QUALITY OF WATER 

COLORADO RIVER BASIN 

Progress Report No. 22 

U.S. Department of the Interior 

Bureau of Reclamation 

Upper Colorado Region 2005
2
TABLE OF CONTENTS 

SUMMARY ...................................................................................................................................... 1 

CHAPTER 1 - INTRODUCTION ..................................................................................................... 3 

AUTHORIZATION FOR REPORT ............................................................................................ 3 

LEGAL ASPECTS ...................................................................................................................... 4 

Water Quantity ................................................................................................................... 4 

Water Quality ..................................................................................................................... 5 

CHAPTER 2 – SALINITY CONDITIONS........................................................................................ 7 

CAUSES OF SALINITY .............................................................................................................. 7 

HISTORIC SALINITY CONDITIONS .......................................................................................... 9 

FACTORS INFLUENCING SALINITY......................................................................................... 9 

Streamflow ..................................................................................................... 9 

Reservoir Storage .......................................................................................... 10 

Reservoir Initial Filling Salt Leaching Impacts to Salinity ................................................. 11 

SALINITY TREND STUDIES .................................................................................................... 14 

NATURAL VARIATION IN SALINITY ....................................................................................... 16 

AGRICULTURAL SOURCES OF SALINITY ............................................................................ 16 

UPPER BASIN IRRIGATION.................................................................................................... 17 

 WATER USE BY AGRICULTURE & MUNICIPAL & INDUSTRIAL USERS............................. 17 

FUTURE WATER DEVELOPMENT ......................................................................................... 18 

COMPLIANCE WITH THE SALINITY STANDARDS................................................................ 21 

SALINITY CONTROL................................................................................................................ 22 

CHAPTER 3 - SALINITY MODELING ......................................................................................... 23 

 ECONOMIC SALINITY DAMAGE MODEL.............................................................................. .23 

 COLORADO RIVER SIMULATION SYSTEM .......................................................................... 24 

 Salinity Model Verification .............................................................................................. .24 

 Future Salinity Projections ............................................................................................... 24 

 CE-QUAL-W2 RESERVOIR MODELING ................................................................................. 26 

 Model Calibration ............................................................................................................. 27 

 Future Salinity Scenarios ................................................................................................. 27 

CHAPTER 4 - TITLE I SALINITY CONTROL PROGRAM .................................................33 

COACHELLA CANAL LINING .................................................................................................. 33 

PROTECTIVE AND REGULATORY PUMPING....................................................................... 34 

YUMA DESALTING PLANT...................................................................................................... 35 

WELLTON-MOHAWK IRRIGATION AND DRAINAGE DISTRICT........................................... 36 

 Acreage Reduction .......................................................................................................... 37

 District Irrigation Efficiency Improvement Program ......................................................... 37 
ii

TABLE OF CONTENTS (Continued) 

 On-Farm Improvements Program ................................................................................... 37 

 Irrigation Management Services Program ....................................................................... 37

 Research and Demonstration Program ........................................................................... 38 

 Education and Infomation Program ................................................................................. 38 

 Results ............................................................................................................................. 38 

 Status ............................................................................................................................... 38 

CHAPTER 5 - TITLE II SALINITY CONTROL PROGRAM ......................................................... 41 

USDA / NRCS .......................................................................................................................... 41 

BLM .......................................................................................................................................... 42 

Planning and Public Involvement .................................................................................... 42 

Nonpoint Source Control ................................................................................................. 43 

Point Source Control ....................................................................................................... 43 

Estimating Salinity Control ............................................................................................... 44 

RECLAMATION ........................................................................................................................ 44 

Background ...................................................................................................................... 44 

Public Review .................................................................................................................. 45 

Guidelines ........................................................................................................................ 46 

Performance Review ....................................................................................................... 46 

CHAPTER 6 - OTHER WATER QUALITY ISSUES .................................................................... 49 

 PERCHLORATE ....................................................................................................................... 49 

 THM........................................................................................................................................... 49 

 ALGAE....................................................................................................................................... 49 

 TMDL's. ..................................................................................................................................... 50 

 URANIUM MINE TAILINGS. ................................................................................................... 51 

REFERENCES CITED ................................................................................................................. 53

GENERAL REFERENCES ........................................................................................................... 56 

APPENDIX A – SALINITY DATA .....................................................................................................63
iii

TABLES

Table 1 – Quantified Sources of Salt Loading ................................................................................ 8 

Table 2 - Hydrology and Salt at Grand Canyon and Virgin River Streamflow Gages................... 12

Table 3 - Upper Basin Depletion Projections ............................................................................... 19 

Table 4 - Lower Basin Depletion Projections ............................................................................... 20 

Table 5 - Salinity Control Requirements and Needs .................................................................... 22 

Table 6 - Probability of Exceeding Numeric Criteria ..................................................................... 26 

Table 7 - Hydrology of the Individual Years Modeled and Percentage of Long Term Averages 

either 1964-2002 or 1992-2002) ................................................................................... 28 

Table 8 - Statistical Hydrology for each trace arraying potential future salinity ranges below 

Glen Canyon and Hoover Dams .................................................................................. 30 

Table 9 - District Pumped Drainage Return Flow ......................................................................... 39 

Table 10 - USDA Salinity Control Program Summary .................................................................. 41 

Table 11 - Estimated Salt Retained on BLM Lands ..................................................................... 44 

Table 12 - Reclamation Basinwide Salinity Control Program Salt Controlled, tons/yr ................. 48 

FIGURES

Figure 1 - Sources of Salinity ......................................................................................................... 7

Figure 2 - Percentage of Salinity Damages..................................................................................... 8

Figure 3 - Mainstem Flow and Salinity ............................................................................................ 9 

Figure 4 - Effects of Glen Canyon Dam on Colorado River Salinity at Lees Ferry ....................... 10 

Figure 5 - Graph of Flow and Salt, with Short and Long Term Trend Lines, Illustrating the 

Change in Salinity over Time below Hoover Dam ........................................................ 11 

Figure 6 - Green River below Flaming Gorge Reservoir, Flow and Salt over Time...................... 13 

Figure 7 - Lake Powell Forebay, Dec 1964 to Dec 2004 Salinity Concentration, mg/L ............... 14 

Figure 8 - Lake Powell Inflow and Outflow Salt Concentration, mg/L ........................................... 15 

Figure 9 - “Bathtub Ring” on Lake Powell ..................................................................................... 15

Figure 10 - Historic and Projected Water Uses ............................................................................ 18 

Figure 11 - 2004 Est. Salinity Control Progress: BOR, NRCS & BLM ......................................... 22 

Figure 12 - Economic Model Damages caused by Increase in Salinity ........................................ 23 

Figure 13 - Calibration of CRSS 1971 – 1995 for Colorado River at Imperial Dam...................... 25 

Figure 14 - Future Salinity Concentration for Colorado River at Imperial Dam ............................ 25 

Figure 15 - Comparison of the Historical Flow Weighted Annual Average Total Dissolved Solids 

(TDS or Salinity) Released from Glen Canyon Dam with the Model Calibration....... 29 

Figure 16 - Comparison of the Historical Flow Weighted Annual Average Total Dissolved Solids 

(TDS or Salinity) Released from Hoover Canyon Dam with the Model Calibration... 29 

Figure 17 - The Array of Potential Future Salinity Concentration Ranges as a Flow Weighted 

Annual Average TDS to be Released from Glen Canyon Dam................................. 30 

Figure 18 - The Array of Potential Future Salinity Concentration Ranges as a Flow Weighted 

Annual Average TDS to be Released from Hoover Dam ......................................... 31 
iv

FIGURES (Continued) 

Figure 19 - Map of Title I Projects ................................................................................................. 33 

Figure 20 – Aerial Photo of Yuma Desalting Plant........................................................................ 35 

Figure 21 – Satellite Photo of Cienega de Santa Clara ................................................................ 40 

Figure A-1 - Colorado River Water Quality Monitoring Stations ................................................... 64 

Figure A-2 - Flow and TDS over time for sites 1-4 ....................................................................... 65 

Figure A-3 - Flow and TDS over time for sites 5-8 ....................................................................... 66 

Figure A-4 - Flow and TDS over time for sites 9-12 .......................................................... 67 

Figure A-5 - Flow and TDS over time for sites 13-16 .........................................................68 

Figure A-6 - Flow and TDS over time for sites 17-20 .........................................................69 

 
alinity 

SUMMARY 

The Colorado River and its tributaries provide municipal and industrial water to about 

33 million people and irrigation water to nearly 4 million acres of land in the United States. 

The river also serves about 3 million people and 500,000 acres in Mexico. The effect of 

salinity is a major concern in both the United 

States and Mexico. Salinity damages in the 

United States are presently about $306 million 

per year at 2004 salinity concentrations. This 

biennial report on the quality of water in the 

Colorado River Basin is required by Public Laws 

84-485, 87-483, and the Colorado River Basin 

Salinity Control Act (Salinity Control Act) 

(Public Law 93-320, as amended by Public Laws 

98-569, 104-20, 104-127, and 106-459). 

The Salinity Control Act authorizes the 

Secretaries of the U.S. Department of the 

Interior (Interior) and U.S. Department of 

Agriculture (USDA) to enhance and protect the quality of water available in the Colorado 

River for use in the United States and the Republic of Mexico. 

Salinity damages to municipal water pipe. 

Title I of the Salinity Control Act authorized the construction and operation of a desalting 

plant, brine discharge canal, and other 

features to enable the United States to 

deliver water to Mexico having an 

average salinity no greater than 115 

parts per million (ppm) plus or minus 

30 ppm over the annual average s

of the Colorado River at Imperial

Dam. The Title I program 

(administered by the Bureau of 

Reclamation [Reclamation]) continues 

to meet the requirements of Minute 

No. 242 of the International Boundary 

and Water Commission, United States 

and Mexico. 

Salinity damages to crop production. 

In 1995, Public Law 104-20 authorized an entirely new way of implementing salinity control. 

Reclamation’s Basinwide Salinity Control Program opens the program to competition 

through a “Request for Proposal” process, which has greatly reduced the cost of salinity 

control. However, as the lowest cost projects are built, the price of salinity control is 

expected to continue to increase in the future. 

The Colorado River Basin Salinity Control Forum (Forum) in accordance with the 

requirements of the Clean Water Act, prepared the 2002 Review, Water Quality Standards for 

Salinity, Colorado River System (Review). The Review reported that by 2025 a target of 1.8 

million tons per year of salt will need to be diverted from entering the Colorado River in 
2

order to meet the water quality standards in the Lower Basin, below Lees Ferry, AZ. The 

combined Reclamation, USDA & BLM salinity reduction reported for 2004 shows that the 

Colorado River Basin Salinity Control Program (Program) has controlled over 1,072,000 

tons of salt per year. In order to meet the 1.8 million tons of salt per year goal, it will be 

necessary to fund and implement potential new measures which ensure the removal of an 

additional 728,000 tons by 2025. The Forum stated that in order to achieve this level of salt 

reduction, the federal departments and agencies would require the following capital funding: 

Reclamation appropriation - $10.5 million per year (bringing the total Reclamation program 

with cost-sharing to $15 million per year); and USDA EQIP appropriation - $13.8 million 

per year (bringing the total on-farm program to $19.7 million per year with Basin states 

parallel program). Beginning in 2005, BLM began a comprehensive program to minimize the 

salt loading from BLM lands in the Colorado River basin. BLM salinity funding from 

Congress began in FY 2006. 

With the reported existing salt controlled, and assuming no reduction of the existing salinity 

control projects, then nearly 35,000 tons of new controls will need to be implemented each 

year to maintain the standards with increased future water development. This Program goal 

is the combined target for the participating agencies within Interior and USDA. The 

participating agencies reported to the Colorado River Basin Salinity Control Advisory 

Council, showing that the agencies efforts have been able to exceed the program’s target 

over the past several years. 

Colorado River flows have averaged only about 50% over the five years of drought from 

1999-2004. Salinity increased significantly during this period, but has not exceeded the 

numeric salinity criteria on the Colorado River below Hoover Dam, Parker Dam and at 

Imperial Dam; 723, 747 & 879 mg/L respectively. Reclamation’s short term future salinity 

modeling scenarios indicate that the numeric salinity criteria should be maintained even with 

an additional 1-2 years of drought. However, the uncertainty of the prediction is within reach 

of the salinity criteria. The salinity criteria could have been exceeded in 2003 or 2004 without 

the salinity control program and other salt reductions. Nevertheless, salinity damages are still 

very high at the 2004 salinity levels. This is the first observation of this level of reservoir 

draw down. This drought is providing new data, which will eventually reduce the uncertainty 

in salinity forecasting. For example, it was not obvious in 2002 that an additional 2 years of 

drought would not cause exceedance of the criteria. 

Other Colorado River Basin water quality issues of concern include reservoir eutrophication 

and algae impacts to drinking water treatment; natural bromide in the water and formation 

of potentially toxic or carcinogenic trihalomethanes (THM) with chlorination or ozonation 

during water treatment; selenium and trace elements from irrigation return flows and their 

impacts to endangered species; contaminants such as ammonium perchlorate into Lake 

Mead; ammonium, trace elements, and radiologicals from the Atlas Uranium Tailings on the 

Colorado River at Moab, Utah; and salinity, eutrophication, agro-chemicals, and selenium at 

the Salton Sea. 
3

Chapter 1 - INTRODUCTION 

The Bureau of Reclamation (Reclamation) of the U.S. Department of the Interior prepared 

this report in cooperation with State water resource agencies and other Federal agencies 

involved in the Colorado River Basin Salinity Control Program (Salinity Control Program). 

This Progress Report is the latest in a series of biennial reports that commenced in 1963. 

AUTHORIZATION FOR REPORT 

The directive for preparing this report is contained in four separate public laws. 

Public Law 84-485 states: 

Section 15 –“The Secretary of the Interior is directed to continue studies and make a 

report to the Congress and to the States of the Colorado River Basin on the quality 

of water of the Colorado River,” 

Section 5c – “All revenues collected in connection with the operation of the 

Colorado storage project and participating projects shall be credited to the Basin 

Fund, and shall be available, without further appropriation, for (1) defraying the 

costs of operation, maintenance, & replacement of, and emergency expenditures for, 

all facilities ...”. The ongoing water quality monitoring, studies, and report are 

considered part of the normal operation of the project and are funded by the Basin 

Fund.” 

Public Law 87-483 states: 

Section 15 - “The Secretary of the Interior is directed to continue his studies of the 

quality of water of the Colorado River System, to appraise its suitability for 

municipal, domestic, and industrial use and for irrigation in the various areas in the 

United States in which it is used or proposed to be used, to estimate the effect of 

additional developments involving its storage and use (whether heretofore 

authorized or contemplated for authorization) on the remaining water available for 

use in the United States, to study all possible means of improving the quality of such 

water and of alleviating the ill effects of water of poor quality, and to report the 

results of his studies and estimates to the 87th Congress and every 2 years 

thereafter.” 

Public Law 87-590 states that January 3 would be the submission date for the report. 

Public Law 93-320 states: 

“Commencing on January 1, 1975, and every 2 years thereafter, the Secretary shall 

submit, simultaneously, to the President, the Congress, and the Advisory Council 

created in Section 204(a) of this title, a report on the Colorado River salinity control 

program authorized by this title covering the progress of investigations, planning, 

and construction of salinity control units for the previous fiscal year; the 

effectiveness of such units; anticipated work needed to be accomplished in the future 

to meet the objectives of this title, with emphasis on the needs during the 5 years 

immediately following the date of each report; and any special problems that may be 
4

impeding progress in attaining an effective salinity control program. Said report may 

be included in the biennial report on the quality of water of the Colorado River Basin 

prepared by the Secretary pursuant to section 15 of the Colorado River Storage 

Project Act (70 Stat. 111; 43 U.S.C. 602n), section 15 of the Navajo Indian Irrigation 

Project and the initial stage of the San Juan-Chama Project Act (76 Stat. 102), and 

section 6 of the Fryingpan-Arkansas Project Act (76 Stat. 393).” 

LEGAL ASPECTS 

Water Quantity 

Colorado River water was apportioned by the Colorado River Compact of 1922, the Boulder 

Canyon Project Act of 1928, the Water Treaty of 1944, the Upper Colorado River Basin 

Compact of 1948, and the United States Supreme Court (Arizona v. California et al., 1963). 

The Colorado River Compact divided the Colorado River Basin between the Upper and 

Lower Basins at Lee Ferry (just below the confluence of the Paria River), apportioning to 

each use of 7.5 million acre-feet (maf) annually. In addition to this apportionment, the 

Lower Basin was given the right to increase its beneficial consumptive use by 1 maf per year. 

The compact also contains provisions governing exportation of Colorado River water. The 

Water Treaty of 1944 obligates the United States to deliver to Mexico 1.5 maf of Colorado 

River water annually, absent treaty surplus or shortage conditions. 

Upper Colorado Use - The Upper Colorado River Basin Compact of 1948 divided and 

apportioned the water apportioned to the Upper Colorado River Basin by the Colorado 

River Compact, allocating to Arizona 50,000 acre-feet annually, with the remaining water 

allocated to Upper Colorado River Basin States as follows: 

• Colorado 51.75 percent 

• New Mexico 11.25 percent 

• Utah 23 percent 

• Wyoming 14 percent 

Lower Colorado Use - States of the Lower Colorado River Basin did not agree to a 

compact for the apportionment of waters in the Lower Colorado River Basin; in the absence 

of such a compact Congress, through Secretarial contracts authorized by the Boulder 

Canyon Project Act, allocated water from the mainstem of the Colorado River below Lee 

Ferry among California, Nevada, and Arizona, and the Gila River between Arizona and New 

Mexico. This apportionment was upheld by the Supreme Court, in 1963, in the case of 

Arizona v. California. 

As confirmed by the U.S. Supreme Court in 1963, from the mainstem of the Colorado River 

(i.e., The Lower Basin): 

• Nevada was apportioned 300,000 acre-feet annually and 4 percent of surplus water 

available, 

• Arizona was apportioned 2,800,000 acre-feet annually and 46 percent of surplus 

water available, 

• California was apportioned 4,400,000 acre-feet annually and 50 percent of surplus 

water available. 
5

Water Quality 

Although a number of water-quality-related legislative actions have been taken on the State 

and Federal levels, several Federal acts are of special significance to the Colorado River 

Basin: the Water Quality Act of 1965 and related amendments, the Federal Water Pollution 

Control Act Amendments of 1972 (Public Law 92-500), commonly referred to as the Clean 

Water Act and related amendments, and the Colorado River Basin Salinity Control Act 

(Salinity Control Act) of 1974 as amended. Also, central to water quality issues are 

agreements with Mexico on Colorado River System waters entering that country. 

The Water Quality Act of 1965 (Public Law 89-234) amended the Federal Water Pollution 

Control Act and established a Federal Water Pollution Control Administration (now 

Environmental Protection Agency [EPA]). Among other provisions, it required States to 

adopt water quality criteria for interstate waters inside their boundaries. The seven Basin 

States initially developed water quality standards that did not include numeric salinity criteria 

for the Colorado River primarily because of technical constraints. In 1972, the Basin States 

agreed to a policy that called for the maintenance of salinity concentrations in the Lower 

Colorado River System at or below existing levels, while the Upper Colorado River Basin 

States continued to develop their compact-apportioned waters. The Basin States suggested 

that Reclamation should have primary responsibility for investigating, planning, and 

implementing the proposed Salinity Control Program. 

