Simulation And Control Of Agricultural Non-point Sources Pollution In Zhaosutai River Catchment Of Jilin Province

Recently, non-point source pollution is causing widespread concern across the worldand becoming one of the major issues who are hard to control because of thecharacteristics such as multiple sources, serious pollution, difficult real-time monitoringand management. Agricultural non-point source pollution is an important aspect ofnon-point source pollution. It has attracted national attention for its increasingly prominentcontribution to water pollution. There were so many related achievements on agriculturalnon-point source pollution, especially in the region of headstream.Zhaosutai River originates in Jilin Province and imports into Liaohe LiaoningProvince. Towns the river flows through are focused on farming and livestock breeding,which made important contributions to food production and economic development ofJilin Province. Its pollution control has far-reaching significance for water quality and thesustainable development of downstream.In recent years, water pollution issues hadbecome increasingly apparent, such as declining water quality, sedimentation andnon-point source pollution. The monitoring data of Lishu monitoring station showed thatZhaosutai river was one of the most polluted tributaries aross provincial borders who wasunable to meet the functional requirements. Agricultural non-point source pollution hadbecome one of the important sources of water pollution, especially when the point sourcepollution got controlled. In this paper, the results of hydrology, geography landscapeecology and the technology of3S and SWAT model were applied to study agriculturalnon-point source pollution of Zhaosutai river basin. In the paper, the spatial, temporaldistribution and the way into river channels of agricultural non-point source pollutionwere analysed. In the end, engineering and managemental measures were proposed toprotect the environment of watershed.According to the characteristics of the watershed, pollution and management offarming, livestock breeding and rural life were investigated. The main land use type wasfarmland, whose proportion was77.61%. Food crops include corn, rice,bean andpotato,etc. Average application of pesticides and fertilizer were369.50t and66180.86t.There were91gardons, mainly distributed in the two sides of the river. The total numberof breeding was2905500. Average of emissions from manure and urine was12.70t and111800t. Zhaosutai river basin has a total population of0.031million. The generation ofsewage, garbage and human waste was0.79,0.001and0.0053million t. In the support of3S technology, spatial database and attribute database of the studyarea were constructed. In order to analyzing SWAT model applicability, sensitivityanalysis, calibration and validation were executed. The results showed that SWAT modelcould be used for the simulation of non-point source pollution in Zhaosutai river basin.The simulation results showed that TN、TP and sediment load were1296.07t、137.68tand36427.36t. The maximum value was in July and August. Meanwhile the two monthswere the rainy season, rainfall and runoff were larger than other months. By correlationanalysis, it was found that rainfall, runoff and sediment, TN and TP had good correlation.The quantity and intensity of rainfall had a great impact on sediment and agriculturalnon-point source pollution load. Runoff played an important role in pollutants transportprocesses. Based on the results, the spatial distribution of pollution was analysed. Thelargest soil erosion was sub-watershed of8,19and26. The largest TN pollution load was7,12,19. TP was12,19. The spatial distribution of agricultural non-point source pollutionhad good correlation with the spatial distribution of rainfall and soil erosion. The spatialdistribution of Land use, soli type, liverstock breeding and rutal life also had a certaininfluence.Rate loss is one of important parameters to describe the ways pollutants into river. Inthis paper, based on the results of the model, the rate loss of each sub-watershed wascalculated, which was used to obtain the spatial distribution of rate loss in the study area.The results showed the gradual increasing regularit of the rate loss of sediment, TN and TPhad from southwest to northwest. The main factor was the elevation and soilcharacteristics of the region. Land use type and slope also affected rate loss. From all landuse types, arable land’s rate loss was the maximum, and the greater slope, the larger rateloss of pollutants. For these feature, different control scheme, including engineering andmanagement measures were proposed, which were applied to control agriculturalnon-point source pollution in the study area. SWAT was used to simulate part ofengineering measures, providing data support for pollution prevention.Through this study, the generation, distribution, route into river and influencingfactors of agricultural non-point source pollution were comprehensively grasped. It’shelpful for developing targeted control measures. The results of the paper providedtechnical support and theoretical guidance for the conservation of the water quality in thewater source region and ecological security and the formulation of controllingtechnologies and management measures for agricultural non-point source pollution.