WSP05261

• File Number: 8271.200
• Description: Colorado River Basin Salinity Control Program - Development and History
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/12/1974
• Title: The Colorado River Basin Salinity Control Act - Western States Water Council - April 12 1974 -
• Water Supply Pro - Doc Type: Report/Study

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Western States Water Council
Meeting

Boise, Idaho
April 1 2, 1 974

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The new Minute is to be recognized as a permanent
and definitive solution to the salinity problem. The
Mexican government has waived its rights but not
those of private citizens to sue for damages.

Minute 242 makes important concessions to Mexido but is
silent on how they will be achieved. Current plans, supported
by legislation introduced by the Administration, HR12834 and
S3094, are as follows: Until the "necessary works," alluded
to but not named or described in the agreement, are authorized
by the Congress, the U.S. will continue to discharge 118,000 AF/yr. of
Wellton-Mohawk return flows below Morelos Dam, Mexico's diversion
point, without charge against Mexico's Treaty allotment and will
substitute a like amount of higher quality water from storage in
upstream U.S. reservoirs and from wells on the Yuma Mesa.

Authorization of the "necessary works" is expected, and
certainly was intended by the negotiators, prior to July, 1974.
Upon authorization all Well ton-Mohawk return flows will be
wasted without charge to Mexico and the U. S. will be required
to substitute 175,000 to 218,000 AF /yr of higher quality water,
the exact amount depending upon the government's success in
efforts to reduce the magnitude of Well ton-Mohawk return flows.

In three years, lining of 49 miles of the Coach ell a Canal
is to be completed. Savings in terms of reduced seepage losses
will provide an estimated 130,000 AF/yr for substitution purposes
through reduced diversions to Coachella. This will permit a
reductiun in the draft on storage to provide substitution waters
to a level of from 45,000 to 88,000 AF /yr again depending on the
success of the program to reduce Wellton-Mohawk returns.

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The largest desalting plant in the world is to be constructed on
the Well ton-Mohawk drain by Decemter, 1978, It will be of
reverse-osmosis design and will desalt a sufficiency quantity of
Wel1ton-Mohawk returns, that when blended with the remainder
of the district's returns, the mix will be at Imperial Dam quality.
With completion of the deslater, the main thrust of the agreement,
the objective of removing the quality impact of Wellton-Mohawk
returns from the Colorado River, will be accomplished with
the magnitude of waste and the requirement for substitution limited
to the magnitude of waste effluent. from the desalter. Once the
desalter is on line, the Coach ell a Canal salvage will be used to repay

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