Study On Non-point Source Pollution In Small Watershed Of Three-Gorge Reservoir In Chongqing

Non-point source pollution is the second after the point source pollution was another concern of the water environment.And agricultural non-point source pollution is the top priority.Agricultural non-point source pollution occurred in random ways and pollution emission uncertainties and wide range of temporal and spatial differences in pollution,determine its degree of difficulty of monitoring,in order to carry out watershed management of non-point source pollution caused great difficulties.In this study,the Three Gorges reservoir area in Chongqing typical small watershed-Chenjiagou watershed as a study of their distribution of non-point source pollution,as well as non-point source pollutants in TN,TP quantitative analysis of its spatial distribution,in order to effectively control non-point source pollution provide a scientific basis.First of all,According to non-point source pollution and soil characteristics to the existing environmental monitoring indicators as the basis,in accordance with the scientific,dominant,the relative usefulness of the principles of independence and the establishment of a set of scientific and reasonable small watershed non-point source pollution monitoring indicators system.The use of selected typical small watershed study from the construction of the 65 indicators selected to monitor the 25 monitoring indicators,through the show:The constructed system of monitoring indicators to reflect the good soil and a typical small watershed between non-point source pollution the close relationship between non-point source pollution,as well as the formation and development of the situation and monitoring the work of a very good guide to monitoring carried out,with the production of practicality.In order to effectively control non-point source pollution may harm caused to provide theoretical and technical support.Secondly,the use of other indicators of pollution load in 2008 on the rural life of the study area of sewage,pesticide loss,loss of chemical fertilizers,soil erosion,livestock breeding 5 to non-point source pollution source evaluation.Evaluation,we can see from the source:Chenjiagou valley COD, NH₃-N,TN,TP.The main contribution of each pollutant source and percentage;Chenjiagou analysis of the proportion of watershed pollutants followed by TP,TN,NH₃-N,CODand chemical fertilizers were the main source of loss and soil erosion,for the next phase of non-point source pollution control to provide a scientific basis.At the same time,the use of empirical model-the output of pollutants pooled coefficient study law.For different landuse on downstream water bodies the size of the contribution rate of pollutants,the decision management program.Finally,this paper Johnes coefficient model output,the output of the selected coefficient is based on the research literature has been combined with the actual local situation,to adjust the final output to determine the appropriate values.Calculated through the model,different landuse contribution to the pollution load capacity,so as to arrive as a result of irrational land use structure and form of the condition of non-point source pollution.