The Development Of Water Supplies For Irrigation In Nevada By Pumping From Underground Sources

Author : James R. Harrill
Publisher :
ISBN 13 :
Total Pages : 116 pages
Book Rating : 4.F/5 ( download)

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Download or read book Hydrologic Response to Irrigation Pumping in Hualapai Flat: Washoe, Pershing, and Humboldt Counties, Nevada, 1960-67 written by James R. Harrill and published by . This book was released on 1969 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second appraisal of the water supply of Hualapai Flatwaa made five years after an initial reconnaissance study~ The first report by Sinclair (1962) described the ground-water flowsystem under near natural conditions and estimated recharge anddischarge to be on the order of 5,000 acre-feet per year. Thisis lower but in reasonable agreement with the estimated perennialyield of 6,700 acre-feet derived in this report.All ground-water development to date and all proposed futuredevelopment .is in the northern half of the area.. Pumping duringthe period spring 1960 to spring 1967 has resulted in an estimatedstorage depletion of 22,000 acre-feet. Net pumpage during the1967 irrigation season was estimated to be 7,400 acre-feet, whichexceeds the estimated perennial yield by about 10 percent.Pumping is both localized and asymmetrically distributedwith respect to natural discharge; consequently, a large quantityof water must be withdrawn from storage before the perennial yieldcan be salvaged. A first approximation shows that before allnatural discharge in the valley could be salvaged by pumping fromthe approximate 1967 area of development, water levels at thenorthern end of the development may decline 150 feet or more,depending on the long-term barrier effects of bedrock boundarieson the valley-fill reservoir and fault barriers within thereservoir. Thus, even though pumping 1e limited to the perennialyieldrate, a local overdraft could develop before all the naturaldischarge of Hualapa1 Flat is salvaged. The amount of naturaldischarge that can be profitably sal7aged by future pumping fromthe same general area as in 1967 le dependent on both economicand hydrologic factors and cannot be precisely determined atthis time. The salvage probably would be at least 4,000 acrefeetbut less than the perennial yield.A first approximation of the distribution of transmiesibilitysuggests that values range from less than 50,000 gallons per dayper foot in the central and southern part of the area to morethan 100,000 gallons per day per foot in parts of the developedarea., The long-term stor•age ooeff:tc1e11t for the entire area may average 12 to 13 percent, but locally may be as high as20 percent in parts of the developed area., However, the smallsize of the valley-fill reservoir and barrier effects causedby alluvial faults in the valley fill must be evaluated ingreater detail before meaningful predictions of water-levelchanges can be made using these coefficients.Chemical quality of the water in 1967 was generally satisfactoryfor irrigation, domestic, and stock use, except in thevicinity of the playa. Over the long term, recycling of pumpedwater and the possibility of migration of poor.quality water frombeneath the playa could result in a gradual deterioration inwater quality in areas of use. The reported decrease in yieldsof a few irrigation wella could be caused by chemical encrustationof the casing perforations, mechanical