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to Use. • • 28
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. . . '- 1 ( Oon HUMBER -.. J. _ ) Ot. J
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Colorado River , e • .. •• 3
Gila River. • • • • • .. • • • • • • • .. • •• 17
General ••••••••••• <> ..... " .... 30
Consideration of Present Conditions and
Contributing Factors .. " .. • • • • • • • •• 30
Problems Associated with Methods of Reducing
Pollutants ••• " 0 34
Additional Measures to Enhance Water QualIty. 34
QualIty RequIrements for SpecIfIed Uses•••• 35
General •• ~ 0 0 •••• 26
Agricultural ~ " 26
Domestic Hater Sources 26
Industrial ~ • • .. • • • •• 27
Propagation of Aquatic and Wildlife
Resources. " .. .. • • • • • • • •
Recreational 0 ~ 0 .
Future Uses of Surface Water • • •
Classification of Waters According
Enhancement of Water Quality ....
General •• ~ 0 ~ ..
. DescrJption of Interstate Waters ~
MInor Basins ~ ..
~ ~ OOCUMENT IS THE Pf\ OP& RTY
~ n 01' THE
H ~ J! 8Ii_ l!-=~~~ GiiIIi~~
6- 2- 1
6- 2- 10 1
6- 2-. 1. 2
6- 2- 2 .
6- 2- 2,2
6- 2- 3
6- 2- 3.1
6- 2- 3.2
6- 2- 303
6- 2- 3,, 4
6- 2- 3.5
6- 2- 3 6 6
6- 2- 3.7
6- 2- 3.8
6- 2- 3.9
6- 2- 4
6- 2- 4.1
6- 2- 4.2
6- 2- 4.3
6- 2. · 4.4
6- 2- 4.5
Article 6
Part 2
Foreword • • • 0 0 • • • • • • • • ~ • • • • • • • • • •
Notice of. Adoption ~ 0 ~ .
Definitions J 6 .
- sm"
I. Tributaries to Colorado River Below Lees Ferry
2. Summary of Diversions from the Colorado River - 1964
3. Arizona Agricultural Statistics
4. Cities Along the Arizona Reach of the Colorado River
5. Industrial Statistics
6. MIneraI Production StatistIcs
7. Recreational Features Along the Arizona Reach of the Colorado RIver
8. Graphs of Total Dissolved Soilds In the Colorado River at Selected
9. Total Dissolved Solids Variation in Lake Powell
10. Graph of Yearly Weighted Average TDS at Selected PoInts In the
Colorado River
11. Farming Practices - \ vater Conservation and Quality Enhancements
12. Water D~ livery System Improvements
13. Arizona Watershed Program
14. Evaporation Control
15~ Phreatophyte Control
16. Water ReclamatIon and Exchanges
17. Water Demineralization at Buckeye, Arizona
18. Activities of the Arizona Water and Pollute~ n Control Association
19. The Role of Arizona sorl Conservation Districts in Conservation
of \ Jater Quality and Quantity
Agrfculture. • • • , • • • • • • • • • • , • 35
Raw Domestic Water • • • • • • • • • • • " • 37
Recreation. • • • • • • • 0 • • • • • • • • 40
Propagation of Aquatic and WI Idl ife
Resources. • • • • • • • • • • • • • • • • 41
Industrial " • • • • • a • • • • • • • • • • 41
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• • 4 •
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• • 0 •
• • • •
• • • •
• • • • • • •
. . . . .
• • • • • • •
• • •
Basic standards Applicable to All Waters •• 44
Additional Water Quality Standards for
Waters that have any of the FoJlowtng
Uses • • ~ • • • • • Q • • • 0 • 0 • • • 0 44
A. Domestic & Industrial Supply •• '. '. • 44
B. Recreation ••••••••• ~ • • • • 45
C. Fish and Wild- I ife · . • • • • • • • • •• 46
D. Agriculture•• , ~ •••••• , • •• 48
Implementation. 0 •••••••••
Surveillance ••••••••••••
Waste Discharge Requirements ••••
General Enforcement••••• ~ •••
• • 0 • • • • • • • • • • • • • • • •
6- 2- 4.6
6- 2- 4.7
6- 2- 4.8
6- 2- 4.9
6- 2- 4.10
6- 2- 5
6- 2- 6
6- 2- 6.2
6- 2- 7
6- 2- 7.1'
6- 2- 7,2
6- 2- 7~ 3
6- 2- 7.4
20. Guidelines for Formulating Water Quality Standards for the
Interstate Waters of the Colorado River System
21. Minute 218 - Recommendations on the Colorado River Salinity
Problem and Memorandum of Understanding
22 0 Gila River System Streamflow Data
23. Major Coldwater and Warmwater Fishing Areas on Interstate Waters
In Arizona
The following definitions appear in Chapter 16 of Arizona Revised Statutes
36- 1851 and apply thoughout this document:
1. IIBoard" means the state board of heal tho
2. " Commissionerll means the commissIoner of publ ic heal tho
3. IICouncil ll means the water qual ity control council establ ished by
this chapter.
4. I'Department ll means the state department of heal th, which for the
purposes of this article includes the council.
5. " Disposal system'l means a system for disposing of wastes, either
by S~( f2Ce or underground methods, and includ~ s seweraga systems,
tr€ at: i1ent works, disposal w~ 11s, and other systems.
6. " tiearlng officer ' l means any individual appointed by the councilor
board to perform the duties of a hearing cfficer at any hearing.
7. IIPermit" means a certificate or letter issued by the department
stating the co~ ditions ~~ d restrictions governing the discharge
of a pcl; u~ ant into any waters of the state•.
8. " Person" means the state or any agency or inst i tut; on thereof, any
mun: c1pul ity, pol itical subdivision, publ ic or private corporation,
individual, partnership, association, or other entity, and includes
any officer or g~ verning or managing body of any municipal ity,
pol itical subdivision, or publ ic or private corporation.
9. '~ ollution~ means such contamination, or other alteration of the
physical, chemical, or biologicui pr0~ erties of any waters of the
state, including change in temperature, taste, color, turbidity,
or odor of the waters, or such discharge of any liquid, gaseous,
sol id, radioactive, or other substance into any waters of the state
as will or is 1ikely to create a publ ic nuisance or render such
waters harmful, detrimental, or injurious to publ ic health, safety,
or welfare, or to domestic, agricultural, commercial, industrial,
recreatio~ al, or other beneficial uses, or to livestock, wild animals,
birds, fish or other aquatic 1ife.
10. " Sewerage system" means pipel ines or conduits, pumping stations,
and force mains, and all other structures, devices, appurtenances,
and f~ cilities used for collecting or conducting wastes to an
ultimate point for treatment or disposal. .
11. " Treatment works" means any pI ant or other works used for the purpose
of treating, stabil izing, or holding wastes.
12. l\ lastes" means sewage, Industrial wastes, and all other liquid
gaseous, sol id, radioactive, or other substance which may
pollute or tend to pollute any waters of the state. The term
" wastes · ' does n, ot include agricultural irrtg.; Jtion and drainage
waters for which water quality standards shall have been es-tablished
pursuant to this article. ' ,
13. " Waters of the state" means all waters within the jurisdiction
of this state including all streams, perennial or intermittent,
lakes, ponds, impounding reservoirs, marshes, watercourses,
waterways, wei Is, springs, Irrigation systems, drainage systems,
and all other bodies or accumulations of water, surface and underground,
natural or artificial, pubi Ic or private, situated wholly
or partly.• ithln or bordering upon the st~ te.
The following terms and symbols which appear in this document are defined
as follows:
' 14. " Biocidell means a material appl ied to plants or soil as a growth
regulator or pest control agent. These include, but are not
1imited to, insecticides and weedicides.
. 0
15. " BOD II means the 5 day arithmetic average of the 20 C biochemical
oxygen demand in mg/ l as determined by the method described in
the current edition of Standard Methods of Examination of Water,
SewaQe and Industrial Wastes. . ,
16. " Eutrophication" means the enrichment of a body of water by the
addition of nutrients that stimulate aquatic growth which may
cause taste, odor and esthetic problems.
17. l'mg/ I" means mi 11 i grams per liter of water 0
18. lIMilJequivalents per I iter" means the concentration of an ion in
mg/ l divided by the equivalent weightc
190 " ppmll means parts per mill ion parts of water by weight. This
term is being replaced by the more popular term mg/ I iter although
the two terms are nearly equivalent.
20, " Fecal Col iform" means those bacteda of the col iform group commonly
found in the intestinal tract of warm blooded animals.
21, IIPrimary contact recreation waters" means waters in which body
contact with the water is made such as swimming and water ski~ ng.
22. IISecondary contact recreation water" means water in which only
minor body contact with the water is made such as fishing and
23. " Cold water fishery" means waters having an environment suitable
for salmonlds.
24. l'Warm water fisheryll means waters having an environment suitable
for species of fish other than salmonids.
25. IlColorado River ll
, IIColorado River Systemll , and IIColorado River
Bas in II; these terms a re used interchangeab Iy throughout the
document. They are meant to include all waters within the
Colorado River Basin with the exception of the Gila River
Drainage. Comments specific to a given portion of the basin are
so identified by using the name of the tributary, reference to
the main stem or other appropriate designation.
26. I'Gila River ll , " Gila River Systemll , and Gila River Basin ll; these
terms are used interchangeably throughout the document. They
are meant to include all waters within the Gila River Basin.
Comments specific to a given portion of the basin are so identified
by using the name of the tributary, reference to the main
stem or other appropriate designation.
This Water Qual ity Control Policy appl ies to all waters of the State. This includes
both interstate and intrastate waters. Interstate waters are identified
for the convenience of the Federal Water Pollution Control Administration.
These standards are Federal standards as well as State standards for interstate
streams upon approval by the Secretary of the Interior.
Dam Site
Dam Site
Waters Controlled
Gene. ra 1 ~,
Article 6
Part 2
Imperial Dam
Laguna Dam _,
Gi'~. Y ,,' l.' pa- i'; ted
Yuma - Rock Dam
~ orelos Dam
°£ ltH.....
~ r]~
y J. h' ... I) t~ ...
I) q ...
MEX ICO 8OiJl)~.... I
Existing Dams .......... \ Charleston Dam Site
Proposed Dams ......... ........ sl.'. N_ oj: l~ . L-
- 1-
6- 2- 1.1
B. Little Colorado River from the New Mexico- Arizona border to its confluence
with the Colorado River.
A. Colorado River from the Utah- Arizona border to the southerly international
boundary with the Republic of Mexico.
C. Virgin River for the entire reach within the State.
D. Chinle Wash from Its source to the Utah- Arizona horder.
E. East main canal from its source to the Arizcna- Mexico border.
F. GTla River from the New Mexico- Arizona border to Ashurst- Hayden Dam.
G. San Francisco River for the entire reaches within the State 2
H. San Pedro River from the Mexico- Arizona border to its confluence with
the GIla River.
I. Santa Cruz River from the Mexico- Arizona border to its confluence with
the GiI a Rive r.
There are several minor basins within the State that are not with 1 the
Colorado River BaS!: l2 Thzsa include the Willcox Playa and several m . i · . I;
drainages along th~ Arlz~~ a- Mexico border. They fall within the clef nition
of the waters of the State and are controlled by this document.
- 2-
Palo Verde Diversion Dam, which also has essentially no storage, is used
to divert water just north of Blythe, California, for irrlgatio!' kin;.- the Palo
Verde Valley of California. While there are some minor drainage returns to
Water released from Hoover Dam flows into Lake Mohave behind Davis Dam which
is located just north of the Nevada- Cal ifornia boundary. Lake Mohave is used
for re- regulation of releases from Hoover Dam. Hydroelectric power is generated
at Davis Dam.
Proceeding downstream, Headgate Rock Dam, located near Parker, Arizona, is
used to divert water for irrigating the lands of the Colorado River Indian
Reservation in Arizona. There is essentially no storage behind this dam,
and no hydroelectric power is generated. Some returns from drainage of the
reservation lands reach the Colorado River north of Palo Verde Diversion Dam,
but the principal drain empties into the river south of this dam.
6- 2- 2
Enroute to Lake Powell, river waters in the Upper Basin ( that portion upstream
of Lee Ferry) are diverted, used, and returned to the system. The
major such diversions and returns are regu! ated by control structures which
are operated under the United States Department of the Interior, Bureau or
Reclamation. Many of the Bureau1s authorized projects in the Upper BasJnremain
to be constructed, and many existing projects are not yet fully developed.
Waters released from Glen Canyon Dam flow in the main stem to Lake Me~ a
which is located behind Hoover Dam. Lake Mead provides most of the storage
and regulation in the Lower Colorado River Basin. Hydroelectric power is
generated at both Glen Canyon and Hoover Dams. Lake'Mead will serve as the
supply reservoir for the Southern Nevada Project. Return flow from the
Southern Nevada Project will reach Lake Mead through Las Vegas Wash.
