WSP04095

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1987
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 13 - January 1987
• Water Supply Pro - Doc Type: Report/Study

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Investigations under the Colorado River Water Quality Improvement
Program began in 1972 as the Littlefield Springs Unit. The initial approach
was to study a series of saline springs along the river at Littlefield Springs
near the USGS gage "virgin River at Littlefield, Arizona." The object of that
investigation was to determine the best method of collecting and disposing of
the water and returning the fresh water to the river or disposing of the
saline water from the springs by evaporation. This project was strenuously
opposed localiy because the springs are the only reliable water supply for
irrigation at Mesquite, Bunkerville, and Riverside, Nevada, during the summer.
The Littlefield Springs study was, therefore, terminated.

In 1977 another study was started to determine the feasibility of
extracting the saline subsurface water flowing in the Virgin River downstream
of the irrigated area. Information on surface flows indicated that less salt
was leaving the area than was entering. It was, therefore, postulated that
salt was leaving the reach in underflow. The results of the study found the
subsurface water concentration was too low for collection, extraction, and
evaporation. A concluding report was published in November 1981.

Since November 1981, the State of Nevada and a power company have
been interested in developing the saline waters of the Virgin River as a
source for powerplant cooling water. In January 1984, the Bureau of
Reclamation reinitiated the Virgin River Unit Study to determine if a dual
purpose water supply and salinity control project would be feasible. The
power company presently plans to construct a new 1,000 MW powerplant in the
area for a 1994 startup. Consequently the study is focussing on formulation
of a project to supply the water needed, about 4,000 acre-feet per year.
Salinity of the available subsurface water ranges from 2,000 to 10,000 mg/L.

12. Mancos Valley Unit (USDA)

This unit has also met the prerequisite for construction and is
awaiting funding. The Mancos Valley Unit is a 9,200-acre irrigated area along
the Mancos River, a tributary to the San Juan River. The report, Irrigation
Improvements for Mancos Valley, was completed in 1985.

The recommended i~~lementation plan includes 3;200 acres of
sprinkler systems and other water management/salinity control treatment on
about 5,500 total acres. About 17 miles of canal and lateral lining would
combine many old earthen laterals. Total salt load reductions are estimated
to be 8,800 tons per year with about 7,700 tons resulting from lateral
improvements. About 57 landowners and 15 lateral companies or groups of
landowners would be involved.

13. McElmo Creek Unit - Dolores Project (Reclamation and USDA)

The McElmo Creek Basin is located in southwestern Colorado and
covers approximately 720 square miles. About 150 square miles of the Basin,
mostly in the east, are agricultural land. Early studies in the area show
that salt loading results from both irrigation and diffuse sources, with
irrigation being the main contributor.

The total irrigation diversion into the drainage area averages
105,200 acre-feet per year. The average salt load contributed by the Basin is
estimated at 119,000 tons per year. The Montezuma Valley Irrigation Company
diverts water from the Dolores River that serves the McElmo Creek Basin. The

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