Effects of watershed subdivision level on semi-distributed hydrological simulations: case study of the SLURP model applied to the Xiangxi River watershed, China

AbstractThis study investigates the impacts of watershed subdivision on hydrological simulations. The SLURP (Semi-distributed Land Use-based Runoff Processes) model was employed in the Xiangxi River watershed, China, with eight watershed subdivision schemes. Under each scheme, the SLURP model was calibrated using both manual and automatic methods to simulate watershed hydrological processes over the period 1991–1998. The results indicate that model performance could be enhanced by increasing the degree of subdivision. However, there is a threshold level, beyond which no significant improvements can be obtained. The simulated water balance components and runoff contributions from different land types were found to vary among subdivision levels. Differences were slight when the watershed was divided into more than 73 sub-watersheds. These results were partly caused by the altitude-based precipitation correction, where the reduced generalization of terrain characteristics could lead to increasing considerati...