OPERATIONAL MODELS FOR FLOOD CALCULATIONS

The development of fifteen years of research has led to a model - which shall be called the IHW model - for calculation of design floods for flood protection reservoirs, which is extensively used by practicing engineers in Germany. The model requires subdividing a catchment into small subcatchments which can be connected to form a basin model. The flood from each subbasin is calculated by means of a design rainfall pattern convoluted with a unit hydrograph. Runoff coefficients and unit hydrographs are calculated from a regionalization model which has been developed from a large number of measured hydrographs. Flood routing models are used to connect the subcatchments. Application examples are shown, and trends for future developments are indicated.