WSP05341

• File Number: 8278.100
• Description: Title I - Yuma Desalting Plant
• Basin: Colorado Mainstem
• Date: 12/23/1992
• Author: USDOI/BOR
• Title: Yuma Desalting Plant - Alternatives for the Interim Period
• Water Supply Pro - Doc Type: Publication

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On November 12, 1992, Reclamation met with WMIDD and the SCS to discuss
program goals, participation, roles, and constraints. It was agreed
that committees, with staff from both Reclamation and WMIDD, would
address management options for reducing return flow and would review and
develop methodology for determining return flow credit. Based on
committee findings, Reclamation intends to propose a program and prepare
a letter of agreement defining the responsibilities of all agencies
involved. If successful, the program would be initiated in the spring
of 1994 and cost about $500,000 per year, some of which would likely be
cost-shared with non-Federal partners.

In the event that local cooperation cannot be obtained to reduce the
drainage flows, Reclamation is prepared to use its regulatory authority,
as Colorado River watermaster, to revise WMIDD return flow credit
methodology to ensure that return flow credits are granted only for that
amount of drainage pumping deemed essential to prevent crop damage and
not that required to allow consumptive use beyond the WMIDD beneficial
consumptive use requirement.

Reclamation's regulatory authority is derived from the Boulder Canyon
Project Act of 1928, the United States Supreme Court Opinion in
Arizona v. California, 1963, and the Federal Code of Regulations,
Part 417 - Procedural Methods For Implementing Colorado River Water
Conservation Measures With lower Basin Contractors and Others. Under
these authorities, Reclamation is responsible to ensure the
implementation of water conservation measures or operating practices
such that the deliveries of Colorado River water not exceed those
reasonably required. for beneficial use.

Recognizing that farming practices and other conditions have changed,
it is uncertain how much drainage is required for essential operation.
Reclamation is confident that return flow can be reduced and plans to
reduce return flow to that essential for operation but does not
currently have a specific projection.

For purposes of analysis, this report will assume that the return can be
reduced to 132,000 af per year or below, as this quantity is consistent
with the quantity of conserved water available to the Secretary from
lining the Coachella Canal. The specific amount that the return flow
will be reduced to (between 132,000 af per year and 97,000 af per year)
does not significantly affect the pro and con arguments of the
alternatives to be discussed.

BYPASS DRAIN

At the time of project construction, the MODE terminated at Morelos Dam,
and the WMIDD drainage water was being discharged to the Colorado River
immediately downstream from the dam. Through construction of ~he
Bypass Drain, the MODE drain was extended 53 miles to allow Desalting
Plant reject stream and other bypass water to be conveyed into Mexico
terminating in the Slough, upstream from the Gulf of California.

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