The enactment of the Federal Water Pollution Control Act Amendments of 1972 affected 

salinity control, in that it was interpreted by EPA to require numerical standards for salinity 

in the Colorado River. In response, the Basin States founded the Colorado River Basin 

Salinity Control Forum (Forum) to develop water quality standards, including numeric 

salinity criteria and a basinwide plan of implementation for salinity control. The Basin States 

held public meetings on the proposed standards as required by the enacting legislation. The 

Forum recommended that the individual Basin States adopt the report, Water Quality 

Standards for Salinity, Including Numeric Criteria and Plan of Implementation for Salinity Control, 

Colorado River System. The proposed water quality standards called for maintenance of 

flow-weighted annual averaged total dissolved solids concentrations of 723 milligrams per 

liter (mg/L) below Hoover Dam, 747 mg/L below Parker Dam, and 879 mg/L at Imperial 

Dam. Included in the plan of implementation were four salinity control units and possibly 

additional units, the application of effluent limitations, industrial use of saline water, and 

future studies. The standards are to be reviewed at 3-year intervals. All of the Basin States 

adopted the 1975 Forum-recommended standards. EPA approved the standards. 

The Salinity Control Act of 1974 (Public Law 93-320) provided the means to comply with 

the United States’ obligations to Mexico under Minute No. 242 of the International 

Boundary and Water Commission, United States and Mexico, which included, as a major 

feature, a desalting plant and brine discharge canal for treatment of WMID drainage water. 

These facilities enable the United States to deliver water to Mexico having an average salinity 

of 115 parts per million (ppm) plus or minus 30 ppm (United States’ count) over the annual 

average salinity of the Colorado River at Imperial Dam. The act also authorized construction 

of 4 salinity control units and the expedited planning of 12 other salinity control projects 

above Imperial Dam as part of the basinwide salinity control plan. 

In 1978, the Forum reviewed the salinity standards and recommended continuing 

construction of units identified in the 1974 act, placing of effluent limitations on industrial 
6

and municipal discharges, and reduction of the salt-loading effects of irrigation return flows. 

The review also called for the inclusion of water quality management plans to comply with 

section 208 of the Clean Water Act. It also contemplated the use of saline water for 

industrial purposes and future salinity control. 

Public Law 98-569, signed October 30, 1984, amended Public Law 93-320. The amendments 

to the Salinity Control Act authorized the U.S. Department of Agriculture (USDA) Colorado 

River Salinity Control Program. The amendments also authorized two new units for 

construction under the Reclamation program. 

In 1993, the Dept. of Interior Inspector General concluded that the lengthy congressional 

authorization process for Reclamation projects was impeding the implementation of costeffective measures. Consequently, a public review of the program was conducted in 1994. In 

1995, Public Law 104-20 authorized Reclamation to implement a basinwide approach to 

salinity control and to manage its implementation. Reclamation completed solicitations in 

1996, 1997, 1998, 2001, and 2004 in which Reclamation requests proposals, ranks the 

proposals based on their cost and performance risk factors, and awards funds to the most 

highly ranked projects. The awards from the first three solicitations consumed the available 

appropriation ceiling of $75 million authorized by Congress to test the new program. 

In 1996, Public Law 104-127 significantly changed the authorities provided to USDA. 

Rather than carry out a separate salinity control program, the Secretary of Agriculture was 

directed to carry out salinity control measures in the Colorado River Basin as part of the 

Environmental Quality Incentives Program established under the Food Security Act of 1985. 

Public Law 104-127 also authorized the Secretary of Agriculture to cost share salinity control 

activities from the basin funds in lieu of repayment. Cost sharing has been implemented for 

both USDA and Reclamation programs. Under this new authority, each dollar appropriated 

by the Congress is matched by $0.43 in cost sharing from the basin funds. 

In 2000, Public Law 106-459 amended the Colorado River Basin Salinity Control Act to 

increase the appropriation ceiling for Reclamation’s basinwide approach by $100 million 

($175 million total). This appropriation authority will allow Reclamation to continue to 

request new proposals under its Basinwide Salinity Control Program. In 2002, Public Law 

107-171, Title II, Subtitle D reauthorized the USDA’s Environmental Quality Incentives 

Program (under which the Secretary of Agriculture carries out salinity control measures). 

Nothing in this report is intended to interpret the provisions of applicable federal law 

including, but not limited to, The Colorado River Compact (42 Stat. 171), The Upper 

Colorado River Basin Compact (63 Stat. 31), The Utilization of Waters of the Colorado and 

Tijuana Rivers and of the Rio Grande, Treaty Between the United States of America and 

Mexico (Treaty Series 994, 59 Stat. 1219), the United States/Mexico agreement in Minute 

No. 242 of August 30, 1973, (Treaty Series 7708; 24 UST 1968), the 1964 Decree entered by 

the Supreme Court of the United States in Arizona v. California et al. (376 U.S. 340), as 

amended and supplemented, The Boulder Canyon Project Act (45 Stat. 1057), The Boulder 

Canyon Project Adjustment Act (54 Stat. 774; 43 U.S.C. 618a), The Colorado River Storage 

Project Act (70 Stat. 105; 43 U.S.C. 620), The Colorado River Basin Project Act (82 Stat. 

885; 43 U.S.C. 1501), The Colorado River Basin Salinity Control Act (88 Stat. 266; 43 U.S.C. 

1571), The Hoover Power Plant Act of 1984 (98 Stat. 1333), The Colorado River Floodway 

Protection Act (100 Stat. 1129; 43 U.S.C. 1600), or The Grand Canyon Protection Act of 

1992 (Title XVIII of Public Law 102-575, 106 Stat. 4669). 
7

CHAPTER 2 - SALINITY CONDITIONS 

CAUSES OF SALINITY 

Sources of Salinity

Natural

47%

M&I

4%

Reservoir

12%

Irrigation

37%

The Colorado River System is naturally very saline. At the USGS gauge below Hoover Dam, 

between 1940 and 1979 an average of approximately 9.4 million tons of salt were carried 

down the river every year. Since 1980, on average, approximately 8.7 million tons of salts 

have been measured in the river each year, with the trend going down (see Figure 2, page 

10). The flow of the river dilutes this salt, and depending upon the quantity of flow, salinity 

can be relatively dilute or concentrated. Since climatic conditions directly affect the flow in 

the river, salinity in any one year may double (or halve) due to extremes in runoff. Because 

this natural variability is virtually uncontrollable, the seven Basin States adopted a nondegradation water quality 

standard. 

Nearly half of the salinity 

in the Colorado River 

System is from natural 

sources. Saline springs, 

erosion of saline geologic 

formations, and runoff all 

contribute to this 

background salinity. 

Irrigation, reservoir 

evaporation, and municipal 

and industrial (M&I) 

sources make up the 

balance of the salinity 

problem in the Colorado 

River Basin. Figure 1 shows 

the relative amounts each 

source contributes to the 

salinity problem. The Environmental Protection Agency (EPA, 1971) estimated that the 

natural salinity in the Lower Colorado River at Imperial Dam, was 334 milligrams per liter 

(mg/L). In 2004, the average annual flow weighted salinity at Imperial Dam was reported to 

be about 706 mg/L, a 372 mg/L increase over the estimated natural salinity. Table 1 on the 

following page quantifies several of these known sources. 

Figure 1 - Sources of Salinity

Salinity of the Colorado River has been increased by the development of water resources in 

two major ways: (1) the addition of salts from water use and (2) the consumption (depletion) 

of water. The combined effects of water use and consumption have had a significant impact 

on salinity in the Colorado River Basin. The basin wide drought, since 1999, has also had an 

influence on the present salinity of the Colorado River. 

Current information indicates that the present salt levels in the Colorado River system have 

few if any negative health effects for EPA’s primary drinking water standards (see Progress 

Report 21, Health section). However, the EPA secondary drinking water standards are 500 

mg/L for TDS (salinity), and 250 mg/L for sulfate. A regression of sulfate versus TDS 
8

Table 1 - Quantified Sources of Salt Loading 

Source

Type of 

Source

Salt Loading 

(tons per year)

Paradox Springs Springs 205,000 1 (Preproject)

Dotsero Springs Springs 182,600

Glenwood Springs Springs 335,000

Steamboat Springs Springs 8,500

Pagosa Springs Springs 7,300

Sinbad Valley Springs 6,500

Meeker Dome Springs 57,000 1 

Other minor springs in the Upper Basin Springs 19,600

Blue Springs (Little Colorado River in Grand Canyon) Springs 550,000 

La Verkin Springs (Virgin River inflow into Lake Mead) Springs 109,000

Grand Valley Irrigation 580,000

Big Sandy irrigation 164,000

Uncompahgre Project irrigation 360,000 1

McElmo Creek irrigation 119,000

Price-San Rafael irrigation 258,000 1

Uinta Basin mostly irrigation 240,000

Dirty Devil River Area non-point 150,000

Price-San Rafael Area non-point 172,000 1

Other, non regulated areas various 5,200,000

Total 8,724,000

Note: - Sources significantly reduced by salinity control projects 1

shows that sulfate exceeds 250 mg/L when the TDS exceeds 612 mg/L below Hoover Dam. 

During dry cycles the secondary 

drinking water standards for TDS 

and sulfate are exceeded at many 

places in the Colorado River in 

both the Upper and Lower Basins, 

including the three salinity criteria 

sites. 

The primary negative impact of 

the salt concentration is seen as 

economic. Present economic 

damages using the 2004 salinity 

levels at Imperial Dam have been 

modeled between $306 and $312 

million per year depending on the 

conditions used. Projected 2025 

salinity levels show damage estimates increasing to $471 million per year without additional 

WQIP projects being implemented. With additional WQIP projects implemented, the annual 

damages decline by $76 million or approximately $187 per ton of salt removed. Salinity 

Estimated Salinity Damages 2004 

($306 million)

49%

26%

7%

5%

5%

6% 2%

Agriculture $149m

Household $81m

Commercial $22m

Utility $14m

Industrial $16m

Groundw ater $17m

Recycled $7m

 Figure 2 – Percentage of Salinity Damages 
related damages are primarily due to reduced agricultural crop yields, corrosion, and plugging 

of pipes and water fixtures. Figure 2 breaks down the percentage of total damages. The 

seven Basin States have agreed to limit this impact and adopted numeric criteria, which 

require that salinity concentrations not increase (from the 1972 levels) due to future water 

development. Salinity levels measured in the river may be low or high due to climatic 

conditions, but the goal of the Water Quality Criteria for the Colorado River Basin and the 

Colorado River Basin Salinity Control Program (Salinity Control Program) is to offset 

(eliminate) the salinity effects of additional water development. 

HISTORIC SALINITY CONDITIONS 

Salinity in the Colorado River is monitored at 20 key stations throughout the Colorado River 

Basin (See Appendix A). Salt loads and concentrations are calculated from daily conductivity 

and flow records using methods developed jointly between Reclamation and USGS 

(Liebermann et al., 1986). Historical streamflow, and salinity concentrations from January 

1941 to present are included in graphical form in Appendix A. Data may be obtained by 

request from Reclamation, Salt Lake City, Utah or by going to Reclamation’s Upper 

Colorado Regional Office Salinity Program web page; 

http://www.usbr.gov/uc/progact/salinity/index.html. 

FACTORS INFLUENCING SALINITY 

Stream flow, reservoir storage, 

water resource development, 

salinity control, climatic 

conditions, and natural runoff 

directly influence salinity in the 

Colorado River Basin. Before any 

water development, the salinity of 

spring runoff was often below 200 

mg/L throughout the Colorado 

River Basin. However salinity in 

the lower mainstem was often well 

above 1,000 mg/L during the low 

flow months (most of the year), 

since no reservoirs existed to 

catch and store the spring runoff, 

and release this fresher water later 

through the year. 

Mainstem Flows

0

5

10

15

20

25

1970 1980 1990 2000 2010

Discharge (maf/yr)

Powell

Imperial

Mainstem Salinity

300

400

500

600

700

800

900

1000

1970 1980 1990 2000 2010

Salinity (mg/L)

Hoover Powell

Imperial

Streamflow

Streamflow directly influences 

salinity. For the most part, higher 

flows (or reservoir releases) dilute 

salinity. The top graph in Figure 3 

shows streamflow at two key 

points in the mainstem. In 1980, Figure3 - Mainstem Flow and Salinity. 

9
10

Lake Powell (Glen Canyon Dam) filled for the first time and spilled. 

This spill went through Lake Mead (Hoover Dam) and on downstream through Imperial 

Dam. In 1983 and on through 1987, flows in the system were again extremely high and 

sustained, reducing salinity to historic lows. As shown in the bottom graph of Figure 3 

(above), relatively low flows in the system after 1987 returned the salinity in the reservoir 

system to more normal levels. Figure 4 shows the salinity concentration below Glen Canyon 

Dam, from 1941 to 2004. 

Salinity Below Glen Canyon Dam 

0

200

400

600

800

1000

1200

1400

1600

1940 1950 1960 1970 1980 1990 2000 2010

Monthly Salinity (mg/L)

Dam closure and 

reservoir storage in 

mid-1960's reduced 

variation in salinity

Figure 4 - Effects of Glen Canyon Dam on Colorado River Salinity at Lees Ferry. 

Reservoir Storage 

The Colorado River Storage Project Reservoirs produce not only major hydrologic 

modifications downstream, but they also significantly alter salinity cycles. The overall long 

term salinity affects of the Reservoirs are beneficial and have greatly reduced the salinity 

peaks (Figures 4 & 5). When Lakes Powell and Mead are full they can contain over 50 

million acre-feet of water. On average Lakes Powell and Mead contain more than 3 years the 

volume of the mean annual flow in the river. During a drought the inflow to Lake Powell 

can drop to well below 5 million acre-feet. The hydraulic retention time of the combined 

volumes of Lakes Powell and Mead during a drought can approach ten times the inflow to 

Lake Powell. Therefore, it can take several years of drought for salinity to peak below 

Hoover Dam following the initiation of a drought in the Upper Basin. For example, the 

salinity below Hoover Dam did not peak until 1994 during the drought of 1990-1992 in the 

Upper Colorado River Basin. 

Water storage has greatly reduced extensive seasonal changes in salinity. As shown in Figure 

4, completion of Glen Canyon Dam in the mid 1960’s greatly reduced the peak monthly 

salinities observed below the dam. The high concentration low flow waters are mixed with 

low concentration spring runoff, reducing the month-to-month variation in salinity below 

the dam from 299 mg/L to 72 mg/L (Mueller et al., 1988). The pre and post dam peak 
11

monthly salinity has been reduced by nearly 600 mg/L. Similar effects can be seen below 

Flaming Gorge, Navajo, and Hoover Dams, greatly improving the quality of water during 

the summer, fall and winter. 

Colorado River below Hoover Dam, Ariz-Nev

0

100

200

300

400

500

600

700

800

900

1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

TDS (mg/L), Flow (AF x 100,000)

TDS 1940-2003 Flow, AFx100,000

Linear (TDS 1940-2003) Linear (TDS 1940-1972)

Linear (TDS 1972-2003)

Figure 5 - Graph of Flow and Salt, with Short and Long Term Trend Lines, Illustrating the Change in 

Salinity over Time below Hoover Dam.

Reservoir Initial Filling Salt leaching impacts to Salinity 

During the initial filling of about 30 million acre feet of storage in the Upper Basin from 

1963-1973, the effects were an overall increase in salinity. Initial filling of the reservoirs in 

the Upper Basin had three major impacts on salinity in the Colorado River 

1. The storage in the Upper Basin resulted in reduced flow in the Lower Basin 

(Table 2), which increased salinity in the Lower Basin by reducing dilution of approximately 

1 – 1.4 million tons of salt entering the system between Glen Canyon Dam and below 

Hoover Dam with only about 0.75 million ac-ft of water with a mean salinity of about 1,300 

mg/L. Reductions in flow appear to increase downstream salinity concentrations. 

 2. The initial filling of reservoirs in the Upper Basin resulted in a salt leach out of the 

newly inundated lands. 

 3. The addition of storage in the Upper Basin resulted in changes in irrigation 

practices which increased irrigation efficiency. Much of the current salinity control in the 

Upper Basin is based on the now proven fact that increased irrigation efficiency decreases 

salt loading (Butler, 2001). 
12

Table 2 - Hydrology and Salt at Grand Canyon and Virgin River Streamflow Gages 

1940 - 1962 1963 - 1972 1973 - 2004 

Colorado R @ Salt (mg/L) 618 697 550 

Grand Canyon Flow (1000 ac-ft/yr) 12,267 8,015 10,872 

Virgin River @ Salt (mg/L) 1,741 1,750 1,654 

Littlefield Flow (1000 ac-ft/yr) 171 142 181 

There were numerous large and small reservoirs that went through initial filling in the 

Colorado River Basin in the 1960-1980’s. Many of the smaller reservoirs should have had 

less overall salinity impact than Flaming Gorge or Lake Powell. However, many of the 

smaller reservoirs were built in Cretaceous geology with higher potential for salt leaching. 

The initial filling and leach out of salts from these reservoirs contributed to the declining 

salinity from the mid 1970’s – 1990’s, as discussed later. 

Large reservoirs like Lake Powell selectively route less saline water while holding more saline 

waters during low inflow periods. The poorer quality waters are then slowly released after 

the inflows have begun to increase, which help keep from exceeding the salinity criteria 

during the drought years. The inflows to Lake Powell were again high in 1993, and the 

salinity downstream below Hoover Dam began to decrease after 1994. When Lakes Powell 

and Mead are only about half full, and the Lake Powell inflow is 150% or more than average, 

then the hydraulic retention time is much smaller (<2 years), and the downstream dilutions 

in salinity may be seen in less time. It is interesting to note the decline in salinity seen in the 

longer term trend line below Hoover Dam (Figure 5) from the early 1990’s to 2003 is about 

equal to the estimated salinity reductions produced by the salinity control program. In the 

early to mid-1990’s, major portions of the Salinity Control Program started to come online, 

preventing about 355,000 tons of salt from entering the river system each year. These salinity 

program salt reductions decreased salinity by about 28 mg/L and helped keep the salinity 

criteria from being exceeded in 1994. This suggests that without the salinity control program 

these continued salinity declines may not be appropriately projected into the future. 

It is postulated that salt leaching from Lake Powell and Flaming Gorge Reservoir alone 

temporarily increased salinity from the mid 1960’s through the initial filling and salinity peak 

in 1972. This salt leaching plus the reduced downstream dilution due to retention of water in 

the upstream reservoirs was at least one factor in the salinity peak concentrations in the 

lower basin from 1968-1972 (see Figures 3, 5, 6 & 7). 

An illustration of the impacts of salt leaching associated with initial filling of reservoirs from 

the mid 1960’s to present is shown in Figure 6 below. Figure 6 depicts the salinity 

downstream from Flaming Gorge Reservoir (Greendale) on the Green River in Utah and 

Wyoming. Bolke and Waddel (1975) and Bolke (1979) of the U.S. Geological Survey 

reported the flow weighted annual Total Dissolved Solids (TDS) below Flaming Gorge Dam 

increased from 386 mg/L to 512 mg/L pre to post Flaming Gorge Dam up to 1975. The 

increased salt loading was primarily in the form of sulfates from internal loading of 1,947,000 

metric tons (2,144,000 tons) for the period 1963-1975 (Bolke, 1979). Therefore, the average 

salt loading from Flaming Gorge Reservoir salt leaching during initial filling from 1963-1975 
13

was approximately 170,000 tons/year. An update of this estimate indicates that the TDS 

below Flaming Gorge Dam at the Greendale Station averaged 460 mg/L from 1993 through 

2003. This would amount to about a 70,000 ton/year decrease in salt loading below Flaming 

Gorge Dam. 

