The Application Of SWAT Model In Agriculture Non-point Source Pollution

At present,the water environment pollution problem is a pervasive pollution problem throughout the world, Non-point source pollution is an important factor in water environment pollution. It is necessary to simulate the Non-point source pollution process and analyze the variartion at temporal and spatial scale, to provide an effective basis for formulate control and management measures of Non-point source pollution. This paper reviews the development of Non-point source pollution study and model, take Shitoukoumen reservoir catchment basin for study area, simulation and research the non-point source pollution problem. Shitoukoumen reservoir is the major water sources of Changchun City and its surrounding counties and cities. At present, the agricultural Non-point source pollution of study area has been very serious.So it has important practical significance and theoretical value to study the agricultural Non-point source pollution at this area.This paper select the Soil and Water Assessment Tool(SWAT) model developed by USDA-ARS,combined with Geographic Information Systems (GIS) and Digital Elevation Model (DEM),then simulation the agricultural Non-point source pollution of study area,the main contents include:1. Preliminary evaluation the Non-point source pollution status of the study area through surveys and analysis, found that the non-point source pollution problem of study area is very serious.In order to protect water quality, It is Great need to study the Non-point source pollution, identify and analyze the key Pollution areas, made protection measures and recommendations.2. Drawing DEM, land-use types and soil type maps of study area,to build the agricultural non-point source pollution spatial database. Search information of study area and model documentation, to build the agricultural non-point source pollution attributes database.3. Take year 2006-2007 for Simulation time, simulation the agricultural Non-point source pollution of study area by SWAT model. Based on DEM, study area was depicted as 23 sub-basins and 103 HRUs. Measured time series stream fiow data were used to ealibrate and verify the model, proved SWAT model applies to the study area.4. Calculation the sediment, nitrogen, phosphorus and other non-point source pollution load of basin.Take years and months as time units, analyze the load distribution at temporal and spatial scale, identify and analyze the key Pollution areas.5. Design typical hydrological years with different rainfall insurance rate (10%, 50%&90%) conditions, simulation and study the agricultural Non-point source pollution of these years.Found that the non-point source pollution is more serious under high precipitation condition.6. Made protection measures and recommendations, suggest improvements for lack of research.