WSP08401

• File Number: 8276.100
• Description: Grand Valley Unit - Colorado River Basin Salinity Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/2/1979
• Title: Grand Valley Unit - Colorado River Basin Salinity Control Project -- Tour for Mr. William McDonald - Director - Colorado River Conservation Board
• Water Supply Pro - Doc Type: Project Overview

SilllMARY SHEET
Grand Valley Unit
Colorado River Basin Salinity Control Project

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LOCATION

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The Grand Valley Unit is located in west-central
Colorado along the reach of the Colorado River
between the towns of Palisade and Mack, and
includes Grand Junction, the largest city in
western Colorado.

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PURPOSE

The purpose of the Grand Valley Unit is to lower
the salt loading to the Colorado River by the
concrete lining of canals and installation of
pipeline on laterals and installation of On-farm
Improvements. The combination of the above
programs would reduce the amount of ground water
allowed to percolate into the underlying highly
saline soils and Mancos Shale FOTIWation. It is
thought that the estimated 650,000 to 850,000
tons of salt added to the river annually can be
reduced as much as 60 percent by the implemen-
tation of the above measures.

STATUS

The Grand Valley Unit is a component of the
Colorado River Salinity Control Project and was
authorized for construction by the Colorado
River Basin Salinity Control Act of 1974 (Public
Law 93-320),

A feasibility study in the Grand Valley was ini-
tiated in FY72 to determine efficiencies of the
conveyance systems to be gained by reducing the
seepage losses. The various studies conducted
include the following: (1) determination of
irrigated acreage; (2) canal and lateral sizing
studies; (3) determination of the location, ca-
pacity, and condition of present canal and
lateral structures; and (4) computations of
quantities of construction materials. This data
is being used to arrive at the feasibility level
cost estimate for the entire project. An ap-
praisal level cost estimate has been made.

Preliminary environmental studies have been con-
ducted on the unit, and a Negative Determination
of Environmental Impact was made by the Regional
Director in June 1978 for an initial phase of
the unit known as Stage One. The Commissioner
concurred with the determination in July 1978.
A draft Special Report for Stage One of the
Grand Valley Systems Improvement Program has
been completed and is under review. Stage One
covers approximately 10 percent of the unit area
and is designed to provide information to fully
analyze the effectiveness of the proposed plan.

The FY80 appropriations include $7,071,000 for
construction and monitoring of Stage One and
continued planning of Stage Two.

PLAN

The preliminary plan for the overall Grand Valley
Unit indicates that the salt loading of the Colo-
rado River in the Grand Valley could be reduced
by about 410,000 tons annually by decreasing the
amount of irrigation return flows and conveyance
system seepage moving through saline substrata
and picking up salts. The reduction would re-
sult in a decrease in the salintty o~ the river

October 9, 1979
Page I of 2

at Imperial Dam of approximately 43 mg/L and
'would be accomplished by a two-segment pro-
gram conducted by the Bureau of Reclamation
in the Department elf the Interior and the
Soil Conservation Service in the Department
of Agriculture. A Water Systems Improvement
program would be celnducted by the Bureau in
which canals and laterals would be lined or
placed in pipe to reduce seepage. Since
only lined canals ,,'ere included in the plan
at authorization, the approval of Congress
would be required to use pipe for those
facilities. On-faITh improvements, including
upgrading of irrigc.tion systems by cost
assistance, improvement of irrigation manage-
ment, improvement c f grazing lands and grazing
practices on private rangeland, and voluntary
wildlife improvement measures would be con-
ducted by the Soil Conservation Service to re-
duce deep percolation from farm operations. A
wildlife area and w'atering ponds would be pro-
vided by the Bureau to compensate for wildlife
habitat losses resulting from the Water Systems
Improvement program.. This wildlife measure 'Was
also not included in the unit plan when it was
authorized and would require the approval of
Congress.

STAGE ONE DEVELOPMENT

The unit would be dev~loped in stages to
allow the Bureau of Reclamation to begin
construction in a portion of the valley where
plans and designs are complete, where suf-
ficient data are available to assess the im-
pact of the initial development while investi-
gations and planning continue on the rest of
the unit, and where environmental impacts

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