200

300

400

500

600

1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Year

TDS (mg/L)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

TDS 

 Flow (1000 Acre-Ft/Yr)

Pre/Post (1963) Flamng Gorge Dam 5

&10 yr. moving average TDS

Flow 

Figure 6 - Green River below Flaming Gorge Reservoir, Flow and Salt over Time

Both Flaming Gorge and Lake Powell selectively retain higher salinity winter inflows in the 

bottom of the pool and route lower salinity overflow density currents from the spring 

runoff. The seasonal and long term affects of this selective retention and routing of salt has 

already been shown below Glen Canyon Dam in Figure 4. Figure 7 further displays this 

retention. A long- term depth versus time profile of salinity in front of Glen Canyon Dam 

on Lake Powell is a pictured history of salinity. The Y (vertical) axis is depth in the water 

column, and the X axis is time in years. The color scale demonstrates changes in salinity. 

Two things are effectively demonstrated by this graphic: 1) Glen Canyon Dam selectively 

retains higher TDS water, especially during initial years of drought, and then routes those 

waters later usually during wetter cycles. 2) Lake Powell has selectively retained higher 

salinity water during drier years, and then routed it with the increased mixing and shorter 

hydraulic retention times of wetter cycles as seen particularly in 1983 (Figure 7). During 

these wetter cycles there is a significant mixing and dilution of these previously stored salts. 

Lake Powell also went through an initial filling salt leach out which actually began with 

temporary water retention behind the coffer dam during construction in the mid-1950’s. An 

immediate increase in salinity occurs with water storage as has been shown at Flaming Gorge 

Reservoir. Long-term linear regression trend lines on the inflow and outflow salinity 

concentrations at Lake Powell indicate that internal salt leaching seems to have declined to a 
14

minimum by the mid-1990’s suggesting a long-term salinity leach out which is approaching a 

dynamic equilibrium (Figure 8). 

3150

3200

3250

3300

3350

3400

3450

3500

3550

3600

3650

3700

Water surface elevation above Sea Level

250

290

330

370

410

450

490

530

570

610

650

690

730

770

810

850

890

930

970

1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Penstock

(feet)

TDS

mg/L

Figure 7- Lake Powell Forebay, Dec 1964 to Dec 2004 Salinity Concentration, mg/L 

SALINITY TREND STUDIES 

Over a century of water resource use and development has had some serious negative 

impacts on the water quality. Although peak salinities have been greatly reduced, the average 

annual salinities have more than doubled from natural historic levels estimated to be about 

334 mg/L at Imperial Dam. 

When the Salinity Forum established the salinity criteria goal to not exceed the 1972 levels, it 

was not obvious that this could be achieved given projected future water development 

within the basin. Figure 5 (page 11) indicates that long term average salinity below Hoover 

Dam has declined since 1940. The salinity control program can account for much, but not all 

of this salinity decline after the wet cycle from 1983-86. Flushing of salt during that wet cycle 

has also had an impact on salinity concentrations, as well as the reservoirs ability to retain 

and route saline water throughout the years. 

Figure 8 is an analysis of salt inflow and outflow for Lake Powell from 1950-2002. Trend 

lines indicate that the inflow was generally within 3-4 % of outflow prior to the coffer dam 

in about 1956. From 1956-1992 Lake Powell leached salt. After 1992 this leaching appears to 

have come to a new dynamic equilibrium. Lake Powell is the largest, but is only one of many 
15

dams built in the upper basin from the 1950’s through about 1987. Each of these reservoirs 

also experienced a leach out period. Flaming Gorge Reservoir experienced a similar leach out 

contributing near 400,000 tons of salt per year during early initial filling. 

300

400

500

600

700

800

900

1000

1950

1952

1954

1956

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Year

Annual Average Salinity (mg/L)

Inflow

Outflow

Linear (Inflow)

Linear (Outflow)

Figure 8 - Lake Powell Inflow and Outflow Salt Concentration, mg/L 

Figure 9- "Bathtub ring" on Lake Powell 
16

NATURAL VARIATION IN SALINITY 

Although seasonal swings in salinity have been greatly reduced, annual fluctuations in salinity 

are still observed. Natural climatic variations in rainfall and snowmelt runoff continue to 

cause large year-to-year differences in both flow and salinity and in some cases nearly 

doubling the salinity in the river. 

Even with the tempering effects of reservoir storage in the river system, natural variations in 

runoff and flows in the Colorado River Basin will continue to cause salinity to vary 

significantly. The water quality standards require that the flow-weighted average annual 

salinity will not rise above the 1972 levels using a long-term mean water supply of 15 maf 

(2002 Review). This means that depending on the hydrology (drought conditions) that 

salinities may actually increase above the numeric criteria and it is not a violation of the 

standards, but is due to natural variations in the hydrologic conditions. Even with full 

compliance with the standards, the actual salinities at Imperial Dam (and elsewhere in the 

Colorado River Basin) will continue to fluctuate with hydrologic conditions in the future. 

The Salinity Control Program is designed to offset the effects of development, even as 

salinity varies from year to year in response to the climatic and hydrologic conditions. 

Assuming continued salinity control and full compliance with the standards, the potential 

range of annual salinities that might be observed in the future at Imperial Dam is quite wide. 

With Colorado River basin reservoir storage tempering the natural variability of the system, 

the range between the high and low salinity values at Imperial Dam has dropped to a 

monthly average of about 480 mg/L and an annual average around 266 mg/L since 1973. 

AGRICULTURAL SOURCES OF SALINITY 

Irrigated agriculture is the largest user of water in the Colorado River Basin and a major 

contributor to the salinity of the system. Iorns (Iorns et al., 1965) found that irrigated lands 

in the Upper Colorado River Basin contributed about 3.4 million tons of salt per year (37 

percent of the salinity of the river). Irrigation increases salinity by consuming water (evapo 

transpiration) and by dissolving salts found in the underlying saline soils and geologic 

formations, usually marine (Mancos) shale. 

Deep percolation mobilizes the salts found naturally in the soils, especially if the lands are 

over irrigated. Through salinity control practices, these contributions to the river system can 

be reduced significantly, helping maximize the future beneficial uses of the river. 

Irrigation development in the Upper Colorado River Basin took place gradually from the 

beginning of settlement in about 1860, but was hastened by the purchase of tribal lands in 

the late 1800’s and early 1900’s. About 800,000 acres were being irrigated by 1905. Between 

1905 and 1920, the development of irrigated land increased at a rapid rate, and by 1920, 

nearly 1.4 million acres were being irrigated. The Upper Colorado Region Comprehensive 

Framework Study, June 1971, reported that more than 1.6 million acres were in irrigation in 

1965. Since that time, development of new agricultural lands has leveled off because of 

physical, environmental, and economic limitations. Reclamation’s latest Colorado River System 

Consumptive Uses and Losses Report 1996-2000 estimated that 1.5 million acres were irrigated in 

the Upper Colorado River Basin in 2000. 

Irrigation development in the Lower Colorado River Basin began at about the same time as 

in the Upper Colorado River Basin, but was slow due to the difficulty of diverting water 
17

from the Colorado River with its widely fluctuating flows. Development of the Gila area 

began in 1875 and the Palo Verde area in 1879. Construction of the Boulder Canyon Project 

in the 1930’s, and other downstream projects, has provided for a continued expansion of the 

irrigated area. In 1970, an additional 21,800 acres were irrigated by private pumping either 

directly from the Colorado River or from wells in the flood plain. In 1980, nearly 400,000 

acres were being irrigated along the Colorado River mainstem. In 2000, total irrigated lands 

for the entire Lower Colorado River Basin were about 1.4 million acres. 

Reclamation and the U.S. Geological Survey (USGS) continuously monitor the flow and 

salinity of the river system through a network of 20 gauging stations (See Appendix A, Fig. 

A1). Reclamation evaluates the data collected to determine if sufficient salinity control is in 

place to offset the impact of water development. In 2004, the actual salinity in the Colorado 

River was below the numeric criteria at the established monitoring stations. However, as the 

impacts of recent and future basin developments work their way through the hydrologic 

system, salinity would increase without salinity control to prevent further degradation of the 

river system. 

UPPER BASIN IRRIGATION 

Many subbasins experienced significant changes in irrigation following development of 

available reservoir storage. Once late season irrigation supplies were assured, less water was 

applied during the snowmelt runoff, and overall irrigation efficiency increased. Based on 

results from the Reed Wash study (Reclamation, 1982) the Colorado River Basin salinity 

control program has depended on improved irrigation efficiency to decrease human-induced 

salt loading. Providing guaranteed late season water supplies from reservoir storage was not 

provided through the Colorado River Basin Salinity Control Program. Examining water and 

salt loading relationships in these subbasins where reservoir storage was developed strongly 

suggests that storage did increase irrigation efficiency, and additionally decreased salt loading. 

The impacts from these subbasins that have increased irrigation efficiency not resulting from 

the salinity control program have not been directly incorporated in the Colorado River 

Simulation System (CRSS). The relationships between natural and irrigation induced salt 

loading have changed, and are being reexamined for modeling purposes. 

WATER USE BY AGRICULTURE & MUNICIPAL & INDUSTRIAL USERS 

Salinity levels are directly influenced by depletion (consumption) of water flowing in the 

river system and salt loading. Agriculture increases salinity by consuming water through 

evapotranspiration and leaching salts from saline soils. Municipal and industrial (M&I) use 

increases salinity by the consumption of the water, thus reducing the dilution of salts in the 

river or by disposal on land. These two types of uses are critical in predicting future salinity 

levels in the basin. 

Reclamation continues to monitor water use and adjusts their future salinity control needs as 

water development plans may be postponed, delayed, or canceled. The depletion schedules 

used to project salinity conditions have been updated so that the implementation needs for 

the Salinity Control Program can be planned to offset the impacts of additional water 

development. 
18

The large amounts of water use once forecasted for steam power generation, coal 

gasification, oil shale, and mineral development have not yet occurred. The few coal-fired 

power plants that have been constructed recently have obtained their water from existing 

agricultural rights rather than from developing additional water. This conversion of use 

reduces the salt loading to the Colorado River by eliminating the pickup of salt from canal 

seepage and on farm deep percolation. 

Most of the irrigation projects that deplete water and increase salt pickup to the river were in 

place before 1965. Moreover, like the newly inundated soils in reservoirs, newly irrigated 

lands are subject to a leach-out period. In cases where lands with poor drainage stored salt, 

these areas were taken out of production. In addition, irrigation practices changed 

significantly with the introduction of canal and lateral lining, sprinkling systems, gated pipe, 

trickle systems and tile drains (initial operation of tile drains increase salt loading, which 

decreases after time). These changes have resulted in reduced return flows and salt pickup. 

 

FUTURE WATER DEVELOPMENT 

Historic and Projected 

Upper Colorado River Basin Uses

0

1

2

3

4

5

6

7

1960 1980 2000 2020 2040 2060 2080

Uses (maf/yr)

Tables 3 and 4 (below), summarize the projected depletions used by Reclamation to evaluate 

the effects of water use and 

depletions for this progress 

report. These water use 

estimates were compiled as 

the first step in the 

evaluation process. Table 3 

summarizes the estimated 

depletion of water through 

full basin development for 

the mainstem Upper 

Colorado River Basin. The 

projections were made in 

consultation with individual 

States within the Colorado 

River Basin and the Upper 

Colorado River 

Commission; however, the States do not necessarily concur with the projections adopted by 

Reclamation for planning purposes. 

Figure 10 - Historic and Projected Water Uses. 

The Upper Colorado River Basin Compact provides that the States of Arizona, Colorado, 

New Mexico, Utah, and Wyoming will share in the consumptive use of water available in the 

Upper Colorado River Basin in the following proportions: Arizona, 50,000 acre-feet; 

Colorado, 51.75 percent of the remainder; New Mexico, 11.25 percent of the remainder; 

Utah, 23.00 percent of the remainder; and Wyoming, 14.00 percent of the remainder. Each 

Upper Colorado River Basin State is charged a proportionate share of the total evaporation. 

Figure 10 illustrates the historic Upper Basin States usage of the Colorado River water and 

their projected future river water use. 

The depletions for the Lower Colorado River shown in Table 4 include only mainstem use 

of the Colorado River in the Lower Colorado River Basin. Reclamation=s river simulation 

model does not model consumptive uses of the Lower Colorado River Basin tributaries. 
19

Table 3 - Upper Basin Depletion Projections (1000 af/yr) 

UPPER BASIN 2010 2020 2030 2040 2050 2060

Arizona 

Total scheduled depletion 50 50 50 50 50 50

State share of 6.0 maf 50 50 50 50 50 50

Remaining available 0 0 0 0 0 0

Percent of State share available 0 0 0 0 0 0

Colorado

Total scheduled depletions 2,580 2,626 2,675 2,703 2,776 2,784

Evaporation storage units 295 295 295 295 295 295

Total 2,875 2,921 2,970 2,998 3,071 3,079

State share of 6.0 maf 3,079 3,079 3,079 3,079 3,079 3,079

Remaining available 204 158 109 81 8 0

Percent of State share available 7 5 4 3 0 0

New Mexico

Total scheduled depletions 548 589 604 605 605 605

Navajo Reservoir evaporation 28 28 28 28 28 28

Evaporation storage units 58 58 58 58 58 58

Total 634 675 690 691 691 691

State share of 6.0 maf 669 669 669 669 669 669

Remaining available 35 -6 -21 -22 -22 -22

Percent of State share available 5 -1 -3 -3 -3 -3

Utah

Total scheduled depletions 1009 1055 1129 1177 1207 1230

Evaporation storage units 120 120 120 120 120 120

Total 1129 1175 1249 1297 1327 1350

State share of 6.0 maf 1369 1369 1369 1369 1369 1369

Remaining available 240 194 120 72 42 19

Percent of State share available 18 14 9 5 3 1

Wyoming

Total scheduled depletions 517 535 571 615 687 760

Evaporation storage units 73 73 73 73 73 73

Total 590 608 644 688 760 833

State share of 6.0 maf 833 833 833 833 833 833

Remaining available 244 225 189 145 74 0

Percent of State share available 29 27 23 17 9 0

Note: Evaporation from storage units - Estimates for evaporation from Lake Powell, Wayne N. Aspinall Unit, 

and Flaming Gorge Reservoirs are allocated as described in Article V of the Upper Colorado River Compact. 

New Mexico will use more than their share of water if the future projected use is met
20

Fixed inflow values are used for the tributaries. Colorado River Basin use data (including 

tributary use) may be found in Reclamation=s Colorado River System Consumptive Uses and Losses 

Reports or on the web at www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html

Table 4 - Lower Basin Depletion Projections (1000 af/yr) 

LOWER MAINSTEM 2010 2020 2030 2040 2050 2060

Nevada

Robert B. Griffith Water Project 264 264 280 280 280 280

Other users above Hoover Dam 7 7 7 7 7 7

Southern California Edison 16 16 0 0 0 0

Ft. Mohave Indian Reservation 9 9 9 9 9 9

Laughlin and users below Hoover Dam 4 4 4 4 4 4

Total 300 300 300 300 300 300

Arizona

Imperial Wildlife Refuge 10 9 10 10 10 10

Lake Havasu Wildlife Refuge 5 5 5 5 5 5

Fort Mohave Indian Reservation 73 73 73 73 73 73

City of Kingman 0 0 0 0 0 0

Mohave Valley I&D District 23 17 17 17 17 17

Bullhead City and other M&I 4 5 6 6 6 6

Cibola Valley I&DD, Parker and others 24 27 30 32 34 34

Lake Havasu I&D District 13 12 12 12 12 12

Central Arizona Project 1425 1419 1406 1398 1395 1395

Colorado River Indian Reservation 414 463 463 463 463 463

Cibola Wildlife Refuge 8 8 16 16 16 16

Gila Project 505 477 476 476 476 476

City of Yuma 27 30 35 41 41 41

Yuma Project - Valley Division 248 234 229 229 230 230

Cocopah Indian Reservation 12 12 12 12 12 12

Other users below Imperial Dam 9 9 10 10 10 10

Total 2800 2800 2800 2800 2800 2800

California

City of Needles 1 1 1 1 1 1

Metropolitan Water District 855 852 852 852 802 802

Fort Mohave Indian Reservation 12 12 12 12 12 12

Chemehuevi Indian Reservation 5 8 8 8 8 8

Colorado River Indian Reservation 19 39 39 39 39 39

Palo Verde Irrigation District 373 366 366 366 366 366

Yuma Project Reservation Division 47 54 54 54 54 54

Imperial Irrigation District 2711 2641 2611 2611 2661 2661

Coachella Valley Water District 376 426 456 456 456 456

Other uses Davis to Parker Dam 1 1 1 1 1 1

Other uses below Imperial Dam 0 0 0 0 0 0

Total 4400 4400 4400 4400 4400 4400

Unassigned

Fish, wildlife, and recreation 515 515 515 515 515 515

Yuma Desalting Plant 120 120 52 52 52 52

Total 635 635 567 567 567 567

Note: In the LC Basin, depletions are from mainstem diversions of the Colorado River only. Does not include 

depletions from diversions of Colorado River tributaries or evaporation from mainstem reservoirs. The Figures 

represent measured diversions less measured and estimated, unmeasured return flow that can be assigned to a 

specific project.
21

COMPLIANCE WITH THE SALINITY STANDARDS 

Reclamation and the Basin States conducted salt-routing studies for the 2002 Triennial Review 

of the Water Quality Standards for Salinity, Colorado River Basin. As part of the triennial review 

process, Reclamation used a spreadsheet format and will use a model of the river system to 

evaluate whether sufficient salinity control measures are in place to offset the effects of 

development. The information provided in the next two sections of the report was used to 

evaluate compliance with the water quality standards. 

In response to the Clean Water Act, the States have adopted water quality (salinity) criteria 

for the Colorado River Basin and the Environmental Protection Agency (EPA) has 

approved them at all three locations in the Lower Colorado River Basin. The standards call 

for maintenance of flow-weighted average annual salinity concentrations (numeric criteria) in 

the lower mainstem of the Colorado River and a plan of implementation for future controls. 

The water quality standards are based on the Water Quality Standards for Salinity, Including 

Numeric Criteria and Plan of Implementation for Salinity Control, Colorado River System, prepared by 

the Colorado River Basin Salinity Control Forum, June 1975. The document was adopted by 

each of the Basin States and approved by EPA. A summary of the report follows:

The numeric criteria for the Colorado River System are to be established at levels 

corresponding to the flow-weighted average annual concentrations in the lower 

mainstem during calendar year 1972. The flow-weighted average annual salinity for 

the year 1972 was used. Reclamation determined these values from daily flow and 

salinity data collected by the USGS and the Bureau of Reclamation. Based on this 

analysis, the numeric criteria are 723 mg/L below Hoover Dam, 747 mg/L below 

Parker Dam, and 879 mg/L at Imperial Dam. 

It should be recognized that the river system is subject to highly variable annual flow. 

