Home Page     News & Information     River Basin Plans     Basin Advisory Groups     Planning Products    


Purpose of Report

This report, the 1999 Review, Water Quality Standards for Salinity, Colorado River System (Review) is prepared and submitted in response to Section 303(c) of the Clean Water Act. Prepared by the seven-state Colorado River Basin Salinity Control Forum (Forum), on behalf of the governors of their respective states, this Review of the water quality standards includes the numeric criteria and the plan of implementation developed and adopted by the Forum. It also includes modifications to previous reviews that have become necessary as a result of changed conditions and the availability of additional information. This Review is the eighth triennial review conducted by the Forum. Section 303(c)(1) of the Clean Water Act requires that:

The governor of a state or the state water pollution control agency of such state shall from time to time (but at least once each three-year period beginning with the date of enactment of the Federal Water Pollution Control Act Amendments of 1972) hold public hearings for the purpose of reviewing applicable water quality standards and, as appropriate, modifying and adopting standards. Results of such review shall be made available to the Administrator.

This Review is consistent with the Environmental Protection Agency (EPA)-approved 1975 standards and deals only with that portion of the Colorado River Basin above Imperial Dam. While this Review will recap past events in an abridged format, its focus is on information gathered since issuance of the 1996 Review. Background information and activities regarding historical actions relative to the development and adoption of salinity standards is contained in the June 1975 standards report. The prior seven Reviews, from 1978 to 1996, contain more specific information on the seven 3-year periods.

Below Imperial Dam, salinity is controlled as a federal responsibility to meet the terms of the agreement with Mexico contained within Minute No. 242 of the International Boundary and Water Commission (IBWC), entitled "Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River." Minute No. 242 requires that measures be taken to assure that Colorado River water delivered to Mexico upstream from Morelos Dam will have an average annual salinity concentration of no more than 115 +- 30 parts per million (ppm) total dissolved solids (TDS) higher than the average annual salinity concentration of Colorado River water arriving at Imperial Dam.

Nothing in this report shall be construed to alter, amend, repeal, interpret, modify, or be in conflict with the provisions of the Boulder Canyon Project Act (45 Stat. 1057), the Boulder Canyon Project Adjustment Act (54 Stat. 774), the Colorado River Basin Project Act (82 Stat. 885), the Colorado River Compact, the Colorado River Storage Project Act (70 Stat. 105), the Upper Colorado River Basin Compact, or the Treaty with the United Mexican States (Treaty Series 994).

History and Background

In the 1960's and early 1970's, the seven Colorado River Basin states and representatives of the Federal Government discussed the problem of salinity levels increasing in the lower reaches of the Colorado River. In 1972, the Federal Government enacted the Clean Water Act which mandated efforts to maintain water quality standards in the United States. At the same time, Mexico and the United States were discussing the increasing salinity of Colorado River water being delivered to Mexico.

The Basin states established the Colorado River Basin Salinity Control Forum in 1973. The Forum is composed of representatives from each of the seven Basin states appointed by the governors of the respective states. The Forum was created for interstate cooperation and to provide the states with the information necessary to comply with Section 303(a) and (b) of the Clean Water Act.

Congress enacted the Colorado River Basin Salinity Control Act (P.L. 93-320) in June of 1974 with the Forum's support. Title I of the Act addresses the United States' commitment to Mexico and provided the means for the United States to comply with the provisions of Minute No. 242. Title II of the Act created a water quality program for salinity control in the United States. Primary responsibility for the federal program was given to the Secretary of the Interior, with the Bureau of Reclamation (Reclamation) being instructed to investigate and build several salinity control units. The Secretary of Agriculture was instructed to support the effort within existing authorities (see Chapter 4 for more detail regarding these authorities).

The EPA promulgated a regulation in December 1974, which set forth a basinwide salinity control policy for the Colorado River Basin. The regulation specifically stated that salinity control was to be implemented while the Basin states continue to develop their compact-apportioned water. This regulation also established a standards procedure, and required the Colorado River Basin states to adopt and submit for approval to the EPA water quality standards for salinity, including numeric criteria and a plan of implementation, consistent with the policy stated in the regulation. A copy of the regulation is included in Appendix A.

The Basin states, acting through the Forum, initially responded to this regulation by developing and submitting to the EPA a report entitled Water Quality Standards for Salinity Including Numeric Criteria and Plan of Implementation for Salinity Control - Colorado River System dated June 1975. Since the states' initial adoption, the water quality standards have been reviewed every three years (1978, 1981, 1984, 1987, 1990, 1993 and 1996) as required by Section 303(c)(1) of the Clean Water Act.

The Colorado River Basin Salinity Control Act was amended in 1984 by P.L. 98-569 to authorize two additional units for construction by Reclamation. The amendments directed the Secretary of the Interior and the Secretary of Agriculture to give preference to the salinity control units with the least cost per unit of salinity reduction. The Act was also amended to establish a voluntary on-farm salinity control program to be implemented by the Department of Agriculture and provided for voluntary replacement of incidental fish and wildlife values foregone on account of the on-farm measures. Many cost-effective salt-load reducing activities were accomplished in the decade following that authorization. P.L. 98-569 also directed the Bureau of Land Management (BLM) to implement salinity controls.

