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

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

period. The Federal cost would be $13.5 million per year until 1996 and
$16.5 million per year thereafter. Water still available from the
Coachella Canal lining would be used to replace the bypassed drainage flows.
Any water generated by the one-third operation would be credited to the future
use of the United States in replacing the water lost from the Desalting
Plant's reject stream. With this alternative, long-term operation of at least
one section of the Desalting Plant would also confirm plant operating and
design data and maintain the technical expertise required to operate the
Desalting Plant. Research on improved water treatment technology would
continue. A decision on the long-term operation of the Desalting Plant would
be postponed until the end of the interim period.

Additionally, under this alternative, operation of the Desalting Plant beyond
one-third capacity would be implemented if non-Federal interests were willing
to fund a proportionate share of the operating cost. Water provided by the
additional operation would be available for use outside of the funding
entity's Colorado River entitlement or banked for future use by the funding
entity.

For purposes of analysis, this report assumed that the WHIDD irrigation
drainage would be reduced to 132,000 af per year or below. On
November 12, 1992, Reclamation met with WHIDD and the Soil Conservation
Service to discuss program goals, participation, roles, and constraints. It
was agreed that committees, with staff from both Reclamation and WNIDD, 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 WHIDD 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.

The recommended alternative is a reasonable approach during the interim
period. It is moderate in cost (only $2.9 million to $5.9 million more than
keeping the Desalting Plant on standby) and demonstrates the United States'
good faith in following through on its previous commitments to the Basin
States and Nexico. It also provides the possibility of greater than one-third
operation and generation of additional water supplies for the non-Federal
participants. From a technical perspective, it allows the Desalting Plant to
be fully tested and maintained with appropriate staff expertise that would
likely be lost with standby or deactivating operations.

viii