xvEPA
United States
Environmental Protection
Agency
Roberts Kerr Environmental Research EPA-600/2-78-15 9
Laboratory July 1978
Ada OK 74820
Research and Development
Las Vegas Valley
Water Budget
Relationship
of Distribution,
Consumptive Use,
and Recharge
to Shallow Ground
Water
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-78-159
July 1978
LAS VEGAS VALLEY WATER BUDGET:
RELATIONSHIP OF DISTRIBUTION, CONSUMPTIVE USE, AND
RECHARGE TO SHALLOW GROUND WATER
by
Ralph 0. Patt
Desert Research Institute
Las Vegas, Nevada 89109
Grant No. R800946
Project Officer
Fredric Hoffman
Region IX
San Francisco, California 94111
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
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DISCLAIMER
This report has been reviewed by the Robert S. Kerr Environmental
Research Center, U. S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U. S. Environmental Protection Agency,
nor does mention of trade names or commercial products constitute endorse-
ment or recommendation for use.
ii
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FOREWORD
Since the vast influx of population began pouring into the Las Vegas
Valley in the 1940"s the hydrologic regime of the Valley has undergone
significant change. The pristine environment of the Valley was desert
with desert vegetation and no perennial flow out of the Valley. With the
increase in population came the proliferation of lawns, shrubs, and trees
throughout the Valley. This domestic irrigation of vegetation together
with wastewater return flows has created a perennial stream leaving the
Valley through Las Vegas Wash. This study was implemented to determine
what is happening in the shallow ground-water zone (0 to 300') within the
Valley, its flow, and the main sources of contamination. Results of this
study have been divided into three volumes, the first volume entitled,
"Land and Water Use Effects on Ground-Water Quality in Las Vegas Valley,"
deals with the problem of how ground-water quality is affected by land
and water use throughout the Valley. This publication, volume two, gives
a detailed picture of the input and outflow of the water being used in
Las Vegas Valley. The third volume, "Simulation Modeling of the Shallow
Ground-Water System in Las Vegas Valley," discusses the problems and water
level fluctuations in the shallow ground-water system.
These three volumes represent an assessment of the shallow ground-
water system in Las Vegas Valley and should be of use to anyone dealing with
that aspect of the hydrologic regime in Las Vegas Valley.
Gilbert F. Cochran
Acting Executive Director
iii
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ABSTRACT
Estimates of quantity and geographic distribution of recharge to the
shallow ground-water zone from water use return flows in Las Vegas Valley
were made for the years 1973, 1965, 1958, 1950, and 1943 as part of a broader
study on the impact of water and land use on ground-water quality. Considered
components of water use in Las Vegas Valley include the following: supply
from surface and ground water; agriculture using potable water; agriculture
using sewage effluent; residential lawn watering; lawn watering of parks,
schools, cemetaries, hotels, motels; golf courses using potable water; golf
courses using sewage effluent water; septic tank recharge; evaporative coolers;
system losses; industrial use; power plant cooling; swimming pool use; con-
sumptive use by phreatophytes; in-valley recharge from precipitation, and
"unaccounted for water". Consumptive use of plants was calculated through
use of the Blaney-Criddle method as 3.47 feet per year and recharge was
assumed to be the difference between applied water and calculated consumptive
use. Data developed during this study indicates consumptive use as determined
by this method could be low by 1.5 to 2 feet per year, and thus the following
estimates of recharge to the ground-water system are considered maximum, in
acre feet: 1973-39,000; 1965-27,600; 1958-26,650; 1950-13,000; and 1943-
21,000.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vi
Abbreviations vii
Metric Conversions vii
Acknowledgment viii
1. Introduction 1
2. Conclusions 2
3. Recommendations 5
4. Background , . 7
5. water Budget, Las Vegas Valley 12
Supply 12
Consumptive use 14
Applied use, evaporation and recharge . . . , 16
Budget description « • 34
References 41
Appendices 43
1. Dwelling unit count and lawn acreage for dwelling units,
cemetaries, parks, schools, motels, hotels, hospitals
and industrial areas, by zones 43
2. Septic tanks by zone for years 1972, 1970, 1965, 1958,
1950, 1943 54
3. Swimming pools by zones, 1971 ...... 60
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FIGURES
Number Page
1 Las Vegas, 1905-1909 8
2 Lower Las Vegas Valley, 1965 11
3 Simplified Las Vegas Valley water budget, 1973 13
4 Water supply, Las Vegas Valley, 1973 15
5 Las Vegas Valley transportation study zones 18
6 Septic tank areas, 1973 24
7 Septic tank areas, 1965 25
8 Septic tank areas, 1958 26
9 Septic tank areas, 1950 27
10 Septic tank areas, 1943 28
11 Water budget for Las Vegas Valley, 1973 32
12 Water budget for Las Vegas Valley, 1965 35
13 Water budget for Las Vegas Valley, 1958 36
14 Water budget for Las Vegas Valley, 1950 37
15 Water budget for Las Vegas Valley, 1943 38
16 Recharge contour map of Las Vegas Valley, 1973 39
TABLES
1 Potable Water Use in Las Vegas Valley, 1973 3
2 Recharge from Irrigation 4
3 Consumptive Use of Lawn Grass in Las Vegas Valley Using
Four Different Methods 14
4 Consumptive Use Data for Representative Single Family
Dwellings in Las Vegas Valley 20
5 Townhouse Metered Water Consumption for Lawn Watering, 1972 . . 19
6 Recorded Water Use of Eight Parks in Las Vegas Valley, 1973 . . 21
7 Golf Course Irrigation Using Potable Water in Las Vegas
Valley, 1973 22
8 Golf Course Use-Rates of Treated Effluent 23
vi
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LIST OF ABBREVIATIONS
A.F.B.
BMI
CCSDTP
CLVSTP
DWR
ET
FHA
ft/yr
gal/day
gpd
Hend.
LWWD
mgd
NASA
VA
WRC
Air Force Base
Basic Management Incorporated
Clark County Sanitation District Treatment Plant
City of Las Vegas Sewage Treatment Plant
Division of Water Resources, State of Nevada
Evapotranspiration
Federal Housing Administration
feet per year
gallons per day
gallons per day
Henderson
Las Vegas Valley Water District
million gallons per day
National Aeronautics and Space Agency
Veterans Administration
Water Resources Center of Desert Research Institute
METRIC CONVERSION
To Convert
acres
acres
acre feet
inches
miles
feet
gallons
Multiply By
4.047 x 10"1
4.047 x 103
1.233 x 103
2.540
1.609
3.048 x lO"1
3.785 x 10"3
To Obtain
hectares
square meters
cubic meters
centimeters
kilometers
meters
cubic meters
vii
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ACKNOWLEDGMENTS
The author gratefully acknowledges the assistance of his many associates
within the Water Resources Center, Desert Research Institute for the effort
put into the project. Mr. Nate Cooper provided invaluable support as a
draftsman and as a tireless administrator charged with handling budgetary
and logistical matters. The wealth of knowledge of Dr. George B. Maxey with
respect to Las Vegas Valley, was of great value. Special thanks are due to
Dr. Richard Bateman and Dr. Martin Mifflin for their detailed and construc-
tive review of the draft. The difficult tasks of data reduction were skill-
fully done by Lucy Dunaway Miller.
Several State, Regional, and County government agency officials were
particularly helpful: Dr. V. Ueckert of the Clark County District Health
Department; Mr. Ferren Bunker, County Extension Agent, Cooperative Extension
Service, University of Nevada; and Mr. Francis Thome of the State Engineer's
Las Vegas Office provided access to his files of well logs, permits and
monitoring data. Assistance with historical information was given by the
City and County Sanitation Districts, under the direction of Mr. Louis Anton
and Mr. James Parrott, respectively. Mr. Aldo Barrozi of the Las Vegas Valley
Water District was most helpful in supplying historical data.
Vlll
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INTRODUCTION
The water budget studies presented herein are a part of a broader
Environmental Protection Agency supported research effort directed at evalua-
tion of the shallow ground-water system of Las Vegas Valley initiated in
1970 and essentially completed in 1974.
In order to study the quantitative and qualitative effects of urban
water use on recharge to the shallow ground-water system in Las Vegas Valley,
it was desirable to develop water use budgets describing water supply and
water use components. Budget components were considered on a geographic
basis to determine where return flow to the ground-water system should be
occurring, and in what quantity. In terms of water quality, budget data for
the various types of water uses and calculated estimates of return flow to
the shallow ground-water system lend perspective to sources of constituents,
magnitude, timing, and distribution (Kaufmann, 1976). In terms of ground-
water modeling, these budget data provide the means to estimate recharge and
discharge values for node points (Westphal, 1977).
Applied use data were developed and distributed in the Las Vegas Valley
in two ways: first, Valley-wide to include most of the urban, commercial and
industrial area, and second, to include only the area of digital models
developed as part of the overall study of the shallow ground-water system of
Las Vegas Valley (Westphal, 1977). Valley-wide budgets and recharge - dis-
charge data for the model area were calculated for base years 1943, 1950,
1958, 1965, and 1973. Aerial photography was available for these years and
facilitated more accurate estimations of irrigation distribution.
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CONCLUSIONS
1. Careful investigation of supply and use of water in Las Vegas Valley
indicates that considerable return flow to the shallow ground-water
system occurs. Since at least 1943 on a Valley-wide basis, recharge
to the shallow ground-water system appears to be in significant
excess of the discharge from the shallow system. This implies net
increase in storage in the shallow system.
2. Domestic residences use about twice the amount of water necessary
to adequately irrigate lawns in Las Vegas. Application rates are
100 percent higher on residential lawns than where professional
gardening is done.
3. There is limited opportunity for significant potable water savings
outside of residential uses.
4. The resort industry does not appear to be a particularly large user
of water (7 percent) when compared to the role it plays in the
community's economy. However, much of the residential water use is
indirectly related to the industry, and the thirteen golf courses in
the Valley reflect the orientation of the economy to resort acti-
vities.
5. Swimming pools, contrary to popular belief, are not a significant
water user (0.4 percent). Consumptive use is approximately the same
as the lawn they commonly replace.
6. Table 1 shows estimated usage of water in Las Vegas Valley in 1973.
7. Aerial photography, particularly infrared, can be used to
accurately determine amounts and geographical location of recharge
to the shallow ground-water system in an urban area.
8. Actual in-house per capita water use is estimated at 107 gallons
per day (gal/day), or about average for the nation.
9. The recharge values adopted, i.e., those of the Blaney-Criddle
method, are believed to yield upper limits of recharge from irriga-
tion. Recharge to the shallow system was calculated as the
difference between applied use and consumptive use. Because
experts disagree on consumptive use methods, recharge values
calculated by the Blaney-Criddle method, Olivier method and con-
sumptive use estimates of local agricultural experts are listed
in Table 2 to show possible variation of recharge from irrigation
in Las Vegas Valley in the study years.
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10. Two obvious problems are present in the budget, one of which is the
"unaccounted for water" which is assumed to evaporate. This value
alone is 13.3 percent of the total 1973 Valley budget. The other
problem, that of establishing true consumptive use by lawn and
agricultural crops is also unresolved and yields a potential error
of 12 percent in the budget.
TABLE 1. POTABLE WATER USE IN LAS VEGAS VALLKY, 1973
Residential lawn watering
Golf courses using potable water
Evaporative coolers
Swimming pools
Crop irrigation using potable water
Parks, schools, cemetaries, hotels,
motels (lawns)
*BMI (industrial)
Nonmetered fire hydrants and
System loss
Inhouse residential use
*Hotels and motels (inhouse use)
*Stores, offices
*Light industry
*Government buildings
TOTAL
Usage in
acre feet
30,000
5,500
3,000
600
2,600
2,200
14,500
10,500
45,000
10,000
10,000
4,200
4,900
143,000
% of Total
21.0
3.0
2.1
0.4
1.8
1.5
10.1
6.3
31.5
7.0
7.0
2.9
3.4
99.9
* Division of Water Resources, State of Nevada records.
