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6 0982 . The purpose of this report is to provide a basis for increased cooperation and understanding among all concerned with the coor- dinated operation of the project. The report has two main parts. One part reports the results of act- ual operations through water year 1972. The other presents opera- tion plans for water year 1973. In establishing the general plan for future operations, three possi- bilities are considered: (1) a reasonable maximum water supply which might be expected, (2) a reasonable minimum, and (3) the most prob- able supply. These three conditions of water supply are derived by statistical analysis of historical water supply data. Statistically, there is one chance in ten that the actual runoff will either be greater or less than the volumes indicated as reasonable maximum and reasonable minimum. Annual inflow of a mapnitude equaled or exceeded 50 percent of the time is considered the most probable supply. Exhibit 1 illustrates the probability curves used. Once established, however, the Annual Operating Plan does not remain rigid. From time to time revisions are made as new information becomes available. Flexibility is a keynote of the plan. Report on Operations During Water Year 1972 . Ruedi Reservoir Ruedi Reservoir had 100,250 acre-feet of water in storage on Octo- ber I, 1971. During the winter months, Ruedi Reservoir was operated essentially as envisioned in the 1972 outlook. Operation of the reservoir through November 15 was in compliance with a request by fish and wildlife interests. Releases from the reservoir were held to 100 c.f.s. for the period October 1 through November 15. Then, in order to provide maximum flood pr.otection below the dam, the ~eser- voir was drawn down to a point where refilling by July 1 would be assured under reasonable minimum inflow conditions. Outflow between November 15 and March 1 ranged from 180 to 190 c.f.s. After the March 1 snow survey data were analyzed, t~e outflow was cut to about 125 c.f.s. At the end of March the content was 62,231 acre-feet. The 1972 operating plan projected an end of month content of 57,300 acre-feet. Storage was to have begun immediately under the mlnlmum inflow con- ditions and under most probable conditions. Under reasonable maximum inflow conditions further draw down was anticipated. The content at end of April under minimum conditions was predicted to be 60,600 acre-feet. Under the other two conditions the end of April content was to be 53,100 acre-feet. .