Application of modular approach in GIS-based hydrological modeling

In this study, the input data for model simulation are collected through internet and field investigation: DEM data, landuse map, soil class map and weather data. The spatial database for runoff simulation and physical attribute database are also created. A distributed hydrological model-SWAT (Soil and Water Assessment Tool), developed by USDA ARS (Agricultural Research service), has been applied to simulate the runoff process in the Lianshui Basin, China. To make the SWAT become applicable in the study area, the experimental modification of SWAT model is also performed by replacing surface runoff module with Xin´anjiang model. This research indicates that SWAT and modified model are reasonable in simulating the monthly average runoff. The simulated values with modified model are more accurate and closer to measured data than the result from the original SWAT.