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<br />0012~1 <br /> <br />greater than the determined flood control space then an Anticipated Flood Control release <br />was made for that year. If an Anticipated Flood Control Release is made then a surplus <br />determination was made available to MWD, SNWS and CAP. <br /> <br />,UNANTICIPATED RELEASE <br /> <br />If actual runoff exceeds the forecast and required flood control space then excess releases are <br />made without a surplus. <br /> <br />EQUALIZATION <br /> <br />Under equalization, the active storage in Lake Powell would be compared with the active <br />storage in Lake Mead. Equalization occurs whenever active storage in Lake Powell is <br />greater than the active storage in Lake Mead. The reservoirs are equalized by increasing the <br />release from Lake Powell, beyond the minimum 8.23 maf release but up to 602(a) <br />limitations, sueh that half of the difference in active storage would be released into Lake <br />Mead during the calendar year. <br /> <br />MODEL ASSUMPTIONS TO BE VARIED <br /> <br />SURPLUS PROVISION <br /> <br />The surplus strategy is the decision-making process used when considering spring runoff and <br />limited storage space, which distributes water, surplus to a normal determination, throughout <br />the water year in advance of flood control releases. <br /> <br />Two methods have been used in the past. The surplus strategy methodology has been based <br />on a Lake Mead threshold capacity in which a surplus is determined whenever the threshold <br />capacity is exceeded. The surplus strategy has also been based on a degree of assurance of <br />being able to anticipate and distribute surplus water to avoid required regulatory flood control <br />releases. Neither of these two methodologies consider a critical period of record nor by <br />themselves automatically protect against potential impacts to shortages. A third method using <br />a 12-year and a 20-year critical period of record was also investigated. <br /> <br />Initial runs focused on alternate strategies which used either a surplus threshold capacity or a <br />spill avoidance probability. During each year modeled, the surplus criteria selected (for <br />example 80 Percent Lake Mead Capacity) was used to determine the selected level of <br />protection. An 80C Threshold Capacity would refer to 80 Percent of Lake Mead capacity. <br />The threshold elevation was checked against the storage elevation at the beginning of the <br />year. If the storage elevation was'greater than the determined surplus threshold elevation, a <br />surplus was made available for that year. A Lake Mead surplus release is made available to <br />MWD, SNWS and CAP. <br /> <br />13 <br />