Sensitivity Analysis of a Physically Based Distributed Model

The objective of this study is to perform a sensitivity analysis of the SHETRAN model on the example of the torrential Lukovska River catchment in Serbia. The sensitivity analysis of the model was performed for the following parameters: the vertical saturated hydraulic conductivity of the subsurface soil, the horizontal saturated hydraulic conductivity in the saturated zone, the Strickler roughness coefficients for overland flow and for streams, the available water content in the soil and the erodibility coefficients due to rain and due to overland flow. It can be concluded that the water and sediment discharge are very sensitive to the values of the vertical saturated hydraulic conductivity of the subsurface soil in the range of 0.001 to 0.1 m/day; to the values of the horizontal saturated hydraulic conductivity in the saturated zone in the range of 0.01 to 5 m/day and to the values of the Strickler’s coefficients for overland flow and for rivers in the range of 0.1 to 100 m1/3s-1 and 15 to 40 m1/3s, respectively. The sediment concentrations in a flow and sediment discharge are very sensitive to the values of erodibility coefficient due to overland flow in the range of 0.5 to 1.5 mg/m2s and to the values of erodibility coefficient due to rain in the range between 0.1 and 40 J-1. The obtained results could be used to simplify the parameter calibration procedure and to facilitate estimation of parameters in ungauged mountainous basins of similar characteristics.