WSP12980

• File Number: 8210.140.20.C
• Description: Imperial Irrigation District ‎(IID)‎
• State: CA
• Basin: Colorado Mainstem
• Date: 1/9/1996
• Author: Imperial Irrigation District
• Title: Water Requirements and Availability Sutdy ‎(draft)‎
• Water Supply Pro - Doc Type: Publication

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be allowed. Mid-lateral reservoirs could also require changes to District operations as additional
zanjeros might be needed to adjust gates when the water users turn water back.

IV.A.3d All-American Canal Reservoirs
The construction of reservoirs along the All-American Canal could provide conservation savings
through additional regulation of the main canal system and by minimizing the flow of surplus
water delivered to Mexico in excess of treaty requirements. Operational efficiency would benefit
as increased storage would aid in the reduction of carryovers and improve system reliability,
although an actual quantity of conserved water resulting from these measures would be virtually
impossible to verify. The surplus waters that end up in Mexico, in addition to their regularly
scheduled orders, generally result from two situations; water ordered but not diverted by
Colorado River water users in the United States, and regulatory water released by the U.S.
Bureau of Reclamation (USBR) for operational purposes. Finally, it is possible that a portion of
the lID storm discharge could be rerouted to reservoirs along the All-American Canal.

A 1991 draft planning study proposed the construction of two reservoirs along the All-American
Canal; at Drop Number 1 and the Westside Main Canal heading. (Draft Potential of Water
Conservation from Construction of Additional Storage Along the All-American Canal,
MWD/IID; December 10, 1991) These reservoirs were designed to capture up to three days of
operational flow and would work in tandem. With storage areas of 8,000 and 3,000 acre-feet
respectively, these two projects would require the acquisition of approximately 1,040 acres of
private land and 105 acres of public land. These figures include about 660 acres of farmland that
would be removed from production that has historically used nearly 4,800 acre-feet of water
annually. Drop l's inlet and outlet capacities would each be sized to accommodate flows of
2,000 cfs and the Westside Main reservoir would utilize inlet and outlet capacities of 500 cfs.
Both reservoirs would be lined with clay soil in order to reduce seepage. Based on computer
models designed to calculate conservation values, and relying on a five year period (1988 to
1992) of historical records detailing surplus flows delivered to Mexico in excess of their legal
allotment, the annual conservation potential of these two reservoirs is estimated to be over
21,000 acre-feet annually.

Draft: Subject To Revision 12/21/95

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