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. operations could be adapted to accommodate recreation and fish- wildlife enhanoement. Other incidental functions of the reservoir would be the retention of sediment carried by flood flows and possibly some water quality control. ASSOCIATED HYDROLOGY S'lUDIES Reservoir Sedimentation A program for estimating the sediment discharge into the potential Idylwilde Reservoir was conducted during the spring and summer of 1964. Random samples were taken at the Rustic gaging station and tested for sediment load. Based on the results of these tests and on an average flow of 261 c.f.s. at the station, the lOO-year sediment inflow to the Idylwilde Reservoir would be insignificant. Tailwater Effects A study was made to determine the effects of the tailwater for normal flows. The conclusion reached was that wi thin the normal flow range no tailwater effects would be experienced. . Streambed Degradation Studies Field observations indicated that the river channel below the Idylwilde Dam site is well armored since the armoring materials appeared to be muoh larger than the 3-inch computed minimum require- ment. Therefore, no appreciable degradation of the streambed could be expected. Inflow Design Flood . The inflow design flood study, completed in 1964, was approved by the Chief Engineer for use in the preparation of a feasibility design. The peak flow rate of the inflow design flood is 52,000 c.f.s. and the 20-daY volume is 206,600 acre-feet; failure of the upstream Chambers Lake Dam is reflected in these results. Quality of Water No analyses were made by the Bureau of Reclamation to indicate the changes in quality of water which might result from operation of the potential unit. Based on water quality analyses of present . 24