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TABLE 2. RECHARGE FROM IRRIGATION
Year
Recharge
Blaney-Criddle Method
/consumptive use\
^ @ 3.47 ft/yr '
Recharge
local agriculture experts
/consumptive use\
^ @ 5.0 ft/yr '
Recharge
Olivier Method
/consumptive use\
^ @ 8.33 ft/yr '
1973
1965
1958
1950
1943
26,900 acre-ft
14,900 "
11,600
9,300
6,800
19,500 acre-ft
9,800 "
7,400
4,800
3,200
9,500 acre-ft
4,200 "
2,900
1,100
350 "
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RECOMMENDATIONS
1. Monitoring Shallow Ground Water
The evidence developed in this study of continued net increase of
shallow ground-water storage (conclusion #1) indicates the desirability of
establishing a comprehensive monitoring program of the shallow ground-water
system to provide the basis for future management decisions. Additional
shallow ground-water monitoring wells should be installed throughout the
area of urban development. Presently, there are very few suitable wells
which can be used to monitor water level and water quality changes in the
shallow ground-water system. If widespread changes are indeed occurring,
they will in some areas have significant impact on 1) land uses and associated
investments; 2) water quality in underlying developed aquifers; 3) location,
amount and quality of shallow ground-water discharge, and 4) potential future
use of these shallow ground waters for additional water supply.
2. Conservation
If or when water rates greatly rise in the future due to increasing
energy costs and greater use of more costly Southern Nevada Water Project
water, there may develop an opportunity to promote conservation of water by
household users. For example: a family of four needs about 500 gal/day or
15,000 gal/month for general household uses. A minimum price per gallon
could be set for the first 15,000 gal and then higher prices per gallon for
water use over 15,000 gal in incremental steps. This would be equitable to
low income families, provide incentive for careful water use, and could lead
to significant savings particularly in lawn irrigation.
Another approach is an effort by local government and water agencies to
promote esthetically acceptable water conservation landscaping, using suitable
native vegetation instead of reliance on lawn grass for decorative purposes.
Consumptive use of trees has not been adequately researched in Las Vegas
Valley. Research needs to be done to determine if the use of trees to cool
single family residences is more efficient than the comparative power cost
to cool unshaded residences. Some types of vines requiring limited watering
may be more efficient for cooling of residences than trees.
3. Reuse of Wastewater
Wastewater can and has been used for irrigation purposes. However, at
the present time (1977) only one golf course is using effluent water for
irrigation. Winterwood golf course stopped using effluent in 1975 due to
severe odor problems.
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Research is needed on salt loading and odor problems that presently
inhibits the use of sewage effluent for irrigation in populated areas.
Possible research areas are 1) treatment and blending procedures for using
treatment plant effluents and shallow, low quality ground water and 2) water
quality requirements and potential demand of wastewater use for various
industrial purposes.
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BACKGROUND
Archaeological investigations have shown that Las Vegas Valley was
occupied by aborigines as long as 10,000 years ago (Harrington, 1933). For
centuries before exploration and settlement the Paiute Indian tribes occupied
campsites near the springs of Las Vegas Valley (Haynes, 1967).
Las Vegas was probably first visited by Spanish explorers about 1770
(Haynes, 1967). From about 1830 until 1848, the springs in the Las Vegas
Valley were a stopping place for Spanish caravans between New Mexico and
California. The diaries of many early visitors (among them John C. Fremont
on May 3, 1844) describe the Las Vegas Springs and associated meadows. The
name Las Vegas was commonly applied by the early Spanish explorers and
traders to meadows or green and fertile areas.
Mormon missionaries established a fort in Las Vegas in 1855 and developed
farms using natural spring discharge (Jones and Cahlan, 1975). Alkali in
the soil was a deterrent to successful farming, and this, coupled with in-
ternal dissension caused the mission to be abandoned in 1857.
According to a map drawn in 1855 by a Mormon settler, John Steele (Paher,
1971), there was a "tooley grass" area along Las Vegas Creek east of the
Mormon Fort two and one-half miles long and about one-half mile wide. A
mesguite "forest" extended from the area of the Mormom fort down Las Vegas
Wash to the base of Frenchman Mountain and toward the Colorado River. Accord-
ing to this map, Las Vegas Creek did not flow to the Colorado River.
It is interesting to note that, based on tule consumptive use estimated
for this study at 76 inches (6.33 feet) per year, the 1.25 square miles
mentioned by John Steele would consume about 5,000 acre feet per year. .The
1906 records of the Las Vegas Land and Water Company (Jones and Cahlan, 1975)
describing flow of 6,400 acre feet per year from the springs feeding Las
Vegas Creek suggest that discharge from Las Vegas Springs remained about the
same for the 51 years from 1855 to 1906. Since consumptive use by tules and
crop irrigation approximately equals spring production, it can be assumed
that spring flow did not reach the Colorado River via Las Vegas Wash from
1855 to 1906.
Octavius Decatur Gass acquired the Mormon Fort in 1865 and, using
irrigation water from Las Vegas Creek, developed a successful 640 acre farm
and ranch he called "Las Vegas Rancho" (Figure 1).- The ranch was sold to
Archibald Stewart in 1882. in 1902 the land was sold to the San Pedro, Los
Angeles and Salt Lake Railroad, later the Union Pacific Railroad, which in
1905 sold plots to develop the townsite of Las Vegas (Clark Townsite). The
three largest springs in the Valley, called the Las Vegas Springs, were the
principal water supply for the City of Las Vegas for many years.
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OLD FORT
#66~ei LAS I/EGAS RMICH
Figure 1. Las Vegas, 1905-1909.
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The other major ranch in Las Vegas Valley before the turn of the century
was developed by Conrad Kiel and his sons. This 240 acres was on the site
of one of the original Mormon farms and was irrigated from springs on the
ranch, discharge being reported at 500 acre feet per year (Maxey and Jameson,
1948). In later years the spelling of the ranch was changed to Kyle. It
was sold to the Utah, Nevada, and California Railroad Company in 1901. In
1907 it was purchased by John Park who drilled two wells and built two con-
crete reservoirs, one of which served as a swimming pool. In 1920 it became
the Taylor Ranch and later was purchased by Edwin Losee.
Four years after the first well was drilled in 1907, there was a total
of 100 wells within Las Vegas Valley, of which 75 flowed. Between 1911 and
1924, only 25 new wells were drilled due to a lack of interest in farming.
These were mainly private residence wells. Between 1910 and 1924 about 22,400
acre feet per year of water were flowing from artesian wells and springs of
which 2,240 acre feet per year were used for municipal supply and about 10,000
acre feet per year were lost from the uncapped artesian wells (Maxey and
Jameson, 1948).
By 1934 the number of wells in the Valley had increased to about 275; in
1944 the total number of wells reached 450. By 1944 the flow from Las Vegas
Springs had decreased to about 1,800 acre feet per year. Water levels con-
tinued to decline in the near surface zone and free flow from artesian wells
had ceased due in part to decreased head and to a program of capping wells
by the Division of Water Resources, State of Nevada (DWR).
A sewer system for the City of Las Vegas was built in 1912. Untreated
effluent was discharged from a pipe at 9th Street and Bonanza and was used
for irrigation of the Stewart Ranch, the old Las Vegas Rancho. The first
sewage treatment plant for the City of Las Vegas was built in 1932 and located
at Harris and 15th Street. An additional plant was built in 1942 at the
corner of Harris and what is now Eastern Avenue. Their combined capacity
was about two million gallons per day (mgd; 2,250 acre feet per year). Ef-
fluents from both plants were used to irrigate the Stewart Ranch. These
plants were abandoned in 1950 after completion of a sewage treatment facility
with a capacity of about four mgd (4,500 acre feet per year) at Harris and
Manning Streets. Sewage effluent from this plant continued to be used for
the irrigation of a ranch located near what is now the Winterwood golf course
in the eastern part of the Valley. The present City of Las Vegas Sewage
Treatment Plant (CLVSTP), located on Vegas Valley Drive, was built in 1958
with a capacity of about 12 mgd (13,500 acre feet per year). Effluent is
still sold for agricultural use and power plant cooling. In 1967 the capacity
was increased to 30 mgd (33,600 acre feet per year).
The Clark County Sanitation District Treatment Plant (CCSDTP) was built
in 1955 with a capacity of 12 mgd (13,500 acre feet per year). The CCSDTP
sells effluent water, for agriculture, power cooling and golf courses.
Nellis Air Force Base used lagoons to evaporate sewage effluent from
1940 until 1971. After 1971, effluent from Nellis A.F.B. was piped to the
CCSDTP and the Nellis sewage treatment system was dismantled. Sewage ef-
fleunt from the City of North Las Vegas is treated at CLVSTP.
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Two treatment plants located near the Basic Management Incorporated (BMI)
tailing ponds handle sewage from the City of Henderson and the BMI industrial
complex. Effluents from these plants are spread in the upper and lower BMI
tailing ponds located northeast of the City of Henderson near Las Vegas Wash.
In 1970 effluent from the Henderson Sewage Treatment Plant was measured
at about 1,000 acre feet per year by personnel of the Water Resources Center
(WRC), Desert Research Institute. In the same period, the BMI sewage treat-
ment plant effluent was measured at about 1,800 acre feet per year for a
total of 2,800 acre feet of sewage effluent spread in the upper and lower
tailing ponds. These figures were used for 1973 budget calculations as
population for the City of Henderson remained about the same as in 1970.
For purposes of this study Las Vegas Wash is divided into upper and
lower reaches at Pabco Road in Henderson, the lower reach being from Pabco
Road downstream to Lake Mead, the upper reach constituting the drainage above
Pabco Road. Perennial flow in lower Las Vegas Wash began about 1944 fed by
a ditch from the BMI plant (Stauffer Ditch) that bypassed the evaporation
ponds (Figure 2) (G. B. Maxey, 1976, personal communication). Perennial
flow in the upper Wash began in 1956 with completion of an outfall effluent
line from the Harris and Manning Street sewage treatment facility to a ditch
near the present CLVSTP site (Lou Anton, Superintendent of Sanitation, CLVSTP,
1973, personal communication).
10
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SUNRISE STATION
POWER PLANT
LAKE
MEAD
CITY SEWAGE F=
TREATMENT
PLANT
U.S.G.S. STREAM
GAGING STATION
COUNTY SEWAGE
TREATMENT PLANT
GRAVEL PIT DRAIN
CLARK STATION
U.S.G.S. STREAM
GAGING STATION
POWER PLANT
, PONDS»*
SEWAGE
TREATMENT
PLANT
Sunset Rood
B.M.I. SEWAGE
TREATMENT
PLANT
LOWER LAS VEGAS VALLEY
CLARK COUNTY, NEVADA
1 CITY OF
I HENDERSON
SCALE IN MILES
Figure 2. Lower Las Vegas Valley, 1965.
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WATER BUDGET, LAS VEGAS VALLEY
A simplified water budget diagram for Las Vegas Valley for 1973 is
shown in Figure 3 to demonstrate the basic components of the budget. Total
Valley water supply to all uses is 143,000 acre feet after usage losses of
evaporation and evapotranspiration; return flow is separated into two compo-
nents, recharge to the shallow ground-water system and sewage effluent.