A. The Main Stem of the Colorado River: The gross watershed of the
Colorado River encompasses portions of the states of Wyoming, Colorado, Utah,
New Mexico, Arizona, Nevada, and California, as shown on Plate I. The upper
portions of the watershed are drained by the Green, Colorado, and San Juan
Rivers. These main tributaries in turn flow into Lake POlell, which is located
behind Glen Canyon Dam near the Utah- Arizona boundary. Flows of these
major tributaries into Lake Powell provide approximately 90 percent of the
total waters available to the lower main stem of the Colorado River. The
average annual undepleted flow of the Colorado River is approximately 15 mill
ion acre- feet.
Water released from Davis Dam crosses the Nevada- Arizona- Cal ifornla boundary
and flows through the broad Mohave Val ley for 33' mi les before reaching
the upper end of Lake Havasu. Lake Havasu, which is a widened portIon of
the Colorado River behind Parker Dam, is about 45 mIles In length. The
Metropolitan Water District of Southern California diverts water from Lake
Havasu for transport to the coastal regions of Southern California. The
Central Arizona Project plans to divert water from Lake Havasu for transport
to Central Arizona. Hydroelectric power is generated at Parker Dam,
the Colorado River from Palo Verde Valley along the adjacent reach, the predominate
farm drainage ret:. Jrns from Palo Verde Val ley are via Palo Verde
Lagoon- Outfall Drain at the most southerly end of the Valley.
Cibola Valley, on the Arizona side, is located near the southern tip of
P210 Verde Valley. River water is pumped into Cibo! a Valley for irrigation.
Imperial Reservoir is located behind Imperial Dam, approximately 15 miles
north of Yuma, Arizona. Imperial Dam is the major diversion structure for
irrigation projects in the Imperial and Coachell Valleys and Yuma areas.
Releases made to the mainstream below Imperial Dam are essentially for the
purpose of satisfying treaty obligations with the Republic of Mexico. There
is only minor river w~ ter st~ rage behind Imperial Dam. No hydroelectric
power is generated.
Senator Wash Dam and Reservoir are located on the California side of the
Colorado River immediately upstream from Imperial Dam. The reservoir provides
offstream regulatory storage a~ d has a maximum available capacity of
12,250 acre- feet. To provide regu1ation; water is either pumped from the
Colorado River int(, the reservoir or released back to the river. t · ! ater released
from the reservoir generates hydroelectric power. The Bureau of
Reclamation estimates that d~ proximately 170,000 acre- feet of water can be
saved an~ uaiiy by short- term storage of releases from upstream dams in excess
of downstrem requests for water deliveries.
Laguna Dam, which is locat~ d about six stieam miles below Imperial Dam,
serves as somewhat of a foundation support for Imperial Dam. There is a
storage capacity of 1,500 aCie- feet behind Laguna Dam. Ability to util ize
this storage and to fluctuate the water leve1 at Laguna Dam is essential to
mov~ ment of sediment downstream from~ e sluiceway channel at Imperial Dam and
for operational contioI of the river. The area between Imperial and Laguna
Dams serves as a depository for silt removed by the desilting works at Imperial
Dam. The importance of this desilting operation is covered in Reg. 6- 2- 3.5.
The routing of water diverted from Imperial Dam and measured surface return
flows to the Colorado River between Imperial Dam and the Republ ic of
MexIco Boundary is difficult to describe verbally, and is better explained
schematically in Plate 2.
Waters reaching Morelos Dam, just south of the Northerly International
Boundc, y with the Republ ic of Mexico, are diverted into the Mexicali Valley
for domestic, irrigation and other beneficial uses.
INTO THE OCEAN. The management afforded by the present system of storage
reservoirs permits delivery of the highest quality water now economically
possible considering that the supply is fully utilized. Water will be wasted
to the ocean only after all of the upstream reservoirs are filled to storage
capacity and all beneficial uses have been satisfied~ This condition is not
anticipated in the foreseeable future.
B. Tributaries to the Colorado River frem Arizona: There are numerous
tributaries to the Colorado River frem Arizona in the 700 river miles between
- 4-
~ Trlbutaries discussed in REG. 6- 2- 2.18
AREA: 110,000 Sc:. MI.
GROSS BASI~ AREA: 242,000 Sq, Mi
AREA' 132,000 Sq. Mi.
Gravi ty Main Canal
° 1...
....::: t l
r- l l _____ _' l _
Southerly International Boundary
I--~ ll'--,-..--~ YUMA PROJECT
- - I LAClJNA DAM I I
I~-~~ II--: N~ ort~ G~ la_ V~ l. l~ y__ ~ I I
I ..,~~ t~ Gil':.., Vall~ y J 1
I 79, 0 j[ a1I. te:! iBy' Retu. rns_ _ _ _. J I
I AF , v 39,480 AF I
I '_ W~ l.! O~ M~ h~ W!:. D. E. a~ n..?° 2,] C2.° fl
I Gila River ~ I \.....-:::.::::.::.....:.:.::...:..=.~----
L.-_-..-.... J l
t. 2l2.5~ 0_ AF
All American Canal
-- -.> Measured surface return flows
-~>~ Diversi. ons
Northerl~ Interna~~ onal Bou_ nEa~ ry~_
Alamo Canal
Page ( Glen Canyon Dam) and Yuma. A brief description of the significant
5tre~ ms follows, and available specific data on quantity and quality of
water co~ tributed appears in Exhibit I where appl icable. The Total Dissolved
Sol ids ( TDS) change given for each tributary is for present conditions.
As the flow from the Upper Basin decreases, the effect is expected
to increase by up to one- third from each tributsry.
J. Paria River - The paria River joins the Colorado River just
downstream of the Lees Ferry USGS gaging station. The river flows through
remote country from southern Utah. The water has a high mineral content, but
is relatively free of other contamination. The TDS load at the Colorado River
is increased less than 2 mg/ l by flow from this tributary. ( See ExhibH. 1)
2. Little Colorado River - The Little Colorado River joins t~ e
Color<: ldo River about 55 miles below Lees Ferry. The river essentially starts
in eastern Arizona near Greer, although there are some minor intermittent
flows in creeks from New Mexico. The water has a medium to high sali~ ity,
depending on the flow rate. A major problem is the contribution of salts
from Blue Springs, about 13 miles upstream from its mouth on the Navajo
Indian Reservation. These springs contribute about 547,400 tons of salt per
ye& r to the Colorado River. The TDS load of the Colorado River is increased
by about 28 mg/ l by this tributary, with about 20 mg/ l attributable to the
Blue Springs. "( hiS p,') ble" l'j ~! j being investigated at the present time by the
Arizona Interstate Stream Commission. ( See Exhiblt 1)
3. Bright Angel Creek - The Bright Angel Creek enters the Colorado
River from the north in Grand Canyon National Park. The flow is most~ y from
springs near the North Rim of the Grand Canyon, and. the qual ity of the water
is good. The TDS ioed of the Colorado River 1s decreased abo~ t one ( 1) mg/ l
by the dilution effect of t~ is tributary. ( See Exhibit 1)
4. Tapeats Creek - Tepeats Creek is fed by springs on the north side
of the Colorado River in the northwest portion of Grand Canyon National Park,
a very remote and primitive are<: l. The meager data indicate the discharge is
of io~ mineralization, and the dilution would reduce the TDS load of the main
stem ~ tow of the Colorado River by about 2 mg/ l. ( See Exhibit 1)
5. Kanab Creek - Kanab Creek has a drainage area of about 1,600
square miles, of which about 1,000 square miles is in southern Utah. The
river crosses the border between Kanab, Utah, and Fredonia~ Arizona. The
water 1s fairly high in mineralization; but the total flow is relatively
small. The TDS Toad of the Colorado River is increased less than one ( I)
mg/ 1 by this tributary. ( See Exhibit 1)
6. Havasu Creek - Havasu Creek drains the Coconino Plateau south of
the Colorado River and enters the river about 13 miles downstream from Kanab
Creek. This is a remote area, and is inhabited by the Havasupai Indians.
The very meager water flow and qual ity data indicate good quality water of
low mineral ization. · The TDS load of the Colorado River Is decreased by about
0.5 mg/ l by dilution from this tributary. ( See Exhibit J)
7. Virgin River - The Virgin River begins in Utah, and flows into
Arizona near LlttJefield, then into Nevada near Mesquite p and then into Lake
- 5-
Mead. The Virgin RIver contributes about 350,000 tons of salts per: year to
the Colorado River System, and the quality of the water Is extremely poor.
The TDS load of the Colorado River is increased 14 mg/ l as a result , of this
tributary. See Plate I and Exhibit I for 10catiAn and details. It appears
that one major source ( abo~ t one. fourth) of these ~ alts is LaVerkin Springs
( Dixie Hot Springs) in southern Utah upstream from St. George. Other specific
sources are not known at this time.
8. Bill Will iams River - The Bill Villiams River discharges into Lake
Havasu just above Parker Dam. The river is erratic In flow since it drains a
desert area ~/ ith sparse rainfall. Flash floods Dre commonplace, and these
are controlled by Parker Dam, and will be further controlled by the. Alamo Dam
now under construction about 35 miles upstream from the mouth of the river.
There is some irrigated < Jcreage in this project. Ha~: er Poilution Surveil1ance
System ( WPSS) data on water quality near the Alamo Dam site between October
1963 and October 1964 indicates that the TDS of the Bill Villiams water is
wit~ in the range of 535 to 698 mg/ l, or less than that of the Colorado River
arriving at Parker Dam.
9. Gila River - The Gila River joins the Colorado River just upstream
of Yuma, and below Laguna Dam. rne Gila River is now almost completely
controlled by upstream dams, and the water is complete~ y utilized, often
many times, Floodwaters have never exceeded the present capacity of the
Gila Rives storage system upstream of its confluence vJith the Salt River and
floodwaters have exceeded the capacity of the Salt- Verde System only twice in
the last 25 years. Painted Rock Dam, northwest of Gila Bend, is. the final
flood control structure on the Gila River, and has onlY been usea once since
completion in 1959. During calendar year 1964, only 103 acre- feet of water
fiowed past Dome, 12 miles up5tream from the mouth of the Gila River near
Yuma, and all of this flow originated downstream of Painted Rock Dam~
10. Other trib~ taries - There are many small streams that flow for a
short period of time after rainstorms, but the flow is so intermittent that
very 1ittle data is available on total flow and water quality~
Many small springs and sprlng · fed tributaries, mostly in the reach
between Glen Canyon Dam and Lake Mead, contribute small quantities of water
and dissolved salts. Since most of these tributaries are in very remote
uninhabited areas, very little data on them is available. The data that
is available is shown in Exhibit 1.
There are seme intermittent creeks flowing from Arizona into Utah,.
above Glen Canyon Dam, and ultimately these may reach the San Juan or Colorado
Rivers. Most of these streams are in remote areas of the Navajo Indian Reservation.
C. Tributaries to the Colorado River from Utah: In addition to tributar ·
ies to the Main Stem of the Colorado River upstream of the Utah- Arizona border,
there are several streams that cross the Utah- Arizona border and flow through
Arizona before reaching the Colorado River. The significant ones are as
1. Paria River - This river is covered in Reg. 6- 2- 2.1 B under
Arizona tributaries.
- 6-
The construction of dams on the Colorado River and its tributaries,
3. Virgin River This river is covered in Reg. 6- 2- 2.1 B under
Arizona tributaries.
1. Virgin River - This river is covered in Reg. 6- 2- 2.1 B under
Arizona' tributaries since it flows through the northwest tip of Arizona.
- 7- liB RMrA;~~~ dlIVES
The area is essentially semidesert, and stream flows are intermittent. Although
rainfall is sparse in this area, the intensity of rainfall may be great
when it occurs, and flash floods have occurred. Flow. and quality data is almost
non- existent.
F. History of the Colorado River Basin Development: The history of the
development of the Colorado River Basin is important to the consideration of
water qual ity.
2. Kanab Creek This creek is covered in Reg. 6- 2- 2.1 B under
Arizona tributaries.
2. Las Vegas ~/ a5h - Las Vegas Uash drains the Las Vegas Valley and
flows into Lake Mead just above Hoover Dam. Although the present flow is
not great ( about 15,000 to 20,000 acre- feet per year), the salt burden is
high, and the flow is expected to increase severalfold upon completion of
the Southern Nevada Project. The TDS load of the Colorado River is increased
about 4 mg/ l by this tributary at the present time.
D. Tributaries to the Colorado River from Nevada: There are a few tributaries
to the Colorado River along the common Nevada- Arizona border. The
significant ones are as follows:
E. Tributaries to the Colorado River from California: The area within
Cal ifornia which drains naturally to the Colorado River is a narrow strip of
land varying in width from about 10 to 40 miles. This strip extends from the
Nevada- Cal ifornia border to the Cal ifornia- Mexico boundtiry.
1. General History - Irrigation development of the Colorado River
Basin started with the beginning of settlement about 1860. The Upper Basin
( above Lee Ferry) irrigated about 800,000 acres by 1905, and about 1,400,000
acres by 1920. Development slowed down after 1920 because of both physicai
and economic 1imitations in the availabil ity of water. In the Lower Basin
Irrigation began in the Palo Verde Valley in 1879, and development of the
Yuma area and Imperial and Coachella Valleys followed. Irrigation on the
Colorado River Indian Reservation was attempted In 1870, but Inadequata f! c~ d
control almost stopped this development until 1942.
