acre-feet of water delivered per year would be 9,260 and 18,520 for the 10 and 20
mgd systems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
$ 16,997.00
76,737.00
318,618.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 4-A.
Reservoir and Booster Station
Transmission Line
25 miles - 36" pipeline @ $27/ft.
25 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x $.0l663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Eas ements
$
$ 16,997.00
76,737.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
20 mgd
10 m8d
10 mgd
Land
809 acres @ $600/acre @ .035 interest
2,741 acres @ $800/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Table 4-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
1,081
60
25
2,600
650
346
437
346
69
277
5.3
75
75
20
138
415
595
415
2,600
650
101
37
1,203
20
277
10.6
1,950
246
5.3
(feet)
(feet)
1,950
246
5.3
26
T1IS-R1OE
Sections 23,
24, 25 and 26
20 mgd
26
T11S-R1OE
Sections
25 and 26
10 mgd
Area V consists of cropland in Sections 10, 11,14, 15, 22, 23, 24, 25, 26 and 27
a.
of T11S-R1OE.
15.
10.
Ii.
12.
13.
14.
9.
8.
4.
5.
6.
7.
3.
2.
1.
Miles from City
Well Field Location
Table 5-A.
750,000.00
799,260.00
10,062.00
250,000.00
4,118,400.00
1,536,720.00
$7,404,442.00
$
406,385.00
375,310.00
781,695.00
874,855.00
41.70
46.00
168,625.00
495,015.00
588,175.00
52.80
62.70
The acre-feet of water delivered per year would be 9,380 and 18,760 for the 10 and 20
mgd systets respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
$ 34,598.00
58,562.00
326,390.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 5-A.
3,706,560.00
341,580.00
10,062.00
250,000.00
400,000.00
1,294,920.00
$6,003,122.00
$
$ 34,598.00
58,562.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area V
1967.
Estimated Cost of
Average Annual
Depreciable Capital
Cost
10 mgd
20 mgd
20 mgd
10 mgd
Land
1,648 acres @ $600/acre @ .035 interest
2,091 acres @ $800/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
26 miles - 36" pipeline @ $27/ft.
26 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
c
(Acre-feet x lift x $.01663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 5-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
20
289
9.0
117
406
659
406
2,600
600
20
289
4.5
58
347
425
347
78
40
1,065
1,179
133
40
75
75
2,600
600
2,000
260
4.5
(feet)
(feet)
2,000
260
4.5
34
T12S-R1OE
Sections 9,
16, 20 and 21
T12S-R1OE
Sections
20 and 21
34
20 mgd
10 tngd
Area VI consists of cropland in Sections 4, 5, 8, 9, 17, 20, 21, 28, 29 and 33 of
a.
T1IS-R1OE and Sections 4, 9, 16, 20 and 21 of TI2S-R1OE.
15.
14.
11.
12.
13.
10.
9.
8.
7.
6.
5.
4.
3.
1.
2.
Miles from City
Well Field Location
Table 6-A.
mgd syst
750,000.00
799,260.00
13,158.00
250,000.00
5,385,600.00
$7,198,018.00
$
391,356.00
361,549.00
752,905.00
837,752.00
40.80
45.40
163,278.00
481,439.00
566,286.00
52.20
61.40
The acre-feet of water delivered per year would be 9,220 and 18,440 for the 10 and 20
respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
$ 84,847.00
318,161.00
$ 84,847.00
Average Annual
Cost
20 mgd
10 mgd
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 6-A.
4,897,040.00
341,580.00
13,158.00
250,000.00
400,000.00
$5,851,778.00
$
Estimated Cost of
Depreciable Capital
10 mgd
20 mgd
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
a
m'd from Area VI,
1967.
Land
4,042 acres @ $600/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
34 miles - 367! pipeline @ $27/ft.
34 miles - 42 pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)c
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 6-B.
4.9
25
60
360
9.8
2,050
290
4.9
25
60
360
4.9
64
424
508
424
2,600
550
42
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
1,041
a.