These return flows then are separated into the following components: apparent
change in ground-water storage, evapotranspiration from Las Vegas Wash, return
flow to Lake Mead via Las Vegas Wash, and, shallow ground-water pumpage to
account for that part of the ground-water supply coming from relatively
shallow, domestic wells. Components of the water budget were analyzed as
follows:
A. Supply from surface water and ground water
B. Consumptive use, applied use, evaporation and recharge.
1. agriculture using potable water
2. agriculture using sewage effluent
3. lawn watering: residential
4. lawn watering: parks, schools, cemetaries, hotels and motels
(separated from residential water irrigation because of
different application rates)
5. golf courses using potable water
6. golf courses using sewage effluent water
7. septic tank recharge
8. evaporative coolers
9. transmission losses
10. BMI industrial use
11. power plant cooling
12. swimming pool use
13. consumptive use by phreatophytes
14. precipitation recharge
15. unaccounted-for water
SUPPLY
During 1973 total water use in Las Vegas Valley was 143,127 acre feet of
which 73,370 acre feet were from Lake Mead and 69,757 acre feet were ground
water.
The Las Vegas Valley Water District (LWWD), a quasi-municipal corpora-
tion and largest distributor of water in the Valley, was created in 1948
by the Nevada State Legislature and encompasses Las Vegas and North Las Vegas.
Although within LWWD boundaries, North Las Vegas and Henderson maintain
separate water delivery systems. Total water delivered by LWWD during 1973
12
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1
GROUND WATER
SUPPLY
70,000
SURFACE WATER
SUPPLY
73,000
ALL USES
143,000
RECHARGE
TO SHALLOW
SYSTEM
46,000
SEWAGE
EFFLUENT
RETURN
43,000
SHALLOW
GROUND
WATER
PUMPAGE
6,900
V
CHANGE IN
GROUND
WATER
STORAGE
23,000
EVAPOTRANS-
PIRATION
FROM LAS
VEGAS WASH
14,000
RETURN
FLOW TO
LAKE MEAD
45,000
EVAPORATION
AND
EVAPOTRANS-
PIRATION
54,000
QUANTITIES IN ACRE-FEET
Figure 3. Simplified Las Vegas Valley water budget, 1973.
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was 81,977 acre feet of which 48,674 acre feet were from Lake Mead and 33,303
acre feet were ground water.
A water supply system for the BMI complex was built in 1942 utilizing
Lake Mead water. Total delivery during 1973 was 21,089 acre feet of which
14,566 acre feet was for industrial use and 6,523 acre feet was sold to the
City of Henderson.
Nellis A.F.B. owns and operates a water distribution system serving a
military population of about 5,000 and about 5,000 civilian employees. Ground
water in the amount of 1,848 acre feet was pumped from two well fields
during 1973. One well field is on the Base, the other is located five miles
to the west along Craig Road. During 1973 an additional 1,276 acre feet of
Lake Mead water was purchased from Southern Nevada Water system, the govern-
mental entity which supplies water from the Southern Nevada Water Supply
Project (Phase I).
Pumpage from metered and unmetered wells, owned by small private water
companies, major casinos, golf courses, trailer parks, and farms, was about
15,870 acre feet during 1973. Pumpage from the approximately 4,000 private
domestic wells during 1973 was about 6,900 acre feet. These data are from
DWR, inventory of Las Vegas Valley, 1973. Figure 4 shows water distribution
in Las Vegas Valley by suppliers.
CONSUMPTIVE USE
Consumptive use by lawns in Las Vegas Valley was estimated by the Blaney-
Criddle method (Blaney and Criddle, 1945). Using a seasonal crop coefficient
of 0.99 for lawn grass in Las Vegas (Tovey, Spencer, and Muckel, 1969), con-
sumptive use of domestic lawns, golf courses, parks, and cemetaries was
estimated at 3.47 feet per year, with an assumed growing season of April 15
to October 15.
Published seasonal crop coefficients for alfalfa range from 0.85 (Blaney
and Criddle, 1945) to 2.61 for an unirrigated, medium soil with a water
table 2.0 feet below land surface (Tovey, 1963). According to Mr. Ferren
Bunker, County Extension Agent-in-Charge, Cooperative Extension Service, Univ-
ersity of Nevada, Reno (personal communication, 1973), lawns and alfalfa
in Las Vegas Valley have about the same seasonal consumptive use. For purposes
of this study, consumptive use by alfalfa was considered to be the same as for
lawns. Possible differences in consumptive use by different types of grass
were not studied. Table 3 compares four methods of estimating consumptive
use for Las Vegas Valley.
TABLE 3. CONSUMPTIVE USE OF LAWN GRASS IN
LAS VEGAS VALLEY USING FOUR DIFFERENT METHODS
Consumptive
Use in ft/yr
Blaney-Criddle 3.47
Thornthwaite 3.67
Penman 6.66
Olivier 8.33
14
-------
Water Supply
Areas, Las
Vegas Valley,
1973
VALLEY v i
j ,', \
WATER DISTRICT :
\ ^
i!
PRIVATE DOMESTIC WELLS
\_\ CITY OF
\J*ENDERSON
Figure 4. Water supply, Las Vegas Valley, 1973.
15
-------
Use of the Blaney-Criddle method for determining consumptive use of lawns
and alfalfa in Las Vegas Valley is clearly open to debate. Some experts
believe that the Olivier method of consumptive use is more accurate for Las
Vegas climatic conditions than Blaney-Criddle method. The Olivier method
gives a much higher consumptive use of 8.33 ft/yr. The best independent check
on consumptive use rates encountered during this study is a sub-study of
eight Las Vegas parks with metered water delivery. Irrigated areas plani-
metered from aerial photographs give an application rate of 6.31 ft/yr,
which is two feet less than potential consumptive use estimated by the Olivier
method and 2.84 feet more than the Blaney-Criddle estimate. Less reliable
data from golf course well pumpage records (DWR) and planimetering also
indicated applied use at about six feet per year. Thus, using the Olivier
method would mean 100 percent irrigation efficiency and no recharge with
application of less than 8.33 ft/yr. It is therefore believed this method
yielded a too high consumptive use figure.
Ferren Bunker (personal communication, 1976) believed consumptive use
is about five feet per year and that optimum application rates for lawns and
alfalfa should be about seven feet per year. Since recharge was calculated
by substracting consumptive use from applied use, the Blaney-Criddle method
yielded a higher recharge value of 27,000 acre feet in 1973 than the Olivier
method which would yield 9,500 acre feet of recharge.
As it is considered unlikely that potential consumptive use was two feet
in excess of application rates and because 9,500 acre feet of recharge per
year is judged low based on general knowledge of the shallow ground-water
system, Blaney-Criddle values have been utilized in this" investigation. In
view of the independent check developed during the study, it is now believed
that the Blaney-Criddle method yielded a consumptive use that is low by as
much as two feet, and that calculated recharge values were probably too
high, perhaps by as much as 8,000 acre feet in 1973. However, differing
conditions such as soil variations, plant density and health, water table
depths, consumptive use of infiltrated water by trees, variability in grow-
ing season (irrigation does occur to some extent at times during winter
months) and variation in crop coefficients make precise calculation of con-
sumptive use an unlikely exercise. Use of the Blaney-Criddle method should
result in recharge estimates from irrigation that are clearly upper limit
in magnitude.
APPLIED USE, EVAPORATION AND RECHARGE
Agriculture Using Potable Water
One farm in the northwest area of the Las Vegas Valley (Gilcrease Ranch)
used 2,460 acre feet of potable well water in 1973 on 396 acres, or an appli-
cation rate of 6.21 feet. Recharge to shallow ground water was 1,100 acre
feet as indicated below:
applied use @ 6.21 ft/yr = 2,500 acre feet per year
consumptive use @ 3.47 ft/yr = 1,400 acre feet per year
recharge @ 2.74 ft/yr = 1,100 acre feet per year
(acre feet values have been rounded)
16
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Agriculture Using Sewage Effluent
Five farms in the southeast area of Las Vegas Valley were reported (DWR)
to have used 4,511 acre feet of effluent on 1,160 acres (WRC) in 1973; an
application rate of 3.88 ft/yr.
Acre feet
LDS Church Farm 2,731
Stout Farm 292
CLV Rehab. Farm 629
Pat McDowell Ranch 784
Stewart Bros. Ranch 75
TOTAL 4,511
A high water table (less than or equal to 10 feet below land surface)
in this area should reduce surface water demand by a phreatophyte crop such
as alfalfa, and possibly explains the reduced water usage as compared with
potable water use for agriculture. Another explanation for this seemingly
low water usage was erroneous data. Recharge to shallow ground water was
500 acre feet as indicated below:
applied use @ 3.88 ft/yr = 4,500 acre feet per year
consumptive use @ 3.47 ft/yr = 4,000 acre feet per year
recharge @ 0.41 ft/yr = 500 acre feet per year
Residential Lawn Watering
A transportation study map developed in 1965 for the Clark County Regional
Planning Commission by Wilbur Clark Associates divides the Valley into numbered
zones generally bordered by major streets (Figure 5). In that study a dwell-
ing unit count was obtained from United States Census Bureau data that was
updated to 1973 with local building permit data for each zone. This provides
an accurate data base of dwelling units per zone. Through use of color infra-
red aerial photos, flown by the National Aeronautics and Space Agency (NASA)
in October of 1971, average area of lawns, percentage of dwelling units with
lawns, total lawn areas for cemeteries, parks, schools, hotels, motels,
industry, and hospitals were estimated by rough measurement of green areas
for each of these zones. Representative areas were then field checked for
accuracy of aerial photo derived estimates. These estimates were then ad-
justed to 1973 levels based on building permit data. Appendix 1 presents
these data by zone number. . j ;
LWWD delivered 36,260 acre feet of water to 42,250 single unit dwellings
from July 1972 through June 1973. The least amount of water delivered for
any month (February) during that period was 1,535 acre feet. Assuming this
value represents base monthly in-house use (minimal lawn watering), multiply-
ing by 12 months and subtracting from the total delivery, 17,840 acre feet
is estimated to have been applied to lawns. Average lawn size of'representative
areas for single family dwelling units in the LWWD service area is estimated
from the NASA aerial photographs to be 1,500 sguare feet. Average lawn size
17
-------
• S-. >T —
ffiJL; rx ] X
d. * ^ X_
Las Vegas Valley Area Tnuuportation
Figure 5. Las Vegas Valley transportation study zones.
18
-------
for the entire Las Vegas Valley is estimated to be 1,000 square feet per
dwelling unit, including apartment complexes. Apartments average 500 square
feet of lawn per dwelling unit. From the above, it is estimated that 12.26
feet of water were applied to lawns in the LWWD service area. Recharge of
8.79 feet is calculated by subtracting the consumptive use of 3.47 feet from
the estimated application of 12.26 feet. Total residential lawn area in
the Valley is estimated at 2,431 acres. At an applied rate of 12.26 ft/yr,
total applied use is calculated at 30,000 acre feet per year. Recharge from
residential lawn watering of 8.79 ft/yr is estimated at 21,500 acre feet per
year.
For comparative purposes and to further determine an approximate range
of lawn water application, data for 19 single family dwellings in the LWWD
service area were developed by interviewing owners and measuring lawn size
(Table 4) . Water billings were provided by the LWWD. In-house use ranged
from 41 gallons per day (gpd) per person to 221 gpd per person and average
108 gpd per person. Owners verified they did not water their lawns during
the base month used to calculate in-house use. For these homes, lawn appli-
cations ranged from 7.67 feet to 45.7 feet and average 14.7. If the highest
value is disregarded, average application is 13.0 feet. This derived use
rate agrees very well with the previously derived value of 12.26 ft/yr resi-
dential use for the entire Valley.
Condominiums studied had separate metering for their sprinkler irrigation
systems. Lawn applications ranged from 5.5 feet to 13.5 feet for the period
July 1972 through June 1973. Average application was 9.1 feet (Table 5)
which is 30 percent less than estimates for lawns at individual residences.