Early development of river control centered around the agricultural
economy of the area. The river flow was very erratic and undependable.
Tremendous floods occurred in the Lower Basin around the Yuma area when both
the Colorado and Gila River Systems reached high flow stages. The Colorado
River carried huge silt loads, and led to the statement that the Colorado
River was IItoo thick to drink and too thin to plow". The salt burden was
low at high flow, but very high when the fl~ 1 was low.
especially the Gila, Salt, and Verde Rivers, brought the river under control,
reduced the silt load, evened out the salt burden, and made agricultural operations
in the Lower Basin stable.
This development of the Colorado River has had considerable political
prob~ ems, and further development, including quality control, will have some
more political and legal problems.
2. Water Compacts and Treaties - The development of the Colorado
River has necessitated a number of compacts and treaties to protect the rights
of individuals and states to the use of water. The following are certainly
important when considering water quality criteria that could affect water use
under existing rights.
a. Colorado River Compact - The water of the Colorado River was
divided between the Upper and lower Basins by the Colorado River Compact of
1922, with the division point at Lee Ferry. The compact recognized the potential
obligation of the United States to the Republic of Mexico.
b. Mexican Treaty - The treaty with Mexico, signed in 1944, provides
for annual delivery by the United States to Mexico of 1,500,000 acrefeet
of Colorado River water, with certain exceptions due to river flow conditions.
c. Upper Colorado River Basin Compact - This compact of 1948
apportioned the waters of the Upper Basin states ( including 50,000 acrefeet
to Arizona annually) to all~~ for orderly and proper development of the
I1rper Basin.
d. Boulder Canyon Project Act - This Act of Congress apportioned
the waters of the Lower Basin among the Lower Basin states and was subsequently
interpreted by the United Sta~ ei Supreme Court in Arizona v. Caiifornia, 373
e. Water Quality - None of the agreements or compacts have specifically
mentioned water quality. The treaty with Mexico provides that Mexico
will take from any and all sources •••• whatever their origin, the waters to
which she is entitled. Water quality is recognized as a factor to be considered
in recent legislation authoriZing the construction of projects in the
G. Diversions of Water Along the Arizona Reach: Major United States projects
divert and use water frcm the Colorado River along the Arizona reach. A
description of these diversions, by states, follows, and data is summarized i~ l
Exhibit 2.
1. Arizona Projects:
a~ City of Page - Page receives its municipal water supply from
Lake Powell. Sewage is treated in sewage lagoons with minor effluent return
to the Colorado River.
b. Colorado River Indian Reservation - This project has 99,375
- 8-
acres in Arizona with assigned water rights as set forth in Arizona vs.
California Supreme Court Decree, and about one- third is presently being
irrigated by diversions at Headgate Rock Dam. About 60% of the water diverted
is returned to the river as measured surface return flows. In addition,
there are unmeasured surface and sub- surface returns to the river.
c. Yuma Project. Valley Division - About 52,000 acres in this
project are served by diversion at Imperial Dam via the All American Canal
to the Yuma Main Canal by a siphon under the Colorado River. A portion of
the water diverted passes through measured surface drains and wasteways
back to the Colorado River south of the Northerly International Boundary
or to Mexico over the Southerly International Boundary near San Luis,
Sonora. Additional drainage facilities are needed in portions of the
valley, particularly in the area adjacent to the mesa.
d. Gila Project - ~ ater is diverted at Imperial Dam via the
Gila Gravity Main Canal to service an authorized project area of 115.000
acres. This project consists of the following units:
1. North Gila Valley Irrigation District
2. Yuma Mesa Irrigation and Drainage District
3. Yuma Irrigation District ( South Gila Valley)
4. Wellton- Mohawk Irrigation and Drainage District
Surface drainage from the Gila Projects is returned to the Colorado
River above the Northerly International Boundary except that the WelltonMohawk
drainage facil ities include a bypass channel which extends past Morelos
Dam. This bypass channel was put into operation on November 16, 1965, and
the Mexican Government has the option of deciding whether the drainage waters
shall be discharged above or below Morelos Dam. About 30% of the water diverted
is returned to the river as measured surface drainage or control water.
e. Yuma Auxiliary Project - Water is diverted at Imperial Dam via
the Gila Gravity Main Canal to irrigate 3,406 acres in this project, which
includes certain \ Jarren Act Lands. There is no measured return flow.
f. City of Yuma - The City of Yuma presently receives most of
its water through the Yuma Main Canal. The cityls contract with the Secretary
of the Interior provides for del ivery of the water from the river.
Sewage from Yuma is now discharged untreated to the river north of the
Northerly International Bou~ dary, but plans are progressing for a sewage
treatment plant.
g. Cibola Valley - v! ater is pumped from the Colorado River for
irrigation of the Cibola Valley.
h. Central Arizona Project - V'hen authorized and built, this
project will divert water frcm Lake Havasu to provide much needed supplemental
water for domestic, industrial and agricultural purposes in Central
Arizona. There will be no return flows from this project. The economic
impact and importance of this project is discussed in Reg. 6- 2- 2.1 H.
I. Fort Mohave Indian Reservation - This project has 14,916 acres
- 9-
in Arizona with assigned water rights as set forth In the Arizona vs.
California Supreme Court Decree.
J. Miscellaneous Diversions - These include domestic, agricultural
and industrial waters, and consist of direct diversions or by ground\
llater pumping in the vicinity of the Colorado River. 1, Iater is used by
cities, recreational centers, small farms, power plants, etc.
2. Nevada Projects: The Southern Nevada Project is authorized to
from Lake Mead, 300,000 acre- feet of water for use in the Las Vegas
The water will be used for domestic, agricultural and industrial pur-
The Bureau of Reclamation anticipates a return flow of approximately
acre- feet of water to Lake Mead annually.
3. California Projects:
a. Metropol itan Water District of Southern California - The
Metropolitan Water District aqueduct provides capacity for th~ annu~ l diversion
of 1,212,000 acre- feet of water for domestic, industrial and agricultural
use on the coastal plain of southern California. Th~ re is essentially
no return flow.
b. Palo Verde Irrigation District - About 900,000 acre- feet of
water is diverted annually at Palo Verde Diversion Dam near Blythe for agricultural
purposes. Approximately 60% is returned to the Colorado River
either as measured surface drainage or excess diverted water, mostly in a
main drain at the lower end of the project.
c. Imperial Irrigation District and Coachella Valley County
Water District - Approximately 3,500,000 acre- feet of water is diverted
annually at Imperial Dam via the All American Canal for various uses within
the Districts. There is no return flow ( other than seepage from the All
American Canal and flow r. egulation water) to the Colorado River. Agricultural
drainage water, canal seepage, and any excess water diverted flows to the
Salton Sea in Cal ifornia.
d. Yuma Project, Reservation Division - About 96,000 acre- feet
of water is diverted annually at Imperial Dam via the All American Canal for
agricultural use in the Bard Valley. · A portion is returned as drainage and
flow regulation water to the Colorado River between Yuma and the Northerly
International Boundary.
H. Economy and Natural Resources of Arizona: The economy of the entire
State of Arizona is intimately associated with the development of the
Colorado River, Arizona is semiarid in character with a low average annual
rainfall and limited natural water supplies. Since 1947, the population of
the State has more than doubled, with more than 7~ 1o of the population residing
in Maricopa and Pima Counties. These two counties, along with Pinal
County, comprise the core area of the Central Arizona Project. This area
is now supplied with water by surface water systems on the Salt, Verde and
Gila Rivers and by pumping fram the groundwater basins. The agricultural,
domestic and industrial users of this area are consuming all of the surface
water available and are pumping approximately 3,000,000 acre- feet, of water
- 10-
per year more than the natural groundwater replenishment. This annual overdraft
is clearly evidenced by the accelerated decline of groundwater levels
and by land subsidence in some areas.
The central Arizona area desperately needs the additional water to be
delivered by the Central Arizona Project Aqueduct from Lake Havasu, but the
supply available is still far short of the present overdraft, and the needs
of the area are still growing. The quality of the presently available water
is not always good with respect to its salt content. This qual ity is further
degraded by multiple reuse since almost all beneficial uses of water
add salts of some variety to the water.
The remaining areas of the State face simi1ar problems of short supply
and/ or quality of water, and it is impossible to separate these factors
completely in any proposed program of supply or regulations on quality.
The total problem can only be solved by a major water augmentation program
for the Lower Colorado River Basin.
The people of Arizona have been strivinq to improve the quality of their
water and extend the supply for many years. long before a Federal program
for pollution control was initiated. The quantity of water available has
been extended and the quality of the water has been enhanced by the following
practices and programs.
1. Farming practices have been steadily improved so that less water
is app1 ied to the land per unit of crop yield. A report on this phase of
water conservation and qual ity enhancement is appended as Exhibit 11.
2. Del ivery systems for both surface and groundwater have been improved
through redesign, lining and conversion to pipe1 ines to reduce seepage,
evaporation, salt pick- up, consumptive use by non- crop plants, and
delivery waste. Statistics on past and future programs are presented in
Exhibit 12.
3. Extensive watershed planning and control programs have been
initiated to increase the yield and improve the qual ity of water del ivered
by the surface water systems. The Arizona Water Resources Committee, representing
wildlands, banking, ranching, water authorities, timber, irrigation,
power, mining, game and recreation and municipal ities, has an annual symposium
( 10th in 1966) to present and discuss experimental results and plan
larger scale experiments. A summary of watershed improvement accomplishments
and future programs is appended as Exhibit 13.
4. Means of evaporation control or reduction of evaporation on reservoirs
and streams have been investigated since evaporation of water from the
surface of reservoirs and streams not only reduces the supply but also increases
the salt content of the water remaining. A summary of activities
in this field is presented as Exhibit 14.
5. Extensive phreatophyte investigation and control programs have
been carried on to eliminate or reduce waste by certain types of vegetation
growing in or near streams. Evapotranspiration by these pJar. t5 concentrates
salts in the soils and contributes to the salinity problems of
- 11-
the bas In; so reduct ion of such growth wou Jd enhance water qua 1ity. A summary
of the phreatophyte control program is presented in Exhibit 15.
o. Programs to supply water of the best available quality for domestic
needs in exchange for treated sewage effluents for needs with lesser
quality requirements are being studied. Other water exchanges have been
implemented between areas of need and surplus, and more are needed. Examples
are presented in Exhibit 16.
7. Buckeye has been a pioneer in providing desalinized water for
domestic use. An expensive electrodialysis process was put in operation in
1962 to remove excessive salts from the only water available to the community,
making Buckeye the first town in the U. S. A. to have its entire water
supply treated by a demineral ization plant. This was a local community
program, and no Federal or State funds were involved in this project. A
report on this project is presented in Exhibit 17.
It should be pointed out that all of the currently available methods
of desalinization separate the influent water into two streams, one relatively
pure, and one very salty. Disposal of the salty brine is a problem
for ~ n area isolated from the oceans where most of the desalinization programs
are promoted and tested.
8. The Arizona ! later and Pollution Control Asso: iation meets annually
( the 40th annual meeting was held in 1967) to he~ r and discuss papers presented
by both local and out- of- state people involved in water supply and
disposal problems. Educational programs are sponsored by the Association
along with other progra, TIs designed to upgrade the quality of Arizona water.
The Association is affiliuted with the I{ ater Poliution Control Federation
and the American Water Works Associationa A report of the Association is
included in Exhibit 18.
9. The Soil Conservation Districts of Arizona, both individually and
through their Association, have been actively engaged in projects aimed at
soil and water conservation and water quality improvement. A summary report
of the Association is presented as Exhibit 19.
10. River channelization projects in the lowe~ Colorado River below
Hoover Dam have been in progress for several years by the Bureau of Reclamation
to reduce consumptive losses, ercsion and quality degradation. This
work is generally opposed by fish and wildl ife interests alleging it destroys
natural habitat areas. Stabilized river flow and storage impoundments m3ce
possible by dam construction have, however, enhanced some fish and wildlife
I. Natural R~ source Values to be Protected: The following natural
resources of Arizona, although presently utilized effectIvely through good
management practices, shall be protected by Arizona1s water quality control
pol icy, and the tabulation is not inter. ded to designate the order of importallce:
1. Agriculture - Arizona1s principal crops ( alfalfa, citrus, cotton,
gr~; ns, and vegetables) are grown on 1,160,000 acres scattered around the
- 12-
State, with some additional acreage for minor crops. Almost all of this
acreage is dependent on irrigation, and over 300,000 acres in addition to
that stated above are out of production due to water shortage. Growing conditions,
and particularly climatic conditions, are well adapted to crop production
under irrigation on a year- round basis, and ma~ y high value crops
such as cotton, winter vegetables and citiuS fruits are produced in addition
to staple crops and feeds. The gross value of Arizona crops was
$ 344,400,000 in 1965. The continued production of these crops is dependent
upon our total water resources in Arizona, considering both quantity
and quality. The quantity of flow must not be unnecessarily reduced by
unrealistic qual ity considerations. Statistics on various phases of agriculture
are shown in Exhibit 3c
2. Urban Development - Urban development of Arizona has been growing
rapidly, and this growth has demanded increased recognition of the
need for a dependable supply of good quality water. Although the growth
has been highest in the Phoenix and Tucson areas, there has also been considerable
growth in cities adjacent to the Colorado Rivero An inventory
of cities along the Colorado River with pertinent water supply and disposal
data is shown in Exhibit 4. The growth of urban arens has accompanied
increased activity in tourism ( due to climate, recreational facilities
and natural attractions), manufacturing and service industries Tor
all State activities, including but not limited to agriculture, construction
and miningo Manufacturing statistics are shown in Exhibit 5.
