WSP02035 - Laserfiche WebLink

Home Browse Search

--1 --1 The graphs in the Surplus Guidelines titled "Mead Start = .,." show the starting contents required in Lake Mead for a specific depletion level (use) that will protect an elevation of 1 050 feet during the critical period of record, In other words, the graph titled "Mead Start = 11,874 kaf, Use = 11,083 kaf" shows that 11,874 kaf (1000 acre-feet) of storage is required at the start of the critical period to satisfy 11,083 kaf of annual use without allowing the reservoir to be drawn down below 1050 feet, Because the Surplus Guidelines protect elevation 1050 feet, which was the original intent of using 1120 feet as a shortage trigger elevation, shortages were not allowed for the purposes of these studies, In the graph titled "Mead Start = 14,469...", two low points occur indicating the system doesn't recover well and a longer critical period of record is being approached, In the graph titled "Mead Starting Contents to Avoid 1050 ft", the system goes to a flood control surplus strategy at the extreme high end of use, Here, surplus can not be declared unless flood control releases are required. The critical period approach proposed in the Surplus Guidelines will not change due to reservoir conditions or projected depletion levels, However, the curves would need to be revised if 1953 no longer started the driest period of record, Additional studies were performed to supplement the Surplus Guidelines and the graphs of results were distributed. These additional studies were intended to correct the situation which arose in the 12/23/93 Surplus Guidelines when surplus is declared but not used, Banked water is the first to spill. Surplus is declared on system water only. The surplus guidelines actually facilitate banking, because the old idea of surplus kept Lake Mead so full there was never any room for banking regularly apportioned water. A surplus declaration lasts only for the current year. When surplus is declared, it will be made available even if inflows are significantly less than forecast, This protects users who plan for the additional water. No Colorado River water is available without a contract, To investigate surplus strategy results if the protected elevation used is 1060 feet (which is maybe an extra 300,000 acre,feet), just shift the graphs by 300,000 acre-feet, The Surplus Guidelines were developed without regard to minimum power head, Therefore in extreme cases, there could be a loss in generation under these guidelines, 3