Runoff and sediment yield simulation in a large basin using GIS and a distributed hydrological model

A GIS-based distributed SWAT (Soil and Water Assessment Tool) model was used to simulate the runoff and sediment yield in the upper basin of the Luohe River, a tributary of the Yellow River. Firstly, the basic GIS database integrating DEM, soil, land-use map, climate, and land management data, is established. To simplify input data preparation and interpretation without compromising simulation accuracy, the paper delineates the basin into 63 sub-basins to perform the simulation. In the process of calibration, the automated digital filter technique is used to separate the surface runoff and base flow. The surface runoff, the base flow, the total runoff, and the sediment yield are then calibrated sequentially. The simulated results demonstrate that the GIS-based SWAT model could be successfully used to simulate long-term runoff and sediment yield in large river basins such as the Yellow River basin where soil erosion is a serious problem.