The frequency, duration, and availability of carryover storage greatly affect the 

salinity of the lower mainstem; and, therefore, it is probable that salinity levels will 

exceed the numeric criteria in some years and be well below the criteria in others. 

However, under the above assumptions, the average salinity will be maintained at or 

below 1972 levels. 

Periodic increases above the criteria as a result of reservoir conditions or periods of 

below normal long-time average annual flow also will be in conformance with the 

standards. With satisfactory reservoir conditions and when river flows return to the 

long-time average annual flow or above, concentrations are expected to be at or 

below the criteria level. 

The standards provide for temporary increases above the 1972 levels if control 

measures are included in the plan. Should water development projects be completed 

before control measures, temporary increases above the criteria could result and 

these will be in conformance with the standard. With completion of control projects, 

those now in the plan or those to be added subsequently, salinity would return to or 

below the criteria level. 

The goal of the Salinity Control Program is to maintain the flow-weighted average 

annual salinity at or below the numeric criteria of the salinity standards. The program 

is not, however, intended to counteract the salinity fluctuations that are a result of 
22

the highly variable flows caused by climatic conditions, precipitation, snowmelt, and 

other natural factors. 

SALINITY CONTROL 

Existing salinity control measures will prevent over a million tons of salt per year from 

reaching the river. By 2004 the salinity control program for Reclamation has controlled an 

estimated 569,000 tons of salt, while the USDA NRCS (NRCS) program has reduced an 

estimated 405,000 tons of salt, and the BLM has controlled an estimated 98,000 tons of salt 

per year from entering the Colorado River (Figure 11). According to the Colorado River 

Salinity Control 

Forum, salinity control 

units will need to 

prevent nearly 1.8 

million tons of salt per 

year from entering the 

Colorado River by 

2025. To reach this 

objective, as shown in 

Table 5, the program 

needs to implement 

728,000 tons of new 

controls beyond the 

existing 1,072,000 tons 

of salinity control presently in place (2004) as reported by Reclamation, USDA & BLM. 

About 35,000 tons per year of new salinity control measures must be added each year if the 

program is to meet the cumulative target of 1,800,000 tons per year by 2025. 

 Figure 11 – 2004 Est. Salinity Control Progress; BOR, NRCS & BLM 

Colorado River Basin Salinity Control Program

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1980 1985 1990 1995 2000

Tons of Salt Removed

To achieve this goal, a variety of salinity control methods are being investigated and 

constructed. Saline springs and seeps may be collected for disposal by evaporation, industrial 

use, or deep-well injection. Other methods include both on-farm and off-farm delivery 

system and irrigation improvements, which reduce the loss of water and reduce salt pickup 

by improving irrigation practices and by lining canals, laterals, and ditches. See Progress 

Report #21 for a more detailed description of each salinity control project and the salinity 

controlled by Reclamation, NRCS and BLM. 

Table 5 - Salinity Control Requirements and Needs 

Salinity control needs (2020) 1,800,000 tons

Measures in place (2004) - 1,072,000 tons

Plan of Implementation Target 728,000 tons
23

CHAPTER 3 - SALINITY MODELING 

ECONOMIC SALINITY DAMAGE MODEL 

The Lower Colorado Salinity Damage Model estimates the economic damages from salinity 

levels above 500 mg/L TDS. The model estimates damages based on agricultural and 

municipal and industrial water (M&I) use as well as local and regional water quality 

requirements within the Lower Colorado River Basin. Agricultural damages are based on the 

changes in gross crop values due to changes in crop yield brought on by different salinity 

levels. For M&I water use, house holds, commercial, industrial, and water utility damages are 

estimated for the major urban areas in the Lower Colorado River basin. For local or regional 

water quality requirements, costs associated with treating recycled water or maintaining 

ground water quality based on changes in Colorado River salinity levels are estimated. Figure 

2 (page 8) shows the breakdown of the salinity costs between the various categories. Using 

the present salinity at Imperial dam, it is estimated that the economic costs to the water users 

will be between $305 - $312 million dollars per year. Figure 12 shows how the increase of 

salinity impacts the cost to various categories. 

Damages by Sector

0

50

100

150

200

250

300

350

500 600 700 800 900 1000

Salinity mg/L

$Millions

Agricultural Household

Commercial Utilities

Industrial Policy Rltd

Figure 12 – Economic Model Damages Caused by Increase in Salinity
24

COLORADO RIVER SIMULATION SYSTEM 

The CRSS model was developed to simulate long-term salinity conditions given future 

development of water, with and without various levels of salinity control. The model is a 

long-term planning tool designed to look out 30 to 50 years into the future. The CRSS is a 

group of programs that are collectively used to evaluate the impact of water development 

and salinity control on the Colorado River. 

Salinity Model Verification 

During the last 6 years Reclamation has critically investigated the data and methodologies 

used within CRSS and these efforts have resulted in an updated version of CRSS. The model 

updates include improvements to both the input data and submodels used by CRSS. 

However, additional critical investigations of sub-basin water and salt relationships will be 

continuing over the next several years. 

The original CRSS included a submodel developed by the USGS (Mueller and Osen, 1988) 

that computed natural salt as a function of natural flow. This submodel was based on data 

from 1941-1983 and could not easily be updated with recent data. Reclamation took the 

need to update the submodel based on current data as an opportunity to incorporate 

improvements from recent research that use nonparametric regression methods (Prairie et 

al., 2005). The improved submodel is based on data from the more recent period 1971-1995. 

Considering the need to periodically update the regressions the improved submodel can 

easily be updated as the historic record is extended. The submodel includes the ability to 

capture nonlinear relationships between natural flow and natural salt that could not be 

captured with the previous version. These nonlinear relationships were observed in the 

historic record. 

The verification of the updated CRSS is shown in Figure 13. For comparison the Figure 

includes the historic salinity concentration, numeric criteria at Imperial Dam (879 mg/L), 

and the result of the CRSS model before the updates were applied. Figure 13 demonstrates 

the updated CRSS model is capable of recreating the salinities that occurred from 1971 until 

1995. Assuming the relationship between flow and salinity will remain similar in the next 20 

years the model can be used with confidence to project a similar natural flow and salt 

relationship in the future. 

Future Salinity Projections 

The verified CRSS model provides long-term (20 years in the future) simulations of salinity 

concentration below Hoover, Parker and at Imperial Dam. These are the three locations 

where the salinity criteria designates numeric criterion that are to be maintained. 

For these recent studies the CRSS model was used with 90 years of natural flow data to 

simulate the range of possible salinities based on the historic flows observed in the Colorado 

River Basin from 1906-1995. Figure 14 displays the results from the CRSS model on the 

Colorado River at Imperial Dam. The plot demonstrates the range of possible salinity that 

may be seen in the future given the current conditions and overlaying the variations of 

natural flow along with the projected future depletions and salinity control levels. The results 

from the model are displayed as exceedance lines. The exceedance percentage for each line 

represents the probability that the concentration will be less than or equal to this value. The 

graph indicates in 2025 the projected salinity levels can be equal to or below 779 mg/L at 
25

500

550

600

650

700

750

800

850

900

950

1000

1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995

Year

Salt Concentration (mg/l)

Historic

Original Model Results

Numeric Criteria

New Model Result

 

Figure 13 - Calibration of CRSS 1971-1995 for Colorado River at Imperial Dam. 

600

650

700

750

800

850

900

950

1000

2000 2005 2010 2015 2020 2025

Year

AboveImperialDamColoradoR Outflow Salt Concentration (mg/l)

10% of NoProjLifeMB.xls

50% of NoProjLifeMB.xls

90% of NoProjLifeMB.xls

Numeric Criteria

Figure 14 - Future Salinity Concentration for Colorado River at Imperial Dam. 
26

Imperial Dam fifty percent of the time. Ninety percent of the time the projected salinity 

concentration should be less than or equal to 924 mg/L. 

Based on these recent CRSS model results, Table 6 indicates the probability of exceeding the 

numeric criteria in 2025 for two scenarios. The first scenario, titled “2025 Existing and 

Potential”, maintains the existing salinity control projects at the levels they are currently 

removing salt and assumes the additional projects that have been approved under that latest 

RFP shall be built as projected. The second scenario, titled “2025 Existing with 

Degradation”, only includes the salinity control projects built until 2004 and models salinity 

control projects degrading with age resulting in decreased efficiency. By 2025 under the first 

scenario salinity control projects are preventing approximately 1.6 million tons per year from 

entering the Colorado River. Under the second scenario salinity control projects are 

removing approximately 900,000 tons per year. 

Though CRSS model results indicate the numeric criteria will likely not be exceeded in 2025 

there is a 34 percent probability it will be exceeded on the Colorado River below Hoover 

Dam under Scenario 2. Under scenario 1 the CRSS model indicates the average salinity 

concentration would be approximately 685 mg/L below Hoover Dam, 708 mg/L below 

Parker Dam and 835 mg/L at Imperial Dam. Though these salinity concentration levels are 

on average below the numeric criteria, analysis performed with the Economic Damages 

Model indicated damages resulting from these salinity levels are significant. 

Table 6 - Probability of Exceeding Numeric Criteria 

Probability of Exceedance 

Numeric 

Criteria 

2025 Existing and 

Potential 

2025 Existing with 

Degradation 

Station Name (mg/L) (%) (%) 

Colorado River Below Hoover Dam 723 16 34 

Colorado River Below Parker Dam 747 16 33 

Colorado River at Imperial Dam 879 14 25 

CE-QUAL-W2 RESERVOIR MODELING 

Since Reclamation is also required to simulate salinity five years into the future (see Chapter 

1- Authorizations), another method is being developed that includes more mechanistic 

models of Lakes Powell and Mead. 

Reclamation’s Upper Colorado Region has built and is still finalizing calibration and testing 

of a River Reservoir Model utilizing the Corp of Engineers CE-QUAL-W2 (W2) model. 

This model will be used to more accurately array near future salinity boundaries to meet the 

five year forecast requirement to be presented in this report. The model currently includes 

only Lakes Powell and Mead. The CRSS model is utilized to array the salinity downstream 

from Hoover Dam in the short term forecast since the downstream reservoirs hydraulic 

detention times generally do not exceed one to two months. 
27

The W2 reservoir model will be able to give more accurate 1-5 year simulations on a 

monthly basis than CRSS. W2 is a two dimensional river/reservoir hydrodynamic water 

quality model that has evolved over a period spanning nearly three decades. The U.S. Army 

Corp of Engineers (CE or COE), J.E. Edinger and Associates (Edinger), and Dr. Scott Wells 

at Portland State University working with Mr. Tom Cole (COE) have been the major 

developers in recent years. All of the above have been helpful and provided some insight on 

the development of this application. 

Previous versions of the model tended to completely mix each winter, and thus did not 

maintain the chemical integrity required to make multi-year simulations feasible. This 

application is a significant test of the capabilities of this model to make multi-year runs on 

deep, chemically stratified, long hydraulic detention time reservoirs. 

Model Calibration 

The model was calibrated from 1992-95, and then further verified for a single run from 

1990-2002 on each of Lakes Powell and Mead. Ungaged inflows and estimated salt loads had 

to be simulated multiple times to get the total salt budget correct for the entire time period. 

In addition to the calibration of salinity at the outflow, temperature was also calibrated at the 

outflow and at seasonal profiles at individual stations within the reservoir. Similarly salinity 

was also calibrated seasonally at the individual stations within the reservoir. The model 

calibration period includes the actual inflow and salt loading from 1990-2002. Table 7 shows 

that this time period is slightly drier than the long term historical average inflows into Lake 

Powell. The model was calibrated from January 1, 1990 through December 31, 2002. This 

period includes two severe droughts and a wet cycle. 

The model calibration parameter of greatest interest for this report is the dam release 

salinity. The model calibration periods illustrated here are comparisons of actual mean 

annual flow weighted salinity concentrations in mg/L versus the model results (Figures 15 & 

16). The differences between the model and the actual data at the higher salinity levels 

suggest that about 20-30 mg/L of calcite may be precipitating out of the reservoir during 

these time periods. However, during rapid refilling in wet cycles the salt from the “bathtub 

ring” around the lake shorelines is added back into the water, offsetting any long term 

salinity improvement. 

Future Salinity Scenarios 

The run scenarios generated for future simulations with W2 are illustrated in Table 8. Each 

run starts with the same initial condition on January 1, 2004, and they remain the same until 

January 1, 2005. Beginning January 1, 2005 individual 7 year traces begin with 1990 through 

2000 as shown in Table 7 (below). The hydrological statistics for each trace are illustrated in 

Table 8. A summary of the 11 traces run through the W2 model are presented as a flow 

weighted annual average salinity discharge from the two dams in Figures 17 & 18. As seen in 

these Figures the W2 model predicts that even if several more years of drought occur, the 

salinity below Hoover Dam could approach, but does not exceed the salinity criteria of 723 

mg/L. This hydrologic sequence of simultaneous drawdown of these two reservoirs is being 

observed for the first time. 

There appears to be other factors reducing the salinity concentrations during this extended 

drought. The mean annual salinity concentration coming into Lake Powell dropped after the 

first three years of this drought. This has never been seen before, and was not expected. 
28

Table 7 - Hydrology of the Individual Years Modeled and Percentage of Long Term Averages (either 

1964-2002 or 1992-2002). 

Actual Lake Powell Inflows (Acre-Feet / Yr.) 

Calendar Year Inflow % of Avg. 

1990 5,042,513 45.0% 

1991 7,349,138 65.6% 

1992 7,099,221 63.4% 

1993 13,281,856 118.6% 

1994 7,032,423 62.8% 

1995 14,862,700 132.7% 

1996 10,675,967 95.3% 

1997 16,545,283 147.7% 

1998 12,788,465 114.2% 

1999 11,871,653 106.0% 

2000 7,399,821 66.1% 

2001 6,471,978 57.8% 

2002 3,742,641 33.4% 

2004 5,872,567 52.4% 

Average 9,551,051 85.3% 

NOTE: The periods of 1990-92 (58%) and 2000-02 +04 (52%) are very dry, while the wet period from 

1993-99 (112%) is a very wet cycle. 

 

Apparently this occurred because the ground water storage basins (particularly associated 

with irrigated areas) take 18-36 months to drain out. When a drought extends beyond three 

years in the Upper Basin two things are believed to happen. First, the saline base flow drops 

off; and second, many of the Upper Basin irrigation areas do not receive a full water supply. 

Many of the saline tributaries that begin far from the mainstem have been dry for most of 

the past two years. Therefore, these tributaries are not delivering normal salt loads to the 

mainstem. Because of these conditions it is important to extend this W2 database through 

the 2003-05 years as soon as the data is available. 

The results of this study should not be interpreted as a worst case salinity scenario for longer 

term conditions based on greater water use in the Upper Basin. The long term conditions are 

modeled with CRSS. 

While this array of potential near future scenarios does not show that the salinity criteria 

should be exceeded in the next few years, it does indicate that a number of future hydrologic 

scenarios leave salinity near the criteria for several more years to come. Relief from the 

current high salinity levels will come only after a couple of years of above average hydrology. 

The measured salinity below Hoover Dam on January 1, 2005 (671 mg/L) is approximately 

in the middle range of Figure 18, modeled future salinity scenarios. 
29

Lake Powell Historical Salinity vs Model Calibration

Mean annual flow weighted TDS released from Glen Canyon Dam

300

350

400

450

500

550

600

1988 1990 1992 1994 1996 1998 2000 2002 2004

TDS, mg/l

Model LP Historical LP

Figure 15- Comparison of the Historical Flow Weighted Annual Average Total Dissolved Solids (TDS or 

Salinity) Released from Glen Canyon Dam with the Model Calibration. 

Lake Mead Historical Salinity vs Model Calibration

Mean annual flow weighted TDS released from Hoover Dam

450

475

500

525

550

575

600

625

650

675

700

725

750

1988 1990 1992 1994 1996 1998 2000 2002 2004

TDS, mg/l

Model LM Historical LM

Figure 16- Comparison of the Historical Flow Weighted Annual Average Total Dissolved Solids (TDS or 

Salinity) Released from Hoover Canyon Dam with the Model Calibration. 
30

Table 8 - Statistical Hydrology for each Trace Arraying Potential Future Salinity Ranges below Glen 

Canyon and Hoover Dams.

Trace Inflow Ave. % of Ave. 

2004, 1990-1996 8,902,048 79.5% 

2004, 1991-1997 10,339,894 92.3% 

2004, 1992-1998 11,019,810 98.4% 

2004, 1993-1999 11,616,364 103.7% 

2004, 1994-2000 10,881,110 97.2% 

2004, 1995-2001 10,811,054 96.5% 

2004, 1996-2002 9,421,047 84.1% 

2004, 1997-2002, 1993 9,746,783 87.0% 

2004, 1998-2002, 1993-1994 8,557,675 76.4% 

2004, 1999-2002, 1993-1995 8,816,955 78.7% 

2004, 2000-2002, 1993-1996 8,667,494 77.4% 

Glen Canyon Dam Outflow Salinity Scenarios

300

350

400

450

500

550

600

650

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Forecast Year

TDS, mg/l

1990 1991 1992 1993 1994 1995

1996 1997 1998 1999 2000

Mean Annual Flow Weighted TDS, mg/L

The initial year of the trace beginning January 1, 2005.

See Table 7 for a description of the traces.

Figure 17- The Array of Potential Future Salinity Concentration Ranges as a Flow Weighted Annual 

Average Total Dissolved Solids (TDS or salinity) to be Released from Glen Canyon Dam. 
31

Hoover Dam Outflow Salinity Scenarios 

500

525

550

575

600

625

650

675

700

725

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Forecast Year

TDS, mg/l

1990 1991 1992 1993 1994 1995 1996

1997 1998 1999 2000

Mean Annual Flow Weighted TDS mg/L

The initial year of the trace beginning January 1 2005.

See Table 8 for a description of the traces. The Salinity

Criteria at this station is 723 mg/L as an annual average.

Figure 18 - The Array of Potential Future Salinity Concentration Ranges as a Flow Weighted Annual 

Average Total Dissolved Solids (TDS or Salinity) to be Released from Hoover Dam. 
32 
33

CHAPTER 4 – TITLE I SALINITY CONTROL 

PROGRAM 

The Colorado River Basin Salinity Control Act (Salinity Control Act), Public Law (PL) 

93-320, as amended, authorized the Secretary of the Interior (Secretary) to proceed with a 

program of works of improvement for the enhancement and protection of the quality of 

water available in the Colorado River for use in the United States and the Republic of 

Mexico. Title I enables the United States to comply with its obligation under the agreement 

with Mexico of August 30, 1973 (Minute No. 242 of the International Boundary and Water 

Commission, United States and Mexico [Minute No. 242]), which was concluded pursuant to 

the Treaty of February 3, 1944 (TS 994). 

Figure 19 - Map of Title I Projects. 

These facilities enable the United States to deliver water to Mexico with an average annual 

salinity concentration no greater than 115 parts per million (ppm) plus or minus 30 ppm 

(United States count) over the average annual salinity concentration of the Colorado River 

water at Imperial Dam. 

COACHELLA CANAL LINING 

To assist in meeting the salinity control objectives of Title I, the Secretary was authorized to 

construct a concrete-lined parallel canal or to line the unlined initial 49 miles of the 
34

Coachella Canal in place. The act required that a contract be executed with the Coachella 

Valley Water District for partial repayment of the cost of the work over a 40-year period. 

