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Show ground sources. All surface water users obtain water from mountain streams except Santa Rosa, which draws directly from the Pecos River. Santa Fe gets its municipal supply from a reservoir in a national forest area. In the Texas portion of the basin, 23 communities with a combined population of 365,900 obtain domestic water from the Rio Grande. Both El Paso and Albuquerque, the largest cities in the basin, have experienced serious water short- ages. In the past several years El Paso has bought certain marginal lands from landowners below Ele- phant Butte to obtain rights to water under arrange- ments with the water districts. So far 2,000 acres have been so acquired and withdrawn from irriga- tion. Albuquerque has installed three new well fields in the last 2 years and temporarily is ade- quately supplied with water. If present rate of growth continues, however, the water supply of that city will become deficient. Quality of surface water undergoes important changes from the San Luis Valley to Fort Quit- man. Analyses of water samples taken at nine sta- tions from Del Norte to Fort Quitman show increas- ing concentrations of dissolved solids, especially of sodium. These increases are on the order of 0.11 ton of salt per acre-foot of water at Del Norte to 2.84 tons, or more than 25-fold, at Fort Quitman. Salinity of ground water is low about margins of the valley but rises toward the middle of the valley and down river. Drain waters from irrigated land increase in dissolved solids from 0.81 ton per acre- foot at Elephant Butte outlet to 2.84 tons at Fort Quitman. Control of salinity in soils calls for ap- plication of enough irrigation water to leach out salts below root zones of crops. Such leached-out salts in return flow can affect down-river irrigated lands. Headwater streams of the Pecos, like those of the Rio Grande, are low in dissolved solids. Concen- tration of salts increases at a much greater rate downstreaan. Salinity of the lower Pecos in New Mexico and in Texas Is too strong for domestic purposes and for irrigation. The dissolved solids per acre-foot vary from 0.75 ton at Santa Rosa to 6.50 tons at Red BlufF and 7.38 tons at Orla, Tex., varying slightly from year to year. Both siarface and ground water are relatively hard. Generally organic pollution of the Rio Grande is absorbed by natural purification proc- esses before the water is withdrawn downstream for domestic use. Except at El Paso, public water supplies taken from surface streams are satisfactory after treatment. The principal problem related to municipal and industrial water arises from the fact that the Rio Grande does not furnish sufficient water for all demands. Water has been overappropriated, giv- ing rise to conflicts among water users. Hydroelectric Power Capacity, Yearly Production, Area Served The power plant at Elephant Butte Dam is the only Federal hydroelectric plant in the Rio Grande Basin. This plant has an installed capacity of 24,300 kilowatts. The only other hydroelectric plant is privately owned and has an installed ca- pacity of 9,600 kilowatts (see table 1). The private plant is a run-of-river plant with no storage. Elephant Butte, primarily an irrigation storage reservoir, has a capacity of 2,197,600 acre- feet. However, power generation is controlled by the Rio Grande Compact which limits use of water below this point to 790,000 acre-feet annually. Restorage of releases in Caballo Reservoir, imme- diately below Elephant Butte, enables more firm power to be produced than would be possible if power operation were confined only to those periods when water is released for irrigation. Power produced at these projects is marketed lo- cally. The possible market area for the potential hydroelectric output from proposed projects in the Rio Grande Basin covers about 310,000 square miles and includes New Mexico, the southern and western parts of Texas, and the southern half of Colorado. In 1948, total installed capacity of util- ity systems in this area was 1,344,000 kilowatts, of which 195,000 kilowatts, 15 percent, was hydroelec- tric and 1,149,000 kilowatts was fuel-electric ca- pacity. Peak power demand in 1948 was 1,176,000 kilowatts and the energy for load, 6.4 billion kilo- watt-hours. The estimated future area load in 1970 amounts to 4 million kilowatts. Facilities in Construction and Authorized One Federal project, the Falcon Dam and power plant with an installed capacity of 31,500 kilowatts, is under construction on the United States side of the lower part of the river. Another plant of equal capacity is being built on the Mexican side to sup- ply an equal amount of power to Mexico. The Export-Import Bank loaned funds to the Mexican 308 |