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I I I I I I I . . I . I . '. '. I I '. J ODn~38 Modeled project demands included storage water diversions for industrial uses by P&M. P&M holds no direct flow diversion rights under this project. It was assumed that the industrial water is diverted directly from the reservoir area and 100 percent consumed with no return flows. Anticipated industrial demands upon the Three Forks storage water is unknown at this time. To quantify realistic industrial demands that the reservoir could meet on a year to year basis, WWC performed a firm yield evaluation using the WIRSOS model. An initial constant industrial demand of 90,000 AF/year was used in the firm yield investigation. In a previous study, WWC calculated a firm yield of about 90,000 AF/year (123 cfs) for a 160,000 AF reservoir (SWEC, November 1984). However, in that study no other projects, such as Pot Hook Reservoir, were operated simultaneously with the Three Forks Reservoir. Additional WIRSOS runs were performed to determine the actual firm yield demand to be used in evaluating downstream flow impacts. Bypass flow requirements for instream flow considerations were included in the WIRSOS modeling. An instream flow requirement of 100 cfs has been suggested for the Little Snake River below Savery Creek by the Wyoming Game and Fish Department. Of this 100 cfs, it was assumed that 24 cfs would come from Savery Creek and Sandstone Reservoir storage releases as modeled in the Sandstone Depletion Study (SWEC, 1987), 24 cfs from Slater Creek and Pot Hook Reservoir, and 24 cfs from the Little Snake River and Three Forks Reservoir. The remaining 28 cfs was assumed to come from Battle Creek and other ungaged inflows. If the model estimates that the 28 cfs is not available, 33