Area VII consists of cropland in Sections 31 and 32 of T11S-R11E; Section 1 of
T12S-RIOE; and Sections 4, 6, 7, 8, 9, 10, 11, 12 and 15 of T12S-R11E.
15.
14.
13.
10.
11.
12.
9.
8.
7.
5.
6.
4.
3.
2.
25
2,050
290
(feet)
Miles from City
71
37
1,145
487
654
487
2,600
550
127
(feet)
Sections
11 and 12
18.25
1.
T12S-R11E
Sections 2,
10, 11 and 12
18.25
T12S-R11E
Well Field Location
Location and Conditions
20 mgd
Location and Pumping Conditions of Area
10 mgd
Table 7-A.
750,000.00
799,260.00
7,063.00
250,000.00
2,890,800.00
1,536,720.00
$6,233,843.00
$
354,550.00
693,484.00
770,281.00
37.20
41.40
161,173.00
427,329.00
504, 126.00
The acre-feet of water delivered per year would be 9,240 and 18,480 for the 10 and 20
mgd systems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
54. 10
45.90
338,934.00
$ 76,797.00
266,156.00
Capital amortized at threeand one-half percent interest over 30 years.
See footnote a, Table 7-A.
2,601,720.00
341,580.00
7,063.00
250,000.00
400,000.00
1,294,920.00
$4,895,283.00
$
$ 76,797.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area VII,a 1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
10 mgd
20 mgd
10 mgd
Land
3,657 acres @ $600/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
18.25 miles - 36" pipeline @ $27/ft.
18.25 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
c
(Acre-feet x lift x $.0l663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 7-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
pumping Water Level (1967)
Annual Decline Following' Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping 1ater Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
(feet)
2,025
320
6.1
25
22
22
(feet)
2,025
320
6.1
25
60
392
6.1
51
25
1,122
471
576
471
2,600
575
79
T12S-R11E
Sections 16,
17, 20 and 21
T12S-RI1E
Sections
16 and 17
1,249
a.
86
37
575
2,600
60
392
12.2
159
551
758
551
20 mgd
10 mgd
Area VIII consists of cropland in Sections 3, 11, 12, 14, 23 and 24 of T12S-R1OE
and Sections 16, 17, 18, 19 and 20 of T12S-R11E.
15.
10.
11.
12.
13.
14.
9.
8.
7.
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 8-A.
$
3,484,800.00
1,536,720.00
6,829,294.00
750,000.00
799,260.00
8,514.00
250,000.00
371,309.00
386,754.00
758,063.00
834,626.00
40.70
44.80
173,714.00
469,016.00
545,579.00
50.40
58.60
The acre-feet of Water delivered per year would be 9,310 and 18,620 for the 10 and 20
mgd systems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
$ 22,484.00
54,079.00
295, 302.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 8-A.
1,294920.00
3,136,320.00
341,580.00
8,514.00
250,000.00
400,000.00
$5,431,334.00
$
$ 22,484.00
54,079.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area iii,a 1967.
Estimated Cost of
Average Annual
Cost
Depreciable Capital
20 mgd
10
mgd
20
mgd
10 mgd
Land
1,285 acres @ $500/acre @ .035 interest
2,575 acres @ $500/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
22 miles - 36" pipeline @ $27/ft.
22 miles - 42" pipeline @ $30/ft.
City Tie-in
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x $.0l663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Taible 8-B.
Location and Conditions
Location and Pumping Conditions of Area i.a
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
40
1,048
71
60
338
3.8
49
387
452
387
2,600
550
25
270
3.8
1,148
121
40
437
2,600
550
7.6
99
437
566
3.8
25
60
338
2,050
270
(feet)
(feet)
2,050
31
29 and 30
T12S-R1OE
Sections
25 and 26
Sect ions
T12S-R11E
20 mgd
31
T12S-R1OE
Sections
25 and 26
10 mgd
a. Area IX consists of cropland in Sections 25, 26, 27, 31, 32 and 33 of T12S-R1OE;
Sections 29 and 30 of T12S-R11E; Sections 4, 5, 6 and 11 of T13S-R1OE; and Section 7 of T133-R11E.
