WSP00291

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

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prescribe certain minimum rates of deliveries during these
months. This will require some change in rviexico's present.
lrrigatioh practiCes, which practices do not now involve any
considerable amount of winter irrigation use. The effect of this
will be to require a more economical use of water in Mexico and
at the same time assure to the United States credit for its return
and other waste waters."

6. Robert L. Lowry, a proponent witness, presented testimony as

to the amount and source of the water which would ultimately make up the

Mexican deliveries. He estimated that there would be 930,000 acre-feet

from return flow, 100,000 acre-feet of desilting water from the works of

Imperial Dam, 100,000 acre-feet from unused Gila River flow and 375,000

acre-feet to be supplied from the main stream.

(See pp. 236-37, Hearings).

Low ry pointed out that the 375,000 acre-feet is the amount which the All-

American Canal is to deliver after 1980 under the terms of Article 15.

(p. 239 Hearings)..

7. R. J. Tipton beginning on page 311 of the Hearings went into

the problem of return flow from a point of view somewhat different from the

Lowry testimony. Tipton made some assumptions as to use patterns in the

United States different from Lowry's. Tipton pointed out that the return flow

from the Gila proj ect would be good quality water, while that which returned

from the Central Arizona area would not be as good (p. 321, Hearings). On

page 322 Tipton makes the following statements with reference to this latter

source of return water:

"Suppose there were sufficient water coming from Central Arizona
to deteriorate materially the other water; there was language put
in the treaty with the knowledge and consent of Mexico specifically

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