Hydrological Sizing of Reservoirs for Flood Protection

Abstract

A flood wave passing through a reservoir is both delayed and attenuated as it enters and spreads over the pool surface; the process depends on the regime and type of the reservoir. The overall objective in a typical flood protection program is the retention of the water volume of the flood waves, partially or fully in the reservoir — thus enhancing the safety of the downstream areas. From a hydrologic point of view, this means the conversion of the time-function of the upstream discharges into the time-function of the downstream flows. The conversion depends on the geometric and hydraulic features of the pool, as well as on the reservoir operation. Good knowledge of this modifying effect is important to determining the proper design parameters and the reservoir operation schedule.