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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Future Hydrology Is Presumed

Reclamation would be presuming that the 85 years of recorded
Colorado River flows is representative of long-term conditions.
In 1974, the average of the Colorado River hydrology was significantly
less than it is today.

National Obligation

The Basin States could argue that under the 1974 Act, operation of the
Desalting Plant was recognized as a national obligation and that the
United States committed to operate the Desalting Plant except at times
when surplus flows are being delivered to Mexico. The reservoirs on the
Colorado River are drawn down, having experienced the 6 driest years on
record. If the Federal Government does not feel compelled to operate
the Desalting Plant under current conditions, there may be some loss of
credibility with the Basin States regarding future Federal commitments.
The Basin States could attempt legal action to stop the loss of their
water supplies and challenge the continuance of the United States
exceeding the 1944 Treaty requirements by delivering to Mexico an
additional 132,000 af per year of Basin State water in order to avoid
desalting WMIDD return flow.

ALTERNATIVE 82: DESALTING PLANT IN STANDBY

Under this alternative, the Desalting Plant would be kept ready to
operat~ during the interim period such that it could be restarted within
3 months. While there may be some loss of Reclamation desalting
expertise, full staff would, in general, be maintained. The water
conserved by lining the Coachella canal, combined with irrigation
management improvements, would replace the additional water released
from storage to meet the delivery obligation to Mexico. This solution
would cost about $10.6 million per year. The Test Plant would continue
to be used to do desalting research. It is not known if the desalting
membranes, which have already been purchased at a cost of $18 million,
can be stored for a long period of time without deteriorating. As a
result, the investment in membranes may be lost under this alternative.

PROS:

Costs

Annual costs would be about $10.6 million per year to maintain the
Desalting Plant on standby condition, compared to $33.7 million per year
for full-capacity operation.

Ready to Operate

The Desalting Plant would be maintained and kept ready to starf up
within 3 months should the Secretary be unable to meet California water
requests or have trouble meeting the salinity differential. In 1993,
the filling of New Waddell Reservoir may require significant CAP
deliveries, reducing the availability of unused Arizona apportionment to
meet California water requests. Should California water requests not be

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