WSP00412

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1982
• Author: USDA
• Title: Colorado River Water Quality Improvement Program - Final Environmental Impact Statement for Lower Gunnison Basin Unit - Montrose and Delta Counties CO and Uintah Basin Unit
• Water Supply Pro - Doc Type: EIS

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II SU~~Y - UI~TAH BASI~ UNIT

Irrigated agriculture on 205,000 acres in the Uintah Basin contributes 240,000
tons of salt to the Colorado River annually. About three-fourths of this
amount (177,200 tons) is from onfarm return flow and one-fourth is from canal
and lateral seepage losses. Other sources contribute another 270,000 tons for
a total of 510,000 tons of salt annually from the Uintah Basin. Improved
management of irrigation water, water measuring devices, improved onfarm convey-
ance systems, improvements or changes in method of application, land leveling,
water control structures, and pumping plants reduce the salt load to the Green
River by 76,600 tons annually in the recommended alternative. Water management
and land treatment measures ~ill also improve crop yields and make better use
of irrigation water supplies. The net increase in river flow will be 20,200
acre-feet annually. Implementation of these measures ~ill reduce salinity
concentrations at Imperial Dam by 10.3 milligrams per liter.

There are no expected changes in the amount of private irrigated cropland and
pastureland which are the principle land uses in the area. However, there
~ill be changes in the wildlife uses of these areas. Changes in air quality
~ill be minor and temporary. There will be 1,870 acres (1 percent) of upland
~ildlife habitat ~ith an acre value of 630 acres disturbed during installation;
6,635 acres of riparian habitat ~ith an acre value of 3,850 acres converted to
upland habitat; 905 acres of wetland habitat with an acre value of 550 acres
converted to upland habitat; 6,855 acres of greasewood and salt cedar with an
acre value of 1,510 acres converted to upland habitat; and 5,465 acres of
grass-sedge habitat ~ith an acre value of 1,750 acres converted to upland
habitat. Historical and archeological resources will be assessed on a measure
by measure basis so that none will be disturbed. Sprinkler irrigation systems
on 79,400 acres will be highly visible during operation. Irrigation pipelines
will replace 1,540 miles of onfarm earthen ditches. There is an ongoing water
quality monitoring program in progress and wildlife mitigation features are
being incorporated into long term agreements ~ith individual farmers and ranchers.

The viable alternatives considered are: Ca) future conditions ~ithout acceler-
ated action; Cb) farmer identified irrigatIon improvements; (c) maximum potential
irrigation improvements; Cd) land retirement from irrigation; and (e) a level
of irrigation improvements that is a combination of portions of a, h, and c.

The onfarm conservation measures to be installed are compatible ~ith and comple-
mentary to the irrigation system improvements being installed in the Public
Law 566, Martin Lateral ~atershed. They are also compatible to other land
treatment watersheds being planned under P.L. 566.

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