WSP07246

• File Number: 8273.100
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1978
• Title: Reject Stream Replacement Study - Status Report Janaury 1978
• Water Supply Pro - Doc Type: Report/Study

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I. INTRODUCTION

The Reject Stream Replacement Study was initiated in an effort

N to identify feasible measures to provide adequate replacement water
N
c.c for the Yuma Desalting Plant reject stream. Authorization for the
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desalting plant and this associated reject stream study, encompassed

in the Colorado River Basin Salinity Control Act of June 24, 1974,

Public Law 93-320, was a consequence of more than a decade of

arbitration between the United States and Mexico concerning the

quality of Colorado River water diverted by Mexico at Morelos Dam, a

mile below the Northerly International Boundary.
The problem began in 1961, when Mexico formally protested to

the United States that ".

. the delivery of water that is harmful for

.

the purposes stated in the Treaty (the treaty between the two coun-

tries, adopted in 1944, which allotted to Mexico 1,500,000 acre-feet

annually of Colorado River water) constitutes a violation of the Treaty."

The reason for the protest was due to a substantial increase that

year in the salinity of Colorado River water that reached Mexico.

Two concurrent factors were responsible for this increase.

First, the above average annual runoff in 1957 and 1958 had

enabled Mexico to divert 1.7 million acre-feet of water (the Treaty

maximum) during 1958, 1959, and 1960. Then followed three conse-

cutive years of low runoff in 1959, 1960, and 1961. This restricted

Mexico more nearly to the 1.5 million acre-feet minimum annual allot-

ment specified in the Treaty. The reduction in excess deliveries to

Mexico brought about an increase in the salinity of Colorado River

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water arriving at the Northerly I nternational Boundary.

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