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46 RELEASE OF COLORADO RIVER WATER for the Mexican water users if the two countries are to achieve the maximum benefit from use of Colorado River water. Potential programs for the United States include- (1) Further river channelization and rectification, and a phreatophyte control program to save water now lost to moisture-wasting weeds; (2) Improvement of stream regulation below Imperial Dam; (3) Increasing the capacity in drainage works in Arizona to permit maximum operation in summer months when the greatest amount of storage water is available for dilution and reduced pumping in the winter when river flows are normally lower: (4) Determining the feasibility and practicality of a special conveyance channel to transport drainage water to a point below Mexico's main diversion at Morelos Dam; (5) Possible establishment of a saline water conversion plant in the Yuma area. Through the International Boundary and Water Commission every possibility of removing the problem will be explored, Secretary Udall said. In its studies the International Commission is also expected to consider complementary programs that might be undertaken in Mexico. The Colorado River has a natural high salt content, particularly at times of low flow. Water users in the United States have recognized this and have adopted irrigation and drainage practices necessary to insure satisfactory use of the water.They have classified their lands to select land resources best suited for sustained irrigation, and have constructed specially designed drainage systems. In addition, they have selected crops and adopted irrigation procedures to match the land and water resources. It is to be expected that Mexico will want to undertake similar measures. Mexico also may wish to evaluate its many existing and potential wells to determine the extent to which they can be integrated into the overall irrigation system, as well as schedule its treaty water so as to permit the best possible seasonal utilization according to the possibilities and Mexico's needs. It should be clarified, Secretary Udall explained, that U.S. soil and water experts are of the opinion that the most saline water that has been delivered to Mexico to date is usable on a short-term basis, for irrigation of crops such as wheat, alfalfa, and cotton under the proper irrigation and drainage practices. In fact, waters much higher in salts are being used full time for irrigation on a number of projects in Arizona, California, New Mexico, and Texas. Also, a group of Mexican water users along the east side of the Colorado River, just south of the valley division of the Yuma project in Arizona, purchase over 100,000 acre-feet of the drainage water annually from the Yuma County Water Users' Association. This drainage water is only slightly less saline than the flows of the Colorado River delivered to Mexico this winter. Secretary Udall said that the return flow of which Mexico complained this winter was a natural and normal consequence of the irrigation process. In 1944 when the treaty was negotiated it was understood by both countries that at times during future winter months Mexico's entire scheduled quantities might consist of return flows and that a large part of that return flow would be drainage water. An important consideration in the U.S. ratification of the treaty and agreeing to a guaranteed annual delivery of 1,500,000 acre-feet of water to Mexico was the understanding that Mexico was willing to accept such drainage water as a part of that amount. Nevertheless, Secretary Udall said, the Federal Government recognizes that the situation can and should be improved by complementary actions on both sides of the border. He expressed hope that the International Boundary and Water Commission could come up soon with agreed recommendations which would permit action to be taken for improvement in the quality of water being delivered to the Mexican farmers. He cautioned, however, that the programs being considered by the Department of the Interior in the United States, if found to be practicable, were for long-range solutions and would not yield significant results for at least 2 to 3 years because of the major construction involved. DEPARTMENT OF STATE, Washington, D.C., February 5, 1962. Hon. CLINTON P. ANDERSON, U.S. Senate. DEAR SENATOR ANDERSON: I have your letter of January 26, 1962, inquiring concerning agricultural development in the Mexicali Valley in Mexico. We have considerable information of this nature accumulated over many years, but agreeEpson Perfection 4870 Photo, 400 dpi, 24 bit, 6,694,400 byte