3. Grazing and Livestock Feeding - T~ is indust; y is extensive in
Arizona, including the area along the Colorado River. The gross value of
1ivestock and products was $ 237,900,000 in 1965. Livestock production requires
water and also produces waste which must be controlled. Statistics
are included in the Agricultural Exhibit 3.
4. Mining Industry - There are only limited mining operations along
the Colorado River, but mining is a major factor in the economy of Arizona
and this industry requires huge quantities of water. Reuse of water in all
phases of mining has been practiced Tor many years, and pollution oT streams
has not been a major problem. The minor problems are being corrected.
The gross value of mineral production was $ 580,170: 000 in 1965. The
principal metals were copper, gold~ silver~ lead and zinc, but subs~ ntial
quantities of sand, gravel, molybdenum, stone, uranium, lime, pumice and
other miscellaneous minerals were produced. Copper produced ahout 86% of
the total value. Statistics 8ie shown in Exhibit 6,
5. Fish and Wild; ife - Although much of Arizona is arid or semiarid,
the State is blessed with fish and wildl ife resources. Protection of this
important natural resource is vital in the development of the Basin's water
resources. Over 3,400,000 man- days of fishing and hunting were enjoyed by
Arizona sportsmen during 1965. Additional man- days of hunting and fishing
were enjoyed on the Colorado River by 1icense holders of adjacent states.
The Colorado River provides excellent feeding and resting areas for migratory
waterfowl, particularly in those portions of the river where oxbows
and sandbars exist. Additional value is created by shoreline vegetation
which provides habitat for numerous species of mammals and birds.
- 13-
Both the State and Federal Government have responsibilities under
existing Jaw to preserve and develop the fish and wildlife resources of the
Colorado River, and cooperation among the states is vital and necessary.
The Federal Government by virtue of existing treaties with Great Britain
and Mexico, is responsible for management of the nation's migratory bird
resource. This responsibility is implemented along the Colorado River by
the Bureau of Sports Fisheries and Wlldl ife of the U. S. Fish and Wildlife
Service. Both National and State Wildlife Refuges have been established to
preserve waterfowl wintering habitats.
The natural habitat has been constantly changing since the area was
settled by man. A significant portion of the habitat no longer exists due
to river control and land development, and the wildlife has decreased ·
accordingly in species and numbers. Channelization and controlled flows
have eliminated many of the productive backwaters, bypasses, and oxbows
that served as spawning and nursery areas for warm water fishes, and have
reduced angling potential for these species.
In contrast, the vast reservoir storage system created by the construction
work of the Bureau of Reclamation has virtually el iminated flood
fiowz, reduced turbidity, and lowered summer water temperatures so that
extensive reaches of the Colorado River are now more suitable for trout.
Fish are supplied by a National Trout Hatchery at Willow Beach and by the
three State Game and Fish Departments involved in the Arizona reach of the
Colorado River.
6. Recreational Use - In addition to the natural recreational resources
in Arizona, the controlled river flows resulting from the operation
of dams and related water projects have created stable recreational resources
in the Colorado River. For the most part, this recreational potential still
remains to be developed. Stable water impoundments behind the dams attract
fishermen, boaters, water skiers, campers and persons interested in being
near the attractive water during the pleasant fall, winter, and spring seasons.
Recreation is a year- round activity, however.
Pub) ic recreation is permitted on substantial portions of the accessible
land along the Colorado River from the Utah- Arizona border to the Mexican
border. There are numerous public forests. parks, marinas and other points
of int~ rest not only to residents of the adjacent areas, but also to national
and international visitors. The major facilities are listed in Exhibit 7.
It is difficult to determine the overall recreational use of the
Colorado River because of the variety of developments spread out over the
745 mile reach of the river in Arizona. The recreationists who come on
peak weekends for special events in seme sections jam commercial and publ ic
facilities and overflow onto every available piece of land along the river.
Somewhat uncontrolled use has occurred on other reaches of the river and
adjacent lands. Individuals and commercial interests have moved onto the (
Federal lands, and have built structures varying from shacks to well- estab-
1ished motels, trailer parks, fishing camps, and resort developments.
Recreational use of the river has created seme serious pollution prob-
- 14-
lems because of the lack of adequate sanitation facilities. Adequate facilities
will have to be provided, and the recreationists themselves are going
to have to cooperate in making the river areas safe and esthetically enjoyable
Recreational use of the Colorado River area will expand along with
the population growth in the contributing metropol itan areas and as the
physical features are developed. The major recreation objective will be
reached if the quantity and qual ity of water are maintained, and the
esthetic vaiues of the area are preserved.
7. Forest Products Industry - The four mill ion acres of commercial
forest land, out of the total of 21 miilion forested acres in the State, are
largely situated in the northern, higher altitude areas. Managed for
multiple use the commercial forest area provides not only timber, but has
important values for water production, recreation, 1ivestock, forage, and
wildl ife. Arizona's forest lands playa big role in providing water to the
consumer. Much of the surface water consumed annually originates within
the State as runoff from the relatively high water- yielding forest.
The forest industry in Arizona annually harvests about 66 million
cubic feet of sawtimber and produces in excess of 300 million board feet
of lumber. The pulp and paper segment annually uses 100,000 cords of
pulpwood and chips from sawmill residual equivalent to an additional
150,000 cords. It produces about 150,000 tons of newsprint and kraft
1inerboard annually. The paper industry requires a significant quantity
of good qual ity water.
J o Water Qual ity Considerations: THE QUALITY AND QUANTITY FACTORS OF
THESE PARAMETERS. Typical main stem flows, major diversions and return
flows are shown along with pertinent salinity data on Plate 3 for reference.
The Colorado Basin States Conferees, in drafting the Guidel ines for Formulating
Water Quality Standards for the Interstate Waters of the Colorado
River System*, recognized that water quality standards could drastically
restrict present and future uses of the Colorado River water under existing
compacts. The following data on the qual ity of water in the Arizona reach
of the Colorado River is presented to provide the basis for stream standards
1isted in Sec. 6- 2- 6 of this Water Quality Control Policy for the Colorado
River in Arizona:
1. Qual ity of ~ ater Reaching Arizona - Historically, the water
reaching Arizona in the Colorado River at Lees Ferry has been high in both
salt and silt burden. Other pollutants have been negligible. The sal inity
has been steadily increasing due to both increased use in the Upper Basin
and to depletions by trans- mountain diversion of the best quality water
near the headwaters of the Colorado River. The quality of the water at
Lees Ferry has been monitored diligently by the USGS, and excellent published
records for the 1941- 1964 period are available for comparison with
other stations on the Colorado River. The Total Dissolved Sol ids ( rDS) in
milligrams per liter ( mg/ l) is probably the best single parameter defining
the quality of the water.
* See Exhibit 20
- 15-
Examinatio~ of the record indicates a wide variation in daily, weekly,
monthly and yearly figures for TDS. and any water quality standards
proposed will have to recognize this feature. In gener. al, the TDS is low
at high water flows and high at low water flows. This variation is discussed
under sources of salinity. Variations in TDS at Lees Ferry are
shown in Exhibit 8.
Further development of the Upper Basin and increased use of the water
upstream is expected to further degrade the water as far as TDS is concerned
e In addition, further contiol of the flow of the river upstream
wi II cause variation of the quality of the water. As an example) the
effect of the closing of the gates at Glen Canyon Dam is seen in the TDS
record for Lees Ferry in Exhibit 8 e A partial explanation is shown in TDS
variations in Lake Powell, Exhibit 9.
Future storage in upstream reservoirs wi 11 ultimately decrease the
flow- in the Colorado River without appreciably changing the total salt
burden, 50 this will increase the TDS. The present predictions are that
the present TOS content wi II increase by 22 to 43% by 1990 ( 7) ( 15) 0 Other
authorities prognosticate a somewhat lesser increase in TDS accompanied by
a deterioration in sodium and chloride content ( 16). These estimates are
not keyed to the year 1990 and hence a direct comparison is difficult.
2. Quality of Water Released from Lake Mead - The water record for
water released at Hoover Dam shows higher average TDS for water than that
at Lees Ferry, but wi th much less f Iuctuat iani n qual i ty because of the
storage in Lake Mead. The TOS content appears to be gradually increasing.
The higher TDS can be attributed mainly to the increased TDS at Lees
Ferry and natural sources of salinity between LeGS Ferry and Lake Mead
since there is negligible use of the Colorado River water in this reach.
Some of these natural sources of salinity were discussed in Reg, 6- 6- 2.1 8] C,
with further data in Exhibit 1. Control of these natural sources of salinity
should be investigated as a means of enhancing water quality, not only
in this reach, but in the Upper Basin.
Evaporation from the surface in the main stream a~ d reservoirs is
a co~ tributin9 factor to the increased TOS. For example, the record shows
that 907,200 acre- feet evaporated from Lake Mead in Water Year 1963, leaving
behind approximately 800,000 tons of salt. Some of this salt is believed
to have been precipitated out ( 7), but much of it undoubtedly contributes
to downstream res. TDS comparisons at various points in the river
are shown in Exhibit 10.
Future river saJinity like future streamflow can be predicted only
from statistical records of past salinity and from knowledge of the changes
in the river caused by impo~ ndment and diminution of flow due to consumptive
use. The most recent predictions on future salinity vary somewhat,
but all indicate that progressive deterioration wi II occur. The Department
of Interior study ( 7) a: 1d the Hill study ( 15) represer~ t the most probable
conditions. Hi II predicts that the TDS load by the ysar 1990 wi Jl increase
to 735 mg/ I at Lees Ferry and to 92~ mg/ l at Lake Havasu, compared to the
- 16-
Stem 8 304 000 AF TDS 72
Change, Storage Zero
Bill Williams River, 18,380 AF
Grand Canyon, TDS 531 Av.
Little Colo. River 17 800 AF
Main Stem 15 250 000 AF
Gila River 0 AF
Main Stem 6 220
Ariz. Projects, 1,218,800 AF
Future Central Arizona Project
' Colo. R. Indian Res., 455,400 AF>
)- ChR..:. I.:.. R~. 177 JOSJ AF _
( Imperial, Coachella, Reservation)
So. Nevada
Bright Angel Creek, 20,460 AF, TDS 19
___ U, ta_ h _
Ari zona
Mexico Projects
TDS 1173 Av
Paria River, 15,090 AF
~ Palo Verde Irr. Dist., 948,100 AF
J~ lcz_ 3~ rde. I. r~ Dist. w .. 57. Q., 600.., AF__
_ Calif.:.. g, etur. E, s. J.. 2l, 28LAL _
TDS- No change t~ 0,9 ~ alif.
-< Calif. Projects, 3,651,610 AF
-< Metropolitan Water Dist., 1,039,377
Schematic diagram of the Colorado River main stem flow with major tributari. es,
diversions and return flows. The inflow- outflow figures do not balance because
of sizeable unmeasured surface and sub- surface return flows to the river.
- 17-
There is apparently 1ittle bacteriological deterioration in this section
of the river, but new habitation along the river could become a source
of pollution.
The City of Yuma is presently discharging untreated sewage to the
river above Morelos Dam) and measures are being taken by the State Department
of Health and the City of Yuma to e] iminate this pol lut! on at the
earliest possible date.
Department of Interior figures of 663 mg/ I and 865 mg/ l at these same stations.
These figures represent increases of 22 to 43% by 1990, and assume
that current practices are not changed, a water augmentation program will
not be implemented, future. Upper Basin developments and trans- mountain
diversions will be made, and that natural sources of sal inity will not be
3. Quality of Water at Parker Dam - There is little rDS change in
the qual ity of water between Hoover and Parker Da~ s. Increased population
in this area, and increased recreational use could degrade the present quality,
especially bacteriologically. Increased control of sanitary waste
disposal from boats and recreational areas will be necessary.
5. Qual ity of Water at Morelos D2m - The flow of the Colorado River
h< Js been reduced to a rnTnlr,; j;- cit this point~ and except for occasional
storm flows, only enough flow is mai~ tained to supply the Mexican Treaty
requirements. The iDS fluctuates somewhat because of change of demand 2S
compcred with volumes of return flows v This prab'lem is of international
concern, and some relief has been afforded by the construction of the
\' Jellton-~ 10ha\" k drain extensio: 1 shown on Plate 2. The final solution of
this problem Is of total Basin concern, and the entire burden should not
be placed on the local area or on one Stata of the Basin.
