WSP06844

• File Number: 8276.200
• Description: Paradox Valley Unit - Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 4
• Date: 11/7/1974
• Title: Environmental Assessment Field Investigations Pump Testing Program
• Water Supply Pro - Doc Type: EIS

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naintaining suitable salinity levels in the Colorado River system. The

co~struction, operation, and maintenance of the Paradox Valley Unit were

authorized by Title II of the Colorado River Basin Salinity Control Act

(Public Law 93-320) of Jlli~e 24, 1974.

Feasibility studies were initiated in Fiscal Year 1972, when stream

gaging and water quality sampling stations were established along the

Dolores River in Paradox Valley. A resistivity survey was conducted along

the river in Fiscal Year 1972. In Fiscal Year 1973, exploratory holes were

drilled. on both sides of the river, and core holes were drilled on the east

;'!O 2@ide 0"' the river. In Fiscal Year 1974, pump tests were conducted on a

',"ell loce.ted in the center of valley on the west bank of the river,

The feasibility investigations have shown that salt enters the

Dolores River in the form of highly saline groundwater. The groundwater

bOdy is overlain by a shallow layer of fresh water to the west of the

river, but the brine surface rises to intersect the stream channel in

several places and is often higher than the streambed near the river.

Studies indicate that the inflow of saline ground water could be controlled

by pumping from a series of wells to lower the hydraulic pressures in the

brine zone. The brine would be conveyed by pipeline to an evaporation pond

for disposal.

Additional field work is necessary to determine whether the most

~easible method of control would be to pump brine from a well field or to

pursue so~e other measure. The work would also provide design data for a

brine well field, pipeline, pumping plants, and evaporation pond if the

tests showed pUIT~ing to be an effective method of control. The data would

be obtained from a six-month investigation progra~, which is scheduled for

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