Study On Contaminant Load Distribution Characteristics At The Peripheral Areas Of Yuqiao Reservoir

Yuqiao reservoir, as one of the most important sources of drinking water forTianjin and the largest storage reservoir in Luanhe-Tianjin Water Diversion Project,undertakes the important task of supplying water. The water quality of YuqiaoReservoir is an important factor that affects social stability and economicdevelopment in Tianjin. With the change of water environment conditions such as theincreasing nutrient load of upland water and so on, the source water quality ofreservoir inflow has become bad evidently and the eutrophication of water body hasbecome more severe in recent years. Therefore, study on the pollution sources anddistribution characteristics of Yuqiao reservoir contributes to the improvement ofwater environment, providing the basis for pollution control planning andmanagement for the reservoir.SWAT (Soil and Water Assessment Tool) model, developed by the U.S.department of agriculture (USDA), is a distributed model of non-point sourcepollution. It is mainly applied to simulate the impact on the agricultural non-pointsource pollutants when taking land management measures. The application experienceat home and abroad has shown that this model has the extensive applicability.In this paper, the SWAT model was used to simulate and calculate the runoff,point source pollution load, and non-point source pollution load at the study area ofYuqiao reservoir, and then the measured data was applied to calibrate and validate theparameters of this model. After verification of the applicability, the model was used toanalyze the pollution loads and their distribution characteristics at the peripheral areasof Yuqiao Reservoir.The results reveal that the annual average inflow of total nitrogen and totalphosphorous are2014.6t and152.8t respectively, the major source of total nitrogen isfrom the diversion input of the upper stream, and the main source of totalphosphorous is from the pollution of the feces of the residents and animals at theperipheral areas. Besides, the output of total nitrogen concentrates on the west andsouth side of the reservoir, while the output of total phosphorous mainly concentrates on the southern and northern part at the middle of the reservoir in the space domain;in the time domain, the non-point source pollution is well correlated with the runoffand sediment yield, while the point source pollution demonstrates an obviousseasonality. The results can be used as reference for the integrated control of thepollution of Yuqiao Reservoir.