伊通河流域农业非点源污染对水环境的影响模拟研究

Simulative Study of Influences of Agricultural Non-point Source Pollution on Water Resources in Yitong River Watershed

针对伊通河流域的农业非点源污染问题,在GIS技术和流域基础数据库的支持下,采用SWAT模型建立了该区农业非点源污染模型。对研究区农药化肥中的氮、磷元素,泥沙的时空分布状况及总氮进入地下水的状况进行了模拟研究。模拟结果表明该模型精度满足要求。通过模型模拟计算,泥沙的输出量1985及2008年分别为7.04×106和3.46×106 t。1985年总氮和总磷的输出量分别为20 400和2 300t;2008年的输出量分别为1985年的1/2。6,7,8这3个月污染物质输出所占比例较大,约占全年的90%。同时模拟结果还显示,通过渗透进入地下水的氮量不能被忽视,1985年和2008年通过下渗进入到地下水中的氮量约为当年其他形式输出量的2.4和5.5倍。

According to the agricultural non-point pollution problems in Yitong River,a model of agricultural non-point pollution in this area was constructed using SWAT model with the support of GIS technology and watershed foundation database.The model was used to simulate the temporal and spatial distributions of N,P and sediment,as well as the total nitrogen delivered into groundwater in the study area.Results from the calibration and verification for the model showed that the precision of the model can meet the requirements.Through the calculation of model simulation,sediment yields in 1985and 2008were 7.031 6and 3.458 7million ton,respectively.In 1985,total nitrogen and phosphorus outputs were 20 400and 2 300ton,respectively,and in 2008,was about half of that in 1985.For one year,pollution output from June to August took up 90% of the total amount.The simulation result showed that the amount of nitrogen delivered into ground water by infiltration was considerable in 1985and 2008,the amounts of nitrogen delivered into groundwater were 2.4and 5.5times of those in other forms of output.