Public Law 106-377 – Appendix B amended Public Law 100-675 to provide that during the 

period of planning, design, and construction of a new lined canal to reduce seepage of water 

from a portion of the All American Canal and its Coachella Branch, the annual repayment 

installments will continue to be nonreimbursable. Also, during the period that the San Luis 

Rey River Indian Water Authority, the City of Escondido, and Vista Irrigation District 

receive up to 16,000 acre-feet per year of the water conserved by the new lined canals, the 

annual repayment installments will continue to be nonreimbursable (114 Stat. 1441A-71). 

An estimated 141,000 acre-feet of Colorado River water were lost each year through seepage 

from this reach of the canal. It is estimated that the lined canal paralleling the old unlined 

canal reduced seepage losses to 9,000 acre-feet per year (af/yr), resulting in an annual savings 

of 132,000 acre-feet. The seepage losses saved are to be used during an interim period to 

substitute for the bypassed Wellton-Mohawk Irrigation and Drainage District (District) 

irrigation drainage waters and for the reject stream from the Yuma Desalting Plant. The 

interim period began when construction was completed in 1980 and ends the first year that 

the Secretary delivers less mainstream Colorado River water to California than requested by 

California agencies and Federal establishments with Colorado River water contracts in 

California. 

PROTECTIVE AND REGULATORY PUMPING 

Section 103(a) of Public Law 93-320 authorized the construction, operation, and 

maintenance of the Protective and Regulatory Pumping Unit (PRPU) by the Bureau of 

Reclamation (Reclamation) to manage and conserve United States groundwater for the 

benefit of the United States and for delivery to Mexico in partial satisfaction of the 1944 

Treaty. The PRPU is located in a zone 5 miles wide paralleling the Southerly International 

Boundary between Arizona and Sonora, Mexico. 

The PRPU was developed to intercept part of the groundwater underflow that moves 

southward from the Yuma Mesa in the United States into Mexico. Before the PRPU was 

constructed, this underflow was increasing because of groundwater pumping in the Sonora 

Mesa Well Field, immediately south of the Southerly International Boundary in Mexico and 

located near San Luis, Mexico. The Basin States expressed their concern about the pumping 

in their July 1973 letter to the President of the United States. 

Currently, 21 of the 35 wells in the planned full complement of wells and associated 

conveyance and energy facilities have been constructed. The wells are connected by a 

15.3-mile pipeline and open concrete-lined canal that carries water by gravity across to the 

Yuma Valley Main Drain where it crosses the Southerly International Boundary. 

With 35 wells, the PRPU would be capable of producing about 125,000 acre-feet of water 

per year. Ultimately, 125,000 acre-feet of water from the PRPU, combined with 

15,000 acre-feet of water from the East and West Main Canal Wasteways in the Yuma 

Valley, would furnish 140,000 acre-feet of Mexico’s 1.5-million-acre-foot annual entitlement. 

The water would be delivered at the Southerly International Boundary near San Luis, 

Arizona. In addition, 35,000 acre-feet could be withdrawn by private wells and/or Minute 

No. 242 wells for use on private land to equal the 160,000-acre-foot limit for pumping in the 
35

5-mile zone. Currently, water from the East and West Main Canal Wasteways and the Yuma 

Valley Main Drain exceed 100,000 af/yr delivered to the Southerly International Boundary. 

Should these wasteway and drain flows diminish in the future, wells would be added to the 

PRPU, as needed, to ensure that approximately 140,000 acre-feet can be delivered at the 

Southerly International Boundary at all times. 

Additionally, as authorized by Title I, approximately 23,500 acres of private, State, and 

State-leased lands have been acquired within the 5-mile zone. The purpose of these 

acquisitions is to limit development and thus, limit United States groundwater pumping to 

160,000 af/yr, as required by Minute No. 242. The acquisitions were completed in 1984. 

Reclamation completed a Resource Management Plan/Environmental Assessment 

(RMP/EA) for the 5-mile zone in April 2004. This RMP/EA provides direction for future 

management decisions according to currently recognized standards of proper land and water 

use and enhances Reclamation’s stewardship of the lands and water within the 5-mile zone. 

YUMA DESALTING PLANT 

The Yuma Desalting Plant (YDP) was built on a 

60-acre tract of land 6 miles west of Yuma, 

Arizona. The purpose of the plant is to recover 

irrigation drainage water from the WelltonMohawk Irrigation and Drainage District (the 

District) so that it can be returned to the 

Colorado River and delivered to Mexico in partial 

satisfaction of the Mexican Water Treaty of 1944. 

The operational design parameters set up for the 

plant determined that a reverse osmosis 

membrane desalting process was technically 

feasible and suitable for the YDP operation. 

Factors utilized in the plant design were projected 

volume and salinity of water to be delivered to Mexico at the Northerly International 

Boundary, the salinity differential required by Minute No. 242, the projected salinity of the 

Colorado River at Imperial Dam, the volume of the District’s drainage water that was 

expected to be treated, the expected salinity of their drainage water, a number of other 

factors related to the dilution of return flows below Imperial Dam, as well as plant 

operational factors. 

A study completed in 1978 by the Advisory Committee on Improving Irrigation Efficiency 

in the District recommended continuation of the on-farm irrigation improvement measures 

in the district. These improvements were expected to reduce irrigation drain flow to around 

108,000 af/yr. In addition, the Colorado River Basin Salinity Control Forum (Forum), 

representing the Basin States, established a numeric criterion at Imperial Dam of 879 mg/L 

(ppm). Using the desalting plant design criteria and a projected agricultural drainage flow of 

108,000 af/yr from the District at 3,200 ppm and a salinity level of about 840 ppm for flows 

arriving at Imperial Dam, it was determined that a desalting plant size of 73 million gallons 

per day would be required to treat the anticipated drainage flow. 

Figure 20 – Aerial Photo of Yuma Desalting Plant. 
36

The YDP was constructed to produce about 72.4 million gallons of desalinated (product) 

water per day when operated at full capacity. This would result in a delivery of about 68,500 

acre-feet of product water per year. The product water would be blended with untreated 

drainage water to salvage an estimated 78,000 acre-feet each year for delivery to Mexico. 

The plant last operated in 1993. Since then, requirements of Minute No. 242 are being met 

by other means. With the construction of the Bypass Drain, and groundwater drainage 

management in the Yuma area, the United States has been meeting its salinity control 

obligations through the bypass of saline agricultural drainage water to the Cienega De Santa 

Clara Slough in Mexico. Under Minute 242, the bypass water is not charged against Mexico’s 

Treaty entitlement and thus results in releases of a like amount of water from Colorado 

River storage. Consistent with Title I, this storage release was off-set by the water conserved 

by lining the first 49 miles of the Coachella Canal until January 1, 2003. 

While in ready reserve, the YDP could be placed in full capacity operation within 2-3 years, 

depending on the availability of funding. When operational, the YDP’s concentrate (brine) is 

sent to the Cienega de Santa Clara Slough (Slough) in Mexico via the Bypass Drain. Due to 

the unexpected time required for construction, flows of the bypassed WMIDD irrigation 

drainage expanded the Slough from a relatively small area to several thousand acres of 

aquatic and wetland environment. Concerns have been raised regarding the effects of 

reduced flow from YDP operation and the associated high saline brine reject on wetlands in 

the Cienega that have grown to cover an area of approximately 14,000 acres (the wetlands 

were approximately 1/100th this size prior to construction of the Bypass Drain). 

Increases in water demand in each of the three lower Basin states has intensified the need for 

more efficient water management of the Colorado River system. This, coupled with the 

effects of a prolonged drought over the entire Colorado River Basin, has increased interest 

in replacing and/or recovering bypass flows to Mexico in order to conserve storage in the 

Colorado River reservoirs. 

Among the issues associated with operating the YDP are high costs, time required for 

reaching operational status, and water supply to the Cienega de Santa Clara Slough. In order 

to identify the best approach for recovery or replacement of bypass flows at the lowest 

possible cost, Reclamation began a public process for identifying and evaluating options for 

replacing or recovering bypass flow to Mexico; maintain the Plant in a "ready-reserve" status 

and, as funds allow, continue correcting design deficiencies identified during and subsequent 

to a short, one-third capacity operation some 13 years ago; and initiate a demonstration 

program to determine the viability of paying holders of Colorado River water delivery 

contracts to temporarily forbear use of water. It is anticipated that the outcome of one, or a 

combination, of these items will lead to an action that will meet the competing needs 

associated with bypass flows to Mexico.

WELLTON-MOHAWK IRRIGATION AND DRAINAGE DISTRICT 

To prevent crop damage from high ground water levels, Wellton-Mohawk Irrigation and 

Drainage District (District) has implemented irrigation drainage pumping of groundwater. 

This groundwater discharge has relatively high salinity concentrations and caused water 

quality problems in the river below Imperial Dam. The Title I Program, authorized by 

section 101(b) of the Salinity Control Act (PL 93-320), has reduced the District’s irrigation 
37

drainage pumping by removing some lands requiring high water use from irrigation and by 

increasing irrigation efficiencies. 

Acreage Reduction Program 

Under this program, the District’s irrigable lands were reduced from 75,000 to 65,000 acres. 

About 6,200 acres of land were purchased from 85 landowners. The remaining 3,800 acres 

were Federal lands from which irrigable status was withdrawn. 

Approximately 4,600 of the irrigable acres purchased were in crop production. As a result of 

the land purchases, deep percolation was reduced about 29,800 af/yr. This program was 

completed in 1978. 

In addition, the Salt River Pima-Maricopa Indian Community Water Rights Settlement Act 

of 1988 removed 2,225 acres of land from irrigation as part of an agreement to reduce 

diversions in the District to make water available to the Pima Maricopa Indian community 

near Phoenix, Arizona. Approximately 22,000 acre-feet was transferred to the Indian 

community, reducing drainage flow from the District around 11,000 af/yr and reducing the 

District’s consumptive use entitlement for Colorado River water from 300,000 af/yr to 

278,000 af/yr. 

In 1993, the Gila River flood severely damaged about 3,000 acres of land near the river 

channel. The District purchased most of this land and, initially, wanted to transfer the water 

use from this agricultural land to municipal and industrial uses. However, District has since 

started development of 3,000 acres of additional farmland elsewhere in the district to bring 

them up to their allotted farmable acreage of about 62,775 acres. 

District Irrigation Efficiency Improvement Program 

Several entities cooperated on this program, including the District and its farmers, several 

Government agencies including Reclamation, NRCS, U.S. Salinity Lab, the USDAAgricultural Research Service and the University of Arizona Cooperative Extension Service. 

Individual measures are discussed in the following sections. 

On-farm Improvements Program 

The objective of this program was to increase on-farm irrigation efficiencies by improving 

on-farm irrigation systems and management practices. NRCS provided design, installation, 

and management assistance for approximately 48,000 acres of land. Significant 

accomplishments included lining 263 miles of on-farm canals; leveling 44,415 acres of land; 

and installing 10 drip irrigation systems and 10,600 on-farm water-control and measurement 

structures. The Federal government contributed 75 percent of the costs; farmers contributed 

the remaining 25 percent. The farmers were under contract to maintain specific irrigation 

efficiency lands for 2 years after the on-farm improvements were installed. 

Irrigation Management Services Program 

Reclamation provided technical assistance through the Irrigation Management Services 

(IMS) Program, which, in turn, provided on-farm, field-by-field irrigation scheduling 

assistance. From 1977 through 1986, irrigation scheduling information was furnished for 

about 49,000 acres of crops each year. However, the District dropped the irrigationscheduling program in 1994 as fewer than 4,000 acres were still participating. By this time, 

technological improvements in irrigation scheduling had made the IMS program obsolete. 

The District decided that with the few acres participating, the benefits no longer warranted 
38

the costs of continuing the program. Farmers participating in the On-farm Improvements 

Program were required to participate in the IMS Program for two years following installation 

of on-farm improvements. 

Reclamation provided technical expertise, training, and funding for the program. The 

District provided one employee and office facilities. Reclamation funding for the IMS 

program ended in 1987. 

Research and Demonstration Program 

Six projects were funded under this program, which provided information on cultural 

practices, equipment, and economic considerations that could lead to improved irrigation 

efficiencies. Projects included monitoring soil salinity, studying emitter clogging in trickle 

irrigation systems, managing pressure irrigation systems for citrus crops, managing dead-level 

irrigation, automating surface irrigation, and evaluating alternative irrigation systems. All 

projects were completed by 1980. 

Education and Information Program 

The objectives of this program, conducted by the University of Arizona Cooperative 

Extension Service, were to (1) provide liaison among the various irrigation efficiency 

programs and (2) educate and encourage growers to adopt recommended irrigation 

efficiency improvement techniques and practices. Program information was provided 

through publications, television, and radio. With grower cooperation, field trials were held to 

demonstrate water management benefits, and field days were conducted on topics such as 

automated irrigation systems, irrigation scheduling and efficiency, and crop consumptive use. 

This program was discontinued in the late 1980’s. 

Results 

Before the irrigation efficiency program, the District’s irrigation efficiency was 56 percent. 

While the program was active, overall their irrigation efficiencies exceeded 72 percent, the 

level estimated to reduce irrigation drainage to 108,000 af/yr. An overall peak irrigation 

efficiency of 77 percent was reached in 1985, and irrigation drainage dropped from 220,000 

acre-feet to a low of 118,500 af/yr. While the program demonstrated an overall positive 

effect, a cause-and-effect relationship for individual measures cannot be established, because 

all of the measures are interdependent upon one another and cannot stand alone. 

Status 

All permanent measures implemented by the District are still in use, although the Federal 

program has been discontinued. Total crop acres have remained relatively stable since the 

early 1970’s because more acreage is double-cropped than when the program was initiated. 

In particular, more vegetable crops are being grown in the district than in the past. More 

recent irrigation efficiency levels and return flow levels for 1990-2004 are shown below. 

Reclamation believes that the impacts of Gila River flows in 1992, 1993, and 1995 make 

irrigation efficiency and return flow data from the district questionable for 1992, 1993, 1994, 

1995, and 1996. In 1993, the Gila River flood destroyed much of the District’s Main 

Conveyance Channel; so most of the drainage pumping went into the Gila River during 1993 

and 1994 until these facilities could be repaired. 

Irrigation drainage pumping has varied since 1990 partly due to a change in the cropping 

(larger acreage in vegetable crops) and partly due to the impacts on the groundwater as a 
39

result of Gila River flows through the district. In 1997, the District conducted a test to 

determine how much pumping of groundwater was needed to maintain existing groundwater 

levels. The District obtained a surplus water contract for additional Colorado River water to 

allow them to conduct the test so they could stay within their consumptive use entitlement 

for calendar year 1997. The testing continued through use of surplus water contracts for 

calendar years 1998, 1999, and 2000. The district was able to pump only 91,695 acre-feet in 

1997, 98,972 acre-feet in 1998, and 94,869 acre-feet in 1999. As a result, these tests indicated 

that the District was able to pump less than 100,000 acre-feet per year to maintain static 

groundwater levels for a relatively short period of time. 

Reclamation continues to investigate means to reduce irrigation drainage pumping in the 

District. In 1998, the District paid out their share of this project and requested transfer of 

title of their project’s facilities from the United States government. As part of the title 

transfer agreement, the District has committed to diligently pursue a goal of permanently 

reducing irrigation drainage pumping to 108,000 acre-feet or less per year. Their water 

conservation plan sets a time frame of 5 years to accomplish that goal. 

Table 9 – District Pumped Drainage Return Flow 

Year

Pumped Drainage 

Return Flow 

(acre-feet)

Irrigation Efficiency, % 

(note: data provided by WMIDD)

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004

138,200 

144,900 

116,200 

8,970 

49,820 

121,500 

119,600 

91,695 

98,972 

94,869 

110,287 

107,908 

119,410 

116,477 

106,002

- 

68.8 

70.4 

68.8 

65.4 

64.3 

60.4 

62.2 

61.9 

63.0 

59.7 

60.9 

61.2 

- 

- 

One of the options the District is pursuing is to combine the Gila Project water entitlements. 

That would allow the District to utilize a portion of the return flows from other districts in 

the Gila Project. Accounting for Gila Project return flow would allow the District the 

flexibility at times to avoid pumping solely to meet their consumptive use requirements. This 

is one option the District may use to pump less than 100,000 acre-feet per year and reduce 

the obligation of the United States to replace their pumped drainage.

A Yuma Area Water Resource Management Group (YAWRMG) has been developed to 

look at ways to more effectively manage groundwater resources in the Yuma Area. This 

includes methods to reduce drainage return flows from the District and other Gila Project 
40

and Yuma Project districts. Reduction of drainage pumping could benefit the United States 

by reducing the U.S. obligation to replace the District’s drainage returns. However, it should 

be noted that significant reductions in drainage return flows to the Cienega de Santa Clara 

Slough may have impacts on wildlife habitat. 

Figure 21 - Satellite photo of Cienega de Santa Clara 
41

CHAPTER 5 – TITLE II SALINITY CONTROL 

PROGRAM 

USDA / NRCS

In 1996, Public Law 104-127 changed the US Department of Agriculture – Natural Resource 

Conservation Service (NRCS) authorities to conduct on-farm salinity control projects. 

Colorado River Salinity Control Program (CRSC) activities were transferred to the 

Environmental Quality Incentives Program (EQIP) established under the Food Security Act 

of 1985. NRCS administers their CRSC activities through its field offices located in the 

counties that serve the local agricultural producers. 

PL 104-127 also amended the Salinity Control Act to allow Reclamation to provide cost 

sharing from the Upper Colorado River Basin and Lower Colorado River Basin 

Development Funds (Basin Funds) to supplement NRCS’s on-farm salinity control activities. 

Through agreements with the individual state administering agencies and NRCS, land 

treatment contracts to implement salinity control measures are developed and executed with 

private landowners and groups. 

In 2004, an on-farm salinity control implementation project was initiated in the Mancos 

River Valley in Colorado. Preparations are being made to begin implementation in the 

Muddy Creek agricultural area near Emery, Utah. Investigations are also underway in at least 

eight additional agricultural areas. 

Table 4 shows the current progress in implementing annual salt control, as well as the cost 

effectiveness of the control. The NRCS implementation schedule is controlled by annual 

appropriations. The implementation schedule for NRCS projects is based upon projected 

salt-load reduction needs, cost-effectiveness analysis, the probability of Federal funding, and 

the Basin Fund cost sharing capability. 

Table 10 - USDA Salinity Control Program Summary 

Salt Potential Expenditure 1Projected 2Cost 

Removed Salt Thru Total Effectiveness 

Unit Thru FY04 Removal FY04 Cost Thru FY04 

(year Initiated) (tons/year) (tons/year) ($/ton) 

L. Gunnison, CO (1988) 69,245 186,000 $38,686,632 $103,916,724 46 

McElmo Creek, CO (1990) 24,082 46,000 $12,036,480 $22,991,366 41 

Uinta Basin, UT (1987) 142,788 140,500 $67,109,572 $67,109,572 39 

Grand Valley, CO (1987) 90,425 132,000 $43,117,774 $62,942,175 40 

Big Sandy, WY (1988) 42,964 52,900 $13,185,980 $16,235,414 25 

Price/San Rafael, UT (1994) 35,441 146,900 $9,731,782 $40,337,428 23 

Mancos River, CO (2004) - 11,900 $0 $4,793,504 - 

TOTALS 404,945 716,200 $183,868,220 $318,326,183 38 

1Projected total costs were estimated using a ratio of existing cost and tons to potential tons. 

