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<br />The terms of thi proposed contract call for the reservoir content to <br /> <br /> <br />be kept between the 20,000 and .24,000 acre-feet limits with an allowance, <br /> <br /> <br />,however, for dry-year sequences during which the conservation pool contents <br /> <br /> <br />may reach a lower limit of 18,000 acre-feet provided it is refilled to the <br /> <br /> <br />20,000 acre-feet level by the end of the year. In this study the expected <br /> <br /> <br />evaporation values were computed on the l280-acre basis that belongs to a <br /> <br /> <br />22,000 acre-feet content with the proper limits computed based on the lower <br /> <br /> <br />l220-acre surface ar,ea and the upper l360-acre surface area. <br /> <br />Historic lake evaporations were computed from ~6 years of consecutive <br /> <br /> <br />precipitation and temperature data collected at the Kassler station on a <br /> <br /> <br />monthly basis. The estimates were made by the Modified Blaney-Criddle <br /> <br /> <br />computation with a crop coefficient of 1.0. The estimated monthly lake <br /> <br /> <br />evaporations npt corrected for precipitation Were summarized on an annual <br /> <br /> <br />basis with the following statistics. The 56-year average was 37.14 inches <br /> <br /> <br />with a standard deviation of 2.01 inches, and the maximum and minimum values <br /> <br /> <br />were 42.01 inches and 32.43 inches, respectively, <br /> <br />A part of the precipitation falling on the conservation pool surface <br /> <br /> <br />area can legally be credited toward reducing the evaporation losses, As <br /> <br /> <br />a general rule, injurious effects on other downstream water rights must <br /> <br /> <br />be considered in determining what part of the precipitation can be legally <br /> <br /> <br />withheld in the reservoir. <br /> <br />Limiting the discussion to precipitation falling on the area occupied <br />by the conservation pool alone, prior to the construction of the reservoir <br />evaporation and water consumption has historically taken place on these land <br />areas. The original vegetation covering the area that probably consisted <br />of native grasses and some brushes has consumed'a part of the precipitation <br />making it unavailable for any downstream water user that appeared at a later <br />time. There are various methods to determine the runoff produced by an <br />area that will end up in the stream and become available as the water supply <br />for some downstream users; however, none of these methods are too accurate. <br />An individual storm analysis that would be the most accurate determination <br />of the runoff production requires a lengthy analysis of each and every indi- <br />vidual storm event coupled with a simultaneous analysis of the soil moisture <br />storage. Unfortunately there are no adequate data on soil moisture and its <br /> <br />- 3 - <br /> <br />M, W. BITTINGER AND ASSOCIATES. INC. <br />