WSP03103

• File Number: 8276.100
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/1/1980
• Title: Salinity Control Program - Grand Valley Unit
• Water Supply Pro - Doc Type: Report/Study

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SUM}!ARY SHEET
Grand Valley Unit
River Basin Salinity Control

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December 1979
Page 1 of 2

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.

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 Formation. 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).

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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.

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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 Special Report fo~ Stage One of the Grand Valley
Systems Improvement Program has been completed.
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 $3,650,000 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 [lows and conveyance
system seepage moving through saline substrata
and picking up salts. The reduction would re-
sult in a decrease in the salinity of the river

at Imperial Dam of approximately 43 mg/L and
would be accomplished by a two-segment pro-
gram conducted by the Water and Power Resources
Service in the Department of the Interior and
the Soil Conservation Service in the Department
of Agriculture. A Water Systems Improvement
program.would be. conducted by the Water and Power
Resources Service in which canals and laterals
would be lined or placed in pipe to reduce seepage.
Since only lined canals were included in the plan
at authorization, the approval of Congress would
be required to use pipe for those facilities.
On-farm improvements, including upgrading of
irrigation systems by cost assistance, improvement
of irrigation management, improvement of grazing
lands and grazing practices on private rangeland,
and voluntary wildlife improvement measures would
be conducted by the Soil Conservation Service to
reduce deep percolation from farm operations. A
wildlife area and watering ponds would be provided
by the Water and Power Resources Service to compen-
sate for wildlife habitat losses resulting from the
Water Systems ImprovE~ment 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 developed in stages to allow
the Water and Power Resources Service to begin con-
struction in a portion of the valley where plans
and designs are complete, where sufficient data
are available to aSSE~SS the impact of the initial
development while investigations and planning
continue on the rest of the unit, and where environ-
mental impacts would not be significant. Results

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