Wyoming State Water Plan
Wyoming State Water Plan
Wyoming Water Development Office
6920 Yellowtail Rd
Cheyenne, WY 82002
Phone: 307-777-7626
Wyoming Water Development Office
6920 Yellowtail Rd
Cheyenne, WY 82002
Phone: 307-777-7626
No problems arose with regard to water deliveries to Mexico between 1945 and 1961 since the salinity of the waters delivered at the Northerly Boundary was generally within 100 parts per million (ppm) of the water at Imperial Dam, the last major diversion point for users in the United States. In 1961 two unrelated events occurred which affected the salinity of the Mexican water deliveries. First, the Wellton-Mohawk Irrigation and Drainage District (part of Gila Project authorized in 1947 and whose construction was completed in 1952) commenced operation of a system of drainage wells which discharged waters with approximately 6,000 ppm into the Colorado River below Imperial Dam but above the Mexican diversion point.
Second, there was a sizable reduction in river flows to Mexico in 1961 because of increased storage in Lake Mead in anticipation of the closure of the gates at Glen Canyon Dam in the Upper Basin in order to store water in Lake Powell. This increased the salinity of the water delivered to Mexico from an average of 800 parts per million (ppm) in 1960 to nearly 1,400 ppm in 1961 and to 1,500 ppm in 1962. In November 1961 Mexico strongly objected to the salinity of the Colorado River waters received by it and negotiations between the two governments took place to resolve the matter. The negotiations resulted on March 22, 1965, a 5- year agreement, designated Minute 218 on practical measures to reduce the salinity of waters reaching Mexico, with each side reserving its legal rights. Under it the United States took the following actions at a cost to it of $12 million:
Mexico rejected this proposal because of the difference in quality between Colorado River water delivered to the United States water users at Imperial Dam and the quality of the waters delivered to Mexico. In the interim, Minute No. 218 was again continued.