This may be a result of separate metering for the sprinklers, professional
gardening, or a combination of same.
TABLE 5. TOWNHOUSE METERED WATER CONSUMPTION FOR LAWN WATERING 1972
Acres Applied rate
in lawn in ft/yr
Desert Spa
Georgetown West
Bradford Place
Greenbriar
AVERAGE
20
4.8
0.7
17.4
13.53
9.14
8.06
5.52
9.05
Parks, Schools, Cemetaries, Motels, Hotels, Hospitals and Industrial Lawns
During 1973, LWWD metered water deliveries to eight parks in the Valley.
Average application rate determined for these parks is 6.3 ft/yr (Table 6).
Data from these parks are used to estimate an application rate which could
reasonably be applied to all park, school, cemetary, motel, hotel, hospital
and industrial lawn areas in the Valley.
19
-------
4. OONSIMPTIVE USE UMTA TOR REPRESENTATIVE SINGLE FAMILY DUELLINGS IN LAS VEGAS VALLEY
Nam;
Feeuey
Pa rise
Scott
Presch
Barker
Sterner
Thornton
to
O llanielson
Ilins
Inmait
Oakes
M.J. Lowry
U>wry
Walsh
EdoKHinds
Starr
Itoig
Licciardo
Stiiibclt
Address
1648 La Jolla
1600 La Jolla
1616 La Jolla
1611 La Jolla
1627 La Jolla
1645 La Jolla
1664 La Jolla
1037 Howard
1029 Howard
1025 Howard
1043 Howard
1055 Howard
1046 Howard
1060 Howard
1067 Howard
1071 Howard
1066 Howard
1044 Howard
1077 Howard
ccupants
I
0
4
4
6
3
2
2
6
3
2
5
3
3
5
2
5
1
2
2
2
§•0
01
a >-
i-l 01
Total „ {J
metercd •£ 3
utr coiisump § JJ
1973 in Bal '
317,000
540,000
335,000
294,000
395,000
54,000
477,000
264.000
281.000
360,000
324,000
330,000
106,000
435,000
459,000
137,000
190.000
96,000
2)2,000
(Average
S 3
8
7
8
8
7
0
9
8
8
7
11
6
6
10
11
5
5
0
8
for
per week
watering
14 144
2LJD
2
2
1
1
2
0
10
I
7
7
1
4
7
4
4
1
7
0
1
ft/year
Use in
gal when Yearly
lawn was in house
not being use in
watered
53,000
135,000
72,000
16,000
41,000
-
84,000
49,000
22,000
57,000
9,000
61,000
31,000
19.000
18,000
27,000
46,000
-
21.000
does not
sal
159,000
324,000
216,000
48,000
98,000
54,000
168,000
147.000
66,000
136,800
108,000
122.000
62,000
115,000
217,000
46,285
78,857
96,000
63,000
include 2 desert
Lawn wtr
use in
sal
158,000
217,000
119,000
246,000
297,000
0
309,000
117,000
215.000
223,300
217,000
208,000
75.000
320.000
242.000
90.715
154,000
0
179,000
landscaping
Per
person
use in
Application house
Size of rate in per
lawn in feet day
S3 ft
2,750
3,200
1,500
3,300
2,500
0
900
800
1,750
2,250
1,700
2,000
900
2,400
2,400
1.250
2,500
0
2,350
homes)
per year
7.7
9.0
10.6
10.0
15;9
0
45.9
19.5
16.4
13.3
17.1
13.9
11.1
17.8
13.5
9.7
8.2
0
10.2
14.7
in gal
108.9
220.9
98.6
43.8
134.2
73.9
76.7
134.2
90.4
74.9
98.6
111.4
41.1
156.2
119.9
136.8
108.0
131.5
86.3
107.7
-------
TABLE 6. RECORDED WATER USE OF EIGHT PARKS IN LAS VEGAS VALLEY, 1973
Park
Gallons*
applied
Acres
Squires
Gray Dexter
Hyde Park
Huntridge Circle
Doolittle Park
Baker Park
Jaycee Park
Hadland Park
14,905,000
8,185,000
9,859,000
6,762,000
27,003,000
9,647,000
17,839,000
20,098,000
5.7
4.1
4.5
3.2
13.06
4.9
7.62
12.5
55.58
TOTAL 114,298,000 (350.7 acre feet)
applied use = 6.31 ft/yr
"* ~~
Metered water records for LWWD.
Planimetered green areas.
It appears that lawns of Table 6 received more professional gardening
and a more conservative application rate because of economic factors. This
lower application rate (6.31 ft/yr) is assumed to be a realistic estimate
for this category of lawn in Las Vegas.
Total acreage for lawns of this type obtained from aerial photographs
was 353.61 acres. Recharge to shallow ground water was 1,000 acre feet as
indicated below:
applied use @ 6.31 ft/yr
consumptive use @ 3.47 ft/yr
2,200 acre feet
1,200 acre feet
recharge @ 2.84 ft/yr = 1,000 acre feet
Golf Courses Using Potable Water
Table 7 lists golf courses using potable water in Las Vegas Valley, their
acreage, and amounts of water applied for irrigation during 1973. Golf course
areas were planimetered from aerial photographs. In most cases, volumes of
water applied werefromDWR records. Quantities of water use for Black Moun-
tain and Nellis golf courses are estimates provided by the respective green-
keepers. Quantities for North Las Vegas and Aladdin golf courses are based
on average unit application rates for the other courses.
21
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TABLE 7. GOLF COURSE IRRIGATION USING POTABLE WATER IN
LAS VEGAS VALLEY, 1973
Golf Courses Using
Potable Water
Aladdin
Black Mountain
Craig Road
Desert Inn
Dunes
International
Las Vegas Municipal
Nell is
North Las Vegas Municipal
Sahara Nevada
Tropicana
TOTAL
AVERAGE
Area
(Acres)
8
80
86
131
124
145
111
62
13
126
49
935
5555.40 4-
Volume of
Irrigation
Water
(acre ft/yr)
47.14*
920.70*
335.42
624.28
829.98
927.97
299.85
484.92*
76.60*
759.94
248.60
5555.40
935
Unit Rate
of Application
(ft/yr)
5.89
11.51
3.90
4.77
6.69
6.40
2.70
7.82
5.89
6.03
5.07
5.94
Estimated volume.
Total volume of potable water applied to golf courses during 1973 was
5,500 acre feet. Estimated recharge to shallow ground water was 2,300
acre feet as indicated below:
applied use @ 5.94 ft/yr = 5,500 acre feet
consumptive use @ 3.47 ft/yr = 3,200 acre feet
recharge
@ 2.47 ft/yr = 2,300 acre feet
Golf Courses Using Sewage Effluent Water
Table 8 lists the two golf courses in Las Vegas Valley that used treated
sewage effluent in 1973, their acreages, and amounts of water applied for
irrigation. Volume of water applied comes from DWR records. Golf course areas
are planimetered for aerial photographs.
22
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TABLE 8. GOLF COURSE USE-RATES OF TREATED EFFLUENT
Golf Courses Using Vol. or Irrigation Unit Rate of
Treated Effluent Acres Water (acre feet) Application (ft/yr)
Paradise
Winterwood
94
109
710.86
495.94
7.55
4.55
TOTALS 203 1,206.80
AVERAGE 1,206.80 i 203 = 5.94
Total area of golf courses using sewage effluent was 203 acres. Volume
of sewage effluent applied was 1,200 acre feet. Water for both golf courses
was purchased for the CCSDTP.
Estimated recharge to shallow ground water was 500 acre feet as indicated
below:
applied use @ 5.94 ft/yr = 1,200 acre feet
consumptive use @ 3.47 ft/yr = 700 acre feet
recharge @ 2.47 ft/yr = 500 acre feet
Septic Tank Recharge
Septic tank leach fields are a source of direct recharge to the "near
surface" zone. Clark County Health Department has maintained records on
septic tanks since 1954. However, locations are sometimes inexact and there
are no records to show homes previously on septic tanks which connect as
sewer service expands. Although dwelling units within 400 feet of sewer
lines are required to connect (Clark County Ordinance 109), this rule is not
always enforced. Therefore, to obtain pre-1954 data and more precise loca-
tions, aerial photographs and telephone company criss-cross directories for
1943, 1950, 1958, 1965, 1970, and 1972 have been used to count dwelling
units more than 400 feet from sewer lines that existed at the time the aerial
photographs were taken. This method yields 3,096 homes on septic tanks in
1970 versus 2,974 according to a United States Census Bureau count for the
same period. Appendix 2 lists septic tanks and populations by the zones as
shown in Figure 5. Figures 6, 7, 8, 9, and 10 show septic tank areas in
Las Vegas Valley in the years 1973, 1965, 1958, 1950, and 1943, respectively.
According to 1970 data, per capita wastewater flow in Henderson, North
Las Vegas, and unincorporated areas ranged from 100 gpd to 133 gpd. Cohn
(1966) states there is no "standard" per capita sewage flow and such flows
from single family dwellings may be in the range of 75 gpd to 125 gpd. The
United States Census Bureau (1970) shows an average of 3.1 persons per single
family dwelling with septic tanks in Las Vegas Valley, serving about 12,400
people. Therefore, recharge to the "near surface" zone from septic tanks
has been estimated to be about 1,750 acre feet. Consumptive use of septic
23
-------
Figure 6. Septic tank areas, 1973.
24
-------
Septic Tank
Areas, 1965
Figure 7. Septic tank areas, 1965.
25
-------
Septic Tank
Areas, 1958
Figure 8. Septic tanx areas, 1958.
26
-------
Septic Tank
Areas, 1950
Figure 9. Septic tank areas, 1950.
27
-------
Septic Tank
Areas, 1943
V
Figure 10. Septic tank areas, 1943.
28
-------
tank effluent by trees near the leach fields would decrease this recharge
volume but no attempt has been made to quantify this factor.
Evaporative Coolers
In 1970, according to the Census Bureau data, there were 23,283 dwelling
units using evaporative coolers. No data was available on industrial use.
Relatively few evaporative coolers have been installed since 1964 because FHA
and VA policy has been to discourage this type of cooling unit, therefore,
the number of units estimated in 1970 has been applied to 1973. An evaporative
cooler evaporates approximately 240 gallons of water a day for 180 day/year,
an average of 43,200 gallons/year (Aldo Barozzi, Assistant to General Manager,
LWWD, 1973, personal communication). Use of 23,283 units consuming 43,200
gallons/year accounts for 3,000 acre feet per year of evaporative loss.
A previous study which considered water use of evaporative water coolers
showed an average use of 120,000 gallons/year (Cochran and Wilson, 1971).
These were coolers without recirculating pumps in Boulder City, Nevada. An
ordinance passed in Las Vegas in 1965 requires recirculating pumps as a water
conservation measure.
Transmission Loss
Transmission loss reflects apparent water loss from meter error, water
main breaks, system leakages, unauthorized use of water taps from hydrants,
flushing of fire hydrants, street cleaning, etc. Transmission losses recorded
for the LWWD delivery system during 1973 were 9.82 percent of total metered
supply. In a study of transmission loss done by Keller (1970) 354 selected
utilities reported an average loss of 10.90 percent. Losses in the 10-20
percent range were considered reasonable.
