Development and testing of a rainfall-runoff model for flood simulation in dry mountain catchments: A case study for the Dez River Basin

摘要

Studying the rainfall-runoff response of the catchments has several important reasons in hydrology. The main reason is limitation of hydrologic parameters that can be measured in hydrological system. Therefore, the model that can estimate the transformation of rainfall to runoff with available range of measurements, particularly to limited gauged catchments can provide a means of prediction that will be useful in decision-making. Now days, various models have been developed around the world to model individual hydrological processes. In this study, the Watershed Modelling System (WMS) software was applied for rainfall-runoff modelling on Dez catchment located in Khuzestan province, IRAN since it faces serious flooding caused by heavy rainfall. The use of WMS software which interconnects the terrain models and the Geographic Information System (GIS) with commercial standard hydrological model including HEC-1 results in higher accuracy and saving time through modelling process. In this study, two historical storms (7 days in March 1993 and November-December 2001) used by applying two different modelling methods to determine the hyetographs which are one part of hydrologic process performing runoff response. Data collected from 29 November to 5 December 2001 were used for the calibration and the model verification were done for the period of 2-7 March 1993. Watershed parameters are calibrated manually to perform a successful simulation of discharge at three sub-basins in DEZ catchments. The outputs of hydrologic process using each method compared with observed data and the model performance were tested using statistical analyses. Considering the importance of parameters uncertainty and its effects on the response of the model, the sensitivity analysis was performed and the parameter which imposed the most impact on the model was identified. It was found that CN and STRTL parameters are the most important parameter in defining the peak flow, runoff volume and time to pe