WSP11214

• File Number: 8200.776
• Description: Uncompahgre River General
• State: CO
• Basin: Gunnison
• Water Division: 4
• Date: 1/1/1983
• Author: West Slope Hydro Par
• Title: Before the United States of America Federal Energy Regulatory Commission - Application for License for Major Project - Uncompahgre Valley Hydroelectric Project Number 2
• Water Supply Pro - Doc Type: Report/Study

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03J935

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shales of the Mancos Formation on its way to drains and the
Unc~mpahgre River. Consumptive use of water and salt pickup
from return flows leave higher concentrations of salts in
water returning to the Uncompaghre and Gunnison Rivers. The
salt loading and consumptive use contribute about 31 milli-
grams per liter (mg/L) to the salinity concentration at
Imperial Dam, the last major diversion point on the river in
the United States. The Colorado River at its headwaters in
the mountains of north central Colorado has a salinity con-
centration of only about 50 mg/L. Tbe concentration pro-
gressively increases downstream as a result of depletions

and salt contributions from a variety of sources and in 1979
1
averaged about 810 mg/L at Imperial Dam.

In 1972, the seven Colorado River Basin States adopted
salinity concentrations at three points on the Lower
Colorado River as salinity control standards. The objective
of the Colorado River Water Quality Improvement Program is
to maintain concentrations at or below these levels while
the Basin States continue to develop their compact-appor-
tioned waters. In recognition of these facts, ~ongress

passed the Colorado River Basin Salinity Control Act (Public

Law 93-320) of June 24, 1974. Title II of the Act author-

ized the Secretary of the Interior to construct, operate,

and maintain four salinity control units in the Upper Basin

as the initial stage of the Colorado River Basin Salinity

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