Transmission loss for 1973 is estimated by applying the measured per-
centage system loss of the LWWD (9.82 percent) to the total amount of water
pumped or purchased by the various municipal water delivery systems in the
Valley (LWWD, NLV, Hend. , Nellis AFB) :
105,800 x 0.0982 = 10,500 acre feet
Mr. Aldo Barozzi, Assistant to the General Manager of the LWWD, states
that he believes about 25 percent of the transmission loss goes to recharge
due to leakage and main breaks and about 75 percent is evaporated (personal
communication, 1976). Recharge to shallow ground water is estimated as
2,600 acre feet as indicated below:
recharge 25% x 10,500 acre feet = 2,600 acre feet
evaporated 75% x 10,500 acre feet = 7,900 acre feet
Basic Management Incorporated (BMI)
BMI imported 14,500 acre feet of Lake Mead water for industrial use in
1973. About 400 acre feet of cooling water was discharged directly to Las
Vegas Wash. In 1971 recharge in the BMI ponds was estimated to be 10,500
29
-------
acre feet and evaporation was estimated at 420 acre feet (Westphal and Nork,
1972). Since 1971 water importation to BMI (14,000 acre feet) was approxi-
mately the same as 1973, it is assumed that recharge and evaporation remained
fairly constant. The unaccounted for water (3,200 acre feet) probably reflects
chemical fluid production, manufacturing and in-plant evaporation.
Power Plant Cooling
Treated effluent is used for cooling purposes at the two Nevada Power
Company power generation stations in the Valley. During 1973, 1,120 acre feet
of effluent from CLVSTP and CCSDTP were used at Sunrise Station and 2,590
acre feet from CCSDTP were used at Clark Station (DWR data). Nevada Power
Company estimates that about 75 percent evaporated and 25 percent or approxi-
mately 900 acre feet was discharged to Las Vegas Wash.
Swimming Pools
There were 4,004 swimming pools in Las Vegas Valley in 1971 as counted
from the NASA color-infrared photographs (Appendix 3). By the end of 1973,
an additional 1,600 permits for pool construction (not including above ground
pools) had been issued. Assuming 5,600 pools with an average surface area
of 400 square feet, and averaging 5.0 feet deep, annual filling would account
for 257 acre feet. Annual evaporation based on average annual Boulder City
corrected pan evaporation of 80 inches using a pan coefficient of 0.7 (Westphal
and Nork, 1972) would account for 343 acre feet for a total of 600 acre feet
evaporation from swimming pool use and season-end drainage. There is some
question as to whether application of the pan coefficient is justified due
to heated pools and as to design and amount of drainage. It is interesting
to note that swimming pools are relatively insignificant users of water
regardless of the estimate uncertainties. They are generally considered to
be a high user by the public. It appears that swimming pools use about the
same amount of water as the lawn they generally replace.
Phreatophyte Consumption
Discharge losses in Las Vegas Wash resulting from consumptive use by
phreatophytes and free surface evaporation are obtained by modifying monthly
use values previously calculated by WRC (Westphal and Nork, 1972). In that
study, approximate evapotranspiration (ET) losses along the Wash were esti-
mated using the Blaney-Criddle method. Estimated ET was 81 inches per year
for salt cedar and 76 inches per year for tules. Using a 1970 area of phreato-
phyte growth along the Wash of 2.84 square miles, estimated annual ET was
9,800 acre feet. To update this value, 1973 aerial photos of the Wash have
been used and a new total phreatophyte area of 2.95 square miles determined,
yielding a new annual ET of 10,300 acre feet. This rate is divided into ET
above and below Pabco Road based on percentage distribution of phreatophytes.
Each of these values is then divided into twelve monthly rates using the
average percentage distribution of annual pan evaporation for the Las Vegas
area. A small component to account for free surface evaporation is then
added to each value as appropriate, based on estimated open water area and
local free surface evaporation rates.
30
-------
Annual consumptive use in the reach above Pabco Road is calculated at
5,800 acre feet and for the reach below Pabco Road at 4,500 acre feet. In the
area near the CLVSTP and CCSDTP, mesquite is the dominant phreatophyte.
Gatewood (1950) reports annual consumptive use of mesquite near Safford, Ari-
zona, which is comparable in climate to Las Vegas, is 3.3 ft/yr. Therefore,
for a phreatophyte area of 1,048 acres, evapotranspiration in the area near
the Las Vegas Sewage Treatment Plan is estimated to be 3,500 acre feet per
year. Total evaporation from Las Vegas Wash is estimated at 13,800 acre feet
in 1973. Phreatophyte consumption estimates for other areas of the Valley
are not attempted. Phreatophyte consumption is of course dependent on density
of plants as well as total area. As no attempt is made to compare densities,
values estimated are subject to considerable error.
Precipitation Recharge
Average annual precipitation in Las Vegas Valley is approximately 3.7
inches per year. Much of this precipitation is derived from moderate to high
intensity rain storms with resulting high runoff rates. Under predevelopment
conditions in the Valley, efficient overland flows of surface runoff and only
minor infiltration along washes probably characterized the situation in much
of the present developed-area of Las Vegas Valley. However, development of
the characteristic urban sprawl of Las Vegas has greatly modified the natural
runoff characteristics (Kaufmann, 1976). The net effect is much greater
opportunity for some portion of this water to be recharged to the shallow
ground-water system. There is no direct or reliable way to estimate this
recharge with existing data.
Tom Mclntyre of the United State Soil Conservation Service (personal
communication, 1976) estimates that about two percent of rainfall in Las Vegas
Valley is recharged, and this seems reasonable based on Kaufmann (1976) water
quality evidence. Using a Valley area of 256,000 acres and an average of
0.31 feet of precipitation, this estimate suggests that approximately 1,600
acre feet is recharged from this natural source each year. As there is no
quantitative basis for the two percent figure, this estimation may be subject
to substantial error.
Unaccounted for Water
Figure 11 is a more detailed water budget diagram than was shown in
Figure 3 for 1973. All components differentiated in this study have been
included in the diagram. In the third row from the top, a box entitled
"unaccounted water" with a magnitude of 19,000 acre feet occurs. The "un-
accounted water" box (Figure 11) shows volumes not accounted for in the
categories listed and therefore is the difference between total water
delivered and the sum of the remaining component uses plus sewage return
flows. It includes such unaccountable items as evaporation from residents
and tourists, cooking, water storage facilities, washing, and industrial
uses, as well as error related to underestimating component uses or over-
estimating supply.
The following considerations lead to determination of the "unaccounted
for water." By adding up known and estimated delivery components:
31
-------
NJ
IN HOUSE
RESIDENTIAL
USE
50.500*
[loo j
Hf.rtDEkSOn
Rf TllhN
2.800+
i
RESIDENTIAL
UOMMF. Nf.tAL
107,700
i
JMOO
tVAI-OViTIVE
OOUKS
3.000
—
[•aooj
LAWN
WiTFMNG
30.000
r«
FOOL
6OO
M
r ~ J
TOTAI W&Tt R SUPPI
..AS /EGAS VAUE
143,000
-------
1. Agriculture potable water 2,600 acre feet
2. Golf courses using potable water 5,500 acre feet
3. Transmission loss 10,500 acre feet
4. Parks, schools, cemetaries, hotels,
motels and industrial lawns 2,200 acre feet
5. BMI 14,500 acre feet
TOTAL 35,300 acre feet,
and subtracting from the total delivery of 143,000 acre feet, 107,700 acre
feet are estimated to be remaining residential, government, commercial, and
industrial delivery. Industrial export from the BMI industrial complex is
estimated by subtracting measured outflow from measured inflow. Known and
estimated deliveries and uses from this 107,700 acre feet are:
1. Septic Tanks 1,750 acre feet
2. Evaporative coolers 3,000 acre feet
3. Lawn watering 30,000 acre feet
4. Swimming pools 600 acre feet
TOTAL 35,350 acre feet.
The total of sewage return flows are:
1. Las Vegas Sewage Treatment Plant 35,500 acre feet
2. Clark County Sewage Treatment Plant 15,000 acre feet
3. Henderson and BMI Sewage Treatment
Plants 2,800 acre feet
TOTAL 53,300 acre feet.
Adding the above two totals of deliveries and sewage return yields the total
accounted for water of the 107,700 acre feet of water:
Deliveries 35,350 acre feet
Sewage return 53,300 acre feet
TOTAL 88,650 acre feet
Therefore, "unaccounted for water" becomes:
107,700 acre feet
- 88,650 acre feet
TOTAL 19,050 acre feet
This water is assumed to be some combination of evaporated water, underesti-
mated error in uses, or overestimated error in supply.
33
-------
BUDGET DESCRIPTION
As demonstrated in a simplified budget diagram in Figure 3, the sources,
distribution, and disposition of water in Las Vegas Valley are elaborated in
more detail in Figure 11 for 1973, and for earlier years of 1965, 1958, 1950,
and 1943, in Figures 12, 13, 14, and 15, respectively. These diagrams
demonstrate recorded and estimated use components, estimation of evaporation
and evapotranspiration, estimations of recharge to shallow ground water,
sewage return flow and sewage use, recorded flow of Las Vegas Wash, and
estimations of precipitation recharge.
The budget diagrams are designed to demonstrate supply sources (top row),
residential use and non-residential use (2nd row), disposition of supply
(third row), recharge estimates to shallow ground water (fourth row), and
return flow disposition (lower part of the diagram). Components dealing with
recharge to the shallow ground-water system are indicated by circles, whereas
components reflecting surface water flows are indicated by diamond shaped
boxes. Evaporation or evapotranspiration is indicated by dashed rectangles.
The lower portion of the budget diagrams generally lays out the disposi-
tion of return flows (sewage effluent, ground-water discharge, and other waste-
water) . In 1973, sewage flow from the CCSDTP and the CLVSTP is 50,500 acre
feet; 9,400 acre fee is diverted for agriculture use, power cooling and golf
course irrigation before it reaches the stream gage on Las Vegas Wash at Pabco
Road (Figure 2). About 900 acre feet of cooling water returns to the Wash
and an estimated 9,300 acre feet is lost to phreatophyte evapotranspiration
before Las Vegas Wash surface return flow reaches the gage at Pabco Bead.
Comparing the sum of these flows in to measured discharge at Pabco Road
gives a deficit of 3,300 acre feet. The 3,300 acre feet deficit is balanced
by shallow ground-water inflow to the Wash. The validity of this addition
is demonstrated by Kaufmann (1976), who indicates there is upward ground-
water movement in the area, and by Bateman (1976) who independently calculated
a ground-water return of 2,200 acre feet in the reach above Pabco Road.
Figure 16 is a recharge contour map of Las Vegas Valley for 1973. To
construct this map the recharge data developed in preceding sections were
plotted on a grid composed of squares 1000 feet on each side to form grid
nodes, and then contour lines were drawn using the node point values of
recharge. Areas of greatest recharge occur in the BMI tailing ponds where
at least 20 ft/yr of recharge occurred in the ponds receiving wastewater.
Golf courses, parks and agriculture areas using potable water show recharge
of about three feet per year. Residential areas show recharge from 0 to 2
feet per year. Although residential areas use about 12 feet of water per year,
the non-irrigated areas such as streets, houses, and sidewalks decrease the
per unit area recharge rate to below the rate of concentrated irrigation
areas such as parks, golf courses and agriculture.
The pattern of recharge is irregular and widely distributed in the
Valley. Kaufmann (1976) has demonstrated the water quality influence of such
recharge, but little data is available to clearly demonstrate, on a Valley-
wide basis, the changes that may be occurring in water tables and associated
ground-water storage. The influence of the industrial wastewater effluent
of the BMI complex has been documented in the southeastern part of the Valley,
34
-------
1965
LAS VEGAS
VALLEY WATER
DISTRICT
WELLS
40,050*
LAS VEGAS
VALLEY WATER
DISTRICT LAKE
MEAD WATER
3,596 *
NCLLIS AIR
FORCE BASE
WELLS
2,333*
NELLS AIR
FORCE BASE
LAKE MEAD
WATER
ANDERSON
LAKE MEAD
WATER
4,988 *
OJ
in
XMCASUNCO QUANTITY
4- REPORTED QUANTITY
Figure 12. Water budget for Las Vegas Valley, 1965.