15.
13.
14.
10.
11.
12.
9.
8.
7.
5.
6.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 9-A.
750,000.00
799,260.00
11,997.00
250,000.00
4,910,400.00
$6,721,657.00
$
365,456.00
355,861.00
721,317.00
794,135.00
38.70
42.60
294,845.00
162,431.00
457,276.00
530,094.00
49.10
56.90
$.01663 is variable pumping cost per acre-foot per foot of lift.
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 9-A.
$5,422,937.00
4,419,360.00
341,580.00
11,997.00
250,000.00
400,000.00
$ 72,818.00
The acre-feet of water delivered per year would be 9,320 and 18,640 for the 10 and 20
mgd systems respectively.
a.
Reservoir and Booster Station
Transmission Line
31 miles
35T1 pipeline @ $27/ft.
31 miles - 421! pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x $.01663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Eas ements
$
$ 72,818.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area IX,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
10 mgd
20 mgd
10 mgd
Land
4,161 acres @ $500/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Table 9-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
2,150
2,150
445
543
445
2,600
450
60
40
995
74
371
5.7
23
65
1,110
101
40
2,600
450
519
712
5.7
65
23
371
11.4
148
519
(feet)
(feet)
5.7
26
T13S-R1OE
Sections 12,
14, 23 and 24
T13S-R1OE
Sections
13 and 14
26
20 mgd
10 mgd
Area X consists of cropland in Sections 8, 9, 10, 13, 14, 15, 16, 20, 22, 23 and
a.
24 of T13S-R1OE.
15.
11.
12.
13.
14.
10.
9.
8.
7.
6.
4.
5.
3.
2.
1.
Miles from City
Well Field Location
Table 10-A.
4,118,400.00
$5,927,142.00
750,000.00
799,260.00
9,482.00
250,000.00
342,974.00
665,233.00
735,565.00
153,720.00
409,673.00
480,005.00
44.10
51.70
$.01663 is variable pumping cost per acre-foot per foot of lift.
39.60
322,259.00
255, 953.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 10-A.
$4,707,622.00
3,706,560.00
341,580.00
9,482.00
250,000.00
400,000.00
$ 70,332.00
The acre-feet of water delivered per year would be 9,290 and 18,580 for the 10 and 20
mgd systems respectively.
a.
Reservoir and Booster Station
Transmission Line
24.5 miles - 36?! pipeline @ $27/ft.
24.5 miles - 42!? pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
(Acre-feet x lift x $.01663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Eas ements
$
$ 70,332.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
m d from Area X
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 md
10 mgd
20 m..d
10 mgd
Land
4,019 acres @ $500/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Table 10-B.
Location and
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
T14S-R11E
Sections
5, 6 and 7
21,5
(feet)
2,225
334
T14S-R11E
Sections
6 and 7
21.5
(feet)
2,225
334
6
78
3
39
417
49
40
881
468
417
2,560
2,600
375
456
558
456
2,560
2,600
375
84
40
955
40
38
378
36
378
40
3
20 mgd
10 mgd
Area XI consists of cropland in Sections 25 and 26 of T13S-R1OE; Sections 30, 31 and
a.
32 of T13S-R11E and Sections 5, 6 and 7 of T14S-R11E.
16.
14.
15.
13.
10.
11.
12.
9.
8..
7.
4.
5.
6.
3.
2.
1.
Miles from City
Conditions
Location and Pumping Conditions of Area
Well Field Location
Table 11-A.
750,000.00
799,260.00
8,320.00
250,000.00
3,405,600.00
$5,213,180.00
$
289,046.00
572,487.00
631,479.00
31.50
133,324.00
354,335.00
413,327.00
38.90
45.40
The acre-feet of water delivered per year would be 9,100 and 18,200 for 10 and 20
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
34. 70
283,441.00
$ 58,992.00
221,011.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 11-A.