Reclamation and the Forum in 1994 concluded that the existing Act, as amended, with its unit-specific approach and authorization ceiling, was limiting salinity control opportunities. In 1995, the Act was amended by P.L. 104-20 to authorize an entirely new way of implementing salinity control. Reclamation's new Basinwide Salinity Control Program opens the program to competition through a public process and has greatly reduced the cost of salinity control. An additional $75 million of expenditures by Reclamation were authorized by P.L. 104-20.

The Federal Agriculture Improvement and Reform Act (FAIRA) of 1996 (P.L. 104-127) further amended the U.S. Department of Agriculture's (USDA) role in salinity control by creating a new conservation program known as the Environmental Quality Incentives Program (EQIP) which combined four conservation programs including USDA's Colorado River Salinity Control Program. FAIRA, provided authority for funding the nationwide EQIP through the year 2002. USDA has created rules and regulations concerning how EQIP funds are to be allocated. The past authority for the states to cost-share from the Basin funds was retained in the new EQIP program with linkage to Reclamation's authority to distribute Basin funds for cost-sharing.

Figure 1.1 Figure 1-1 displays a cumulative estimation of the annual salt removal by the Colorado River Basin Salinity Control Program.

Overview of Standards

The Forum proposed, the states adopted, and the EPA approved water quality standards in 1975, including numeric criteria and a plan of implementation, to control salinity increases. The standards require that a plan be developed which will maintain the flow-weighted average annual salinity at or below the 1972 levels while the Basin states continue to develop their compact- apportioned water supply. The Forum selected three stations on the mainstem of the lower Colorado River as being appropriate points to measure the salinity of the Colorado River. These stations are located at the following points on the Colorado River: (1) below Hoover Dam; (2) below Parker Dam; and (3) at Imperial Dam. Numeric criteria were established for these points as required by the 1974 regulation. A plan of implementation was also developed in 1975 by the Forum and participating federal agencies as part of the standards. It was designed to ensure compliance with the numeric criteria for salinity. The numeric criteria and plan of implementation are further described in Chapters 3 and 4 of this Review. During each triennial review, the numeric criteria are reviewed and the plan of implementation is updated to ensure continuing compliance with the standards.

The Colorado River water quality standards for salinity, and the approach taken by the Basin states in complying, are unique. The Forum relied on the Basin states' projections of use of compact- apportioned waters. The salinity projections are based on the long-term mean water supply of 15 million acre-feet per year. The plan of implementation is revised as necessary to ensure compliance with the standards.

Program Funding

Adequate funding is required to meet the standards. Funds are provided from federal and non-federal sources. Federal appropriations, Basin states cost-share funds, and local participant funds are used to implement the Colorado River Basin Salinity Control Program. The Basin states and the local producers have funds available and stand ready to implement the program called for in this report.

Annual appropriations to Reclamation were as large as $34,566,000 as recently as 1992, but in 1998 they were only $7,600,000. Because of improved cost effectiveness, the Basin states believe the appropriation to Reclamation can be smaller than in the past, but find that about $17,000,000 is needed each year through the planning period of this report. An increased funding ceiling is now needed for the Reclamation program.

Federal funding is provided to USDA each year for distribution to environmental enhancement efforts through the nationwide EQIP. In 1991 and 1992, $14,783,000 was made available to the USDA's Colorado River Salinity Control Program by Congress, but in 1998 and 1999 USDA allocated only $3.9 million and $5.1 million. A solution to this under-funding problem is for USDA to designate the Colorado River Basin a national conservation priority area and increase funding to the Colorado River salinity control activities of EQIP.

BLM has an important roll to play in controlling salt contributions from nonpoint sources from the very sizeable amount of federal land it manages. Accounting procedures used by BLM have not allowed for an analysis to occur as to the expenditure for salinity controls measures being implemented by the agency. Recent efforts by BLM staff to determine the effects of management practices being implemented is providing new information and it is hoped that in the near future BLM accomplishments can be estimated and the adequacy of the effort and the level of funding for the activities can be evaluated.

The EPA has programs that give financial assistance to the states to implement nonpoint source pollution control efforts. Recently, the federal assistance has been increased and now the salinity control effects of these efforts need to be evaluated.


Section 303 of the Clean Water Act requires that water quality standards be reviewed from time to time, but at least once during each three-year period. Accordingly, the seven-state Colorado River Basin Salinity Control Forum (Forum) has reviewed the existing state-adopted and Environmental Protection Agency (EPA)-approved water quality standards for salinity consisting of numeric criteria and a plan of implementation for salinity control for the Colorado River System. Since the issuance of the 1996 Review, the U.S. Bureau of Reclamation (Reclamation) has initiated development of a new model to analyze the Colorado River System, including salinity. The model development is not yet completed, and new salinity projections are not available for this Review. Projections developed for the 1996 Review are used in this Review. This 1999 Review updates funding and salinity control component implementation requirements following 1999. The Forum's recommendations are to be submitted to each of the Basin states for consideration at a public hearing prior to adoption.

