WSP10867

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 3/1/1962
• Author: IBWC
• Title: Mexican Water Treaty -Appendix E -Water Supply
• Water Supply Pro - Doc Type: Publication

.",'\
.: ..
'~'."
.,""

APPENDIX "E"

WATER SUPPLY

It is axiomatic that the main item of concern in the Mexican Water Treaty

and in its negotiation was the water supply. Both the proponents and opponents of

the treaty agreed that Mexico was entitled to some water from the Colorado River,

the question seemed to be "how much". There were divergent views 'as to the quantity

of water available from uncommitted river sources, return flow, seepage, regulatory

losses, and desilting basin uses. Views also differed as to the basis for making an

allocation and as to data to support the basis.

We will attempt to outline the issues as raised and the arguments advanced

on both sides. Besides the quantity question, there was discussion on the prior use

of water in Mexico, the use and potential use of water in the United States, the need

for a diversion dam for Mexico and related sub-issues. .

The conflicting views are summarized in the majority and minority reports

of the Committee on Foreign Relations to the Senate. (Executive Report No.2,

79tl1Congress, 1 sf Session)-:-On pages 'I ana-Softne Majority Report, we find

the following language:

"This water is to be delivered mainly in the boundary section
of the river, but proVision is made for the delivery of a portion
through the All-American Canal and a small portion across the land
boundary in the vicinity of Yuma, Ariz. Certain limitations are placed
upon the schedules of delivery so as to insure to the United States
credit for substantially all return flows and other waste waters emana-
ting from projects within the United States and generally reaching
the river at points too Iowan the stream to be susceptible of further
use within the United States. This is largely composed of water
which has been used for the irrigation of lands within the United
States and which returns to the river through drainage canals or
through underground seepage. Not all of the water which is put