3,065,040.00
341,580.00
8,320.00
250,000.00
400,000.00
$4,064,940.00
$
$ 58,992.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and 20
mgd from Area i,a 1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 md
10 mcd
20 md
10 mgd
Land
3,371 acres @ $500/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
21.5 miles - 36" pipeline @ $27/ft.
21.5 miles - 42" pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)C
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 11-B.
1.
a. Area XII consists of
and Section ii of T15S-RI1E.
16.
13.
14.
15.
11.
12.
10.
9.
8.
7.
6.
5.
4.
3.
cropland
11a
38
363
2.8
36
399
447
399
2,560
2,600
275
32
40
746
38
363
1.4
18
381
405
381
2,560
2,600
275
46
40
and 34 of T14S-R11E
2,325
322
1.4
40
2,325
322
1.4
40
742
(feet)
16
T14S-R11E
Sections 27,
33 and 34
14 mgd
(feet)
16
T14S-R11E
Sections
27 and 34
7 mgd
in Sections 4, 8, 9, 27, 29, 33
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
Miles from City
2.
and Pumping Conditions of Area
Location and Conditions
Location
Well Field Location
Table 12-A.
1,858,560.00
213,840.00
6,192.00
250,000.00
300,000.00
$2,628,592.00
$
534 , 400. 00
550,000.00
553,740.00
6,192.00
250,000.00
$3,894,332.00
$
14 md
211,735.00
166,240.00
377,975.00
431,210.00
28.20
32.20
82,674.00
225,591.00
278,826.00
33.70
41.60
The acre-feet of water delivered per year would be 6,700 and 13,400 for the 7 and 14
mgd systems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
$ 53,235.00
14 m
142,917.00
$ 53,235.00
md
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 12-A.
Reservoir and Booster Station
Transmission Line
16 miles - 30" pipeline @ $22/ft.
16 miles - 42" pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
c
(Acre-feet x lift x $.0l663)
Delivery Cost
(Pmortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Eas ements
Wells and Pumping TJnits
6 @ $50,000
11 @ $50,000
Collection Line
7 mgd
Estimated Costs for the Diversion of Irrigation Water to Tucson at 7 mgd and at 14
mgd from Area XII,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
Land
3,042 acres @ $500/acre @ .035 interest
Table 12-B.
Location and Conditions
Location and Pumping Conditions of Area XIII.
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
a
2.8
36
264
312
264
2,560
2,600
50
36
40
390
246
270
246
2,560
2,600
50
72
40
408
30
50
228
18
1.4
30
50
228
1.4
175
1.4
2,550
(feet)
23.5
T15S-R1OE
Section 33
TI6S-RIOE
Sections 4 and 5
8 mgd
175
2,550
(feet)
23.5
Section 4
T 16 S - RIOE
T15S-R1OE
Section 33
4 mgd
Area XIII consists of cropland in Sections 21, 28 and 33 of T15S-RIOE and Sections
a.
4, 5 and 8 of T16S-R1OE.
16.
10.
11.
12.
13.
14.
15.
9.
8.
7..
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 13-A.
1,985,280.00
112,860.00
9,094.00
250,000.00
200,000.00
$2,557,234.00
$
3,350, 160.00
350,000.00
300,960.00
9,094.00
250,000.00
$4,260,214.00
$
45,270.00
276,898.00
298,230.00
39.70
42.70
23,680.00
162,717.00
184,049.00
The acre-feet of water delivered per year would be 3,490 and 6,980 for the 4 and 8
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
.
46 60
52.70
231,638.00
$ 21,332.00
139,037.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 13-A.
7 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
23.5 miles - 24" pipeline @ $16/ft.
23.5 miles - 36" pipeline @ $27/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)C
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Wells and PumpingUnits
4 @ $50,000
$ 21,332.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 4 mgd and at 8 mgd
from Area XIII,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
4 mgd
8mgd
8 mgd
4mgd
Land
1,219 acres @ $500/acre @ .035 interest
Table 13-B.
Location and Conditions
Location and Pumping Conditions of Area XIV.a
5.
