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contents where the initial contents were adjusted to force flood control releases at Lake Mead. The 25% probability hydrology act similar to ~he minimum probable hydrology. The initial contents of Lake Powell and Lake Mead are full in order to cause a small flood control release in January, 1992. As can be seen in the summary below, in September. 1988, Lake Powell would contain just less than 7 million acre-feet more water under the 25% hydrology than under the 5% hydrology. The reservoir system experIences a net loss of surface contents for all hydrologic scenarios through the 50% probabilities. By the 75% probability of nonexceedence, the reservoir system gains contents. The current low system contents reveals itself in the lack of anticipated flood control releases until the hydrology exceeds the 90% probability scenario. Lake Powe 11 Surface Storage f End of Sepcember, 1996 Under Various Hydro10gys Minimum Minimum 25% 25% 50% 50% 75% 75% 90% 95% Probable Probable (Flood) (Plood) (Flood) (Flood) 6928 15828 13896 20152 17083 22876 20429 23483 23410 23455 Lake Mead Surface Storage. End of September, 1996 Under Various Hydrologys Minimum ~linimum 25% 25% 50% 50% 75% 75% 90% 95% Probable Probable (Flood) (Flood) (Flood) (Flood) 13658 18371 13923 20252 17109 22895 20424 23457 23522 24642 virr. Conclusions The Commission staff believes that the use of a 5 year window, current reservoir conditions, and selected hydrologic scenarios can and should be used to guide the determination of surplus, normal. and shortage conditions as specified anticipated by the operating criteria. This method defines a clear process for discrimination between "surplus" and normal conditions. Under this process, "surplus" is identified as that quantity of water which would be lost to the system through a flood control release 5