WSP05700

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 2/17/1973
• Author: IWBC by Harshbager
• Title: Memorandum Report MR-73-1 Appendices, A - Groundwater Conditions in the Colorado River Delta Area, United States and Mexico and Appendix B - Pumping Regimens, Effects and Prediction Analysis
• Water Supply Pro - Doc Type: Publication

23 '

Consequently, the Pumping Regimen No.3 would effectively

reduce the groundwater flow to about the same magnitude as the

virgin flow that occurred in the early part of the century

(20,000 AF/yr).

Thus, the studies indicate that to counterbalance the

Mexican pumping and to recover waters now flowing to Mexico

due to irrigation on the Yuma Mesa, there will be required, in

time, the installation of additional wells in the United States

to-pump about 200,000 AF/yr.

The computed water level change at the end of 50 years for
this pumping Regimen No. 3 was subtracted from the 1972 ,.later
level contours as shown on Figure A-II. The results of this
analysis are shown on Figure B-13, ,.:hich comprises a prediction
of the actual water level contours, 50 years after pumping from
the wells in United States and Mexico. It is apparent that,
along a 15 mile sector of the Arizona-Sonora boundary, no ground-
water flow crosses the boundary; consequently, the net result of
the effects indicates that adequate counter measures to intercept

United States ground\1ater sources could be achieved. Also, of

the total water pump~d (21 million acre-feet), about 10-1/2

million AF \-,'ould be obtained fl-om united States and about 10-1/2
million l\F would be obtained from Mexico at the end of 50 years
(Table 2) . This Pumping Regimen No. 3 could be considered to
comprise a balanccd pumping condition. as about equal amounts

of water would originate from each country.