WSP09978

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1994
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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Laguna Dam due to excess water from rain flooding upstream, or from rejected water orders
due to rain. These higher releases serve to maintain the river channel capacity. This
occasional practice reduces channel maintenance expense without impairment of water
conservation or power production.

Gila River Flows

The calendar year 1993 scheduled delivery to Mexico is 1,850 MCM (1.500 MAF) in
accordance with ArtiCle '15 of the 1944 Mexican Water Treaty and Minute No. 242 of the
IBWC. Total calendar year 1993 delivery is expected to be 5,551 MCM (4.500 MAF) due
to flood control releases from the Corps of Engineers' Painted Rock Dam on the Gila River,
Releases from Painted Rock Dam peaked at 736.3 m3/s (26,000 cfs) in February.
Subsequently, discharges were incrementally reduced, until the first of July, when discharge
volumes reached 62.3 m3/s (2,200 cfs), Releases will remain at 62.3 m3/s (2,200 cfs) until
the end of December at which time the reservoir will have been evacuated, Of the
1,678 MCM (1.360) MAF scheduled for delivery during calendar year 1993 at the Northerly
International Boundary, as much as 1,079 MCM (.875 MAF) will have been delivered from
the Gila River; consequently, a like amount of Colorado River mainstem water will be
retained in Lake Mead for future use,

The high flows on the Gila River damaged the saline water bypass channel used to meet the
salinity requirements of Minute 242 for the Mexican water deliveries, The bypass channel
will be sufficiently repaired to divert pumped drainage water from the Gila River channel by
December to continue meeting the salinity requirements as the Gila River flows end,

Yuma Desalting Plant

The Yuma Desalting Plant will not be operated for the remainder of calendar year 1993 due
to damage sustained by the Wellton Mohawk Main Conveyance Canal, Main Outlet Drain,
and Main Outlet Drain Extension reaches of the pumped drainage channel from Gila River
flooding, Funding for operation of the plant is available for fiscal year 1994. However, due
to the repairs required upon the reaches described above, the desalting plant will not be able
to operate until April, 1994, at the earliest. If the plant is operated during fiscal year 1994\it
will be at one third capacity.

During 1993, the salinity differential defined in Minute 242 of the IBWC is anticipated to be
met by releases from Painted Rock Reservoir of sufficient volume to prevent adverse salinity
impacts at Morelos Dam. These releases are necessary to overcome salinity that is resulting
from the direct discharge of Wellton-Mohawk Irrigation and Drainage District pumped
drainage into the Gila and Colorado Rivers,

During 1994, the salinity requirements of the Minute will be met by diverting the Wellton-
Mohawk pumped drainage into the Main Outlet Drain Extension near the Colorado and Gila
River confluence. Should the desalting plant be made operational, the water recovered will
be returned to the Colorado River, and hence reduce the amount bypassed.

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