4, Qual ity of ' dater at Imperial Dam - The TDS of the water reaching
Imperia: Dam shows a steady incre2se, A substantial part of this increase
is due to agricultural drainage from the Colorado River Indian Reservation,
the Palo Verde Valley, and probably some from the Cibola Valley. Reduced
flow! n the river due to consumptive use and diversions out of the basin
has substantially reduced the assimilative and dilution capacity of the
stream. A part of the increased TDS can be traced to evaporation frol'!!
the water surface and phreatophyte growth along the river. The TDS record
is shovm in Exhibit 10.
A. The Main Stem of the Gila River: The gross watershed of the Gila
River System upstream of Dome, Arizona ( 12 miles upstream of the confluence
with the Colorado Rtver) Is approximately 57,477 square miles, excludJng
all closed basins upstrc~~ r Tha main stem of the GIla Rtver upstream of
the last U. S. Geologic~) Survey gaging station in New Mexico near Virden
( 16 miles upstream of th~ New MexiCO- ArIzona border) has a druinage area of
3,203 square miles. There are no major control structures on the Gila River
in New Mexico, although Hooker Dam has been proposed. The watershed of the
Gila River System in Arizona is shown in Plate 4.
The Gila River enters Arizona near Duncan, flows throu~ h Duncan V~ lley,
is joined by the San Francisco River near Clifton, and flows westward
through Safford Valley to the San Carlos Reservoir behind Coolidge Dam,
the first major control structure on the river. Fater released from
Coolidge Dam flows westward through remote mountain country until it
reaches the San Pedro Valley where the San Pedro River joins the Gila
River. The combined rivers flow through more remote mountains past the
Buttes Damsite to Ashurst- Hayden Dam near Florence.
All of the water reaching Ashurst.. Hayden Dam, with the exception of rare
flood flows, are diverted for beneficial use in the San Carlos Project.
Sluicing of the heavy sediment load at Ashurst~ Hayden Dam has been replaced
by mechanical sediment removal equipment, so there is essentially no flow
in the Gila Ri'ver belo\" this dam. All of the water in the mainstream Gila
River, from a point ten miles upstream from the eastern boundary of Arizona
to the Gila Crossing ( near the confluence of the Salt and Gila Rivers), is
allocated under the Globe Equity No. 59 Decree of June 29, 1935 ( 17). The
provisions of that Decree are enforced by the Gila Water Commissioner appointed
by the Arizona District Court of the United States.
The Gila River below Ashurst- Hayden Dam is situated in an arid desert
area. Intense desert storms contribute some flow to the Gila River at infrequent
intervals for short periods of time. There are small diversion
dams near Olberg ( Sacaton D; version Dam) and Gila Crossing before the Salt
River joins the Gila River near Avondale. Annual flow data for vlater Year
1965 at various points on the Gila River are shown on Plate 2.
The Salt River System contributes very 1ittle water to the Gila River because
of upstream use. This facet is discussed in Reg. 6- 2- 2.2 B under
tributaries to the Gila River.
Almost all of the water which accumulates in the Gila River below AshurstHayden
Dam is diverted at the Buckeye Irrigation Company diversion dam, the
Arlington Canal Company diversion works, and at Gillespie Dam for irrigation,
Except for storm flows and gate leakage at the dam, there is no surface flow
between Gillespie Dam and Painted Rock Dam approximately 60 miles downstream.
Painted Rock Dam was completed in 1959 as a flood control darn to protect
the Yuma area from flash floods following intense desert rainstorms.
Below Painted Rock Dam, the Gi1a River channel is dry except for occasional
storm flo\ vs. Irrigation drainage water from the vIe I I ton- Mohawk
Valley has contributed some flow at Dome ( 12 miles upstream from the confluence
of the Gila River with the Colorado River) in the past> but a new
drainage system completed in 1961 has steadily decreased the contribution.
In addition to the annual flow data for Water Year 1965 presented in
Plate 5, flo\' I data at various points in the Gila River System is given in
Exhibit 22.
B. Tributaries to the Gila River: There are numerous tributaries to
the Gila River in the 508 river miles between the New MexiCO- Arizona
- 18-
- t- Existing Dam
+ Proposed Dam
- -- ARIZONA- -- --------- t
• I ~ i
1 0
-~~ <
Ix z w o,:::: E
co o
Q) .. g_, I ......,,
~ \
\ l
) ~~, ~ 1\
, ' J'l'\
t .
~_.- - ARI_ ZO._ NA-- l' -
o~ IoU
< r Painted Rock Dam fTl
( 5198)[ 882J :: D l> ( J)
Dome( 5205)[ 279J -< - f (/ 1
-- f ARIZONA r' 1 MEXICO : s: ITI ( J)
Morelos Dam 0 :: r
fTl : s: :> U1
- l
Calva( 4665)[ 90,960J
San Carlos Res. ( 4690)[- 34,830J
Coo I i dge Dam
Pedro R. ( 4710)[ 16 : 40
San Simon R. ( 4570)[ 7 550J
Virden( 4320)[ 96,290J
[ 18,840J Duncan- Virden - - - - Valley ( 4325)
San Carlos R.
( 4685)[ 24,550_,
P~ oenix
-) 0-
L __ ... s
Hassayampa R.
Glenwood( 4440)[ 41,010J
Salt River Val ley
( 4490)
Fria R.
See Plate
Wadde I I Dam
Granite Reef
~ Roosevelt
g Horse Mesa
a a Mormon Flat - co
a ~ Stewart Mountain
~ +..----
....... l- J ( 5020)[ 203,200
( 5113) 625 600
( 5138)
Verde River
-..'--+-- y- l~ U- I"~"'-: L~~"""" LS~ aWJni... l.. F.!.. r~ a~ nc~ i s~ c~ o::.....:..:.:....~~;;..;:':" 7"~ ~'" 4450)[ 6,290J ...
~ ~~ rseShoe
~ ..
g = Bartlett
....... l- J
( 4320) USGS Gage Station
( 9- before each no.)
[ 279]- Flow at Station
Acre- feet/ year
~ Existing Dam
~ Proposed Dam
boundary and the confluence with the Colorado River near Yuma. Flow data
for the major tributaries is given for Water Year 1965 on Plate 5, and~ xpanded
flow data is presented in Exhibit 22.. Descriptions of the significant
tributaries are as follows:
1. San Francisco River - The San Francisco River has its headwaters
in Arizona near Alpine. It flows eastward through Luna Lake into New Mexico
and back into Arizona northeast of Clifton. The gross drainage area of the
San Francisco River above the last gaging station near C} ifton ( 9.9 miles
upstream from mouth) is 2,766 square miles. The salt load of the San
Francisco River varies with the flo\, J rate. Available data shows the TDS
( Total Dissolved Sol ids) load ranges from 200 to 1200, mg/ l. Diversions are
made for mining, municipal and irrigation use upstream of the confluence
with th~ Gila River. The Clifton Hot Springs is a source of salt which
degrades the water quality of the river.
2. Eagle Creek - Eagle Creek drains a 377 square ! flUe area on the
north side of the Gila River. In addition, water is pumped into Eagle
Creek from the Black River in the Salt River watershed. A large portion
of the water flowing in Eagle Creek is diverted by pumping for industrial
and municipal use in and near Morenci and C1 if ten. The water is of excellent:
qual ity.
3. San Simon River - The San Simon River drains a 2,192 square mile
area in the San Simon Valleyo There are some minor intermittent flows from
New Mexico into the valley. The San Simon River joins the Gila River between
Solomon and Safford. There, is very little rainfall in this drainage
basin, and the river usually flows only during sto!;' m periods, and available
data shows a TDS load of 500 to 900 mg/ l in the floodwater. The sediment
load is also high. Flood flows are partly regulated by six flood control
detention structures.
4. San Carlos River - The San Carlos River drains a 1,027 square
mil~ area north of San Carlos Reservoir. Although the 36~ year average
discharge of this tributary is 32,070 acre- feet per year, there are periods
of no flow each year. The meager data on quality indicates fajr
quality during high flows to poor quality during low flows.
5. San Pedro River - The San Pedro River drains an area of 4,449
square miles, of which 696 square miles are in Mexico. The first gaging
station in Arizona is near Palominas, approximately 4.5 miles from the
Arizona- Mexico border. The total flow at this point has averaged 21,000
acre- feet per year for the 23- year record: but the flow rate has varied
from ° to 22,000 cubic feet per second ( cfs). Diversions above Charleston,
where a dam is proposed as a part of the Central Arizona Project, are
mostly by groundwater pumping. Downstream of Charleston, surface flow
decreases. Diversions, both by surface flow and groundwater pumping, are
made for irrigation, domestic and industrial use. The San Pc: dro River joins
the Gila River near Vinkelman. Quality records on the San Pedro River are
meager. Records of quality on the Gila River at Kelvin~ 17 miles downstream
of the confluence is the best index available.
6. Mineral Creek - Mineral Creek drains approximately 98 square
- 19-
miles of area north of the Gila River at Kelvin., This creek was named
Mineral Cr~ ek In' 1846 by a military scouting party because of Its saline
qualities and brown color. The flow varies from zero to approximately
30,000 cfs. There is one flood control structure which has silted up and
is no longer effective. Another structure is being considered. A large
open pit copper mine is situated on this creek, and the natural channel is
being replaced to allow for mine expansion.
7. Queen Creek - Queen Creek drains a desert foothills area north
of the Gila River, and flow is restricted to periods of heavy rainfall,
usually during the summer and fall. The flow is controlled by Whitlow
Dam, and it Is doubtful if any surface flow would ever reach the Gila River.
8. Santa Cruz River - The Santa Cruz River drains 8,581 square miles
before it reaches the Gila River near Laveen. There is a 348 square mile,
drainage area in Mexico. The 23- year record shows an average annual flow
at the mouth of 14,550 acre- feet, with no flow at all for the majority of
the time. There was a measured flow during 54 days of the 1965 water year,
and 6~ 1o of the flow occurred during 3 daYs. There are many diversions,
mostly , by groundwater pumping, for irrigation, municipal and industrial use.
9. Salt River System - The Salt River System physically joins the
Gila River System west of laveen. The Salt River System includes the Salt
and Verde Rivers and their tributaries. The Salt and Verde River flow is
controlled by dams except for periods of extreme flooding ( the capacity has
been exceeded only twice since 1941), and essentially all of the flow is
diverted for irrigation, municipal and industrial use at Granite Reef
Diversion Dam east of Phoenix. The Salt River Valley area~ including
parts of the water distribution system, is shown on Plate 6. There are
13,000 square miles of drainage area above Granite Reef Dam. Hater in
the Salt River System is adjudicated under various court decrees ( 18),
( 23), ( 24).
There is very 1ittle contribution of surface water to the Gila River
System by the Salt River System. Irrigation return flow, mostly excess diversion,
is utilized in the immediate area. There is considerable groundwater
pumping in the area. There is a sewage effluent flow to the Salt
River from Phoenix, and complete reclamation of this sewage effluent for
reuse is being studied. This effluent is being delivered by the Buckeye
Irrigation Company for irrigation of non- edible crops. '
10. Aqua Fria River - The Aqua Fria River drains an area of 1,459
square miles upstream of Waddell Dam. Except for flood flows, all of the
water is diverted for irrigation use by the Maricopa County Municipal Water
Conservation District No. 1 before it reaches the Gila River. The average
flow for the 37- year record period is 59,440 acre- feet per year.
II. Hassayampa River - The Hassayampa River drains an area of 1,470
square miles before it reaches the Gila River upstream of Gillespie Dam.
The average flow for the 19- year record at Box Damslte near Wickenburg is
7,820 acre- feet per year, with many periods of no flow. There are diversions
for irrigation and mining operations along the river. The river
below Wickenburg is alternately wet and dry, and most diversions are by
- 20-
groundwater pumping. Flow records at the confluence with the Gila River
are very poor, but the total flow in the Gila as measured at Gillespie Dam
indicates negligible contribution from the Hassayampa.
12. Centennial ~/ ash - Centennial \ lash joins the Gila River just upstream
of Gillespie Dam. Flow consists of storm runoff, and the record is
extremely poor.
13. Miscellaneous Tributaries - There are numerous small tributaries
to the Gila River, most of them intermittent in flow. It is beyond the
scope of this pol icy document to discuss each of them.
C. History of the Gila River Basin: Part of the area of the Gila River
Basin was ceded to the United States in 1848 after the Mexican War and the
southern area was included in the Gadsden Purchase of 1853. In 1870, valuable
mineral deposits were found in the area of Clifton, and this area is
now one of the most important copper producting areas in the United States.
The first irrigation of the land in the basin above the Coolidge Dam
area was begun about 1872 by Mexican immigrants and Mormon pioneers in the
Safford Valley, and irrigation in the Duncan- Virden Valley followed shortly.
Below the Coolidge Dam area, early development centered around agriculture.
The Hohokam Indians irrigated lands more than a thousand years ago. This
civilization vanished. Irrigation practices were resumed in the lower Gila
and Salt River Valleys by subsequent Indian inhabitants at dates unknown and
by non- Indian settlers in the 1860 1 s. Varying flows made irrigated agri~
culture a very risky affair, and storage systems were planned. Picacho
Reservoir was built for irrigation storage water , in 1890. The Fed~ ral
Reclamation Act of 1902 paved the way for construction of many more storage
dams for irrigation water. The Salt River Valley \~ ter Users l Association,
the first organization of its kind formed to take advantage of the act, was
incorporated in 1903. Roosevelt Dam on the Salt River was begun in 1905
and completed in 1911. More dams on the Salt and Verde Rivers followed.
