where V is the water storage in the reservoir at the end of each day; Vstored is the volume of water stored in the reservoir at the beginning of a day; Vflow in andVflow out are the volumes of water entering and flowing out of the reservoir throughout a day, respectively; andVpcp , Vevap , andVseep are the volumes of precipitation falling into the reservoir, the water removed by evaporation and the water lost by seepage, respectively.