Evaluation of Clark instantaneous unit hydrograph in estimation of flood in Kasilian Watershed

The proper application of instantaneous unit hydrograph theory is very efficient for watershed with lack of rainfall data. Therefore، the present study has been conducted to evaluate the efficiency of Clark instantaneous unit hydrograph model with the help of geographical information system in regenerating flood unit hydrograph in Kasilian watershed in Mazandaran province. The comparative evaluation is conducted between the 3h-unit hydrographs simulated using Clark model and the one obtained from averaging the observed ones. This comparison is made with the help of statistical criteria viz. relative error، root mean square of error، coefficient of efficiency and bias. It verified high level of compatibility between two unit hydrographs using the Clark model and the hydrograph obtained by averaging the observed data.