-------
Ul
^ MEASURED QUANTITY
-f- Rf PORTED OUANTny
Figure 13. Water budget for Las Vegas Valley, 1958.
-------
U)
-vl
LAS VEGAS
VALLEV WATER
DISTRICT
WELLS
o
JK MEASURED OUAMTITT
-4- RtFOMTEO OUANTfTV
Figure 14. Water budget for Las Vegas Valley, 1950.
-------
CJ
00
LAS VEGAS
VALLEY WATER
DISTRICT LAKE
MEAD WATER
o
NELLS AIR
FORCE BASE
LAKE MEAD
WATER
NELLIS AIM
FORCE BASE
WELLS
0
HENDERSON
LAKE MEAD
WATER
IOOO*
TOTAL WATER SUPPLY
LAS VEGAS VALUT
.4O.OOO
* MCASUMCO OUANTITT
-f KtWTID OUANTITT
LAS VC6AS MUM
UXKR LAS VEGAS WASH
ALL FWUI«3 IN ACT* FT /T»
Figure 15. Water budget for Las Vegas Valley, 1943.
-------
LEGEND
0-1 ft/yr recharge
1-2 ft/yr recharge
2-3 ft/yr recharge
Figure 16. Recharge contour map of Las Vegas Valley, 1973.
39
-------
and shallow water table conditions have developed in the LDS farms area of the
upper Las Vegas Wash. In other areas, there is less firm evidence for signi-
ficant storage changes in the shallow system, and base line data to compare
changes are rare to absent. Some original shallow saturation areas were
probably due to predevelopment ground-water discharge.
The budget analyses also indicate that changes in shallow saturation
should be occurring. For each year of analysis, a positive value for change
in storage in the shallow system results. Figure 16 clearly demonstrates why
long term increase in shallow ground-water storage has not been particularly
noticeable except in the above-mentioned localized areas. Shallow wells,
perforated only in the uppermost zone of saturation, are generally absent
throughout much of the Valley. Based on this study, where water tables are
presently near land surface (see Kaufmann, 1976), rising water tables might
be expected to increasingly cause problems as .continued increased water use
occurs in the Valley, and shallow saturation gradually rises to near land
surface positions.
40
-------
BIBLIOGRAPHY
Blaney, H. F. and W. C. Griddle. 1945. A Method of Estimating Water Require-
ments in Irrigated Areas from Climatological Data. U. S. Department of
Agriculture, Soil Conservation Service.
Cochran, G. F. and W. C. Wilson. 1971. Arid Urban Water Management: Some
Economic, Institutional and Physical Aspects. Center for Water Resources
Research, Desert Research Institute, Technical Report H-W II. 62 pp.
Cohn, M. M. 1966. Sewers for Growing America. Certain-teed Products Corpora-
tion, p. 71.
Gatewood, J. S. 1950. Use of Water by Bottom-Land Vegetation in Lower Safford
Valley, Arizona. U. S. Geological Survey, Water Supply Paper 1103.
Harrington, M. R. 1933. Gypsum Cave, Nevada. Southwest Museum Papers, no.
8. 206 pp.
Haynes, V. C. 1967. Quaternary Geology of the Tule Springs Area Clark County,
Nevada. Nevada State Museum Anthropological Papers No. 13. 110 pp.
Jones, F. L. and J. F. Cahlan. 1975. Water, A History of Las Vegas. Las
Vegas"Valley Water District Publication, Vol. I. 171 pp.
Kaufmann, R. F. 1976. Land and Water Use Effects on Ground-Water Quality, in
Las Vegas Valley. Water Resources Center, Desert Research Institute.
In final preparation for EPA under grant No. R800946. 215 pp.
Keller, C. W. 1976. Analysis of Unaccounted-For Water. . American Water Works
Association Journal, Vol. 68,, No. 3. 3 pp.
Maxey, G. B. and C. H. Jameson. "1948. Geology and Water Resources of Las
Vegas, Pahrump and Indian Spring Valleys, Clark and Nye Counties, Nevada.
Nevada Department of Conservation and Natural Resources, Water Resources
Bulletin No. 5. 121 pp.
Nevada Division of Water Resources (DWR). 1973. Las Vegas Valley Water
Inventory. Las Vegas, Nevada. 44 pp.
Olivier, H. 1972. Irrigation and Water Resources. London, Edward Arnold
Publishers Ltd.
Paher, S. W. 1971. Las Vegas, As It Began, As It Grew. Nevada Publications.
181 pp.
41
-------
Thornthwaite, C. W. and J. R. Mather. 1957. Instructions and Tables for
Computing Potential Evapotranspiration and the Water Balance. Publica-
tions in Climatology, vol. 10, no. 3. Centerton, N.J.: Drexel Institute
of Technology. 38 pp.
Tovey, R. 1963. Consumptive Use and Yield of Alfalfa Grown in the Presence
of Static Water Tables. Agricultural Research Service, Technical Bulletin
232. 65 pp.
Tovey, R., J. S. Spencer and D. C. Muckel. 1969. Turf Grass Evapotranspira-
tion. Agronomy Journal, Vol. 61: 863-867. 61 pp.
U. S. Bureau of Census. 1976. Census Data for Nevada.
Westphal, J. A. 1977. Simulation Modeling of the Shallow Ground-Water
System in Las Vegas Valley. Water Resources Center, Desert Research
Institute. In final preparation for EPA for grant No. R800946.
Westphal, J. A. and W. E. Nork. 1972. Reconnaissance Analysis of Effects of
Wastewater Discharge on the Shallow Ground-Water Flow System Lower Las
Vegas Valley, Nevada. Center for Water Resources Research, Desert
Research Institute, Project Report 19. 36 pp.
42
-------
Appendix 1. Dwelling Unit Count and Lawn Acreage for Dwelling Units,
Cemetaries, Parks, Schools, Motels, Hotels,
Hospitals and Industrial Areas, By Zones
JUKE 1973 DUELLING UNITS
CLARK COUNTY REGIONAL. PLANKING 30ARD
LAS VEGAS VALL2Y WATER DISTRICT
Zone
101
102
103
104
105
106
107
108
109
110
111
112
201
:o2
203
204
205
206
207
203
209
c
r* tfl
** U
a -4
IS
34
632
465
1389
682
31
128
2
308
0
0
0
0
0
384
963
879
1589
2036
1316
0
Sq. Ft.
AvS.
Lawn
100
2000
1500
1500
2000
1500
1000
1000
1000
1000
500
300
0
0
1500
3000
1500
1500
1500
1800
0
7.
With
Lawn
90
30
30
70
90
90
80
1000
30
100
100
100
0
0
30
90
30
30
30
30
0
Total
Sq. ?t. of
Lawns
7,560
1,091,200
658,000
1,458,450
1,227,600
41,350
102,400
2,000
24,640
0
0
0
0
0
1,060,300
2,600,100
105,480
1,906,800
2,443,200
1,395,040
0
Cemetaries,
Parks ,
Schools
0
130,680
0
591,500
0
5,000
5,000
0
0
0
0
0
0
0
5,000
653,000
196,000
105,000
40,000
25,000
0
Industrial
Hotels
Motels
Hospitals
10,000
6,000
'• -'i
30,000
0
0
0
0
0
0
0
0
3,000
0
0
0
0
0
0
0
0
Sq. Ft.
Total
Lavms
17,560
1,227,380
588,000
2,049,950
1,461,600
46,350
107,400
2,000
24,640
0
0
0
3,000
0
1,066,800
3,253,100
1,250,800
2,011,800
2,483,200
1,920,040
0
Total
Acres
.4
23.17
13.49
47 . 06
23.13
1.08
2.47
.04
.56
0
0
0
.06
0
24.49
7&.63
28.71
46.13
57.01
44.08
0
43
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Las Vegas Valley Water District
Industrial
Zone
210
211
212
213
214
215
216
217
213
301
302
303
304 .
305
306
307
303
309
310
311
312
313
D.U.
248
821
231
534
0
1
200
772
0
796
631
751
1814
1363
176
1764
880
84
0
0
0
0
Sq. Ft.
Avg.
Laun
3000
1300
1500
1500
0
500
2000
1500
0
1800
2000
2000
1500
1500
2500
1500
1500
2000
0
0
0
0
7.
With
Lawn
80
80
80
30
0
100
90
90
0
85
80
80
80
80
90
90
90
30
0
0
0
0
Total
Sq. Ft. of
Lawns
595,200
985,200
277,200
700,800
0
500
360,000
1,389,600
0
1,217,880
1,009,600
1,201,600
2,176,800
1,635,600
196,000
2,381,400
1,188,000
134,400
0
0
0
0
Cemetaries, Hotels
Parks, Motels
Schools Hospitals
0
0
21,000
16,000
0
0
0
0
0
100,000
80,000
0
0
0
0
225,000
80,000
400,000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Sq. Ft.
Total
Lawns
595,200
985,200
298,200
716,800
0
500
360,000
1,389,600
0
1,317,880
1,089,600
1,201,600
2,176,800
1,635,600
396,000
2,606,400
1,268,000
534,400
0
0
0
0
Total
Acres
13.66
22.62
6.35
16.46
0
.01
8.26
31.90
0
30.25
25.01
27.58
49.97
37.55
9.09
59-83
29.11
12.27
0
0
0
0
44
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
las Vegas Valley Water District
Industrial
Zone
314
401
402
403
404
405
406
407
408
409
410
411
412
501
502
503
504
505
506
507
508
509
D.O.
0
170
440
350
912
469
667
829
700
655
427
153
624
246
678
451
384
127
533
1894
384
256
So.. Ft.
Avg.
Lawn
0
200
800
2000
800
800
1500
1000
1500
800
1200
500
500
1800
500
1500
150
2000
1500
1800
500
1000
7.
With
Lawn
0
40
50
90
50
70
80
80
90
70
70
50
80
90
90
90
90
100
85
90
80
80
Total
Sq. Ft. of
Lawns
0
13,600
176,000
630,000
36,480
26,264
800,400
663,200
945,000
366,800
358,680
38,250
249,600
398,520
305,100
608,850
51,840
254,000
568,650
3,068,280
153,600
204,800
Cemetaries,
Parks ,
Schools
0
0
0
0.
0
0
20,000
51,000
720,000
128,000
225,000
0
0
180,000
0
60,000
0
2,386,500
445,000
99,500
20,000
0
Hotels
Motels
Hospitals
•0
0
•0
0
:0
0
0
0
0
0
0
0
15,000
8; 000
;0
0
67,000
•o
0
3,000
<0
0
Sq. Ft.
Total
Lawns
0
13,600
176,000
630,000
36,480
26,264
820,400
714,200
1,665,000
494, 8t>0
583,680
38,250
264,600
586,520
305,100
668,850
118,840
2,640,500
1,013,650
3,170,780
173,600
204,800
Total
Acres
0
.31
4.04
14.46
8.3-Zi
6.03
18.83
16.39
38.22
11.35
13.40
.87
6.07
13.46
7.00.
15.35
2.73
60.61
23.27
72.79
3.98
4.70
45
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
^as Vegas Valley Water District
Industrial
Zone
S10
511
512
601
602
603
604
605
606
607
608
609
610
511
612
613
614
615
616
617
613
619
D.U.
142
680
472
47
0
0
0
0
0
0
0
385
240
269
471
1374
686
958
238
284
780
807
Sq. Ft.
Avg.
Lawn
1000
1500
1500
500
0
0
0
0
0
0
0
500
500
500
500
700
700
2000
2000
500
2000
1500
7.
