WSP04539 - Laserfiche WebLink

Home Browse Search

" .'." , ,1" ODJJSS WATER SUPPLY FOR THE' SAN JUAN-CHAMA PROJECT 11 other uses, including exportation, at 28,800 acre-feet. . In summary, he shows the stream depletions from the San 'Juan River runoff result- ing from presently developed use in the basin in Colorado to be 146,000 acre-feet and estimates the potential future stream depletion require- ment for full basin development in Colorado to be an additional 163,000 acre-feet, resulting in an estimate of total ultimate stream depletion of 309,000 acre-feet for uses iil Colorado. During the hearings, Mr,Reynolds and Mr, Sparks were questioned about an operation study prepared by the Colorado Water Conserva- tion Board entitled "Navajo Reservoir and San Juan-Chama Study I-A." This study has been placed in the record of the hearings. The study covers the period of 1943 to 1956 during which historic flows at Blanco, less 45,000 acre-feet for possible future use, averaged only 733,200 acre-feet annually compared with 1,095,600 acre-feet annually for the period 1914-58. After diversions for the initial stage of the San Juan-Chama, the demands on the reservoir were indicated to total 785,000 acre-feet, comprising 508,000 acre~feet for Navajo irrigation project, .23,000 for Hamrr.ond project, 224,000 for municipal and industrial supply, 96,000 for other Indian uses, 34,000 for reservoir evaporation, and an allowance of 100,000 acre-feet annually for usable return flows. The results of the study showed the reservoir completely empty in 4 years and New Mexico demands exceeding its entitlement (assumed to be 787,000 acre-feet annually) when water was available and suffering heavy shortages in the last years of the study. .' Mr. Sparks testified that this study was designed only to reflect the worst sequence of years of record that could be found and that it was deliberately stopped in 1956 because 1957 was a year of very high flow. He stated that this period was designed to get a progressive lO-year series during the most critical history of the river and pointed out that during this period the river flowed only at 65 percent of the normal flow. Mr. Sparks pointed out that in the study he had de- liberately created conditions which he believed could not exist and that this was done for the purpose of attempting to create a shortage against Colorado. The assumptions were continually revised and the demands increased until a shortage on the river was forced. He stated that when that shortagl) was reached the conditions as~ sumed were completely absurd. The study was designed to show that the New Mexico projects could not have any adverse effect on the Animas-La Plata project. in Colorado. Upper Oolorado River Oommission studies The staff of the Upper Colorado River Commission has completed a, study covering the availability of water in the San Juan Basin. The study covers the water supplies for the San Juan-Chama project, initial phase, the Navajo Indian irrigation project, and the Animas- La Plata project, and the overall effects of these projects on the water supply of the San Juan River basin during the critical period~942-56. In the Navajo Reservoir operations, potential upstream depletions are assumed for the authorized Pine River extension project (62,800 acre-feet) and the Weminuche Pass diversion project (18,600 acre- feet). When added to the average annual depletion for the initial phase of the San Juan-Chama project (105,100 acre-feet), the total potential upstream depletions would average 186,500 acre-feet annually.