(feet)
2,600
83
4
4
(feet)
2,600
83
3.2
50
30
119
3.2
119
40
241
282
0
40
0
161
215
161
2,560
2,600
40
6.4
83
202
311
202
2,560
2,600
40
42
T16S-R14E
Sections 6,
7, 18 and 19
T16S-R14E
Sections
6 and 7
3.2
50
30
20 mgd
10 mgd
a.
Area XIV Consists of the cropland in Sections 35 and 36 of T16S-R13E; Sections 6, 7,
18, 19, 20, 29, 30, 31 and 32 of T16S-RI4E; and Section 1 of T17S-RI3E.
16.
11.
12.
13.
14.
15.
10.
9.
8.
7.
6.
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation (Gravity)
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction--30-irich (Gravity)
Other Lines
Overall Pumping Head
Drawdom at 1,500 gpm
4.
3.
2.
1.
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Miles from City
Well Field Location
Table 14-A.
750,000.00
799,260.00
1,548.00
250,000.00
633,600.00
$2,434,408.00
$
132,359.00
86,946.00
219,305.00
346,495.00
11.80
18.70
37,153.00
122,153.00
249,343.00
13.20
26.90
The acre-feet of water delivered per year would be 9,270 and 18,540 for the 10 and 20
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
$127,190.00
85,000.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 14-A.
570, 240.00
341,580.00
1,548.00
250,000.00
400,000.00
$1,563,368.00
$
$127,190.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
mgd from Area XIV,
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20
10 mgd
10 mgd
20 mgd
Land
3,634 acres @ $1,000/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
4 miles - 36" pipeline @ $27/ft.
4 miles - 42" pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)C
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 14-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation (Gravity)
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction (Gravity)
Other Lines
Overall Pumping Head
T17S-R14E
Sections 5,
6, 7and8
(feet)
2,700
118
3.4
20
75
10
200
6.8
88
288
404
288
2,560
2,600
40
0
40
368
T17S-R14E
Sections
6and7
(feet)
2,700
118
3.4
20
75
10
200
3.4
44
244
302
244
2,560
2,600
40
40
324
0
20 mgd
10 mgd
Area XV consists of cropland in Sections 5, 6, 7, 8, 17, 18, 19, 29, 30 and 31 of
a.
T17S-R14E and Section 5 of Tl8S-R14E.
16.
14.
15.
10.
11.
12.
13.
9.
8.
7.
5.
6.
3.
4.
2.
1.
Miles from City
Well Field Location
Table 15-A.
1,584.000.00
$3,387,130.00
750,000.00
799,260.00
3,870.00
250,000.00
184,158.00
113,095.00
297,253.00
412,438.00
16.10
22.30
49,786.00
181,418.00
296,603.00
19.60
32.10
The acre-feet of water delivered per year would be 9,240 and 18,480 for the 10 and 20
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
$115,185.00
131,632.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 15-A.
1,425,600.00
341,580.00
3,870.00
250,000.00
400,000.00
$2,421,050.00
$
$115,185.00
Estimated Costs for the Diversion ofIrrigation Water to Tucson at 10 mgd and at 20
mgd from Area XV,° 1967.
Estimated Cost of
Average Annual
Cost
DeDreciable Capital
20 md
20 mgd
10 mgd
10 m7d
Land
3,291 acres @ $1,000/acre @ .035 interest
Wells and. Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
10 miles - 36" pipeline @ $27/ft.
10 miles - 42" pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)c
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 15-B.
Location and Conditions
Location and Pumping Conditions of Area XVI.a
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation (Gravity)
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction (Gravity)
Other Lines
Overall Pumping Head
-
11.5
(feet)
2,720
123
4.3
40
11.5
(feet)
2,720
123
4.3
40
38
170
362
0
40
0
2,560
2,600
40
40
306
2,560
2,600
40
56
226
298
226
4.3
T17S-R13E
Sections 12,
13, 24 and 25
T17S-R13E
Sections
12 and 13
38
170
8.6
112
282
428
282
20 mgd
10 mgd
a.
