Hydrological Simulation by SWAT Model with Fixed and Varied Parameterization Approaches Under Land Use Change

Land use and land cover (LULC) change within a watershed is recognized as an important factor affecting hydrological processes and water resources. Modeling the hydrological effects of land-use change is important not only for after-the-fact analyses, but also for understanding and predicting the potential hydrological consequences of existing land-use practices. The main aim of the study is to understand and quantify the hydrological processes in a rapid urbanization region. The SWAT model and the Qinhuai River basin, one of the most rapidly urbanizing regions in China were selected to perform the study. In the study, a varied parameterization strategy was developed by establishing regression equations with selected SWAT parameters as dependent variables and catchment impermeable area as independent variable. The performance of the newly developed varied parameterization approach was compared with the conventional fixed parameterization approach in simulating the hydrological processes under LULC changes. The results showed that the model simulation with varied parameterization approach has a large improvement over the conventional fixed parameterization approach in terms of both long-term water balance and flood events simulations. The proposed modeling approach could provide an essential reference for the study of assessing the impact of LULC changes on hydrology in other regions.