2Cost per ton of applied measures amortized over 25 years at 6.625% interest. 
42

Public Law 98-569 directs the Secretary of Agriculture to carry out a monitoring and 

evaluation program to evaluate the effectiveness of NRCS’s CRSC program. The three 

general purposes of the M&E effort are to (1) collect salinity control data; (2) evaluate the 

effect of salinity reduction practices on salt reduction; and (3) verify costs, project 

effectiveness, economic benefits, and impacts on wildlife habitat. 

Monitoring and evaluating NRCS’s CRSC program is under way in the seven active project 

areas in Colorado, Utah and Wyoming. Reports are published annually and can be accessed 

at www.usbr.gov/uc/progact/salinity/index.hml/

Research is necessary to develop new salinity control technologies. The Agricultural 

Research Service (ARS), Cooperative Research Service (CRS), and the State Agricultural 

Experiment Stations conduct research funded from State and Federal sources. 

Some of the salinity research activities being conducted by ARS at the U.S. Salinity 

Laboratory, Riverside, California, and at the Northern Plains Area Natural Resources 

Research Center, Fort Collins, Colorado, include: 

• Suitability of salt-affected water for irrigation reclamation models 

• Mobility of potentially toxic trace anions in irrigated root zones 

• Field-scale and regional distributions of solute loading to groundwater 

• Salt and specific tolerance in crop plants 

• Movement of water, salts and agricultural chemicals in the root and vadose zones 

of salt-affected soils. 

• Crop water use from high, saline water tables 

• Salt movement under level basin irrigation 

• Salinity assessment by rainfall simulation of runoff from rangelands 

BLM

The BLM’s current strategy is to provide the best management of the basic resource base. 

Successes with the resource base are designed to translate into improved vegetation cover, 

better use of onsite precipitation, and stronger plant root systems. In turn, a more stable 

runoff regime and reduced soil loss should result; thus, benefiting water quality of the 

Colorado River. 

Salt enters the Colorado River and its tributaries from ground-water flows, surface runoff, 

and from point sources such as saline springs and flowing wells. Dissolution of evaporite 

deposits in the Upper Colorado River Basin results in highly saline ground water that 

ultimately contributes the largest amount of salt to the Colorado River System. The natural 

salt load for the Colorado River at Lees Ferry, Arizona, is estimated to be about 4.4 million 

tons per year. Contributions from BLM lands are included in this estimate. Surface runoff 

from BLM-administered lands above Lees Ferry is estimated to contribute about 700,000 

tons per year, or about 16 percent. The remaining 3.7 million tons are contributed primarily 

by ground-water inflow and saline springs, and runoff from other Federal, Tribal, State, and 

private land. 
43

Planning and Public Involvement 

BLM continues to use its land-use planning process, the Resource Management Plan (RMP), 

as the primary vehicle for carrying forward the solutions to salt-loading problems. In 

addition to RMPs, in 2003 the BLM created and filled a salinity coordinator position. The 

salinity coordinator position became permanent at the beginning of January 2005. Budget 

planning is on-pace to allocate Congressional salinity funds for the 2006 fiscal year through a 

more accountable tracking method. Longer-term writing and compiling of salinity-control 

proposals (FY 2007-2009) is also occurring. 

The Report to Congress (pursuant to Public Law 106-459) on implementation of the 

comprehensive program for minimizing salt contributions to the Colorado River from lands 

administered by the BLM was signed by the Secretary at the beginning of 2005 and 

transmitted to the Committee on Energy and Natural Resources of the Senate and the 

Committee on Resources of the House of Representatives. 

Nonpoint Source Control 

Controlling salinity in rangeland surface runoff is closely related to controlling soil erosion, 

which is an objective of BLM’s Soil, Water, and Air program. Vegetation cover is usually the 

most important management variable influencing runoff and erosion rates on rangelands. 

On systematically targeted watersheds, the payoff for salinity control is that decreased 

sediment yields and moderated flood flow energies should combine to transport less salt 

from the uplands, as well as from gullies and established channels. 

Vegetation management, either indirectly through the design and implementation of 

livestock grazing plans or directly through vegetation manipulation, is an important erosion 

and salinity control technique. Reduced runoff and erosion combine to achieve reductions in 

the amount of salt that moves off site. 

Proper land use, including the objectives of grazing systems that incorporate increased 

cover, appropriate seasons of use, and riparian protection, is a preferred salinity control 

technique, as is minimizing activities that disturb the surface. However, on the most highly 

saline sites, maximum potential plant cover is usually inadequate to provide leverage for 

significant control of surface runoff, erosion, and associated salt mobilization. In those cases 

where watershed condition is so severely degraded that recovery will be ineffective under 

normal land management practices, mechanical land treatments and structural alternatives 

may be the only effective salinity control options. Land treatments involve soil tillage 

techniques such as contour furrowing, ripping, and rangeland pitting. Structural features 

include rangeland dikes, retention and gully plugs, and retention and detention reservoirs. 

BLM manages riparian-wetland and aquatic zones to achieve healthy and productive 

conditions for long-term benefits and values and, in Utah and Colorado, salt controls have 

been created by establishing riparian pasture and off-channel livestock watering practices. 

Cottonwood and willow tree poles have been planted on several ephemeral drainages. The 

planting areas are protected until the poles are well established. Soil-vegetation ecological site 

surveys continue to be an important baseline information source to understand from where, 

and by what processes, salts are transported to surface or groundwater. 

Point Source Control 

Many point sources of saline water exist on the public lands as either wells or springs. Close 

cooperation with the State is required for plugging of orphaned wells, and good field-level 
44

coordination with the private entities operating in oil and gas fields has led to additional 

point source control accomplishments. BLM has developed a water source inventory to 

identify and characterize water uses and respective sources on the public lands. Saline springs 

are identified through the program. Control of saline springs is analyzed through BLM’s 

land-use planning process with major sources being brought to Reclamation’s attention. 

Estimating Salinity Control 

It is difficult to estimate the actual reduction in the salinity of the Colorado River that may 

be attributed to BLM management activities. There are many physical, chemical, and 

biological processes that affect the movement of salt from an upland project area to the 

Colorado River or a perennial tributary to the Colorado. As the distance between a project 

and the nearest perennial flow increases, it quickly becomes impossible to quantify the 

amount of salt that would reach the perennial flow and the amount of time required for the 

salt to arrive at the perennial flow. For these reasons, BLM prefers to estimate the amount of 

salt that is retained on the project site by management actions. It is assumed that the salt 

retained would have been moved off site by surface runoff if the project had not been 

implemented. Table 11 shows the estimated salt retained by BLM management in the Basin 

through 2004. Utah’s estimate substantially increased due to the plugging of 2 saline-flowing 

wells. 

Table 11 – Estimated Salt Retained on BLM Lands (tons per year) 

State Thru 1996 1997 1998 1999 2000 2001 2002 2003 2004 

Arizona na 40 50 50 70 1,360 1,400 1,400 1,400 

Colorado na 670 810 840 1,350 4,140 4,140 4,140 4,140 

Nevada na 10 30 60 70 70 70 70 * 

New Mexico na 380 420 900 920 960 980 950 1,000 

Utah na 1,370 1,650 1,830 1,910 2,090 2,140 2,140 6,060 

Wyoming na 380 410 1,220 1,300 1,360 1,400 1,590 1,750 

Totals na 2,850 3,370 4,900 5,620 9,980 10,130 10,290 14,350 

Cumulative Total 36,170 39,020 42,390 47,290 52,910 62,890 73,020 83,310 97,660 

Note: Rounded to the nearest 10 tons. 

* Nevada no longer receives salinity control funding and is not tracked 

RECLAMATION 

Background 

The Bureau of Reclamation involvement in the Colorado River Basin Salinity Control 

Program dates back to the early 1960’s. In 1968, Reclamation initiated a cooperative 

reconnaissance study in the Upper Colorado Basin with objectives to identify feasible 

control measures and estimate their costs. This investigation evolved into a number of 

several salinity control units. In 1974, Public Law 93-320 authorized the construction of the 
45

Grand Valley, Paradox, Crystal Geyser, Las Vegas Wash Units. In 1984, Public Law 98-569 

authorized the construction of the Lower Gunnison and McElmo Creek Units. 

By 1993, Reclamation had gained 20 years of experience with the program and identified 

new and innovative opportunities to control salinity, including cooperative efforts with 

USDA, BLM, and private interests, which would be very cost effective. However, these 

opportunities could not be implemented because the Congress did not specifically authorize 

them. The DOI Inspector General’s audit report (1993) noted the Salinity Control Act 

directed that “the Secretary shall give preference to implementing practices which reduce 

salinity at the least cost per unit of salinity reduction.” The Inspector General concluded that 

the congressional authorization process for Reclamation projects impedes the 

implementation of cost-effective measures by restricting the program to specific, authorized 

units (specific areas). 

The Inspector General recommended that Reclamation seek changes in the Salinity Control 

Act to simplify the process for obtaining congressional approval of new, cost-effective 

salinity control projects. Specifically, the Inspector General recommended Reclamation seek 

authorities similar to those provided to USDA in the 1984 amendments to the act, wherein 

USDA was empowered with programmatic planning and construction authority. At the time, 

USDA had only to submit a report to the Congress and wait 60 days before it could proceed 

if the Congress did not object. In contrast, Reclamation was required to seek approval of its 

projects through legislation. This had proved to be a cumbersome way to manage the 

program. With broader authorities, Reclamation would be able to take advantage of 

opportunities as they presented themselves, thus reducing costs. 

Reclamation agreed with the Inspector General and wanted to explore any other innovative 

ideas, which would help improve the effectiveness of its program and take advantage of 

opportunities that were not envisioned 20 years ago. With most of the cost-effective 

portions of the authorized program nearing completion, this was a pivotal moment for the 

program. It would either be reauthorized or end in 1998 due to appropriation ceiling limits. 

From Reclamation=s point of view, it seemed a very appropriate time to reassess the 

direction of the program. 

Public Review 

In 1994, Reclamation initiated a public review of the Salinity Control Program. The goal of 

the public review was to completely reexamine the program and its authorities, to gather a 

broad range of new ideas, to review the lessons of past experiences, to formulate new 

guidelines and methodologies, and to draft new salinity control legislation to bring this 

program into the next century. 

The public review began on March 24, 1994, with a news release and individual notices 

mailed to more than 400 entities including congressional representatives; members of the 

Forum; local, State, and Federal agencies; environmental organizations; and other interested 

parties. The notices stated Reclamation’s purpose in conducting the review, provided 

background on the salinity problem in the Colorado River Basin, and the current program 

for addressing those problems. The notices then suggested several options regarding the 

Salinity Control Program. 

Reclamation received responses from private individuals and local, State, and Federal 

agencies. The majority of the comments were from local and State agencies expressing 
46

support for Reclamation=s leadership role in the program, having found that the old program 

could be improved in several ways. 

The public review of the program found that in the future, the program should: 

• Consider alternatives to Government planned projects 

• Allow non-Federal construction 

• Consider proposals to control salinity anywhere in the Colorado River Basin 

• Consider non-traditional methods 

• Be competitive (consider cost and performance risk in its ranking criteria) 

• Continue to be voluntary (rather than regulatory) 

 

The comments supported implementing the Inspector General’s recommendation (to seek 

broader authorities for Reclamation). In 1994, Reclamation and the Basin States developed 

legislation to broaden Reclamation=s authorities so that it could manage the implementation 

of the program without further congressional approval. This legislation was introduced in 

the Congress late in 1994 and was approved and signed into law (Public Law 104-20) in 

1995. The 1995 amendments to the Salinity Control Act authorized Reclamation to pursue 

salinity control throughout the Colorado River Basin and required Reclamation to develop 

guidelines on how it would implement this new, basinwide approach to the Program. 

Guidelines 

Reclamation has prepared guidelines for its new Basinwide Salinity Control Program, which 

implements the recommendations made in the review of the program. As an alternative to 

adopting new, specific regulations, Reclamation administers the program through existing 

procurement techniques and established Federal regulations. Since February 1996, the 

program has been made available to the general public through this annual competitive 

process. 

In 1984, Public Law 98-569 directed the Secretary to give preference to those projects which 

reduce salinity at the least cost per ton of salinity control. Since that time, cost effectiveness 

(cost per ton of salt removed) has been used to prioritize the implementation of salinity 

controls. However, cost effectiveness is only an estimate (prediction) of the project=s cost 

and effectiveness at controlling salinity. Depending upon the project, there can be a degree 

of uncertainty in either of these values. Given the diversity of proposals that Reclamation 

may receive, an evaluation of the proposal=s risks has been included in the current selection 

process. 

Ultimately, there is a tradeoff between risk and cost. In the end, eliminating risk may cost 

more than accepting some risk. A ranking committee is assembled to evaluate the tradeoffs 

between cost effectiveness and performance risks. The ranking committee is made up of 

representatives from the two cost-sharing partners, the Basin States and Reclamation. After 

the committee ranks the proposals, Reclamation attempts to negotiate the final terms of an 

agreement with the most highly ranked proponents. The first awards under this new process 

began in FY97. 

Performance Review 

One of the greatest advantages of the new program comes from the integration of 

Reclamation=s program with USDA=s program. Water conservation within irrigation projects 
47

on saline soils is the single most effective salinity control measure found in the past 30 years 

of investigations. By integrating USDA=s on-farm irrigation improvements with 

Reclamation=s off-farm improvements, extremely high efficiencies can be obtained. If the 

landscape permits, pressure from piped delivery systems (laterals) may be used to drive 

sprinkler irrigation systems at efficiency rates far better than those normally obtained by 

flood systems. The new authorities allow Reclamation much greater flexibility (in both 

timing and funding) to work with USDA to develop these types of projects. 

The new authorities also allow Reclamation to respond to opportunities that are timesensitive. Cost-sharing partners (State and Federal agencies) often have funds available at 

very specific times. Under its old methods of planning, authorization, funding, and 

construction, it would often take significant time periods - even decades - for Reclamation to 

be ready to proceed with a project. None of Reclamation=s past projects were able to attract 

cost sharing because of this. For example, the Ashley Project (a joint effort by Utah, 

Reclamation, and the Environmental Protection Agency [EPA]) will eliminate 9,000 tons of 

salt per year. Reclamation=s Basinwide Salinity Control Program is a relatively minor, but 

important part of the project ($3 million in a $18 million project). Once Reclamation had 

committed to fund its part of the project, funds were included in EPA=s budget by the 

Congress to complete the partnership. 

Another significant advantage of the program is that projects are “owned” by the proponent, 

not Reclamation. The proponent is responsible to perform on its proposal. Costs paid by 

Reclamation are controlled and limited by an agreement. Yet, unforeseen cost overruns can 

occur. The proponent has several options: the project may be terminated or the proponent 

may choose to cover the overruns with their own funds or borrow funds from State 

programs. The proponent may also choose to reformulate the project costs and recompete 

the project through the entire award process. For example, pipeline bedding and materials 

costs for the Ferron Project were underestimated in the proposal and subsequent 

construction cooperative agreement. The proponent was denied permission to award 

materials contracts for the pipeline, since the costs were beyond those contained in the 

agreement. After months of negotiations and analysis, the proponents elected to terminate 

the project, reformulate it, and recompete against other proposals the following year. Their 

project was found to be competitive at the reformulated cost and was allowed to proceed. 

Since this project ran into difficulties, none of the other projects have shown any problems. 

In 1998, Reclamation received a record number of proposals. Many were well within the 

competitive range awarded in 1997. Proposals included a proposal to improve the efficiency 

of Reclamation=s deep well injection project (Paradox Valley Unit), an extension of a project 

awarded in 1997, one reformulated project awarded in 1997, an industrial use proposal, a 

cost-shared selenium control demonstration project, and several irrigation improvement 

projects. No new projects were awarded in 1999/2000 due to appropriation ceiling limits in 

P.L. 104-20. With the additional $100 million provided by P.L. 106-459, Reclamation 

reopened its request for proposal process in 2001. Projects have been completed and in 2004 

a new request for proposals was issued for new projects. Table 12, below, shows the 

Reclamation projects and the salinity controlled since 1998. 
48

Table 12 – Reclamation Basinwide Salinity Control Program Salt Controlled, tons/year 

GRAND GRAND

VALLEY VALLEY BOR BOR BOR BOR BOR Total

STAGE 1 STAGE 2 Meeker Las Vegas Uinta LG McElmo Hammond Paradox PSR BOR

1998 21,900 109,400 48,000 3,800 41,380 23,000 16,043 128,000 21,580 413,104

1999 21,900 109,400 48,000 3,800 41,380 23,000 24,065 128,000 21,580 421,125

2000 21,900 109,400 48,000 3,800 18,685 43,675 23,000 32,087 76,000 21,580 398,127

2001 21,900 109,400 48,000 3,800 18,685 43,675 23,000 40,108 109,000 21,580 439,149

2002 21,900 109,400 48,000 3,800 18,685 43,675 23,000 48,130 109,000 21,580 447,170

2003 21,900 109,400 48,000 3,800 18,685 43,675 23,000 48,130 112,000 21,580 450,170

2004 21,900 105,600 48,000 3,800 138,374 43,675 23,000 48,130 112,000 24,629 569,108

Lower Gunnison (LG) 

Price San Rafael (PSR) 
49

CHAPTER 6 - OTHER WATER QUALITY ISSUES 

Salinity is not the only water quality concern in the Colorado River Basin. Other issues 

include selenium and trace element toxicity to aquatic life, boron’s toxic effects to plants and 

crop growth, ammonium perchlorate contamination in both domestic water and crop 

irrigation as well as Uranium mine tailings. 

PERCHLORATE 

Ammonium perchlorate is a salt which is used as an oxidizer for solid propellants, 

explosives, fireworks and some munitions. The perchlorate ion is water soluble and 

environmentally stable. It has been found in surface and groundwater in the Colorado River 

basin, as well as some lettuce and milk samples collected in the lower basin. Health wise, 

perchlorate can disrupt normal thyroid functioning (National Academy of Science, 2005). 

THM 

Bromide and algae combine to produce taste, odor, and potentially toxic trihalomethanes 

(THM) with oxidation by either chlorination or ozonation during potable water treatment. 

Specific entities involved with water treatment in California, Nevada, and Arizona have 

requested that Reclamation and USGS look at existing data and consider adding bromide 

analysis to water sampling in the basin to quantify the sources of bromide. The formation of 

brominated disinfection by-products during drinking water disinfection is possible if the raw 

water contains bromide. Chloroform is normally the predominant THM species; however, in 

the water containing bromide, brominated trihalomethanes, bromodichloromethane, 

chlorodibromomethane, bromoform, and bromate as well as chloroacetic acids and 

bromoacetic acids and dichloroacetonitrile can be formed (Bull and Kopfler, 1991). Two 

trihalomethanes, chloroform and bromodichloromethane, are suspected carcinogens for 

humans. These THM products formed during water treatment have human health concerns, 

and are not easily treated. High organic matter in water due to algal blooms also influences 

the THM process. 