Cool idge Dam on the Gila River was completed in 1928 by the Bureau of Indian
Affairs. The Buckeye Canal Company was formed and the first 5 miles of the
diversion canal was cohstructed in 1885, and the Arl ington, Enterprise, and
Citrus Valley diversions and canals were f~ nctioning before Gillespie Dam
was constructed. Gillespie Dam on the Gi~ a River was completed as a private
venture in 1921 to irrigate 10,000 acres in the Gila Bend and Theba areas,
but this area has suffered from a shortage of water. The remainder of the
Gila River Valley has sparse irrigation except for the area around \>! ellton
and Yuma served with Colorado River water.
Pumping of groundwater began in the 1920 1 5 and became widespread throughout
the basin by about 1940.
The surface storage system was developed primarily for agriculture, but
domestic and industrial needs are now also supplied. The use of water in
Arizona, especially surface water, is covered by legal water rights. Expanding
population and changes from a strictly agricultural and mining economy
have caused many water problems.
D. Major Diversions from the Gila River System: As described in
- 21-
Reg. 6- 2- 2.2 A, all of the water in the mainstream Gila River, from a point
ten mi les upstream from the eastern boundary of Arizona to the Gila Crossing
( near the' confluence of the Salt and Gila Rivers), is allocated under
the Globe Equity Decree. Diversions from the San Pedro River upstream of
its confluence with the Gila River have not been adjudicated. There are
numerous withdrawals of water from these rivers upstream of Ashurst- Hayden
Dam both by surface diversion and by pumping of groundwater. The G~ obe
Equity Decree provided for irrigation diversions of 1/ 80 of a" cubic foot
per second per acre of land, with a total of 6 acre- feet for each acre annually.
The areas defined by the Globe Equity Decree are chronically'and
critically short of water and even supplemental pumping does not add enough
water to the surface diversions to provide an adequate supply to the lands.
The major diversions from the Gila River under the Globe Equity Decree are
as follows:
1. Duncan- Virden Valley - The decreed area for irrigation in thiS
valley in both New Mexico and Arizona is 8,061 acres. Between 8,000 and
20,000' acre- feet per year has been diverted during the past five years,
and the additional water required has been pumped from the groundwater.
Almost all of the return flow to the river is subsurface. .
2. Safford Valley - The decreed area for irrigation in the Safford
Valley is 32,512 acres. Water is diverted through thirteen canal systems,
and supplemental ltlater is diverted by pumping, both from the river and from
the groundwater. The diversion from the river during the last five years
has varied from 39,630 to 104,700 acre- feet per year depending on the riyer
yield. Most domestic water is supplied by pumping from the groundwater.
3. San Carlos Project - The decreed area for irrigation in this
project is 100,546 acres. There are two sections to this project-- the
" Tndian Lands" and the 1'~ Jhite Lands" as given in the Globe Equity Decree.
The acreage is approximately equal. Surface flow is supplemented by pumping
from the groundwater. The diversion from the river has ranged from
42,450 to 247,820 acre- feet per year during the past five years, There is
some storage on the project in the Picacho Reservoir. Domestic needs in
the area are served by pumping from the groundwater.
4. Miscellaneous Diversions - There are numerous diversions for
irrigation, domestic and industrial uses along the river. These uses are
covered in the Globe Equity Decree.
Other decrees have adjudicated waters of the Gila River System, and there
are other diversions. Under the Haggard Decree ( 1903), 1,080 acres of
Indian lands at the confluence of the Gila and Salt Rivers were decreed
diversion rights ( 24). Under the Benson- Allison Decree ( 1917), 19,865.5
acres of land served by the Buckeye Canal were decreed diversion rights,
6,033 acres served by smaller canal systems were decreed diversion rights,
and rlg, hts of the 1,080 acres of Indian lands were reaffirmed ( 23). The ,
Arlington Canal diversion is between the Buckeye Heading and Gi llespie Dam.
Diversions at Gillespie Dam were adjudicated to lands of Enterprise Ranch
( Enterprise Co: lnal) and to Gila River Ranches and Narramore Ranch ( Gillespie
Canal), under a 1922 Court Decree. .
- 22-
E. Economy and Natural Resources of the Gi la River_ Syste~: The economy
of the entire- area of the Gila River System is limited by the ". later supplYi
The economy and natural resources discussed in Reg. 6- 2- 2. 1 H of the
Colorado River apply equally to the Gila River System, and will not be
repeated except to emphasize that the Central Arizona Project is vitally
needed to- help sustai~ the economy and to help reduce the quantity of the
more mineral ized groundwater being pumped to supply various needs.
F. Water Quality Considerations: THE QUALTTY AND QUANTITY FACTORS OF
IMPCSSIBLE TO SEPARATE THESE PARAMETERS. The flow data on the main stem of
the Gila River and its tributaries for the 1965 Water Year is shown schematically
on Plate 5 and" expanded for other years in Exhibit 22 to illustrate
the variable flow parameters.
The variable flow in the Gila River is due mainly to storm runoff which
carries a considerable silt load. Flow from the Gila River is first controlled
at the San Carlos Reservoir which acts as a silt control works.
\ later released from Cool idge Dam is relatively clear, but inflol! from the
San Pedro River and other tributaries is uncontrolled and the silt load
at Ashurst- Hayden Dam is again appreciable, causing silt control problems
in the San Carlos Project. The si It load requires, constant canal cleaning
and prevents a canal 1ining program vital to water conservation. Buttes
Dam, when authorized and b~ ilt, will reduce the silt load in the canals so
that a lining program will be feasible.
The variable flow rates also contribute to the sal inity problem. :! n
general, the sait concentration increases as the f. low decreases, but the
watersheds of different tributaries contribute different quantities and
types of salts. To illustrate, the Total Dissolved Sol ids ( TDS) and sodium
concentrations in the Gi 1a River water at Kelvin are plotted against flow
rate in Plate 7 for the 1962 to 1964 period. The different pattern of the
data for the total salt content and single ion content illustrates the
effect of - different watersheds on the qual ity of ' later.
The TDS content of the water entering Arizona in both the Gila and San
Francisco Rivers historically varies between 200 and 500 mg/ l. The fluoride
content has been consistently high, normally above one ( 1) mg/ l even
in periods of high flooding ( 9). The fluoride content of many of the
groundwaters of the entire Gila River Casin is high, probably due to redeposition
of these salts washed downstream from the upper basin. The
groundwater in the, Duncan-\ lirden Valley varies from very low to over 5000
mg/ l of dissolved, salts, and some salt load is added to the Gila River
water before it is'joined by the S~ n Francisco River.
The Cl ifton- Morenci area contributes considerable salt to the San Francisco
River, some<, from solution pick- up from the saline soils and some from
the highly mineralized hot springs. r Long term continuous data on quality
is not av~ ilable for this arC5.
Downstream of the confluence of the Gila and San Francisco Rivers, the
tributaries contqin varying salt loads. Eagle and Ronita Creek water contains
about 300 mg/ l of salts. The San Simon River contributes water with
- 23-
a TO, S , of 500- 900 mg/ l during flood stage. There are some artesian flows
in , t'he' Safford Valley vlhich contribute a variety of salts to the Gila River
flow. The groundwater in the Safford Valley is generally highly mineralized.
The San Carlos Reservoir acts somewhat as an equalizing reservoir for
the salt content of the Gila River water, but downstream flow is again influenced
by hot springs and runoff from other watersheds as seen in Plate
7. By the time the water reaches Kelvin, the TOS load varies between 400
and 2000 mg/ l. Generally speaking, the TOS load is below 1000 mg/ l if the
flow remains above 200 cubic feet per second.
Very little quality data exists for flows belovi Kelvin. Except for
occasional flood flows, all of the water reaching Ashurst- Hayden Dam ( 19.5
miles below Kelvin) is diverted for use in the San Carlos Project, and there
is no return flow to the river as a surface stream. The proposed ~ uttes
Dam, in addition to its function as a silt control structure, , would contain
the flood flows which enter the Gila below Coolidge Dam, particularly
from the San Pedro River. There is considerable groundwater pumping in the
area, and the Central Arizona Project is needed in this area for supplemental
water and quality control.
The Salt River System waters vary in quality, but not quite as drastically
as the Gila River and its other tributaries. The extensive reservoir
systems on the Salt and Verde Rivers tend to equalize the extremely high
and low salt waters. The TDS of the Salt River below Stewart Mountain Dam
has varied from 361 to 1300 mg/ 1 during the period of 1950 to, 1964,. The
TDS of the Verde River below Bartlett Dam has varied from 158 to 550 mg/ l
during the same period. The quality of water delivered to the users in
the Salt River Valley depends on how much water is available from each of
the rivers. The ratio varies from year to year as seen in Exhibit 22 for
Stations 5020 and 5100.
The surface flow of the Salt River System is not sufficient to satisfy
the needs of the Salt River Valley, and there is considerable groundwater
pumping. The amount pumped in the valley greatly exceeds the annual recharge.
In addition, the groundwater is quite sal ine in most areas. The
Central Arizona Project is desperately neeqed in this area to allow, for
water importation. Such importation would help with respect to both the
quality and quantity.
The next surface flow in the Gila River is at Gillespie Dam. TheTDS
load- at this point averages 5,000 to 6,000 mg/ l. T~ is water is diverted
for irrigation purposes. The water usually has a fluoride concentration of
2 to 4 mg/ J.
With the meager amount of quality data available in the Gila River System,
it is difficult to isolate any single source of gross degradation of the ,
water. Tt appears that much of the degradation is the result of natural
sources of salinity.
Some drainage water from agricultural facilities downstream of Painted
Rock Dam and occasional floodwaters reach the Colorado River near Yuma.
- 24-
a a a
o a a
a a a
r< l ~ U\
r< l oq- U\
a a a
a a 0
r< l ~ U\
o 0 0 o 0 0
r< l ~ U\
1962- 1964
a a a
r< l ~ U\
a a 0
r< l ~ U\
~ · ..
, •
• ..
• ,
• • ",
• . '., ,
. • • • ...-. 0 · . • •• .0 ~
• • 0 . .. • ~
i- .. • ·
• , t I I • • I • • • • • 0 0
01- • • . , 0
0 • , , 0 ' .. 0 • • • .,
0 . , . 0 . • ... • ~ • · 0
0 · • • • ~ . • •• • . , ,', , . 0 . .•
. • .' 0 ~ 10 , .
- o'
tf) 500
-' 400
tf) o
6> 200
20 aN
~ 300
co z
~ 50
oo 40
......... 100 en
The drainage water is now almost completely contained In the concrete lined
drainage channel of the Vel Iton- Mohawk Irrigation and Drainag~ District.
The effect of this drain is seen in the data for U. S. G. S. Station 5205
( Dome, Arizona) in E~ hibj. t 22. The flow in the Gila River has decreased
to less than an acre; foot per day since Water Year 1963. The subject of
salinity beloW this point of the Gila River is discussed in the Colorado
River Policy Document. It should be pointed out, h~ vever, that rate of
floodwater release from Painted Rock Dam can drastically affect the salinity
problem in the lower Gila and Colorado Rivers. Floodwater has been released
only once since completion of the dam in 1959.
B. Gila River - Diversions for agricultural use are made throughout the
basin. Boron content from natural sources limits the use on some crops.
In some cases, the TDS and Sodium percentage also limit crop use.
A. Colorado River - Diversions for agricultural use are made throughout
the bas~- The major diversions are below Parker Dam. Crops grown include
citrus, vegetables, forage, feed, grains and cotton.
A. Colorado River - The volume used for domestic il'lClter is minimal, however,
the use is scattered from Page to Yuma along the Colorado main stem.
There is only one known domestic use of surface flows in the little Colorado
Basin at the present time.
6- 2- 3
6- 2- 3. 1
6- 2- 3.2
6- 2- 3.3
All of the surface waters of Arizona are subject to either the appropriative
rights doctrine or to water use cont'racts with the Secretary of
the Interior. Th~ re are no riparian water r. ights in Arizona. Some of
Arizona's decreed entitlement to main stem waters bf the Colo~ ado River is
not now diverted and is being used by other states until additional Arizona
faci1 ities are authorized and built. The f~ 11owing beneficial water uses
are being made of waters in the Colorado River and Gila River sasins in
Arizona. This tabulation is not intended to designate order of importance
or rights to such use.
Water for domestic purposes is of prime importance throughout the Arizona
Reach of the Colorado River. Although the application of conventional water
treatment including flocculation, coagulation, filtration and disinfection
to Colorado River water will generally not provide a water meeting the recommended
drinking wilter standards of the U. S. Public Health Service, such
treatment does provide a water meeting the mandatory requirements of the
drinking water standards. Since a better alternate source of supply is
usually not readily available, Colorado River water is used as a source of
raw domestic water.
