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no, ""1"3 IJ J o. . . ['~ Vi' ,vel j;;J q /9' " I , e. Cf."'4.v.J t'r~~;,.j RESERvom EV AlOHA nON .~ Gross Evaporation = Net Evaporation + Precipitation ~Net Pan Evaporation = Hook Reading = Gross Pan Evaporation - Precipitation ~ Net Reservoir Evaporation = 0.7 x Pan Evaporation = 0.7 x Hook Reading Physical Hydrolo~: If all of the precipitation is kept in the reservoir and the evaporation pan is at the reservoir site, the following equation applies: Net Reservoir Evaporation = [0.7 x (Hook Reading)] x Reservoir Area Ifall of the precipitation is kept in the reservoir and the evaporation pan is WIt at the reservoir site, the following equation applies: Net Reservoir Evaporation = [0.7 x (Hook Reading + Precipitation at the evaporation pan site)- Precipitation at the Reservoir site] x Reservoir Area The reservoir water volume balance equation for the Physical Hydrology is: e. Change in storage = Inflow - Release - Net Reservoir Evaporation Computed Inflow = Change in Storage + Release + Net Reservoir Evaporation Example: Change in Storage = 100 aT Reservoir Release = 200 a.f. Hook Reading = 2 inches Precipitation = I inch Reservoir Surface Area = 500 acres Computed Inflow = 100 + 200 + [(0.7 x (2)) x 1/12 x 500] = 358.33 a.f. Accounti~ Hydrolo~: \ { N.. _ e'n._~ ,,\I ~ (#on-$.fc..r",-b{t.. ~,..".\, Effective Precipitation is defined as the precipitation that would have resulted in runoff had the reservoir not been constructed, and the remainder of the precipitation is consumed by plants, trees, and other types of vegetation. As a matter of example, utilize 30% of precipitation that results in runoff and 70% consumed by vegetation. e The State of Colorado allows the Reservoir owner to retain the portion of precipitation that would have gone to the plants (i.e. 70%) and the runoff portion (i.e. 30%) must be returned to the