Simulation Of Agriculture Non-point Source Pollution In Dongliaohe Watershed Based On SWAT Model

With the increasing of human activity intensity, the water pollution problem has become an environment pollution problem throughout the global. When point source pollution has obtained the better control and governance, Non-point source pollution has become the main threat to the water environment pollution. Non-point source pollution is the main cause of the surfer water environment pollution but the agricultural non-point pollution is the biggest proportion. It is necessary to simulate the Non-point source pollution through the agricultural non-point pollution model and analyze the variartion at temporal and spatial scale. This will provide an effective way for control and management of agricultural non-point pollution.At present, the agricultural non-point source pollution of dongliaohe Watershed has been extremely serious. So it is practical and theoretical significance to study the agricultural non-point source pollution at this area. This paper simulates and researches the non-point source pollution problem, take Dongliaohe Watershed for study area and select the Soil and Water Assessment Tool-SWAT model developed by USDA-ARS, combined with Digital Elevation Model and Geographic Information Systems, including the main contents:1. The water environmental quality in the study area is evaluated through single factor pollution index and comprehensive pollution index. And analyze the causes of pollution through factor analysis.2. DEM, landuse map, soil map and weather data are collected for SWAT model applying, then they must be projected and transformed to meet the need of the model by GIS software, to build the agricultural non-point source pollution spatial database and attributes database. Study area was depicted as 27 sub-basins and 357 HRUs.3. Through sensitivity analysis of model parameters, identify main sensitive factors. Measure stream flow data of dongliaohe watershed were used to ealibrate and verify the model, proved SWAT model applies to the study area.4. Take 2008—2009 for Simulation time, simulate and calculate the sediment, nitrogen, phosphorus and other the agricultural Non-point source pollution of study area by SWAT model. Take years and months as time units, we analyze the agricultural non-point source pollution at temporal and spatial scale and identify the key pollution areas of the study area.5. Under the different rainfall insurance rate conditions, design typical hydrological years, simulate and study the agricultural Non-point source pollution of these years. Found that the higher precipitation, the more serious agricultural non-point source pollution.6. We generate the future climate scene of dongliaohe watershed through the statistical drop scale model (SDSM). Forecast the hydrological response of dongliaohe watershed under the futher climate scenarios, the results show that the different periods of runoff will be reduce in the future, shortage problem of water resources is becoming more and more severe.7. Made the agricultural non-point source pollution control and management measures.