WSP09503

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 5/10/1962
• Author: CWCB - D. Hamburg
• Title: Mexican Water Treaty Negotiations Pertaining to the Colorado River
• Water Supply Pro - Doc Type: Publication

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INTRODUCTION

The Treaty between the United States of America and
the United Mexican states relating to the utilization of the
waters of the Colorado and Tia Juana Rivers and of the Rio Grande
from Fort Quitman, Texas, to the Gulf of Mexico, was signed in
Washington on February 3, 1944. The Senate of the united States
of America by their resolution of April 18, 1945, two-thirds of
the Senators present concurring therein, did consent to the rati-
fication of said Treaty subject to certain understandings. For
a period of approximately five years prior to the ratification
of the Treaty extensive negotiations took place. During the period
between the signing of the Treaty and the ratification of same by
the Senate, extensive hearings were held by the Committee on Foreign
Relations of the United States Senate and numerous documents were
written concerning the Mexican Treaty.

During this period and for many years prior to 1940 the
Colorado Water Conservation Board took an active part in the
entire proceedings. Fortunately for us today an accurate record
of all that transpired was kept by the Colorado Water Conserva-
tion Board.

It is the purpose and intent of this paper to summarize
what transpired prior to the ratification of said Treaty. It is
realized that significant changes have taken place on the Colorado
River since 1945. with a summary of the negotiations of this
Treaty, it is hoped that we can better understand the present
problem facing the Colorado River Basin today.

PROBLEM

The problem under the Treaty, causing the present dis-
pute between the United States and Mexico, involves the quality
of return flows that are being delivered to Mexico from the Colo-
rado River. Within the last year, the Bureau of Reclamation has
completed a $12 million extension of a project in southwestern
Arizona called the We 11 ton-Mohawk project. The depth of the ground
water table within the Wellton-Mohawk has risen to such an extent
that many lands within the project have had to be abandoned. To
overcome this, pumps and drainage facilities were installed and
the ground water is being pumped into the Colorado River.

The return flows from the Wellton-Mohawk are very
saline; however, when this water is mixed with other waters of

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