WSP12517

• File Number: 8282.400
• Description: Colorado River Operations and Accounting - Deliveries to Mexico
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/2001
• Author: Robert Ortega
• Title: A Report on Salinity Operations on the Colorado River Under Minute Number 242 - January 1 through December 31 1999 - RE-Colorado River-Mexican Delta Issues - 06-01-01
• Water Supply Pro - Doc Type: Report/Study

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A REPORT ON SALINITY OPERATIONS
ON THE COLORADO RIVER UNDER MINUTE NO. 242

January 1 - December 31,1999

This report presents the results of operations from January 1 through December 31, 1999 under the
agreement with Mexico entitled, "Permanent and Definitive Solution to the International Problem
ofthe Salinity ofthe Colorado River", incorporated in Minute No. 242 dated August 30, 1973 ofthe
International Boundary and Water Commission, United States and Mexico (IBWC). The operations
began on June 25, 1974, immediately following approval ofthe Enabling Legislation, Public Law
93-320.

This report is based upon records of flows and salinities determined jointly by the United States and
Mexican Sections of the IBWC, the United States Bureau of Reclamation (USBR) and the United
States Geological Survey (USGS). Locations and features referred to in this report are shown in
Exhibit 1.

The records show that the United States operations resulted in compliance with the agreement in
Minute No. 242.

The Salinity Differential

Minute No. 242 provides in Point 1 that:

"The United States shall adopt measures to assure that. . . the approximately
1,360,000 acre-feet (1,677,545,000 cubic meters) delivered to Mexico upstream of
Morelos Dam, have an annual average salinity of no more than 115 p.p.m. :t 30
p.p.m. U.S. count (121 p.p.m. :t 30 p.p.m. Mexican count) over the annual average
salinity of Colorado River waters which arrive at Imperial Dam. . ."

The records show that during 1999:

1) Scheduled deliveries of water from the Colorado River in the quantity of 2,096,931,000
cubic meters (1,700,000 acre-feet) were made to Mexico in accordance with Article 10 of
the 1944 Water Treaty consisting ofl,932,288,000cubicmeters (1,566,525 acre-feet) atthe
river bed above Morelos Dam and 164,643,000 cubic meters (13 3,477 acre-feet) across the
land boundary near San Luis, Arizona and at the limitrophe section of the river below
Morelos Dam.

Other waters delivered to Mexico in the limitrophe section amounted to 1,472,914,000 cubic
meters (1,194,106 acre-feet).

2) The annual flow weighted average salinities ofthe waters ofthe Colorado River a) upstream
of Morelos Dam, b) arriving at Imperial Dam, and the resulting salinity differentials were
as follows:

1