Development of Study on Model-SWAT and Its Application
ZHANG Yinhui ( Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China; Graduate School of the Chinese Academy of Sciences,CAS, Beijing 100101, China)
SWAT (Soil and Water Assessment Tool) is a conceptual, continuous time model that was developed in the early 1990s to assist water resource managers in assessing the impact of management and climate on water supplies and non-point source pollution in watersheds and large river basins. SWAT is the continuation of over 30 years of model development within the US Department of Agriculture's Agricultural Research Service and was developed to 'scale up' past field-scale models to large river basins. Model components include weather, hydrology, erosion/sedimentation, plant growth, nutrients, pesticides, agricultural management, stream routing and pond/reservoir routing. The model SWAT is meanwhile used in many countries all over the world. It is a flexible model that can be used under a wide range of different environmental conditions as this paper will show. It intends to describe the history and development of the SWAT model and summarize primary application into five categories: (1) hydrologic applications; (2) climate change impacts on hydrology; (3) non-point source pollution study; (4) HRU (Hydrologic Response Units) and other input effects on simulation result; (5) adaptations of SWAT. Increasingly, the model SWAT has been modified against its shortcoming to serve special study. The application of SWAT model in China is mainly focused on hydrologic application and non-point source pollution and little work has been done on adaptations. The model SWAT is mainly used as a tool in Chinese application and its shortcomings have been also pointed out, but few study has made adaptation work to overcome the shortcomings. Suggestions are made in this paper on adaptations of the SWAT model to help water and land resource planning and conservation and explore its applicability in China.