WSP03614

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1981
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 10 - January 1981 -- Part 1 of 2 -- Title Page through Part IX - page 98
• Water Supply Pro - Doc Type: Report/Study

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HISTORY OF WATER RESOURCE DEVELOPMENT (continued)

Consistent with the regulation, the recommended flow-weighted average
annual numeric salinity criteria for three locations in the lower main stem
of the Colorsdo River System sre as follows:

Below Hoover
Below Parker
Imperi a 1 Dam

Salinity
in mg/L
723
747
879

Dam.
Dam

The plan of implementat ion comprises a number of Federal and non-
Federal projects and measures to. maintain the flow-weighted average annual
salinity in the lower main stem at or below the recommended numeric cri-
teria through 1990, as the Basin States continue to develop their compact-
apportioned waters. The principal components of the plan are as follows:

1. Prompt construction and operation of the initial four salinity
control units authorized by Title II of Public Law 93-320, the Colorado
River Basin Salinity Control Act.

2. Construction of the 12 other units listed in Title II of Public
Law 93-320 or their equivalent after receipt of favorable planning reports.

3.
National
provided

The placing of effluent limitations, principally under the
Pollutant Discharge Elimination Systems (NPDES) permit program
for in Section 402 of Public Law 92-500 on industrial discharges.

4.
Federal

The reformulation of
water projects to reduce

unconstructed,

previously authorized, but
the salt loading effect.

5.

Use of saline water for industrial purposes whenever practical,
by water users to cope with the river's high salinity, studies of
minimize salinity in municipal discharges, and studies of future
salinity control programs.

programs
means to
possible

The report recognizes that many natural and man-made factors affect
the river's salinity. Consequently, the actual salinity will vary above
and below the recommended numeric criteria. However, under the assumptions
of streamflow equivalent to the long-term average, a "moderate" rate of
increase in water depletions, and full implementation of needed salinity
control measures, the average salinity can be maintained at or below 1972
levels during the study period of the next 15 years.

The Federal regulations provide for temporary increases above the
1972 levels if control measures are included in the plan. Should water
development projects be completed before control measures are identified or

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