ALGAE 

Algal blooms also play an important role in water treatment issues, and noxious and 

potentially toxic blue-green algae blooms are a particular concern. Dillion Reservoir in the 

Colorado River headwaters, Scofield Reservoir on the Price River in Utah, and Las Vegas 

Bay in Lake Mead, Nevada have or need specific nutrient control programs to reduce algal 

problems. Specific blue-green algae species and associated organic chemical by-products 

have now been identified and added to EPA’s list for study as potential future maximum 

contaminant level (MCL) compounds for drinking water standards. Knowledge of health 

issues and drinking water treatment problems due to potential toxic chemical by-products 

from blue-green algae break down has greatly increased over the past decade. Concerns over 

the toxic chemicals associated with these blooms continue to grow. Algae blooms are also a 
50

concern to aesthetics, fish, and wildlife uses of water at other locations in the Colorado River 

Basin. 

TMDL’s 

Nutrient Total Maximum Daily Loading (TMDL’s) program are being developed in several 

watersheds. A Selenium TMDL Project is ongoing on the Gunnison River in Colorado. The 

Salton Sea is the major surface water sink for a significant portion of the Colorado River’s 

salt and trace elements. Salinity, algae, anoxia and hydrogen sulfide generation are significant 

water quality problems at Salton Sea. The Salton Sea has become a major winter waterfowl 

area for both Pacific Flyways in North and South America. Fish and waterfowl kills at Salton 

Sea are increasingly becoming a concern with several endangered species at risk (Barnum, 

2005). Recent studies have shown that generation of hydrogen sulfide and degassing within 

Salton Sea is an important process causing fish kills. The precipitation of calcite, gypsum, 

and other minerals in Salton Sea are also important to understanding the salt budgets and 

cycles at Salton Sea (Holdren and Montano, 2002). Recent studies also indicate that 

hydrogen sulfide generation and degassing is also a major component of salt loss in the 

Salton Sea (Amrhein, 2005). 

The Colorado River Basin Salinity Forum established a selenium sub-committee in 2004. A 

basinwide selenium budget was presented in Progress Report 21. The Department of the 

Interior’s National Irrigation Water Quality Program jointly conducted a salinity/selenium 

reduction off-farm conveyance pilot project in the Gunnison River Basin (Butler, 2001). 

Reclamation, USGS, Colorado Gunnison River Selenium (TMDL) Committee, and U.S. Fish 

and Wildlife Service (FWS) participated in this project. It was determined that approximately 

0.1 pounds of selenium were reduced per ton of salt reduction. Additional joint selenium 

studies by Reclamation and the USGS (Stephens et al., 1992) found that selenium could be 

reduced and precipitate or simply pass through on-farm areas near Jensen, Utah. The 

Colorado pilot project site was chosen because it had a high potential for reduction of 

selenium. Therefore, the 0.1 pound reduction of selenium per ton of salt is probably the high 

end of selenium reduction from irrigation efficiency improvement salinity control. However, 

if an additional 400,000 tons of future salt reduction from irrigation efficiency improvements 

are built in the future with a selenium reduction of only 0.05 pound/ton of salt; the selenium 

reduction may not be insignificant. If selenium can be reduced from a long term average 

below Glen Canyon Dam from 2.4 μg/L to about 1.8 μg/L this would meet the lower basin 

states selenium standards of 2.0 μg/L. Furthermore, it could produce about a 25% reduction 

of selenium in agricultural drains and shallow wetlands around Salton Sea, a reduction of 12 

to 9 μg/L. 

In the hotter climates around the Salton Sea selenium does not appear to be accumulating 

and recycling in the food chain at the water sediment interface in shallow wetlands. In the 

cooler climates in the upper basin and with higher selenium inflow concentrations the 

accumulation of high sediment selenium concentrations appears to be an important factor in 

reaching a selenium hazard. If a hotter climate and higher permeable soils beneath a shallow 

wetland have less a tendency to accumulate selenium to toxic levels for waterfowl and 

aquatic life, then this selenium reduction may not be insignificant (Miller, 2005). Selenium 

concentrations in fish are generally high throughout the Colorado River Basin. However, 

proving selenium hazards, particularly in the lower basin, has been difficult. 
51

URANIUM MINE TAILINGS 

A large pile of Uranium mine tailings are found upstream from Lake Powell at Moab, Utah. 

The Department of Energy (DOE) Web page for the Moab Atlas Uranium Tailings Clean 

up is http://gj.em.doe.gov/moab/moabnews.htm. The Final Environmental Statement can 

be found at http://gj.em.doe.gov/moab/eis/feis.htm. The Record of decision was issued in 

September 2005. The FES calls for ground water remediation taking decades and costing 

around one million/year. DOE has announced that the preferred alternative is the off-site 

disposal near Cresent Jct, Utah using predominantly rail transportation to haul the material 

(http://gj.em.doe.gov/moab/release04_06_2005.pdf). Total costs could approach 400 

million dollars. Ground water remediation will remove water quality impacts to fish in the 

river primarily from ammonia. The risk of a major flood washing away significant parts of 

the tailings was a consideration in picking an alternative. All downstream States and water 

users have preferred an off-site remediation alternative which removes the tailings from the 

river bank. 

A small Uranium mill site at White Canyon, Utah was run from 1949 to 1953 which 

generated about 23,000 tons of tailings. The mill was removed before Lake Powell inundated 

the site in 1964, but the tailings were left. The site is in the inflow zone of Lake Powell and 

has been, and continues to be covered with sediment. Reclamation scientists have examined 

the area and found that there is over 30’ of sediment covering the mill site containing the 

tailings and the “gross alpha” levels (radioactivity measurement) in the water downstream 

from the tailing site are no different than those of the inflow water above the mill site. 
52 
53

REFERENCES CITED 

American Heart Association (AHA). 2000. Sodium. AHA Recommendation. 

http://www.americanheart.org/Heart_and _Stroke_A_Z_Guide/sodium.html. 

Amrhein, C. and M.A. Anderson. 2005. Geochemistry of the Salton Sea and Agricultural 

Evaporation Basins. International Salinity Forum Conference, April 25-28, 2005. Riverside, 

CA. 

Anderson, J.C., and A.P. Kleinman. 1978. Salinity Management Options for the Colorado River. 

Water Resources Series Planning Report No. P-78-003, Utah Water Resources Laboratory, 

Logan, Utah. 

Bolke, E.L. and K.M. Waddell. 1975. Chemical Quality and Temperature of Water in 

Flaming Gorge Reservoir, Wyoming and Utah, and the Effect of the Reservoir on the Green 

River. Geological Survey Water-Supply Paper 2039-A. US Government Printing Office, 

Washington DC. 

Bolke, E.L. 1979. Dissolved-Oxygen Depletion and Other Effects of Storing Water in 

Flaming Gorge Reservoir, Wyoming and Utah. Geological Survey Water-Supply Paper 2058. 

US Government Printing Office, Washington DC. 

Bureau of Reclamation. 1999. Salinity management study final report: Long term strategy & 

recommended action plan. Metropolitan Water District of Southern California. 

Bureau of Reclamation. 2003. Colorado River System Consumptive Uses and Losses Report 

1996-2000. Upper Colorado Regional Office, Salt Lake City, Utah. 

Bull, R.J. and F.C. Kopfler. 1991. Health Effects of Disinfectants and Disinfection Byproducts. AWWA Research Foundation and American Water Works Association. 

Butler, D.L., 2001. Effects of Piping Irrigation Laterals on Selenium and Salt Loads, 

Montros Arroyo Basin, Western Colorado. U.S. Geological Survey Water Resources 

Investigations Report 01-4204, 14p. 

Butler, D.L. 1996. Trend Analysis of Selected Water-Quality Data Associated With SalinityControl Projects in the Grand Valley. In the Lower Gunnison River basin, and at Meeker 

Dome, Western Colorado. Water Resources Investigation Rep. No. 95–4274, United States 

Geological Survey, Denver. 

Holdren, G.C. and A. Montano. 2002. Chemical and Physical Limnology of the Salton Sea, 

California – 1999. Technical Memorandum No. 8220-03-02, U.S. Department of the 

Interior, Bureau of Reclamation, Denver, CO. 

Iorns, W.V., C.H. Hembree, and G.L. Oakland. 1965. Water Resources of the Upper Colorado 

River Basin - Technical Report. U.S. Geological Survey, Professional Paper 441. 

Kleinman, A.P., and B.F. Brown. December 1980. Colorado River Salinity, Economic Impacts on 

Agricultural, Municipal, and Industrial Users. Bureau of Reclamation, Engineering and Research 

Center, Colorado River Water Quality Office, Denver, Colorado. 

Kurtzweil P. 1995. Scouting for sodium and other nutrients important to blood pressure. 

Washington, DC: U.S. Food and Drug Administration, FDA Consumer. 
54

Laronne, J.B. 1977. Dissolution Potential of Surficial Mancos Shale and Alluvium. Unpublished 

Ph.D. dissertation, Department of Earth Resources, Colorado State University. 

Liebermann, T.D., and B.D. Nordlund. 1986. Estimates of Dissolved Solid and Major 

Constituents for 70 Streamflow-Gaging Stations in the Upper Colorado River Basin. U.S. 

Geological Survey draft report. 

Lohman, L.C., et al. 1988. Economic Impacts of Salinity of the Colorado River. Bureau of 

Reclamation, Denver, Colorado. 

McWhorter, D.B., J.W. Rowe, et al. 1979. Surface and Subsurface Water Quality Hydrology in 

Surface Mined Watersheds, Part I. Text Interagency Energy/Environment R&D Program 

Report, EPA-600/7-79-193. 

Midgley JP, Matthew AG, Greenwood CMT, Logan AG. 1996. Effect of reduced dietary 

sodium on blood pressure. A meta-analysis of randomized controlled trials. JAMA 

275:1590-1597. 

Mueller, D.K., and L.L. Osen. 1988. Estimation of Natural Dissolved-Solids Discharge in the Upper 

Colorado River Basin, Western United States. U.S. Geological Survey, Water Resources 

Investigation Report 87-4069. 

Mueller, D.K., and T.D. Liebermann. 1988. Extension of Streamflow and Dissolved Solids Records 

at Selected Sites in the Colorado River Basin: Arizona, California, Colorado, Nevada, New Mexico, 

Utah, and Wyoming, 1940-83. U.S. Geological Survey, Water Resources Investigations Report 

87-4203. 

Parker, R.S., and J.M. Norris. 1983. Simulated Effects of Anticipated Coal Mining on Dissolved 

Solids in Selected Tributaries of the Yampa River, Northwestern Colorado. U.S. Geological Survey, 

Water Resources Investigation Report 83-4084, Lakewood, Colorado. 

Ponce, S.L. 1975. Examination of a Non-Point Source Loading Function for the Mancos Shale 

Wildlands of the Price River Basin, Utah. Ph.D. Thesis, Utah State University, Logan, Utah. 

Prairie, J., Rajagopalan, B., Fulp, T., and Zagona, E., (2005). "Statistical Nonparametric 

Model for Natural Salt Estimation." Journal of Environmental Engineering, 131(1), 130-138. 

Riley, J.P., et al. 1982. Potential of Water and Salt Yields from Surface Runoff on Public Lands in the 

Price River Basin. Water Resources Planning Series UWRL/P-82/01, Utah Water Research 

Laboratory, Logan, Utah, 94 pp. 

Reclamation. 1982. Grand Valley Salt Pickup Calculations. Colorado River Basin Salinity 

Control Project, Colorado. U.S. Bureau of Reclamation. Grand Junction, Colorado. June, 

1982. 

Riley, J.P., et al. 1982. Salt Uptake in Natural Channels Traversing Mancos Shales in the Price River 

Basin, Utah. Water Resources Planning Series UWRL/P-82/02, Utah Water Research 

Laboratory, Logan, Utah, 194 pp. 

Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin 

PR, Miller ER III, Simons-Morton DG, Karanja N, Lin PH. 2001. Effects on blood 

pressure of reduced dietary sodium and the dietary approaches to stop hypertension (DASH) 

diet. New England Journal of Medicine 344(1):53-55. 
55

Schumm, S.A., and D.I. Gregory. 1986. Diffuse-Source Salinity: Mancos Shale Terrain. 

U.S. Department of the Interior, Bureau of Land Management, Technical Note No. 373, 

Denver Service Center, Denver, Colorado. 

Sowers, JR, Lester M. 2000. Hypertension, hormones and aging. Lab Clin Med 135:379-

386. 

Stephens, D.W., B. Waddell, L. Peltz, J. Miller. 1992. Detailed Study of Selenium and 

Selected Elements in Water, Bottom Sediment, and Biota Associated with Irrigation 

Drainage, in the Middle Green River Basin, Utah, 1988 – 1990. U.S.Geological Survey 

Water-Resources Investigations Report 92-4084. 

Svetkey LP, Sacks FM, Obarzanek E, Vollmer WM, Appel LJ, Karanja N, Harsha D, Bray 

GA, Aickin M, Proschan M, Windhauser MM, Swain JF, McCarron PB, Rhodes DG, Laws 

RL. 1999. The DASH diet, sodium intake and blood pressure trial (DASH-Sodium): 

rationale and design. J Am Diet Assoc 99:S96-S104. 

Taubes, G. 1998. The (political) science of salt. Science 281:898-907. 

Treuman, D. 1995. Land Retirement – Alternative for salinity control. Bureau of 

Reclamation. 

Uintex Corp. 1982. A Study of Runoff and Water Quality Associated with the Wildlands of 

the Price River Basin, Utah. Bureau of Land Management Contract No. YA553-CT1-1064. 

U.S. Department of Agriculture (USDA). 1976. Grand Valley Salinity Study, Investigation 

of Sediment and Salt Yields in Diffuse Areas. Soil Conservation Service, Memorandum, 

March 5, 1976. Mesa County, Colorado. 

U.S. Department of Agriculture (USDA). 2000. Nutrition and your health: Dietary 

guidelines for Americans, 5th ed. Home and Garden bulletin No. 232. U.S. Department of 

Health and Human Services, Washington, DC. 

U.S. Department of the Interior. 1984. Status Report, Bureau of Land Management, 

Technical Note No. 364, Denver Service Center, Denver, Colorado. 

U.S. Department of the Interior. 1985. Draft Environmental Impact Statement, James 

Creek Coal, Preference Right Lease Application. Bureau of Land Management, Craig 

District, Colorado. 

U.S. Department of the Interior. 1990. Colorado River Damage Estimate Program. Bureau 

of Reclamation, Chief, Analysis, Contracts, and Lands Division, Denver Office, 

Memorandum, October 25, 1990, Denver, Colorado. 

U.S. Environmental Protection Agency (EPA). 1971. The Mineral Quality Problem in the 

Colorado River Basin, Summary Report, EPA Regions VIII and IX. 

U.S. Environmental Protection Agency (EPA). 1999. Health effects from exposure to sulfate 

in drinking water workshop. Office of Water. Washington, DC. EPA 815-R-99-002. 

Vaill, J.E., and Butler, D.L. (1999). “Streamflow and Dissolved-Solids Trends, Through 

1996, in the Colorado River basin Upstream from Lake Powell- Colorado, Utah, Wyoming.” 

Water Resources Investigation Rep. No. 99-4097, United States Geological Survey, Denver. 

World Health Organization (WHO). 1993. Guidelines for drinking water quality, 2nd ed. 

Vol. 1. Recommendations. Geneva, Switzerland. 
56

GENERAL REFERENCES 

Agricultural Research Service. 1982. Minimizing Salt in Return Flow Through Irrigation 

Management. Report No. PUB-744; EPA-600/2-82-073, 181 pp. 

Battelle Pacific Northwest Labs. 1982. Western Oil-Shale Development: A Technological 

Assessment. Vol. 6: Oil-Shale Development in the Piceance Creek Basin and Potential Water- Quality 

Changes. Department of Energy, Report No. PNL-3830-VO2.6, 22 pp. 

Bentley, R.G., K.O. Eggleston, and E.B. Janes. 1980. Salinity Status Report, 1978-79, Control of 

Salinity from Point Sources Yielding Groundwater Discharge and from Diffuse Surface Runoff in the Upper 

Colorado River Basin. Report No. BLM-YA-TR-80-01, Bureau of Land Management, Denver 

Service Center, Denver, Colorado, 37 pp. 

Bowles, D.S., et al. 1982. Salt Loading From Efflorescence and Suspended Sediments in the Price 

River Basin. Water Resources Planning Series UWRL/P-82/05, Utah Water Research 

Laboratory, Logan, Utah, 142 pp. 

Brenniman, G.R. 1981. Relationship Between High Sodium Levels in Municipally Softened Drinking 

Water and Elevated Blood Pressures. Water Resources Center, Illinois University, Research 

Report 158, NTIS PB81-212615, 27 pp. 

Bulke, E.L., and K.M. Waddell. 1975. Chemical Quality and Temperature of Water in Flaming 

Gorge Reservoir, Wyoming and Utah, and the Effect of the Reservoir on the Green River. 

U.S. Geological Survey, Water Supply Paper 2039-A. 

Burdge, Irelan. 1971. Salinity of Surface Water in the Lower Colorado River, Salton Sea Area. U.S. 

Geological Survey, Professional Paper 486-E. 

Bureau of Land Management. 1978. The Effects of Surface Disturbance on the Salinity of Public 

Lands in the Upper Colorado River Basin, 1977 Status Report. U.S. Department of the Interior, 

Denver Service Center, Denver, Colorado, 208 pp. 

Bureau of Reclamation. 1981. Saline Water Use and Disposal Opportunities: Colorado River Water 

Quality Improvement Program. Special Report, Bureau of Reclamation, Denver, Colorado, 167 

pp. 

Bureau of Reclamation. 1981. Water Assessment for the Lower Colorado River Region, Emerging 

Energy Technology Development. Bureau of Reclamation, Boulder City, Nevada, 170 pp. 

Bureau of Reclamation. 2003. Colorado River System Consumptive Uses and Losses Report 1996- 

2000. Upper Colorado Region, Salt Lake City, Utah. 

Bureau of Reclamation. 1984. Development, Verification, and Use of Methods to Model Chemical 

and Thermal Processes for Lakes Powell and Mead. Engineering and Research Center, Colorado 

River Water Quality Office, Denver, Colorado. 

Bureau of Reclamation. May 1985. Colorado River Simulation System Documentation System 

Overview. USBR Engineering and Research Center, Denver, Colorado. 

Bureau of Reclamation. 1986. Etiwanda Ion-Exchange Pilot-Plant Testing. Denver, Colorado.

CH2M Hill. 1982. Salinity Investigation of the Price-San Rafael River Unit, Colorado River 
57

Water Quality Improvement Program. Bureau of Reclamation, Contract No. 1-07-40-51637, 

Utah Projects Office, Provo, Utah. 

Cissell, Jeffery A., V. Dean Adams, Joel E. Fletcher, Daniel S. Filip, and Dennis B. George. 

1982. Water Requirements and Pollutant Potential in the Gasification of Carbonaceous Shales. Report 

Nos. UWRL/Q-82/04; W83-02211; OWRT-A-043-UT(1), Utah Water Research 

Laboratory, Logan, Utah, 68 pp. 

Colorado Water Resources Research Institute. 1981. A Five Year Plan for Water Research in 

Colorado. Office of Water Research and Technology, Report No. W82-05531, 133 pp. 

Cowan, Michael S., R. Wayne Cheney, and Jeffrey C. Addiego. 1981. Colorado River 

Simulation System: An Executive Summary. Bureau of Reclamation, Engineering and Research 

Center, Denver, Colorado, 19 pp. 

