WSP12542

• File Number: 8282.400
• Description: Colorado River Operations and Accounting - Deliveries to Mexico
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 5/1/2001
• Author: David and Lucille Packard Foundation
• Title: Immediate Options for Augmenting Water Flows to the Colorado River Delta in Mexico - RE-Colorado River-Mexican Delta Issues - 05-01-01
• Water Supply Pro - Doc Type: Report/Study

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. Periodic releases of larger volumes of water to the Delta for flushing purposes would
increase the risk of shortages in the United States unless the reservoirs were
subsequendy refilled with high runoff; and,

. Delivery of operational over-deliveries ~f Colorado River water to Mexico in excess
of the Treaty delivery requirements to the Delta wetlands is limited by needs of
agricultural water users in Mexico and canal capacity. Also, as a part of the program
to line the All American Canal, plans are being developed to build additional
regulating reservoirs, that could reduce the magnitude and frequency of such
operational over-deliveries of water to Mexico and to the Delta.

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While recognizing that all potential sources of Delta water supplies are problematic, the
report does not dismiss or .endorse any of them as a water supply for long-term Delta management.
Ultimately, the solution to the ecological problems of the Delta will require considerable technical
inquiry that could take years. Agreement on the goals and the design of a truly comprehensive
approach for protection of the Delta's ecosystems will require the collaboration al!d best efforts of
all interested parties. TIlls report merely attempts to identify and test alternatives that appear to have
the least political, legal, and financial complications and that could be implemented in a relatively
short time.

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Two combinations of supplies were selected that the authors of this report believe could
provide a sustainable near-term supply of water for protection and enhancement of Delta ecological
resources. These options are not entirely free of physical, economic, institutional, social, and
environmental problems; however, they appear to offer a feasible means of providffig important
near-term ecological benefits. The two options are:

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A. Fresh Water Sources

TIlls alternative involves the purchase and retirement from willing Mexican landowners of
about 2,000 hectares (5,000 acres) of marginal, privately-owned agricultural land west of Mexicali or
south of the Compaction Zone. 1bis would provide approximately 15,000 acre-feet of water per
year that could be designated to restoring Delta habitat. The 2,OOO-hectare objective was developed
with the assistance of local CNA staff and represents an estimate of the marginal agricultural land
. that could be retired from an operational perspective with minimal impact on established agricultural
uses. As a comprehensive Delta management program is developed, the opportunity to expand
such purchases can be explored.

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The United States now provides operational over-deliveries of Colorado River water, when
available. These waters are expected to average about 30,000 acre-feet per year. When they occur,
the flow volumes often exceed the water delivery needs of water users in District 014 under current
operation strategies. Operational over-deliveries that exceed demands flow into the river corridor
below Morelos Dam.

Together, these two sources would provide an average of 45,000 acre-feet per year of fresh
water to the Delta. CNA would be requested to use its infrastructure to deliver the 15,000 acre-feet
per year of purchased water rights and to divert and wheel unused operational over-deliveries to
identified tracts of land within the river corridor betWeen Morelos Dam and the confluence with the

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