With
Lawn
60
80
70
80
0
0
0
0
0
0
0
5.0
50
60
60
70
80
90
90
90
90
90
Total
Sq. Ft. of
Lawns
85,200
816,000
495,600
18,800
0
0
0
0
0
0
0
96,250
60,000
80,700
141,300
673,260
384,160
1,724,400
428,400
127,800
1,404,000
1,089,450
Cemetaries,
Parks ,
School
0
0
538,000
0
150,000
0
50,000
0
0
15,000
0
0
0
0
0
80,000
0
150,000
0
0
0
0
Hotels
Motels
Hospitals
0
5,000
6,000
0
0
0
0
0
0
0
0
0
0
30,000
0
0
7,000
0
0
4,000
0
0
Sq. Ft.
Total
Lawns
85,200
821,000
1,039,600
18,800
150,000
0
50,000
0
0
15,000
0
96,250
50,000
110,700
141,300
753,260
391,160
1,874,400
428,400
131,800
1,404,000
1,089,450
Total
Acres
1.95
18.84
23.87
.43
3.44
0
1.14
0
0
.34
0
2.21
1.37
2.54
3.24
17.29
8.98
43.03
9.83
3.03
32.23
25.01
46
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Us Vegas Valley Hater District
Industrial
Zone
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
D.U.
812.
132
2083
215
56
1960
508
865
903
493
574
190
466
479
375
162
562
450
109
1291
0
0
Sq. Ft.
Avg.
Lawn
500
2000
400
700
100
300
300
1500
1500
1500
2000
2000
500
1800
1800
1800
1500
v 1800
1800
200
0
0
7.
With
Lawn
90
90
90
90
50
50
50
80
80
80
80
60
95
90
90
80
80
90
90
90
0
0
Total
Sq. Ft. of
Lawns
365,400
237,600
749,880
135,450
2,800
294,000
76,200
1,038,000
1,038,600
591,600
918,400
228,000
221,350
775,980
607,500
233,280
674,400
729,000
176,580
232,380
0
0
Ceme Caries,
Parks ,
School
0
0
490,000
0
0
49,000
0
0
0
200,000
14,000
60,000
0
0
0
0
0
60,000
320,000
50,000
0
0
Hotels
Motels
Hospitals
0
0
0
0
0
0
0
0
0
0
32,500
10,000
0
80,000
0
0
10,000
0
25,000
20,000
0
0
Sq. Ft.
Total
Lawns
365,400
237,600
1,239,880
135,450
2,800
343,000
76,200
1,038,000
1,083,600
791,600
964,900
298,000
221,350
855,980
607,500
233,280
684,400
789,000
521,580
302,380
0
0
Total
Ac re a
8.39
5.45
28.46
3.11
.06
7.87
1.74
23.83
24.88
18.17
22.15
6.84
5.08
19.65
13.94
5.36
15.71
18.11
11.97
6.94
0
0
47
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Las Vegas Valley Water District
Industrial
Zone
642
701
702
703
704
70S
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
D.U.
336
262
15
2081
2372
1179
1351
466
2711
5474
786
226
750
0
114
1948
591
907
235
2631
79
234
Sq. Ft.
Avg.
Lawn
2000
100
500
500
1500
2000
1000
500
500
500
2000
2000
2000
0
100
250
500
2000
2000
1500
200
100
%
With
Lawn
90
90
90
100
80
90
85
95
95
95
90
80
80
0
90
95
95
90
80
80
30
60
Total
Sq. Ft. of
Lawns
604,800
23,580
6,750
1,040,500
2,846,400
2,122,200
1,148,350
221,350
1,287,725
2,600,150
1,414,800
361,600
1,200,000
0
10,260
462,650
280,725
1,632,600
376,000
3,157,200
4,740
14,040
Cemetaries,
Parks ,
School
0
0
0
0
794,000
0
192,000
0
0
0
0
37,500
0
0
0
0
420,600
85,000
0
190,000
0
0
Hotels
Motels
Hospitals
0
250,000
250,000
0
0
0
0
40,000
100,000
0
0
0
Q
0
0
0
0
0
0
0
300,000
280,000
Sq. Ft.
Total
Lawns
604,800
273,580
256,750
1,040,500
3,640,400
2,122,200
1,340,350
261,350
1,387,725
2,600,150
1,414,800
399,100
1,200,000
0
10,260
462,650
701,325
1,717,600
844,000
3,347,200
305,400
294,040
Total
Acres
13.88
6.28
5.89
23.89
83.57
48.72
30.77
5.99
31.86
59.69
32.48
9.16
27.55
0
.24
10.62
16.10
39.43
8.63
76.84
.10
6.75
48
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Las Vegas Valley Water District
Zone
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
801
802
803
804
805
306
TOTAL
D.U.
0
1309
36
651
223
490
101
54
95
1725
0
595
1369
215
489
524
267
24
0
244
0
0
86,647
Sq. Ft. 7.
Avg. With
Lavra Lawn
0
1000
2000
2000
2000
2000
2000
1500
3000
1500
0
•1000
1000
2000
800
200
1000
500
0
1000
0
0
Square Feet
Acres
0
60
90
80
80
80
80
80
90
60
0
80
80
90
70
70
80
80
0
50
0
0
Total
Sq. Ft. of
Lawns
0
785,400
64,800
1,041,600
356,800
784,000
161,600
64,800
256,500
1,552,500
0
476,000
1,095,200
387,000
312,960
73,360
213,600
9,600
0
122,000
0
0
35,723,174
1,968
Cemetarles,
Parks,
School
0
0
0
58,600
0
0
0
150,000
0
0
0
0
0
0
0
0
0
•"-:, o
0
0
0
0
11, 167, 880
256
Industrial
Hotels
Motels
Hospitals
0
0
0
0
0
0
0
35,000
0
0
0
0
0
0
0
0
0
0
0
0
0
1,699,300
39
Sq. Ft.
Total
Lawns
0
785,400
64,800
1,100,200
356,800
784,000
161,600
249,800
256,500
1,552,500
0
476,000
1,095,200
387,000
312,960
73,360
213,600
9,600
0
122,000
0
0
98,590,354
Total
Acres
0
18.03
1.49
25.26
8.19
17.99
3.71
5.73
5.89
35.64
0
10.93
25.14
8.88
7.18
1.68
4.90
.22
0
2.80
0
0
2,263
49
-------
June 1973 Dwelling Units
riark County Regional Planning Board
Me 11 is Air Force Base
Zone
532
534
D.U.
747
492
Sq. Ft.
Avg,
Lawn
1200
500
7.
With
Lawn
95
100
Total
Sq. Ft. of
Lawns
851,580
246,000
Cemetaries
Parks ,
School
0
0
Industrial
, Hotels
Motels
Hospitals
0
0
Sq. Ft.
Total
Lawns
851,580
246 , 000
Total
Acres
19.55
5.64
TOTAL 1,239
Square Feet
Acres
1,097,712
1,097,580
25.19
Lawn Acreage Distribution by Hater Districts - 1973
Las Vegas Valley Water District
North Las Vegas
Henderson
Nellis AFB
Private Wei!s
TOTAL
Duelling
Units
86,
12,
4,
1,
647
783
220
239
4.000
108,889
Lawns
1968
223
79
25
136
2431
acres
acres
acres
acres
acres
acres
Cemetaries
Parks
Schools
256
31
1
3
0
288
acres
acres
acre
acres
acres
acres
Industrial
Hotels
Motels
Hospitals
39 acres
2
0
0
0
41
acres
acres
acres
ac^es
acres
50
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Henderson Hater District
Zone
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
TOT.U
D.U.
128
450
242
184
72
58
161
210
228
78
64
124
840
392
270
120
0
0
599
4,220
Sq.. Ft
Avg.
Lawn
1000
1000
1000
1000
1000
1000
1500
1000
1000
1000
1000
1000
1000
1000
1000
1000
0
0
1000
Square
Acres
7.
With
Lawn
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
0
0
80
Feet
Total
Sq. Ft. of
Lawns
102 ,400
360,000
193,600
147,200
57,600
46,400
193,200
168,000
182,400
62,400
51,200
99,200
672,000
313,600
216,000
96,000
0
0
479,200
3,440,400
Cemet arias
Parks,
School
0
0
0
0
0
0
0
0
0
0
0
0
20,000
0
0
0
5,000
0
0
25,000
Industrial
Hotels
Motels
Hospitals
0
0
0
0
0
0
0
0
0
0
0
0
0
0 •'
0
0
0
0
0
0
Sq. Ft.
Total
Lawns
102,400
360,000
193,600
147,200
57,600
46,400
193,200
168,000
182,400
62,400
51,200
99.200
692,000
313,600
216,000
96,000
5,000
0
479,200
3,465,633
Total
Acres
2.35
8.26
4.44
3.38
1.32
1.07
4.44
3.86
4.19
1.43
1.18
2.28
15.89
7.20
4.96
2.20
.11
0
11.00
7Q
51
-------
June 1973 Dwelling Units
Clark County Regional Planning Board
Borth Las Vegas Water District
Zone
413
414
415
416
417
418
419
421
512
513
514
515
516
517
513
519
520
521
527
528
529
530
531
TOTAL
LJk
0
718
781
0
0
11
0
0
0
1428
77
1460
2
1503
1135
1898
407
218
456
729
156
635
1169
Sq. Ft.
Avg.
Lawn
0
1000
1000
0
0
500
0
0
0
1500
1000
1200
500
1000
800
1200
1200
1500
500
100
500
800
600
Square Feet
Acres
%
With
Lawn
0
80
80
0
0
50
0
0
0
80
50
80
100
70
80
80
80
80
80
90
80
60
70
Total
Sq. Ft. of
Lawns
0
574,400
624,800
0
0
2,750
0
0
0
1.713,600
38,500
1,401,600
1,000
1,052,100
726,400
1,822,080
390,720
261,600
182,400
65,610
62,400
304.800
490,980
9,713,880
223
Cemetaries,
Parks ,
School
0
0
0
0
0
0
0
0
0
55.000
0
419,500
0
592,000
0
130,000
30,000
60,000
0
0
0
80,000
0
1,366,500
31
Industrial
Hotels
Motels
Hospitals
12,000
0
0
0
0
0
57; ooo
0
0
0
0
0
3,200
0
0
0
0
0
0
0
0
0
0
72,800
2
Sq. Ft.
Total
Lawns
12,000
574,400
624,800
0
0
2,750
57,000
0
0
1,768,600
38,500
1,821,100
4,200
1,644,100
726,400
1,952,080
420,720
321,600
182,400
65,610
62,400
384,800
490,980
11,153,180
Total
Acres
.27
13.19
14.34
0
0
.06
1.30
0
0
40.60
.88
41.81
.10
37.74
16.68-
44.81
9.66
7.38
4.19
1.51
1.43
8.83
11.27
256
52
-------
Appendix 2. Septic Tanks by Zone for Years
1972, 1970, 1965, 1958, 1950, 1943
(zones not listed did not have septics from 1943-1972)
SEPTIC TANKS
1975
LV Trans
Study
Zone #
105
106
107
108
109
110
111
112
203
204
207
210
211
213
214
215
218
301
302
303
305
306
307
309
311
312
313
1943
D.U.*
0
0
7
0
0
0
10
0
46
0
0
9
8
0
0
0
0
8
6
0
0
4
0
0
0
0
0
Pop.
0
0
21
0
0
0
30
0
138
0
0
27
24
0
0
0
0
24
18
0
0
12
0
0
0
0
0
1950
D.U.
7
0
0
0
0
0
10
0
115
75
0
13
79
0
0
17
0
4
5
63
5
33
0
1
0
0
0
Pop*
17
0
0
0
0
0
24
0
276
180
0
31
190
0
0
41
0
10
12
151
12
79
0
3
0
0
0
1958
D.U.
7
0
0
0
0
0
10
0
181
6
0
0
15
0
0
0
0
0
0
200
5
59
21
1
0
0
0
Pop.