Dean, A.V. and Lamarra, V.A. (editors). 1981. Aquatic Resources Management of the Colorado 

River Ecosystem (Proceedings of the Symposium). Ann Arbor Science Publication, Ann Arbor, 

Michigan, 697 pp. 

DeLon, L.L. 1982. Water Quality of Streams and Springs, Green River Basin, Wyoming. U.S. 

Geological Survey, Water Resources Investigations Report 82-4008. 

Eisenhauer, R.J. 1983. Characterization of Glenwood Springs and Dotsero Springs Water. Bureau of 

Reclamation, Engineering and Research Center, Report No. 83-10, Denver, Colorado, 58 pp. 

Eisenhauer, R.J. 1986. Characterization of Glenwood Springs and Dotsero Springs Source Aquifers. 

Bureau of Reclamation, REC-ERC-86-1, Denver, Colorado. 

Eisenhauer, R.J. 1987. Characteristics of Big Sandy River Drainage Basin Water and of Salty Aquifer 

Water. Bureau of Reclamation, REC-ERC-87-2, Denver, Colorado. 

Evans, R.G., W.R. Walker, and G.V. Skogerboe. 1982. Defining Cost-Effective Salinity Control 

Programs. Journal of the Irrigation and Drainage Division, Proceedings of the American 

Society of Civil Engineers, vol. 108, No. 4, pp. 265-272. 

French, Richard H. (Ed.). 1984. Salinity in Watercourses and Reservoirs. Proceedings of the 

1983 International Symposium on State-of-the-Art Control of Salinity, July 13-15, 1983, Salt 

Lake City, Utah, Butterworth Publishers, Stoneham, Massachusetts. 

Gloss, S., and D.E. Kidd. Application of the Nutrient Loading Concept and Effects of Nutrient 

Perturbations on Phytoplankton Productivity. Lake Powell Research Project, Bulletin No. 59. 

Green, S.L. 1981. Water Resources Investigations of the U.S. Geological Survey in 

Wyoming, Fiscal Year 1980. U.S. Geological Survey, Open-File Report 81-201, 118 pp. 

Haselhoff, Donald A. 1983. Water for Las Vegas Metropolitan Area, Journal of Environmental 

Engineering, vol. 109, No. 3, pp. 700-715. 

Holburt, M.B. 1982. Colorado River Water Allocation. Water Supply and Management, vol. 6, 

No. 1-2, pp. 63-73. 

Howells, L., et al. 1987. Base of Moderately Saline Groundwater in the Uinta Basin, Utah. U.S. 

Geological Survey, Open-File Report 87-397. 
58

Hyatt, M.L., J.P. Riley, M.L. McKee, and E.K. Israelson. 1970. Computer Simulation of the 

Hydrologic-Salinity Flow System Within the Upper Colorado River Basin. PRWG54-1. Utah Water 

Research Laboratory, Utah State University, Logan, Utah, 255 pp. 

Israelsen, C. E., et al. 1980. Use of Saline Water in Energy Development. Water Resources 

Planning Series UWRL/P-80/04, Utah Water Research Laboratory, Logan, Utah, 128 pp. 

Jackson, W.L., R.G. Bentley, and S. Fisher. 1984. Results of BLM Studies on Public Lands in the 

Upper Colorado River Basin. BLM Technical Note YA-PT-84-008-4340, Bureau of Land 

Management, Denver Service Center, Denver, Colorado. 

Johnson, D.H., C.M. Leboeuf, and D. Waddington. 1981. Solar Pond-Driven Distillation and 

Power Production System. Solar Energy Research Institute, Report No. SERI/TR-631-1248, 

Department of Energy, Golden, Colorado, 24 pp. 

Johnson, R.K., and S.A. Schumm. 1982. Geomorphic and Lithologic Controls of Diffuse-Source 

Salinity, Grand Valley, Western Colorado. National Technical Information Service, 

PB82-256587, 99 pp. 

Kidd, D.E., E. Hansmann, and S. Gloss. Trophic Status Investigations at Lake Powell Reservoir. 

Lake Powell Research Project Bulletin No. 60. 

Koch, R.W., T.G. Sanders, and H.S. Morel-Seytoux. 1982. Regional Detection of Change in 

Water Quality Variables. Water Resources Bulletin, vol. 18, No. 5, pp. 815-821. 

Laronne, J.B., and S.A. Schumm. l977. Evaluation of the Storage of Diffuse Sources of Salinity in 

the Upper Colorado River Basin. Environmental Resources Center, Colorado State University, 

Completion Report Series No. 79, 111 pp. 

Laughlin, J.K. 1984. Appraisal Study of Saline Water Use Equipment for Power Plant Cooling. 

Bureau of Reclamation, Denver, Colorado. 

Laughlin, J.K. 1985. Final Report - Study of Saline Water Use at Jim Bridger Power Plant. Bureau 

of Reclamation, Denver, Colorado. 

Laughlin, J.K. 1986. Final Report - Study of Saline Water Use at Harry Allen Generating Station. 

Bureau of Reclamation, Denver, Colorado. 

Laughlin, J.K. 1987. Final Report - Study of Saline Water Use at the Etiwanda Generating Station. 

Bureau of Reclamation, Denver, Colorado. 

Law, J.P., Jr., and A.G. Hornsby. 1982. The Colorado River Salinity Problem. Water Supply and 

Management, vol. 6, No. 1-2, pp. 87-104. 

Liebermann, T.D., et al. 1987. User’s Manual for Estimation of Dissolved-Solids Concentrations and 

Loads in Surface Water. U.S. Geological Survey, Water Resources Investigations 

Report 86-4124. 

Liebermann, T.D., D.K. Mueller, J.E. Kircher, A.F. Choquette, and R.A. Bell. 1986. 

Characteristics and Trends of Dissolved Solids in the Upper Colorado River Basin, Arizona, Colorado, 

New Mexico, Utah, and Wyoming. U.S. Geological Survey, Open-File Report 87-568. 

Lindskov, K.L., and B.A. Kimball. Quantity and Quality of Streamflow in Southeastern Uinta Basin, 

Utah and Colorado. U.S. Geological Survey, Water Supply Paper 2224. 
59

Martin, R.G., and R.H. Stroud. 1973. Influence of Reservoir Discharge Location on Water Quality, 

Biology, and Sport Fisheries of Reservoirs and Tailwaters, 1968-71. U.S. Army Corps of Engineers, 

Waterway Experiment Station, Contract No. DACW31-67-C-0083. 

Mayer, L.M. 1977. The Effect of Lake Powell on Dissolved Silica Cycling in the Colorado River. Lake 

Powell Research Project Bulletin No. 42. 

Maynard, D.P., and Caputo, R. 1982. Assessment of Saline Water Use in Coal Transport and 

Multipurpose Systems. Jet Propulsion Laboratory, Report No. JPL-D-425, Pasadena, 

California, Bureau of Reclamation, Engineering and Research Center, Denver, Colorado, 

156 pp. 

Merritt, D. and Johnson, N. 1977. Advective Circulation in Lake Powell, Utah-Arizona. Lake 

Powell Research Project Bulletin No. 61, Institute of Geophysics and Planetary Physics, 

University of California, Los Angeles, California, 72 pp. 

Miffin, M.D. 1983. Reuse Versus Return Flows: Considerations for Selecting a Water Supply Strategy. 

University of Nevada, Desert Research Institute, Reno, Nevada. 

Miller, J.B., D.L. Wegner, and D.R. Bruemmer. 1980. Salinity and Phosphorus Routing Through 

the Colorado River/Reservoir System. Bureau of Reclamation, Salt Lake City, Utah. 

Moody, C.D., and D.K. Mueller. 1984. Water Quality of the Colorado System: Historical Trends in 

Concentration, Load, and Mass Fraction of Inorganic Solutes. Bureau of Reclamation, Report No. 

EC-ERC-84-9. 

Mueller, D.K., and L.L. Osen. 1988. Estimation of Natural Dissolved Solids Discharge in the Upper 

Colorado River Basin, Western United States. U.S. Geological Survey, Water Resources 

Investigations Report 87-4069. 

Mundorff, J.C. 1972. Reconnaissance of Chemical Quality of Surface Water and Fluvial Sediment in 

the Price River Basin, Utah. Utah Department of Natural Resources Technical Publication 39. 

Mundorff, J.C., and K.R. Thompson. 1980. Reconnaissance of the Quality of Surface Water in the 

San Rafael River Basin, Utah. U.S. Geological Survey, Open-File Report 80-574. 

Narayanan, R., and D.R. Franklin. 1982. An Evaluation of Water Conservancy Techniques in the 

Upper Colorado River Basin. Water Resources Planning Series UWRL/P-82/07, Utah Water 

Research Laboratory, Logan, Utah. 

Paulson, L.J. 1981. Nutrient Management with Hydroelectric Dams on the Colorado River System. 

Technical Report No. 8, Lake Mead Limnological Research Center, University of Nevada, 

Las Vegas, Nevada, 39 pp. 

Paulson, L.J., and J.R. Baker. 1981. The Effects of Impoundments on Salinity in the Colorado River: 

Proceedings of the Symposium on the Aquatic Resources Management of the Colorado River Ecosystem, 

November 16-19, 1981, Las Vegas, Nevada. Ann Arbor Science, Ann Arbor, Michigan. 

Paulson, L.J., and J.R. Baker. 1983. The Limnology in Reservoirs on the Colorado River. Technical 

Report No. 11, Lake Mead Limnological Research Center, University of Nevada, Las Vegas, 

Nevada. 

Paulson, L.J., J.R. Baker, and J.E. Deacon. 1980. The Limnological Status of Lake Mead and 

Lake Mohave Under Present and Future Powerplant Operation of Hoover Dam. Technical Report No. 

1, Lake Mead Limnological Research Center, University of Nevada, Las Vegas, Nevada. 
60

Prentki, R.T., L.J. Paulson, and J.R. Baker. 1981. Chemical and Biological Structure of Lake Mead 

Sediments. Technical Report No. 6, Lake Mead Limnological Research Center, University of 

Nevada, Las Vegas, Nevada, 89 pp. 

Rittmaster, R.L., and D.K. Mueller. 1985. Solute Loading Sources in the Dirty Devil River Basin, 

Utah. Bureau of Reclamation, REC-ERC-85-5, Denver, Colorado. 

Robson, S.G., and G.J. Saulnier, Jr. 1981. Hydrogeochemistry and Simulated Solute Transport, 

Piceance Basin, Northwestern Colorado. U.S. Geological Survey, Professional Paper 1196, 65 pp. 

Sandberg, G.W., and L.G. Sutlz. 1985. Reconnaissance of the Quality of Surface Water in the Upper 

Virgin River Basin, Utah, Arizona, and Nevada, 1981-82. Utah Department of Natural 

Resources, Technical Publication No. 83. 

Schumm, S.A., and D.I. Gregory. 1986. Diffuse-Source Salinity: Mancos Shale Terrain. 

U.S. Department of the Interior, Bureau of Land Management, Technical Note 373, Denver 

Service Center, Denver, Colorado. 

Seiler, R.L., and R.L. Baskin. 1987. Hydrology of Alkali Creek and Castle Valley Ridge Coal-Lease 

Tracts, Central Utah, and Potential Effects of Coal Mining. U.S. Geological Survey, Water 

Resources Investigations Report 87-4186. 

Shacklette, H.T., and J.G. Boerngen. 1984. Element Concentrations in Soils and Other Surficial 

Materials of the Conterminous United States. U.S. Geological Survey, Professional Paper 1270. 

Shen, H.W., et al. 1981. Role of Sediment in Non-Point Source Salt Loading Within the Upper 

Colorado River Basin. Colorado Water Resources Research Institute Completion Report 

No. 107, 213 pp. 

Skogerboe, G.V., and G.E. Radosevich. 1982. Future Water Development Policies. Water 

Supply and Management, vol. 6, No. 1-2, pp. 221-232. 

Skogerboe, G.V., W.R. Walker, and R.G. Evans. 1982. Salinity Control Measures for Grand 

Valley. Water Supply and Management, vol. 6, No. 1-2, pp. 129-167. 

Trueman, D.P. 1998. Colorado River Basin Salinity Control Program, 1998 Review. Proceedings 

of the Shared Rivers Conference, U.S. Committee on Irrigation and Drainage, Park City, 

Utah. 

U.S. Department of the Interior. 1984. Aquatrain Corridor Study Report. Bureau of 

Reclamation, Denver, Colorado. 

U.S. Environmental Protection Agency. l971. The Mineral Quality Problem in the Colorado River 

Basin. Summary Report. Regions VIII and IX, 65 pp. 

Warner, J.W., and F.J. Heimes. 1979. A Preliminary Evaluation of Groundwater 

Contributions to Salinity of Streams in the Upper Colorado Basin in Colorado and Adjacent 

Parts of Wyoming and Utah. U.S. Geological Survey, Denver, Colorado, contract to Bureau 

of Land Management. 

Water Resources Council. 1981. Synthetic Fuels Development in the Upper Colorado Region: Section 

13(a) Water Assessment Report. Technical Report, 138 pp. 

Whittig, L.D., et al. 1983. Salinity Investigations in West Salt Creek, Colorado. California Water 

Resources Center Completion Report, University of California, Davis, California, 161 pp. 
61

Yahnke, J. 1982. Fryingpan River and Rued Reservoir Water Quality Studies. Part I, Bureau of 

Reclamation, Working Paper, Engineering and Research Center, Denver, Colorado. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
62 
63

APPENDIX A – SALINITY DATA 

The historical flow and quality of water data have been calculated using the U.S. Geological 

Survey (USGS) database and computer techniques developed jointly by the Bureau of 

Reclamation (Reclamation) and USGS. The purpose of the analysis was to develop a 

consistent, documented methodology for the calculation of monthly salt loads in the 

Colorado River Basin. 

The salinity computation method was originally developed for the trend studies conducted 

by Reclamation and USGS (Liebermann, et al., 1986). Several procedures were evaluated. A 

3-year moving regression was determined to be the best overall method in terms of 

providing the most complete record, preserving short-term fluctuations, and being 

insensitive to minor errors in the data. Using this method, daily salt load (L) was computed 

from discharge (Q) and when available, conductivity (S): L = aQb

Sc. For days without 

specific conductivity data, a slight variation of the equation for load as a function of 

discharge was used: L = a’Qb

’. 

The coefficients a, b, and c for each year of record were typically estimated by regression 

analysis using data from a 3-year period surrounding the year of interest. For example, 

coefficients for 1990 were derived with data from l989 through 1991. The last year of salinity 

data computed for this report uses 2 years of data for obvious reasons. It is subject to 

change and will be updated in the next report as data become available to complete the 

analysis for that year. 

Daily loads were added to yield the monthly values given. Monthly values were then added 

to yield annual values. All values shown are rounded but were computed using un-rounded 

values. 

For this analysis, salt-load data were based on total dissolved solids (TDS) as the sum of 

constituents, whenever possible. Sum of constituents was defined to include calcium, 

magnesium, sodium, chloride, sulfate, a measure of the carbonate equivalent of alkalinity 

and, if measured, silica and potassium. If a sum-of-constituents value could not be 

computed, TDS as residue on evaporation (at 180 degrees Celsius) was substituted. 

Extensive error analyses were performed on the data. Suspect values were corrected 

according to published records or deleted. The resultant data set is considered by 

Reclamation and USGS to be the best available for stations in the Colorado River Basin. 

Annual values based on the new method were compared to values in previous Quality of 

Water Colorado River Basin Progress Reports for selected stations. The observed 

differences were between plus or minus 5 percent, with mean differences approximately 

zero. Changes in the progress report database can, therefore, be considered generally 

insignificant and unbiased. 
64

Figure A1 - Colorado River Water Quality Monitoring Stations.
65

Green River near Green River, Wyoming

Site 1

150250350450550

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

03,0006,0009,00012,000

Flow 1,000 (ac-ft)

TDS Flow 

Green River near Greend

Site 2

200300400500600

1940 1950 1960 1970 1980 

TDS (mg/L)

T

Yampa River near Maybell, Colorado

Site 3

100150200250300

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

03,0006,0009,00012,000

Flow 1,000 (ac-ft)

TDS Flow 

Duchesne River near Rand

Site 4

0

300600900

12001500

1940 1950 1960 1970 1980 

TDS (mg/L)

TDS Flow 

Figure A-2. Flow and TDS over time for sites 1-4. Site locations shown in Figure A-1. 
66

White River near Watson, Utah

Site 5

250350450550650

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

01000200030004000

Flow 1,000 (ac-ft)

TDS Flow 

Green River at Green Rive

Site 6

250350450550650

1940 1950 1960 1970 1980 

TDS (mg/L)

TDS 

San Rafael River near Green River, Utah

Site 7

0

500

1,0001,5002,0002,5003,0003,500

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

03006009001200150018002100

Flow 1,000 (ac-ft)

TDS Flow 

Colorado R. near Glenwood Sp

Site 8

50

150250350450

1940 1950 1960 1970 1980 

TDS (mg/L)

TDS Flo

Figure A-3. Flow and TDS over time for sites 5-8. Site locations shown in figure A-1.
67

Colorado River near Cameo, Colorado

Site 9

150250350450550650

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

05,00010,00015,00020,00025,000

Flow 1,000 (ac-ft)

TDS Flow 

Gunnison R. near Grand Junc

Site 10

100300500700900

11001300

1940 1950 1960 1970 1980 1

TDS (mg/L)

TDS Flow 

Dolores River near Cisco, Utah

Site 11

0

500

1000150020002500

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

03,0006,0009,00012,00015,000

Flow 1,000 (ac-ft)

TDS Flow 

Colorado River near Cisco

Site 12

100400700

10001300

1940 1950 1960 1970 1980 1

TDS (mg/L)

TDS Flow 

 Figure A-4. Flow and TDS over time for sites 9-12. Site locations shown in Figure A-1
68

San Juan River near Archuleta, NM

Site 13

0

50

100150200250

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

01,0002,0003,0004,0005,000

Flow 1,000 (ac-ft)

TDS Flow 

San Juan River near Bluf

Site 14

0

200400600800

1940 1950 1960 1970 1980 1

TDS (mg/L)

TDS 

Colorado River at Lees Ferry

Site 15

200400600800

1000

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

020,00040,00060,00080,000

Flow 1,000 (ac-ft)

TDS Flow 

Colorado River near Grand 

Site 16

200400600800

10001200

1940 1950 1960 1970 1980 19

TDS (mg/L)

TDS F

 Figure A-5. Flow and TDS over time for sites 13-16. Site locations shown in Figure A-1.
69

Virgin River at Littlefield, Arizona

Site 17

400800

1,2001,6002,0002,400

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

04008001,2001,6002,000

Flow 1,000 (ac-ft)

TDS Flow 

Colorado River below Hoov

Site 18

400500600700800900

1940 1950 1960 1970 1980 19

TDS (mg/L)

TDS Flow 

Colorado River below Parker Dam

Site 19

400500600700800900

1940 1950 1960 1970 1980 1990 2000

TDS (mg/L)

015,00030,00045,00060,00075,000

Flow 1,000 (ac-ft)

TDS Flow 

Colorado River at Imperia

Site 20

200400600800

1000

1940 1950 1960 1970 1980 1

TDS (mg/L)

TDS 

 Figure A-6. Flow and TDS over time for sites 17-20. Site locations shown in Figure A-1.