WSP08407

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1983
• Title: Colorado River Water Quality Improvement Program - Big Sandy River Unit - Draft Planning Report/Advance Draft Environmental Impact Statement - October 1983
• Water Supply Pro - Doc Type: EIS

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CRAPTER II

NEED FOR ACTION

the EPA approved 1972 salinity concentrations at three points on the

Lower Colorado River as salinity control standards. These standards are

shown below.

1972 salinity

concentration
Annual flow-
weighted
concentration
(mg/L)
723
747
879

Station
Below Hoover Dam
Below Parker Dam
At Imperial Dam

The goal of the CRWQIP is to maintain concentrations at or below

these levels while the Basin States continue to develop their compact-

apportioned waters. Depletions within the Colorado River Basin are pro-

jected to increase from a 1970-79 mean of 9.7 million acre-feet per year

to 12.6 million by the year 2010.

With full development of compact-

apportioned water supplies in the basin, depletions could increase to 15

million acre-feet per year.

Salinity at Imperial Dam attributable to

future development is estimated to increase from the 1981 level of 810

mg/L to a mean of 1,089 mg/L by 2010 unless salinity control measures

are implemented to prevent the increase in salinity (Bureau of Reclama-

tion, 1983).

Based on recent findings, full implementation of the authorized

units of the Colorado River Basin Salinity Control Project and the units

of the CRWQIP under investigation could reduce the salinity at Imperial

Dam to a mean of 894 mg/L in 2010. During some years the concentrations

would exceed those predicted levels.

Both of these projections exceed

the standard of 879 mg!L.

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