B. ~ iver - High f~ uoride content from natural sources restricts
the use of the Gila River above its confluence with the Salt River as a
domestic water source if alternate sources are available. There is some
use of surface water of the Gila River as a raw domestic source. Use of
the water has resulted in mottled teeth in children, and an alternate
source of water is recommended.
Surface water of the Salt River system is extensively used as a raw
domestic source for the metropolitan Phoenix area.
There is negligible direct use of surface water as a raw domestic source
below the confluence of the Salt and Gila Rivers.
- 26-
- 27-
B. Gi la River - \- Iaters are diverted all along the flO\. ving streams for
industrTar- purposes such as mining, manufacturing and cooling water.
This operation results in a varying but heavy silt deposition in the
area between the dams, and a rapidly varying water depth. The operation
is absolutely essential in maintaining a low si lt content water del ivery
into the canal systems of both Arizona and California.
6- 2- 3.4
Colorado River
6- 2- 3.5
On most of the other tributary streams, the surface flow is so undependable
and variable in qual ity that domestic water is suppl ied from groundwater.
Future demands in certain areas are dependent upon augmentation
from outside sources.
1. The Colorado River System contains aquatic and wildlife resources.
Such resources include production of organisms, both plant and animal, that
contribute to the food chain supporting a fish population, and populations
of other animal 1ife including waterfowl and shore birds.
A. Colorado River - Industrial uses currently are minor. Major use is
for hydroelectric power generation. Several steam generating plants are
being proposed. \ later when diverted through the Central Arizona Project
will be partially used for industrial purposes.
The reach between Imperial and Laguna Dams is used primarily as a
silt depository for the desilting works at Tmperial Dam and for operational
control. Measures for the protection of aquatic and wildlife
resources in this section will be practiced to the fullest extent possible
consistent with the normal operation of the facil ity as a desilting
works. Prior to the construction of the Tmperial Dam and desilting works,
most of the silt load of the Colorado River flowed through the canal system
onto the irrigated fields, and silt control cost about one mill ion
dollars annually. Although the amount of silt decreased with the completion
of Hoover Dam, channel degradation, bank erosion and storm runoff
still contribute a heavy silt load at Imperial Dam ( about 805,000
tons in calendar year 1965). The bulk of this silt is removed continuously
in six classifier type basins on the California side and by a single
basin with periodic sluicing of silt on the Arizona side of the river.
The sediment from the basins is sluiced downstream to a sediment retention
basin for removal by dredging. Removal of this sediment from the sluiceway
channel is required for satisfactory operation of the desilting basin and
overall sediment control measures at Imperial Dam.
2. Water is used in the operation of the National v! ildlife Service
Refuges, the Havasu Lake, Cibola and Imperial ~ ildlife Refuges. This water
use is covered by the Arizona vs. talifornia Supreme Court Decree. Consideration
is being given to dedication of a portion of the Lower Palo
Verde- Cibola Valley region to waterfowl management purposes, to provide
enough buffer lands to protect the waterfowl and to provide for future
re 1a tedrecrea tiona J needs.
3. Water is used at Mittry Lake, an Arizona State waterfowl area
in the downstream area from Imperial Dam. A State Wildl ife area is being
farmed for waterfowl habitat preservation and feed in the Cibola Valley.
B. Gila River - The Gila River System contains aquatic and wildl ife
resourc~ s in most of the flowing streams and impoundments. Such resources
include production of organisms, both plant and animal, that contribute
to the food chain supporting a fish population, and populations of other
animal I ife, including waterfowl and shore birds.
B. Gila River - The Gila is used for a variety of recreational pursuits,
including primary body contact uses. Some uses are restricted in certain
areas due to confl icting water rights and uses, but are generally available
in most areas in which sufficient flowing or stored water is available.
A. Colorado River - The Colorado main stem is used for a variety of
recreational pursuits, including primary body contact uses, between Page
and Yuma. The remainder of the river and the various tributaries are used
for secondary body contact uses with the exception of some impoundments
which may be used for primary body contact sports.
Future consumptive uses of surface water of the Colorado and Gila Rivers,
other than those specifically mentioned as allocated, are of necessity
restricted until a major water augmentation program is real ized. It is
probable that some uses wil I have to be replaced by a higher priority use
under due procesS of law with ful I recognition of legal water rights.
1 i
Specific classification of waters by designation through finite geographic
boundafizs cannot be made. The uses of the waters of the State
vary to a much greater extent than they normally do in more humid cl imates.
This is due to the fact that the majority of our streams are intermittent
and nearly al I streams having a perennial flow are completely regulated.
Thus varying uses are made of these waters depending upon the amount of
flow available, either from natural precipitation or releases from storage.
For example, most releases for agricultural purposes are made on a demand
basis, however when sustained flows are anticipated, plantings of fish may
create a fishery where none normally exists. A delineation of major cold
and warm water fishing areas on interstate waters in Arizona is shown in
Exhibit 23. Nearly all perennial waters are used for recreational pursuits.
Use of surface waters for domestic and industrial purposes are
necessarily I imited to those areas having a dependable supply. Numerous
wei Is for domestic and industrial suppl ies are located in or adjacent to
the stream bed and a re great Iy inf I uenced by the surface waters that may
flow sporadically, therefore protection of such supplies is essential even
- 28-
- 29-
though the stream may not properly be classified as a surface water source
of such suppl ies.
All waters of the State governed by this document are protected for
esthetic values. This intludes perennial, intermittent and ephemeral
streams, and intermittent lakes.
In view of the present qual ity of Colorado River water and the prospect
of further degradation by upstream development, it is imperative that a
major water augmentation program be instituted for the Colorad~ River System.
Since this program would entail interstate cooperation and Federal
sponsorship, the efforts of other appropriate State and Federal agencies
are necessary to effectuate it.
The Gila River is completely util ized by consumptive uses at the present
time. A water augmentation program would enhance these waters as well.
Control of natural sources of sal inity and discharge requirements for waste
systems can be used to maintain or improve the present quality of the water.
I. The consideration of present conditions and contributing factors, an4
2. Qual ity iequirements for specified uses.
CONSIfJERATION OF PRESENT CONDITIONS AND CONTRIBUTUJQ
FAt: TORS
6- 2- 4
6- 2- 4.2
B. Ch' 2mi~~ Li: li.:~.:. ai:. teris!~~~ 2"- Disr. harg;;( ro: Ti fut~ re Upper Basin developments
may ll1c' 82:: 8 c(" ltrib'..! t! OnS of cherr; kal::- t{) , vaters enterin9 Arizona.
In ariC: itlo", f:. i!" ther d8Vel:: ipr' 18nt in adjacet; 1: sta"': 8£ could C3use the same
problem. Sho:..: ld s:. Jc.!~ cr;(; L:~' or threaten, corrective measures wo<.: ld be L, itlally
sought through cooperative efforts wit~ the Basin States.
Although the water qual ity indicators under consideration ~ fe numerous,
they may effectively be grouped in:
The ne · v:: l fer water conservation in the Southwest j; · tclicatcs th,~ t beneficial
reuse of sewage effluents should be encaurao~ d, The increased
recreational use of the entire area could contr! L~ te human pathogens to
offset the effect of the el iminat ion of properiy trec: ted effl uents. Tn is
00jective wnl ( Ie met by e~:. ablishment of eff1\;;; llt u! scharge req~ irements
on sanitary \' ia::; tes rrcm pr. r'i~~ te and co" nmunit;: ::?"' I"' S~ ;:;~/ S!. F.:: 11S, ol'ganic
processing plants, recreational fa::: il it1es ai · td boats,
A. Bacter: oloqical - The objective is to keep waters of the State
bacteriologically safe for beneficial uses. The contributory sources of
patriogens Mr~ disposals of sanitary wastes from c,? mrnuilities, from private
estah 1 i 5hrnents) and from boats. -~',.:,,:-,?
i . Nat~ Jrc: 1 SOi~.~ c f !': 2: 1n i tI_ L' t · ...,.? ;; rg'~~' l:: l: of the Co lorado
. B. I~~ L - Some of the r. atural sources of sa: inity hav;~ been elUmerated in
previc'. J:; sections. The Arizona I:- li: erstCite Stre- 3m C0i11r; 1ission is currently
funded to conduct a st~ dy of the Little Colorado River Basin potential
\ ihich incL.: des Biue S::> ringsj~ o as: ertain its optimum role in con~ rol and
cevelopment: for the water resources progri: liil in .4rizcna.
Interstate coo;:; eratio'l will be necessary to evalua;:: e ard reduce the
531 inity cf waters re2-: hing t;, e Cc'o;-- ad,} Ri'ier frcm dc; jaCer1t stu;: es as
covered prp.'/ io ' lsly. '!!": e soii: 3 of the Colorado R. iver Basin closely resembie
the ? eological fcrmi':: i:; ons of their orisin, i'ameiy igneo;': 5, sedimentary
and metamcrphi::. Th; 3 slIts removed by const3! lt ero.,; j.') n of th~ uF=- per areas
have been dep': Jsited in tl-, e Lower Basin to form the great delta of the
Colorado River. These slIts contain large quantities of salts such as
sodium, calciu:. 1, and f: 12Si18Sii,: 11 ccmbii1ed \ vit~ ::: hioride:;~ car'cori3tl~, biczrbonate
and sL; if:: l~ es. PI:': S t~ je soi~ s cf :: 1', e Coloredo r<; ver Ed:::: in 2re ~ he
bask source of t!~ e sa1 init)' i: l the \ v: iter, C:' I:)' 1 Imited a~ · E: · 3S have o--= en
leac:' ed sufficiently to ren'~.) ve these solutle s~ 1ts, and mO> l: lands of;: he
Basin must be ~ eached befQ~ a they will became productive.
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Efforts to control the natural sources of sal inity between Lees
Ferry and Lake Mead may meet with opposition from certain conservation
groups who have been attacking further development of the Colorado River
in this area. Every effort must be made to reconcile the many differences
of opinion on river development.
Gypsum reefs are quite common in the Lake Mead area, and there is
no feasible method of isolating these areas. Fortunately, they do not
appear to contribute a large amount of total salt as evidenced by U. S. B. R.
reports on Lake Mead and the Colorado River. The answer could be found in
deposition of silts and/ or precipitation of calcium carbonate as a crust
over the gypsum beds.
2. Natural sources of sal initv in the Gila River drainaqe area There
are numerous natural sources of sal inity in the drainage area. The
alluvial soils and rocks contain soluble salts. Although this source is
difficult to control, water management and watershed manipulation may help
reduce the effect of this source in the future. Salt springs and salt beds
in the vicinity of rivers and creaks are being sought out and methods of
control studied and more work must be done.
3. Aqricultural sources of sal inity - An operational salt balance
must be establ ished in all agricul tural operations. In general, all of
the salt entering the root zone of an agricultural project must be removed
from the area if a sustained operation is to be possible. Failure to resolve
this problem may have contributed to the destruction of great civil izations
in the past, including the Hohokam Indian civil ization in the Salt
River Valley of AriIDna a few hundred years ago. With efficient irrigation
practices, about two- thirds of the water appl ied to crops is removed by
transpiration from the plants, use by the plants, and by evaporation from
the soil itself, concentrating all the salts originally present in the remaining
one- third of the water. This water must be drained away from the
root zone to prevent salt damage to future crops. Thus agricultural drainage
water will have a higher concentration of dissolved salts or iDS than is
present in the appl ied water. It is obvious that the incremental increase
of TDS in drainage waters of the lower basin will be much higher than for
a similar operation in the upper basin because of the higher TDS in the
appl ied water.
The TDS concentration of drainage water resulting from the leaching
of new lands can be higher than the concentration resulting from a salt
balance operation. The effect, however, diminishes rapidly.
The programs outl ined in Reg. 6- 2- 2.1 ( canal I ining, pipe installation,
land levell ing, phreatophyte removal, watershed improvement, etc.)
are the current methods of water conservation which contribute to water
qual ity enhancement. These programs should be continued, giving considerntion
to their effect on other beneficial uses ( recreation and fish and
wiidl ife propagation). New, practical processes for reducing the sal inity
of irrigation return flows should be appl ied as they are developed.
The water tables in the Gila River System are generally quite low,
and there is very I ittle return flow to the rivers by surface drainage
- 31-
systems. Canal 1 ining, pipe Installation, land levell lng, phreatophyte
removal, watershed Improvement, etc. are the current methods of water conservation
which contribute to water qual ity enhancement. These programs
should be continued, giving consideration to their effect on other beneficial
uses ( recreation and fish and wildl ife propagation). New, ~ rectical
processes for reducing the sal inity of irrigation return flows should be
appl ied as they are developed.
It should be recognized that such programs, while beneficial in preserving
and enha~ cing water quantity and qual ity, may produce undesirable
effects on recreation and wildl ife values.
4. Industrial sources of sal ini~ - There are a few minor sources
of sal inity in industrial operations along the Arizona reach of the Colorado
River. Most of these can be held to a minimum by proper discharge requirements.
5. Municipal sources of sal init~ - Salts are added to water used
for domestic purposes. Domestic sewage generally has a TDS increase of
about 300 mg/ l over the supply water. This increase can be attributed to
a number of factors such as, but not I imited to human waste, water softener
operation, washing clothes and dishes, garbage disposals, etc. The most
significant increase is in sodium chloride.