The Forum recommends no change in the numeric salinity criteria at the three stations located on the lower mainstem of the Colorado River. The numeric criteria at these stations will remain:

Station Salinity in mg/L
Below Hoover Dam
Below Parker Dam
Imperial Dam

The plan of implementation as set forth in this Review is designed to meet the objective of maintaining the salinity concentrations at or below the numeric criteria while the Basin states continue to develop their compact-apportioned waters. The plan is based on maintaining the numeric criteria under a long-term mean water supply of 15 million acre-feet annually at Lee Ferry, the Compact Point. The Forum recommends that the plan of implementation described in this report be carried out. The plan of implementation includes:

  1. Completion of Reclamation, Bureau of Land Management, and U.S. Department of Agriculture salinity control measures to the extent that each unit remains viable and appropriately cost-effective.

  2. Implementation of the Forum's recommended and adopted policies for effluent limitations, principally under the National Pollutant Discharge Elimination System (NPDES) permit program established by Section 402 of the Clean Water Act as amended. The implemented policies (included in Appendix B of this Review) are the following:

    "Policy for Implementation of Colorado River Salinity Standards Through the NPDES Permit Program;"

    "Policy for Use of Brackish and/or Saline Waters for Industrial Purposes;"

    "Policy for Implementation of the Colorado River Salinity Standards Through the NPDES Permit Program for Intercepted Ground Water;" and

    "Policy for Implementation of the Colorado River Salinity Standards Through the NPDES Permit Program for Fish Hatcheries."

  3. Implementation of nonpoint source management plans developed by the states and approved by EPA.

Item 1 of the plan listed above is to be implemented by federal agencies in conjunction with state, local, and private participants. The Forum works jointly with federal agencies on developing measures to be implemented. The Forum also urges Congress to ensure that the funds necessary to successfully fulfill this plan of implementation are appropriated as needed. Items 2 and 3 above are primarily implemented by each of the Basin states.

The major components of this Review's plan of implementation are the federal programs. Table 1 summarizes the salinity control achieved by federal participants through 1998, and the salinity control measures which must be implemented to meet the goal of approximately 1.477 million tons of salt-load reduction annually by 2015. As 1.105 million tons of salt load reduction were required by 1998, and only 721,000 tons of salt load reduction achieved, a shortfall of 384,000 tons must be made up. In order to do so, the Forum recommends that salinity control be accelerated to remove 87,000 tons/year through 2005. This includes 64,000 tons/year over the next six years to eliminate the shortfall, and 23,000 tons/year throughout the entire period to maintain the numeric criteria through 2015. The federal programs are described in detail in Chapter 4 of this Review.

The plan of implementation is designed to control enough salt to maintain the numeric criteria under a long-term mean water supply of 15 million acre-feet per year. It is recognized that the river system is subject to highly variable flows. Consequently, salinity will vary from year to year and may temporarily exceed the adopted numeric criteria in some years and remain well below the criteria in others.

Table 1
Colorado River Basin Salinity Control Program
Plan of Implementation
By 2015
(Values in Tons of Salt Load Reduction Per Year)

Bureau of Reclamation 421,000 501,000 922,000
U.S. Department of Agriculture 262,000 242,000 504,000
Bureau of Land Management 38,000 13,000 51,000
TOTAL 721,000 756,000 1,477,000

Salinity concentrations at the three stations on the Lower Colorado River in 1997 were:

Station Salinity
in mg/L
Below Hoover Dam
Below Parker Dam
Imperial Dam

Based on the data available, the Forum concludes that the measured salinity will not exceed the numeric criteria during the next three years. The plan of implementation adopted herein by the Forum provides for the control of about 1.477 million tons of salt load reduction annually by the year 2015.

Should more water development projects be completed than are projected to occur before control measures are identified or brought on line, temporary increases above the numeric criteria could result. However, these increases will be deemed in conformance with the standards if appropriate salinity control measures are included in the plan.

Increases above the criteria as a result of below normal annual river flows and/or low reservoir storage conditions will also be considered in conformance with the standards, provided that when river flows return to normal, and satisfactory reservoir conditions prevail, concentrations will then be at or below the criteria level.

The Forum has reviewed the impact of the program on projected salinities and finds that by the year 2015 the plan will control salinity levels so that, with long-term mean water supply conditions, salinity levels will be below the numeric criteria at the three stations. The salinity standards provide protection from long-term increases in economic damage to downstream users.

Because of the long lead-time required to conduct salinity studies; complete environmental and feasibility reports; implement; and achieve full salinity reduction effects at the lower Colorado River mainstem stations, continued funding is necessary for the recommended plan of implementation to proceed as set forth in this Review. Non-federal funds are available to cost-share with federal appropriations, and Basin irrigators stand ready with cost-share dollars to install salinity reducing measures.

   Citizen    Government    Business    Visitor   Privacy Policy