Area XVI consists of cropland in Sections 12, 13, 24, 25, 35 and 36 of T17S-RI3E;
Sections 1, 2, 11, 12 and 14 of T18S-R13E; and Section 6 of T18S-R14E.
16.
10.
11.
12.
13.
14.
15.
9.
8..
7.
6.
5.
3.
4.
2.
1.
Miles from City
Well Field Location
Table 16-A.
750,000.00
799,260.00
4,450.00
250,000.00
1,821,600.00
$3,624,310.00
$
197,108.00
109,324.00
306,432.00
424,802.00
16.90
23.40
46,206.00
189,496.00
307,866.00
20.90
33.90
The acre-feet of water delivered per year would be 9,080 and 18,160 for the 10 and 20
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
$118,370.00
143,290.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 16-A.
1,639,440.00
341,580.00
4,450.00
250,000.00
400,000.00
$2,635,470.00
$
$118,370.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
1a 1967.
mgd from Area
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
10 mgd
20 mgd
10 mgd
Land
3,382 acres @ $1,000/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
11.5 miles - 36" pipeline @ $27/ft.
11.5 miles - 42" pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)C
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 16-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (AGS)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation (Gravity)
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction (Gravity)
Other Lines
Overall Pumping Head
ii.a
(feet)
2,880
119
3.1
35
43
168
6.2
81
249
354
249
2,560
2,600
40
(feet)
2,880
119
0
40
329
0
40
288
2,560
2,600
40
35
43
168
3.1
40
208
260
208
3.1
17.5
T18S-R13E
Sections 13,
23 and 24
20 mgd
17.5
T18S-R13E
Sections
13 and 24
10 mgd
Area XVII consists of cropland in Sections 13, 23, 24, 26, 27, 34 and 35 of T18S-R13E;
a.
Section 8 of T18S-.R14E; and Sections 2, 3, 4, 9, 16, 20, 21, 29, 30, 31 and 32 of T19S-R13E.
16.
15.
13.
14.
10.
11.
12.
9.
7.
8.
6.
5.
4.
3.
2.
1.
Miles from City
Well Field Location
Table 17-A.
750,000.00
799,260.00
6,772.00
250,000.00
2,772,000.00
$4,578,032.00
$
100,343.00
349,251.00
476,511.00
43,919.00
233,842.00
361,102.00
25.50
39.40
The acre-feet of water delivered per year would be 9,170 and 18,340 for the 10 and 20
mgd syems respectively.
$.0l663 is variable pumping cost per acre-foot per foot of lift.
19.00
26.00
248,908.00
$127,260.00
189,923.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 17-A.
2,494,800.00
341,580.00
6,772.00
250,000.00
400,000.00
$3,493,152.00
$
$127,260.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 10 mgd and at 20
a
m'd from Area XVII
1967.
Average Annual
Estimated Cost of
Cost
Depreciable Capital
20 mgd
10
mgd
20
mgd
10 mgd
Land
3,636 acres @ $1,000/acre @ .035 interest
Wells and Pumping Units
8 @ $50,000
15 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
17.5 miles - 36T? pipeline @ $27/ft.
17.5 miles - 42h1 pipeline @ $30/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
c
(Acre-feet x lift x $.0l663)
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 17-B.
Location and Conditions
Location and Pumping Conditions of Area
Average Well Field Elevation
Average Static Water Level (1965)
Average Annual Decline
Estimated Specific Capacity
Drawdown at 1,500 gpm
Pumping Water Level (1967)
Annual Decline Following Development
Thirteen-Year Decline
Pumping Water Level (1980)
Pumping Water Level (1997)
Average Pumping Head over 30 Years
Martin Reservoir Elevation
Elevation of 22nd Street Reservoir
Booster Head--Well Field to 22nd Street Reservoir
Transmission Line Friction
Other Lines
Overall Pumping Head
iii.a
(feet)
2,450
81
3.8
25
60
149
7.6
(feet)
2,450
81
25
60
149
6
40
4
40
392
444
99
248
377
248
2,560
2,600
150
3.8
49
198
263
198
2,560
2,600
150
3.8
3
T15S-R13E
Sections
10 and 15
10 mgd
3
T15S-R13E
Sections
10 and 15
5 mgd
Area XVIII consists of cropland in Sections 34 and 35 of T14S-R13E and Sections 3,
a.
