WSP10289

• File Number: 8276.100
• Description: Grand Valley Unit - Colorado River Basin Salinity Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 5/18/1979
• Title: Grand Valley Unit - Colorado River Basin Salinity Control Project -- Tour for the Colorado River Conservation Board
• Water Supply Pro - Doc Type: Project Overview

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SUMMARY 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 1s to lower
-the salt loading to the Colorado River by the
concrete lining of canals and installation of
. pipeline on laterals, installation of On-farm
Improvements, and the implementation of Irriga-
tion Management Services (1MB). The combina-
tion of the above practices would reduce the
amount of groWld water allowed to percolate
into the unaerlying highly saline salls and
Mancos Shale Formation. It 1s thought that
the estimated 550,000 to 850,000 tons of salt
added to the river annually can be reduced as
much as 60 percent by the implementation of the
above measures.

STATUS

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

A feasibility study in the Grand Valley was
initiated in FY72 to determine efficiencies of
the conveyance systems to be gained by reducing
the seepage losses. The various studies con-
ducted include the following: (1) determination
of irrigated acreage; (2) canal and lateral
sizing studies; (3) determination of the loca-
tion, capacity, 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
appraisal level cost estimate has been made.

Irrigation Management Services has been inaugu-
rated and has achieved some success in the
valley. As a continuing program, it is expected
to decrease salinity contributions from irriga-
tion and to increase crop yields. Changeove,r
from Government to private control of Irrigation
Management Services is anticipated after comple-
tion of an adequate study program..

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.
The Draft Definite Plan 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. Stage One will be constructed and moni-
tored to determine whether the remainder of the
unit would be an effective and appropriate
method of salinity control before construction
is initiated. The Definite Plan Report ou Stage

May 18, 1979
Page 1 of 2

Two is scheduled for winter 1985, and the Draft
Environmental I~pact Statement and public hear-
ing for spring 1985. The Final Environmental
Impact Statement is due in early fall 1985.

The FY79 appropriations include $4,159,000 and
the President's proposed budget for fi80 in-
cludes $7,071,000 for construction of Stage One
and continued planning of Stage Tw04

PLAN

The overall unit would be designed to reduce
the salt loading of the Colorado River in the
Grand Valley by .about 410,000 tons annually by
'decr~as~ng the-amo~~.oi,irrigation return
flows and conveyane-e sys tem seepage mving
through saline substrata and picking up salts.
A Water Systems Improvement Program would be
conducted by the Bureau of Reclamation in
which 185 miles of canals and 450 miles of
laterals would be lined or placed in pipe to
reduce seepage. An Irrigation Management
Services (IMS) program is presently being con-
ducted by the Bureau in conjunction with the
unit to provide irrigators with precise data
conceming optimum. timing and application of
irrigation water. A wildlife area and watering
ponds would be provided to compensate for wild-
life losses.

"On-farm Improvements, including upgrading of
irrigation systems by cost assistance, improve-
ment of irrigation management, improvement of
grazing lands and grazing practices on private
rangeland, and v~luntary wildlife improvement
measures would be conducted by the Soil Conser-
vation Service to reduce deep percolation from
farm operations.

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