Return flows from lawn and garden watering follows the pattern set
forth for agricultural drainage previously discussed.
Light industrial and commercial operations in cities usually contribute
salts to the municipal sewage or to the groundwater eventually returning
to the river. Although the individual contribution may be small,
the collective total can become appreciable, and all sources should be
evaluated for effective control.
6. The total sal inity problem - The salts added by the natural
and beneficial use sources I isted above combine with diminishing flows due
to consumptive use and diversions out of the Colorado River Basin to present
a serious sal inity problem for all of the users of the Colorado River
water downstream of Lake Mead. The Bureau of Reclamation and Geological
Survey are cooperating in an electric analog study of the diversions, use
and returns for the area downstream of Imperial Dam, but this study is
far too 1imited in scope and tends to convey the idea that the sal inity
problem is the responsibil ity of this one area alone, whereas it is a
total Basin problem. This concept of a local ized problem as set forth in
l1inute 218 ( Exhibit 21) is totally unacceptable to Arizona, and the temporary
alleviation procedure effective until November 16, 1970 must be replaced
by a more acceptable procedure which recognizes total Basin responsibil
ity. The Council will cooperate with the above agencies in working
out a satisfactory pol icy on sal inity control.
A report on the study and suggestions on the problem solution by
the Bureau of Reclamation and the Geological Survey is due on May 16 t 1970.
7. Heavv metals and associated chemicals - The concentrations of
- 32-
these chemicals in waters of the State are historically very low. Wastes
containing these elements are widely scattered and can be controlled by
discharge requirements on the individual waste stream. Each discharge requirement
wi Jl be based on appropriate factors such as, but not limited
to the di lutlon capacity of the stream and beneficial uses of the stream.
The setting of stream standards at USPHS drinking water limits
could be interpreted by a discharger as meaning that he could discharge
these chemicals into the stream up to the limit. In effect, then, standards
could be unjustly used to discriminate against downstream users because
there is no di lution capacity left. This problem of apportionment
of dilution capacity of the stream must be solved on an entire basin level
before specific limits can be placed on the main stem of the Colorado and
Gi la. This task is expected to take one to three years.
Unti I specific limits are set, the policy of the Council through the
State Department of Health is to minimize any discharge of these chemicals
to the river in accordance with the Statement of Policy. Generally, industry
is the source of disposals containing these chemicals; ' and also
generally! these wastes are contained in relatively small volumes of water
which could be economically disposed of elsevihere.
8. Biocides - Biocides have been the subject of much discussion
in the past, and probably wi II be discussed for many years. Prudent use
of biocides has enabled our agriculturaJ industry to provide ample food
and fiber products for our high standards of living. EstheticaJly, we
can have better gardens and a more healthful existence because of biocides.
Uncontrolled use of biocides is not beneficial, and should not be allowed.
Generally speaking, biocides are expensive, and over applications are seldom
made. Discharges of wastes containing biocides from manufacturing and
tank cleaning operations must not be allowed.
More research and study of the cumulative effects of biocides on
humans and wi ldlife must be made, and appropriate safeguards applied as
standards for the waters of the State.
Types and effects of biocides are too numerous and varied for tabulation.
Further, the intricacies and variations of technical analysis
for biocides presently defy the prescription of anyone or a few tests for
their detection or determination. Bio- assay tests can be used to establish
allowable limits for biocides.
Application of biocides in agricultural operations which could result
in biocide levels in waters of the State which are deleterious to
human, animal, plant or aqcatic life shall be subject to abatement. Mere
detection of a biocide in the water is not cause for abatement.
9. Radioactivity - Radioactivity in waters of the State is contained
within satisfactory limits. There are no wastes containins radioacti~
ity being discharged into the Arizona reaches. Future problems wi II
be controlled by discharge requirements.
10. Other chemical characteristics - Boron reduction wi 11 be con-
- 33-
sidered along with reduction of sal inity in agricultural return flows.
Phenols and organic chemical concentrations are not now a problem,
and there are no known discharges. Any proposed discharges will be subject
to regulations commensurate with timely technology.
Eutrophication, although not a major problem at this time, could become
a problem if the nutrient concentration in the water increases. Minimization
of nutrient contributions to the river systems is mandatory.
3. When waters containing considerable dissolved salts are being
considered for discharge to the river, total resource effects should be
determined, and the decision should not be made on the basis of the concentration
of the discharge alone. This concept is vital in the conservation
of total water supply in the stream. Unwarranted depletions could
deprive downstream user~ of valuable rights to water use.
The major problem associated with control of pollutants in the waters
of the State is that the method chosen may reduce the quantity of water
available to downstream users, or may adversely affect the user downstream
by a chemical or physical change in the water. Factors such as the following
should be considered in setting numerical stream standards.
2. Disposal of sewage effluents outside of the river area can
reduce the total flow of the river and reduce the assimilative capacity
of the river downstream, denying the downstream user of his legal entitlement
to use of the water.
I. Hardness in domestic water is undesirable, and can be removed
by several processes. Ion exchange or precipitation methods can alter the
cation balance of the water to the extent that the change can adversely
affect penetration rates of water in agricultural operations.
4. In view of the fact that water disposed of on land in a basin
could return to the river underground in worse condition than when " disposed
ofII , careful consideration of requirements for disposal on land
must be made. In effect, such disposal could be similar to reclamation
of new land for agricultural purposes as far as sal inity buildup is concerned.
8. Investiqations - In view of the changing topography and increasing
A. Water augmentation - The need of a major water augmentation program
for the Colorado River System is immediate. Institution of this important
program requires cooperative actions and representations between local,
state, interstate and federal agencies. The Council and the State Department
of Health will do all that it can to expedite the institution of such
water augmentation program to improve water qual ity in the Colorado and
Gila River Systems.
REG. f,- 2- 4.4 ADDITIONAL MEASURES TO ENHANCE WATER QUALITY
- 34-
intensity of multiple use of waters of the State, it is necessary that
periodic investigations be conducted in the river or on the watershed to
remain apprised of the most recent conditions which may degrade water
qual ity, and which may affect any particular beneficial use of the river
waters. The scope of such investigations will vary from cursory field
inspections to technical studies of water qual ity conditions. The investigations
will be conducted under the direction of the Council by the
State Department of Health staff either alone or in cooperation with other
agencies. However, where specialty is required, the State Department of
Health will either request or contract the necessary services.
Special emphasis wil 1 be placed on finding practical means of reducing
the sal inity of agricultural drainage water, since this beneficial use
requires that large quantities of water be returned to the river in order
to maintain a salt balance.
C. Coordination with other agencies - The Council and the State Department
of Health, in the pursuance of their water qual ity control activittes
will at all times remain in advisement and consultation with the several
interested agencies, and will work cooperatively with these agencies to
produce the most effective water qual ity control program.
Each beneficial water use requires certain indicators of water qual ity
as desirable or essential. Pertinent indicators are investigated for
adequate protection of each beneficial use. Hater qual ity objectives
are formulated in consideration of these indicators, and effects upon
the economy of the area which may result from various levels of control.
Where more than one level of an indicator is under consideration in the
protection of various beneficial uses, preferential selection is given
to that level which represents the superior water qual ity.
In the selection of standards for a particular water qual ity objective,
consideration must be given to the economic and social effects which may
result therefrom.
General water quality objectives are:
l. To provide the highest qual ity water practicable for all benef
ic ia I uses.
2. To protect the publ ic health.
3. To preclude pollution of the waters of the State.
The most important water qual ity indicators for protection of irrigated
agriculture are sal inity, sodium relationships, boron and bicarbonate
effects. These Indicators are as follows:
I. Sal inity - Excessive sal inity in the root zone causes adverse
effects upon plant life, ranging from leaf- burn to death of the plant.
Sal inity characteristics of water for agricultural appl ications are most
- 35-
effectively indicated by measuring the:
a. Total Dissolved Solids ( TDS), in mg/ l.
b. Electrical Conductivity ( ECxI06), micromhos.
The records indicate some increase of sal inity in Colorado River
water released towards Arizona, as well as continuing increase in total
quantities of salts returned to the main stem from farm drainage on both
sides of the river along the Arizona reach.
The use of waters of the State for irrigation requires special management
for salinity control. Adequate drainage must be provided, and" crop
selection must be I imited to those crops which wifl tolerate the existing
salt content at the point of use.
TDS I imits for stockwatering are far more I iberal than are those for
irrigation. Therefore, sal inity control is oriented towards irrigation requirements.
2. Sgdium relationships - The predominance of sodium salts in soil
is detrimental to maintenance of proper tilth and structure for agricultural
purposes. High concentrations of sodium in agricul tural supply waters
( relative to calcium and magnesium) will cause cationic exchange whereby
sodium will replace calcium and magnesium in the so! L The water qual ity
indicator which expresses the level of sodium, relative to calcium and
magnesium, is called " percent sodium" and is expressed mathematically as
Na x 100
Na+ Ca+ Mg+ K
where the basic constituents are expressed as mill iequivalents per 1iter.
The sodium percentage of a water can change as water concentrates
by evaporation. For this reason, the " alkal i factor", or ratio of sodium
to chloride plus sulfate, in millequivalents per I iter, could be a more
definitive term for sodium hazard, and its use is gaining in popu~ arity.
An alkal i factor of 1.0 or greater represents a " black alkal i" condition
( an excess of bicarbonate over calcium plus magnesium), which is more damag~
ing than the " white alkal i" which is essentially sodium chloride and sodium
sulfate. An alkal i factor less than 0.70 would be satisfactory for irrigation
use. A lower I imit of 0.40 to 0.50 would probably be suitable for
the benefit of non- agricultural users.
Percent sodium in Colorado River water ranges from approximately 28
at Lees Ferry to approximately 51 at Imperial Dam. The recommended safe
1imit of this characteristic for continuous appl ications is 50. The
alkal i factor increases from about 0.49 to 0.55 between Lees Ferry and
Imperial Dam. In view of the low soil permeabil ity of many Lower Basin
areas being irrigated with this water, every effort should be made to control
sodium content in Colorado River waters, such that the present Jevel
of this indicator wilJ. not be fncreased at Imperial Dam. Sodium and alkal i
figures vary widely in. the Gila River Basin.
- 36-
3. BO~£ Q - The symptoms of boron injury, particularly in trees
which are less tolerant to this constituent, are leaf yellowing and burning,
premature leaf drop, and reduced yield. Citrus trees are among the
crops most sensitive to boron. The critical concentration is accepted as
0.4 to 0.5 mg/ l in irrigation waters. Citrus is one of the main crops in
both the Yuma area of Arizona and the Coachella Valley of Cal ifornia.
Both of these areas draw water from Imper ia I Dam. Our in9 1964, the average
boron content of Colorado River water at Imperial · Dam was 0.2 mg/ I and
the maximum content was 0.4 mg/ I.
To protect the extensive citrus industries cited, the qual ity of
Colorado River water at Imperial Dam, as represented by boron concentrations,
must be at least maintained, and this qual ity should be enhanced
if at all possible. Boron concentrations in the Gila varies widely and
this restricts its use for some crops.
4. Bicarbonate effects - Bicarbonate in irrigation water adds to
the sodium hazard by precipitating out the calcium and magnesium salts,
with the resultant proportional increase in sodium content. This effect
is usually expressed in terms of the " res idual sodium carbonatell ( RSC),
defined as
RSC 0 ( C03 + HC03) - ( Ca + Mg)
The RSC levels of Colorado River water in Arizona are as follows
( 1962 water year, the last data available before the fill ing of Lake Powell)
These ionic constituents are expressed as mill iequivalents per liter.
Waters containing 1.25 - 2.5 meq. per 1iter of RSC are of marginal quality
for irrigation purposes. Waters containing over 2.5 meq. per I iter of RSC
are not suitable for irrigation purposes.
Lees Ferry
Hoover Dam
Imperial Dam
RSC Level
- 3.7 meq/ l
- 4.1 meq/ I
- 3.8 meq/ l
Similar negative RSC levels are found in Gila River water.
In view of the negative values, it appears that the bicarbonate
level of the waters of the State are well within the safe range for agricultural
The State Department of Health is the unit of State Government with
primary responsibil ity for formulating and enforcing qual ity of water de-l
ivered for domestic purposes. This responsibil ity also includes consideration
of the qual ity of raw water being diverted for domestic use.
The USPHS Drinking Water Standards are appl ica, bl. e, but I iberal interpretation
must be used because of the high natural. sal inlty of Arizona waters.
REG. 6- 2- 4.7 RA\ t! DOMESTIC WATER
It Is recognized that USPHS Standards apply to treated drinking water
- 37-
suppl ies. However, since many: of the indicators cannot be removed by
conventional or reasonable treatment, the USPHS I imits for most of the
Indicators are applicable to raw domestic water supplies. Bacteriological,
physical, chemical and radioactivity indicators must be considered as
I. Bacteriological Quality - Publ ished records show that existing
coliform counts in certain reaches of the'Colorado River are appreciable~
Col iform counts at WPSS Stations in the Upper Colorado River Basin have
been consistently higher than those at Page, Arizona. The long stretches
of the river in remote, inaccessible areas
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