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<br />. <br /> <br />w <br />~ <br />~ <br />~ <br /> <br />. <br /> <br />. <br /> <br />following consultation with the Bureau that the relationship may not ade- <br /> <br /> <br />quately represent future conditions and that a longer period of analysis, <br /> <br /> <br />including both falling and rising reservoir cycles, is needed to test the <br /> <br /> <br />validity of the relationship. It was, therefore, decided not to incorporate <br /> <br /> <br />the relationship into the mathematical model but to use the average annual <br /> <br />salt loss of 135,000 tons. <br /> <br />Bank Storage in Lake Powell. - The amount of water going into or coming <br />out of bank storage in Lake Powell was, in the previous salt routing studies, <br />assumed to be 10 percent of reservoi r storage changes. A mass-ba1ano,e <br />analysis covering the period 1963 through 1976 indicated the percentage of <br />water going into bank storage can be considerably greater. This period, <br />however, encompassed the initial filling cycle of Lake Powell during which <br />the soils within the reservoir experienced their initial saturation. It is <br />reasonable to expect that future bank storage will be less than occurred in <br />the past. It was decided, therefore, that until additional data become <br />available, the 10 percent value for bank storage will continue to be used. <br />Comparison With 1978 Procedures. - Using the revised salt load estimate <br />and a virgin flow at Lee Ferry of 14 million acre-feet per year, the salt <br />load under 1979 conditions is 741,000 tons per year less than it would have <br />been using the earlier relationships and procedures. A comparison of the <br />salt loads estimated by the two procedures for the model input items that <br />were modified is shown in table 2. <br /> <br />17 <br /> <br />" "', <br /> <br />,I <br />, " <br />~f~ <br />