WSP06578

• File Number: 8278
• Description: Title I
• Basin: Colorado Mainstem
• Date: 6/18/1975
• Author: USDOI/BOR
• Title: Final Environmental Statement - Colorado River Basin Salinity Control Project Title I
• Water Supply Pro - Doc Type: Publication

SlIMMARY

Draft

( X )

Final

Environmental Statement

Prepmed by Department of the lnterior, Bureau of Reclamation, Lower Colorado Region

I. Type of Action:
( X) Administrative
Brief description of action:

)

Legislative

o
4.

The project was authorized by Title I of Public Law 93-320, Colorado River Basin Salinity Control
Act, of June 24, 1974. Title I provides for a program of works to enhance and protect the quality
of water available in the Colorado River for use in the United States and Mexico and to enable
the United States to comply with its obligations under agreement with Mexico under Minute No.
242 of the Intemational Boundary and Water Commission, United States and Mexico. Objectives
are: reduce the salinity of Colorado River water delivered to Mexico; more efficiently utilize water
resources; and manage ground-water withdrawal.

The three major features are: (l) the desalting complex which will consist of: (a) a membrane-process
desalting plant of approximately 100-million gallons per day capacity to treat Wellton-Mohawk
Division, Gila Project drainage water; (b) the extension of the concrete-lined bypass drain from
Morelos Dam to Santa Clara Slough in Mexico; and (c) replacement of an existing metal flume
in the Main Outlet Drain Extension with a concrete siphon. Nonstructural measures consist of:
(a) an irrigation efficiency improvement program in the WeUton-Mohawk Division, a cooperative
program of irrigation management services, and Federal cost-sharing assistance for on-farm irrigation
system improvements; (b) an irrigable acreage reduction program in the WeUton-Mohawk Division;
and (c) acquisition of land, if needed, in Painted Rock Reservoir. (2) Construction of a concrete-lined
replacement canal for the first 49 miles of unlined CoacheUa Canal. Nonstructural measures provide
for acquisition of lands involving 4,200 acres, on the Imperial East Mesa which received or have
the right to receive irrigation water. (3) Protective and regulatory ground-water pumping plan which
includes two well fields within 5 miles of the Arizona-Sonora Boundary with a designed capacity
to pump 160,000 acre-feet per year. Nonstructural measures include acquisition of 23,500 acres
of land or interests therein that lie within 5 miles of the Boundary. Project features will be located
in Yuma County, Arizona; Imperial County, Califomia; and Sonora, Mexico. Construction is
scheduled to begin in 1975 and completed in 1981 at an estimated cost of $155,500,000 (April 1973
prices).

3. Summary of environmental impacts and adverse environmental effects:

The project will result in the savings of 424,000 acre-feet per year of Colorado River water. Electrical
energy re.quirements will amount to a maximum of 424,000,000 kWh per year. Fish and wildlife
habitat losses will amount to about 297 surface acres of open water and 5,200 acres of riparian
vegetation. Mitigation measures will be provided on up to 3,500 acres of land. These measures
will compensate for aU fish losses and most wildlife losses. There will be retirement from agricultural
uses or restrictions on future agricultural development of 37,300 acres of land. Rights-of-way
amounting to a maximum of about 2,700 acres of land will be required for construction of new
project facilities.

4. Alternatives considered:

1. Total shutdown of the WeUton-Mohawk Division
2. Augmentation of the Colorado River
3. A moratorium on future development in the Colorado River Basin
4. No Action
5. Other

5, List of entities from whom comments were requested: See attached list.

6. Date made available to CEQ and the public:
Draft statement (DES 74-39): April], 1974
Supplement to Draft statement (DES 74-83): August 27, 1974
Final Statement:

JUN 18 1975