CALIBRATION CONSIDERING FLOOD FORECASTING APTITUDES FOR HYDROLOGICAL PARAMETERS OF A DISTRIBUTED RUNOFF MODEL

Abstract

The hydrological parameters of a flood forecasting model are normally calibrated based on an entire hydrograph of past flood events with an error assessment function such as mean square error and relative error. However the specific parts of a hydrograph, peak discharge and the rising part, are particularly important for flood forecasting in the sense that underestimation may lead to a more dangerous situation due to delay in flood prevention and evacuation activities. The purpose of this study is to develop an error assessment method for calibration appropriate for flood forecasting. The PWRI distributed hydrological model is applied to fifteen past floods in the Gokase River basin with 10,001 patterns of parameter sets determined by the Latin Hypercube Sampling. The cases with non-underestimation in the peak discharge and the rising part of hydrograph are analyzed as the appropriate cases for flood forecasting. Furthermore, the applicability of the appropriate parameter set for flood forecasting is validated by applying it to another flood event.