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<br />averaged 20 m higher during drought months. Rain-gage data for stations west <br />of the Wasatch Plateau showed fewer days with precipitation during drought <br />months, but about the same preCipitation per event. Stations to the east of <br />the Wasatch Plateau had fewer days with precipitation and less precipitation <br />per event during drought periods. Rawinsonde data on "stormy" days at Salt <br />Lake City, Ely, Las Vegas, and Grand Junction were analyzed for cloud charac- <br />teristics, inversions, and winds aloft. No dramatic differences between <br />drought and nondrought periods were noted. The results of this study suggest <br />that, while fewer storms occur during drought periods, the weather modifica- <br />tion potential of the storms should be no less than those of more normal <br />periods. A design study for standby cloud seeding operations is being <br />ini tiated. <br /> <br />Dr. David Bowles summarized the efforts of the Utah Water Research laboratory <br />of Utah State University on: (1) estimating the increase in reservoir <br />inflows resulting from precipitation augmentation during drought years, <br />(2) determining the ownership of such increases according to the water rights <br />system, and (3) evaluating the potential for modifying reservoir operation <br />when early warnings of drought are made. For the reservoir inflow study, <br />five reservoir systems were selected and streamflow, reservoir contents, <br />precipitation, evaporation, snow course. water supply forecast, and diversion <br />data were collected. In addition. water rights and reservoir operation <br />poliCies were obtained from the river commissioners. The National Weather <br />Service water supply forecasting procedure was adopted for estimating runoff <br />at reservoir inflow locations. Procedures for obtaining reservoir inflow <br />hydrographs by backrouting recorded outflow hydrographs through reservoirs <br />using records of reservoir contents and evaporation estimates are under <br />development. Techniques for estimating reservoir inflows where outflows are <br />not recorded are being formulated. Dr. Bowles' team also performed a frequency <br />analysis of runoff volumes at several stations for different time periods to <br />determine the probability of occurrence of drought events. Preliminary <br />results show good agreement with frequency analyses of Palmer Drought Indexes. <br /> <br />16 <br />