WSP01110

• File Number: 8273.100.10
• Description: Colorado River Basin Salinity Control - Federal Agencies - Bureau of Reclamation
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 5/1/1995
• Title: Colorado River Basin Salinity Control Project - Report on Public and Agency Review of the Program and Implementation Plan for the Basinwide Program - Discussion Draft
• Water Supply Pro - Doc Type: Report/Study

control would not be cost effective. Therefore, in January 1988, Reclamation terminated the planning
investigation for the PVID Unit. However, water samples are collected from the main drains and
analyzed on an annual basis.

The Paradox Valley Unit was authorized for investigation and construction by the Colorado River
Basin Salinity Control Act of 1974, Public Law 93-320. The unit is located in southwestern Colorado
along the Dolores River in the Paradox Valley,
formed by a collapsed salt dome. Ground water
in the valley comes into contact with the top of
the salt formation where it becomes nearly
saturated with sodium chloride. Salinities have
been measured in excess of 250,000 mg/L, by
far the most concentrated source of salt in the
Colorado River Basin. Ground water then
surfaces in the Dolores River. Studies
conducted by the Bureau of Reclamation show
the river picks up more than 205,000 tons of
salt annually as it passes through the Paradox
Valley.

Paradox Valley Unit

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In its definite plan repon (September 1978),
Reclamation recommended that a series of wells
be drilled on both sides of the Dolores River to
intercept the brine before it reached the river. The brine would then be pumped to an evaporation
pond in Dry Creek: Basin. A draft environmental statement was prepared for this plan and made
public on May II, 1978; a final statemem was filed with the Environmental Protection Agency (EPA)
on March 20, 1979. Due to the potential for environmental impacts, EPA recommended that
Reclamation investigate deep-well injection as an alternative method of disposal. .

A private consulting firm completed a feasibility study of deep-well injection and concluded it to be
technically, economically, and environmentally feasible. Reclamation then contracted with a second
consulting firm to do a more detailed study of injection and to design the disposal system including
Injection well and surface facilities. A final design for the test injection well was completed in
August 1985.

A full production test at 400 gpm was begun in August 1994. At this rate of injection, the facility
should be capable of 128,000 tons per year of salt disposal. Testing will continue into 1995. Normal
operations are scheduled to begin in 1997. Nano-fiItration of sulfates may allow for higher
concentrations of brine to be injected. Additional studies to improve the efficiency of the well will
continue.

Price-San Rafael Rivers Unit

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