WSP07652

• File Number: 8278.400
• Description: Title I - Mexican Treaty and Minute 242
• Basin: Colorado Mainstem
• Date: 1/1/1998
• Author: IBWC
• Title: Minute 242 Annual Report
• Water Supply Pro - Doc Type: Annual Report

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I This report is based upon records of flows and salinities detenninedjointly by the United States and
Mexican Sections of the ffiWC, 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
I Exhibit 1.

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The records-show -thafthe UniterlStcites opera1iouns resulted ~in . compli~mce witlnh-eagteemenrin- - ~- ~~ u_ - -
I Minute No_ 242.

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

January 1 - December 31, 1998

This report presents the results of operations from January 1 through December 31, 1998 under the
agreement with Mexico entitled, "Permanent and Definitive Solution to the International Problem of
the Salinity of the Colorado River", incorporated in Minute No. 242 dated August 30, 1973 of the
International Boundary and Water Commission, United States and Mexico (ffiWC). The operations
began on June 25, 1974, immediately following approval of the Enabling Legislation, Public Law 93-
320.

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
MorelosDam, have an annual average salinity of no more than 115 p.p.m. :t30 p.p.m.
US. count (121 p.p.m. :t 30 p.p.m. Mexican count) over the annual average salinity
- - of Colorado- River waters which aniveat Imperial Dam . . ."

The records show that during 1998:

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 of! ,93 7,149,000 cubic meters (1,570,466 acre-feet) atthe
riverbed above Morelos Dam and 159,782,000 cubic meters (129,537 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 3,723,206,000 cubic
meters (3,018,435 acre-feet).

2)

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

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