21
0
0
0
0
0
30
0
543
18
0
0
45
0
0
0
0
0
0
600
15
177
63
3
0
0
0
1965
D.U.
28
25
10
0
3
7
11
3
94
43
0
0
55
50
3
0
11
0
0
197
0
288
62
33
4
6
133
Pop.
103
172
33
0
4
11
31
7
310
172
0
0
169
215
7
0
36
0
0
685
0
1094
244
94
14
20
494
1970
D.U.
40
38
11
1
3
4
24
6
94
43
0
0
61
56
6
0
12
0
0
202
0
326
68
46
4
5
132
Pop.
120
120
33
2
8
11
56
15
310
172
0
0
183
168
20
0
35
0
0
606
0
978
204
134
14
16
474
1972
D.U.
57
93
14
2
4
19
33
6
94
43
1
0
63
56
6
0
12
0
0
205
0
341
73
64
4
6
135
Pop.
171
279
42
6
12
57
99
15
310
172
3
0
189
168
20
0
35
0
0
615
0
1023
219
192
14
18
405
53
-------
Septic Tanks
1975
LV Trans
Study
Zone #
401
402
403
405
406
407
408
409
411
412
413
414
415
416
417
418
419
420
421
422
501
504
505
506
507
508
509
1943
D.U.*
11
12
26
0
23
0
2
11
8
0
2
0
2
0
0
0
0
0
0
0
0
5
0
0
0
0
97
Pop.
33
36
78
0
69
0
6
33
24
0
6
0
6
0
0
0
0
0
0
0
0
15
0
0
0
0
291
1950
D.U.
117
10
145
13
26
18
3
67
40
7
1
3
16
0
0
1
2
1
3
2
101
237
6
4
13
4
136
Pop.
280
24
348
31
62
43
7
161
96
17
3
7
38
0
0
2
5
2
7
5
242
569
14
10
31
10
326
1958
D.U.
0
0
68
0
53
59
0
0
297
9
3
4
35
0
0
2
4
26
6
14
0
0
0
0
11
29
338
Pop.
0
0
204
0
159
177
0
0
891
27
9
12
105
0
0
6
12
78
18
42
0
0
0
0
33
87
1014
1965
D.U.
0
0
68
0
0
65
0
0
343
14
21
7
5
0
37
8
78
89
12
26
0
0
0
0
0
8
0
Pop.
0
0
204
0
0
204
0
0
12
80
63
31
21
0
77
29
196
336
42
101
0
0
0
0
0
32
0
1970
D.U.
0
0
68
0
0
65
0
0
344
14
0
7
5
• 3
39
7
76
109
14
36
0
0
0
0
0
11
0
Pop.
0
0
204
0
0
204
0
0
1078
0
0
31
21
11
127
23
370
338
40
133
0
0
0
0
0
33
0
1972
D.U. Pop.
0
0
68
0
0
68
0
0
344
17
0
7
5
3
46
14
92
150
31
38
0
0
0
0
0
20
0
0
0
204
0
0
204
0
0
1078
58
0
31
21
11
161
51
447
465
88
140
0
0
0
0
0
60
0
54
-------
Septic Tanks
1975
LV Trans
Study 1943 1950 1958 1965 1970 1972
Zone # D.U.* Pop. D.U. Pop. D.U. Pop. D.U. Pop. D.U. Pop. D.U. Pop.
510
511
512
513
514
515
516
517
518
519
520
521
523
524
525
526
527
528
529
530
531
622
623
632
635
636
637
36
83
0
0
0
0
0
0
3
8
0
0
0
0
2
0
0
0
0
0
0
0
4
0
0
12
0
108
249
0
0
0
0
0
0
9
24
0
0
0
0
6
0
0
0
0
0
0
0
12
0
0
36
0
39
320
14
15
37
83
13
129
6
19
2
1
9
29
2
1
17
1
2
19
3
149
9
1
4
30
2
94
768
34
36
89
199
31
310
14
46
5
2
22
70
5
2
41
2
5
46
8
357
22
3
10
74
5
212
327
0
0
16
285
37
330
81
166
4
3
104
92
28
25
57
21
23
18
13
23
17
0
4
0
0
636
981
0
0
43
855
111
990
243
498
12
9
312
276
84
75
171
63
69
54
39
69
51
0
12
0
0
0
0
0
0
0
0
0
0
0
0
0
6
24
0
0
0
0
0
0
2
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
19
72
0
0
0
0
0
0
8
48
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
24
0
0
0
0
0
0
4
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
72
0
0
0
0
0
0
12
48
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
28
5
0
0
0
0
0
4
18
1
0
0
0
o .
0
0
0
0
0
0
0
0
0
0
0
0
0
84
15
0
0
0
0
0
12
54
3
0
0
0
0
0
55
-------
Septic Tanks
1975
LV Trans
Study
Zone #
639
640
641
642
704
705
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
721
1943
D.U.*
27
0
3
0
7
0
10
11
0
0
0
0
0
0
1
1
2
0
0
0
1
1
9
2
4
0
0
Pop.
81
0
9
0
21
0
30
33
0
0
0
0
0
0
3
3
6
0
0
0
3
3
27
6
12
0
0
1950
D.U.
113
0
0
0
2
8
0
6
52
0
4
0
0
1
5
1
9
5
1
0
31
44
20
6
10
1
6
Pop.
271
0
0
0
5
20
0
15
125
0
10
0
0
3
13
2
22
13
3
0
74
106
50
15
25
3
15
1958
D.U.
0
0
0
0
6
3
0
15
55
4
28
13
2
1
8
10
26
9
5
0
57
49
21
46
44
9
30
Pop.
0
0
0
0
18
9
0
45
165
12
84
39
6
3
24
30
78
27
15
0
171
147
63
138
136
27
90
1965
D.U.
0
23
42
2
0
0
0
0
55
0
0
0
0
0
0
0
0
14
7
7
0
51
0
0
18
0
75
Pop.
0
66
130
5
0
0
0
0
165
0
0
0
0
0
0
0
0
42
21
16
0
153
0
0
75
0
237
1970
D.U.
0
59
47
4
0
0
0
0
55
0
0
0
2
0
0
0
0
22
11
8
0
60
0
0
0
0
82
Pop.
0
165
113
10
0
0
0
0
165
0
0
0
8
0
0
0
0
66
33
24
0
121
0
0
0
0
246
1972
D.U.
0
82
63
6
0
0
0
0
55
0
0
0
10
0
0
0
0
30
14
11
0
65
0
0
0
0
85
Pop.
0
229
151
15
0
0
0
0
165
0
0
0
30
0
0
0
0
90
42
33
0
195
0
0
0
0
255
56
-------
Septic Tanks
1975
LV Trans
Study
Zone #
728
729
730
731
732
733
734
•735
736
737
804
805
806
1943
D.U.*
0
0
0
0
0
6
0
0
0
0
0
0
0
Pop.
0
0
0
0
0
18
0
0
0
0
0
0
0
1950
D.U.
6
3
12
42
1
16
0
0
0
0
27
0
1
Pop.
15
8
30
101
2
40
0
0
0
0
65
0
3
1958
D.U.
16
6
27
17
1
0
0
0
0
0
49
0
1
Pop.
48
24
81
51
3
0
0
0
0
0
147
0
3
1965
D.U.
0
0
77
48
2
0
0
0
0
3
138
48
9
Pop.
0
0
267
204
6
0
0
0
0
8
544
166
37
1970
D.U.
0
0
93
51
3
0
125
0
0
4
Pop.
0
0
279
153
10
0
375
0
0
12
368 1104
58
20
154
62
1972
D.U.
0
0
101
55
29
0
127
1
1
5
Pop.
0
0
303
165
87
0
381
3
3
15
427 1281
66
23
198
69
Area north of
Centennial Parkway
and west of Piedomont
183
549
TOTAL
530 1590 2791 6720 4078 11721 2514 8762 3096 9320 3731 11518
57
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Appendix 3. Swimming Pools by Zones, 1971
(zones not listed did not have swimming pools in 1971)
SWIMMING POOLS IN LAS VEGAS VALLEY - OCTOBER 1971
LV Trans. Study Number of Pools LV Trans. Study Number of Pools
Zone Number in Zone Zone Number in Zone
102
103
104
105
106
107
203
204
205
206
207
208
210
211
212
213
216
217
301
302
303
304
305
306
307
308
403
406
34
24
68
76
3
2
65
192
60
82
77
9
76
232
23
53
63
94
103
70
25
53
62
48
74
36
6
3
407
412
420
501
502
503
504
506
507
508
512
513
514
515
517
518
519
520
521
523
524
525
526
527
530
604
605
606
13
2
4
1
6
30
1
17
68
8
4
55
2
14
13
3
27
2
1
1
3
2
2
4
4
1
1
1
58
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Swimming Pools in Las Vegas Valley
LV Trans. Study Number of Pools LV Trans. Study Number of Pools
Zone Number in Zone Zone Number in Zone
607
613
614
615
616
617
618
619
620
621
622
623
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
642
2
2
8
2
4
1
2
19
23
7
15
6
31
9
15
63
33
33
19
15
26
12
12
13
13
2
13
11
701
702
703
704
705
706
707
708
709
710
711
712
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
8
12
59
176
152
35
20
84
53
257
66
25
10
35
3
63 :
72
97
2
20
9
79
2
8
11
41
7
2
59
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Swimming Pools in Las Vegas Valley
LV Trans. Study Number of Pools LV Trans. Study Number of Pools
Zone Number in Zone Zone Number in Zone
730
731
733
734
735
736
801
804
805
901
910
912
914
915
916
919
31
19
7
15
23
14
8
9
1
1
1
3
6
4
4
2
TOTAL 4,004
60
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-78-159
2.
3. RECIPIENT'S ACCESSIO!»NO.
4, TITLE AND SUBTITLE
Las Vegas Valley Water Budget: Relationship
of Distribution, Consumptive Use, and Recharge
to Shallow Ground Water
5. REPORT DATE
July 1978 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Ralph 0. Patt
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Desert Research Institute
Las Vegas, Nevada 89109
10. PROGRAM ELEMENT NO.
. 1CC614
11. CONTRACT/GRANT NO.
R-800946
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
13. TYPE OF REPORT AND PERIOD COVERED
Final; 11/1/69 - 1/31/74
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
Project Officer: Fredric Hoffman, Region IX, San Francisco, CA 94111
16. ABSTRACT
Estimates of quantity and geographic distribution of recharge to the
shallow ground-water zone from water use return flows in Las Vegas Valley
were made for the years 1973, 1965, 1958, 1950, and 1943 as part of a broader
study on the impact of water and land use on ground-water quality. Considered
components of water use in Las Vegas Valley include the following: supply
from surface and ground water; agriculture using potable water; agriculture
using sewage effluent; residential lawn watering; lawn watering of parks,
schools, cemetarics, hotels, motels; golf courses using potable water; golf
courses using sewage effluent water; septic tank recharge; evaporative coolers;
system losses; industrial use; power plant cooling; swimming pool use; con-
sumptive use by phreatophytes; in-valley recharge from precipitation, and
"unaccounted for water". Consumptive use of plants was calculated through
use of the Blaney-Criddle method as 3.47 feet per year and recharge was
assumed to be the difference between applied water and calculated consumptive
use. Data developed during this study indicates consumptive use as determined
by this method could be low by 1.5 to 2 feet per year, and thus the following
estimates of recharge to the ground-water system are considered maximum, in
acre feet: 1973-39,000; 1965-27,600; 1958-26,650; 1950-13,000; and 1943-
21,000.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Ground water
Ground water recharge
Water consumption
Las Vegas Valley
13/B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES
69
20. SECURITY CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
61
#U.S. GOVERNMENT HINTING OFFICE: 1978-757-140/1462 Region No. 5-11
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