10 and 15 of T15S-RI3E.
16.
15.
10.
11.
12.
13.
14.
9.
8.
7.
6.
4.
5.
3.
2.
1.
Miles from City
Well Field Location
Table 18-A.
250, 000. QO
400,000.00
341,580.00
1,161.00
427,680.00
$1,420,421.00
$
77,228.00
61,285.00
138,513.00
291,463.00
16.70
35.10
27,054.00
81,431.00
234,381.00
19.60
56.50
The acre-feet of water delivered per year would be 4,150 and 8,300 for the 5 and 10
mgd systems respectively.
$.01663 is variable pumping cost per acre-foot per foot of lift.
$152,950.00
54,377.00
Capital amortized at three and one-half percent interest over 30 years.
See footnote a, Table 18-A.
348,480.00
150,480.00
1,161.00
250,000.00
250,000.00
$1,000,121.00
$
$152,950.00
Estimated Costs for the Diversion of Irrigation Water to Tucson at 5 mgd and at 10
iiia 1967.
mgd from Area
Average Annual
Estimated Costs of
Cost
Depreciable Capital
10 mgd
5 mgd
10 mgd
5 mgd
Land
1,748 acres @ $2,500/acre @ .035 interest
Wells and Pumping Units
5 @ $50,000
8 @ $50,000
Collection Line
Easements
Reservoir and Booster Station
Transmission Line
3 miles - 30" pipeline @ $22/ft.
3 miles - 36" pipeline @ $27/ft.
Total Capital Cost
Amortized Capital Cost
b
(Capital cost x $.05437)
Pumping Cost
$01663)c
(Acre-feet x lift x
Delivery Cost
(Amortized capital cost and pumping cost)
Total Cost
(Delivery cost and inerest on land)
Delivery Cost/Acre-Foot
Total Cost/Acre-Foot
Table 18-B.
LIST OF REFERENCES
ARIZONA AGRICULTURE 1966. Bulletin A-44, Agricultural Experiment
Station and Cooperative Extension Service, The University of
Arizona, Tucson, Arizona.
ARIZONA STATE SUPREME COURT:
Bristor v. Cheatham, 75 Ariz, 227, 255 Pac 2d 173 (1953)
Howard v. Perrin, 8 Ariz. 347, 26 Pac 460 (1904)
CITY OF TUCSON.
Unpublished Data, Pima County, Arizona.
(1962) "Prospectus and Call for Bids, $5,000,000 Water
Revenue Bonds and $1,000,000 Street and Highway Improvement
Bonds," Pima County, Arizona.
(1966) Population Study, Tucson Standard Metropolitan
Statistical Area, Pima County, Arizona.
CLARKE, DANIEL W, (1967) Personal Communication, Vice President,
Southern Arizona Bank and Trust Company, Tucson, Arizona.
DEPARTMENT OF AGRICULTURAL ENGINEERING. (1960-65) Unpublished Data,
The University of Arizona, Tucson, Arizona.
DAVIS, G. E. and SCHWALEN, H. C. (1964) "Present and Future Water
Requirements and Sources of Supply for the Tucson Region,"
Unpublished Research, Department of Agricultural Engineering,
The University of Arizona, Tucson, Arizona.
FOURTH ARIZONA TOWN HALL ON ARIZONA'S WATER SUPPLY, APRIL 6-8, 1964.
(Arizona Academy, P. 0. Box 1429, Phoenix, Arizona), The
University of Arizona, Tucson, Arizona.
FRAESDORF, WILLIAM 0., JR. (1967) Personal Communication, Real Estate
Broker, Canyon State Land Company, Tucson, Arizona.
