Study On Non-point Source Pollution Load Calculation For Gongjing Parts Of Xushui River

With the improvement of the control over point source pollution, non-point source pollution has become a major source that affects the deterioration of environment quality of water bodies, and that also cause great harm to the environment of rivers and other water bodies. The non-point source pollution owns the characteristics of uncertainty, long-term existence, randomness and sluggishness, which makes the control of non-point source pollution even harder, and also results in the relatively lag of corresponding research and management, therefore, non-point source pollution load has high research value.This paper intends to carry out the research of load calculation of non-point source pollution of the Gongjing section in Xushui River. It is aimed at exploring the river load ratio of non-point source pollution of the Gongjing section in Xushui River and then providing the basic data to the environment capacity calculation of non-point source pollution and non-point source pollution control in Gongjing section. The results are as follows:(1) The basic database of non-point source pollution study in the watershed has been established. Adopting the Arc GIS provided by the American companies. ESRI, establishing the digital elevation model (DEM) in the river basin, obtaining the land use map of Gongjing District in Zigong City provide the basic database for the non-point source pollution study.(2) This research divides the study area into output units and typical basins. Divide the sewage unit with the GIS tools. The study field was divided into18sewage units.(3) In the load estimate process of non-point source pollution, the emissions export coefficient and Rainfall difference method were adopted to determine the non-point source pollution load. And CODcr. TN (total nitrogen) and TP (total phosphorus) are determined as the estimation index of pollution load. The results are as follows:The export coefficient of different land use types is not alike, and the pollution indicators have a big difference.The arrived rate in wet period of the two typical basins CODcr. TN. TP were:0.7.0.8,0.7(0.8). in the water period were:0.6.0.6.0.6(0.7), in dry season ignore the non-point source pollution. The Application of the method to estimate watershed non-point source pollution load, provide a calculation method to solve the water shortage in estimating the measured data.