HALPENNY, L. C., et al. (1952) Groundwater in the Gila River Basin and
Adjacent Areas, Arizona--A Summary, United States Department
of the Interior, United States Geological Survey, Tucson,
Arizona.
HODGE, ANDREW W. (1967) Personal Communication, Assistant Vice President,
Bank of Tucson, Tucson, Arizona.
146
147
LIST OF REFERENCES--Continued
KELSO, MAURICE M. (1967) "Amortized Average Annual Cost Formula,"
Department of Agricultural Economics, The University of
Arizona, Tucson, Arizona.
KELSO, MAURICE M. and JACOBS, JAMES J. "Economic Analysis of Transfer
of Water From Irrigation to Municipal Use: A Case Study of
Tucson" to be published in Water Resources and Economic
Development of the West, Report No. 16, Conference Proceedings
of the Committee on the Economics of Water Resources Development
of the Western Agricultural Economics Research Council, San
Francisco, California, December 1967.
MARTIN, WILLIAM E. and BOWER, LEONARD C. (1966) "Patterns of Water
Use in the Arizona Economy," Arizona Review, Vol. 15, No. 12,
Division of Economic and Business Research, The University of
Arizona, Tucson, Arizona.
MATLOCK, W. G., SCHWALEN, H. C. and SHAW, R. J. (1965) Progress Report
on Study of Water in the Santa Cruz Valley Arizona, Report
No. 233, Agricultural Experiment Station, The University of
Arizona, Tucson, Arizona.
RAUSCHER, J. F. (1967) Personal Communication, Chief Engineer, City of
Tucson Water and Sewerage Department, Pima County, Arizona.
(N.D.) "Easement Costs Formula," Chief Engineer, City of
Tucson Water and Sewerage Department, Pima County, Arizona.
STRUTHERS, ROBERT E. (1963) The Role of Irrigation Development in
Community Economic Structure, Grand Valley Trade Area,
Colorado, United States Department of the Interior, Bureau
of Reclamation, Washington, D. C.
TENTH ARIZONA TOWN HALL ON DO AGRICULTURAL PROBLEMS THREATEN ARIZONA'S
TOTAL ECONOMY? APRIL 9-12, 1967 (Arizona Academy, P. 0. Box
1429, Phoenix, Arizona) The University of Arizona, Tucson,
Arizona.
UNITED STATES DEPARTMENT OF COMMERCE, BUREAU OF CENSUS. (1961) United
1960, PHC(l)-l61,
States Censuses of Population and Housing:
Office,
Washington,
D. C.
United States Government Printing
UNITED STATES DEPARTMENT OF THE INTERIOR. Unpublished Data, Grand
Valley Trade Area, Colorado, Washington, D. C.
148
LIST OF REFERENCES--Continued
WFIEELER, PETERSON, AND COFFEEN, ENGINEERS, SURVEYORS AND PLANNERS, INC.
(1965) Feasibility Study and Report of Altar-Avra Valley Water
Supply for the City of Tucson, Arizona, Pima County, Arizona.
WHITE, NATALIE D., MATLOCK, W. G., and SCI-IWALEN, H. C. (1966) An
Appraisal of the Groundwater Resources of Avra and Altar
Valleys---Pima County, Water Resources Report No. 25, United
States Department of the Interior and the Agricultural
Experiment Station, United States Geological Survey, Tucson,
Arizona.
WILLIAMS, GARDNER S. and HAZEN, ALLEN (1945) Hydraulic Tables, Third
Edition, Revised, John Wiley and Sons, Inc., New York, New York.
WRIGHT, N. GENE. (1967) Personal Communication, Research Associate,
Department of Agricultural Economics, The University of Arizona,
Tucson, Arizona,
YOUNG, ROBERT A. and MARTIN, WILLIAM E. (1967) "The Economics of
Arizona's Water Problem," Arizona Review, Vol. 16, No. 3,
Division of Economic and Business Research, The University of
Arizona, Tucson, Arizona.
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