基于GIS的尼洋河流域农业面源污染负荷分布特征

Using GIS to Analyze Spatial Distribution of Contaminants Emanating from Nonpoint Pollution Source in Niyang River Basin

【目的】揭示尼洋河流域农业面源污染的现状特征,探明其首要污染源和关键污染区。【方法】采用输出系数模型中农村生活污水、农田化肥流失、畜禽养殖流失污染模型3个模块,基于林芝市2014年的农业统计资料,从水文、地形和行政区划3个角度,对尼洋河流域农业面源污染强度进行了估算和空间分析,并分析了COD、总磷、总氮、氨氮的污染负荷空间分布特征。【结果】4类污染物输出负荷量最大的区域为中游左控制单元;4类污染物负荷强度最大为下游左、右控制单元;畜禽养殖流失污染源是尼洋河流域首要污染源。【结论】尼洋河流域中游左岸是今后流域防治的主要对象,畜禽养殖流失污染源是主要的控制对象。

【Objective】Environmental pollution caused by contaminants emanating from nonpoint sources in agricultural fields is an increased concern and the purpose of this paper is to take Niyang River Basin as an example,analysing its pollution sources and contaminants spreading.【Method】Based on the origin of the pollutants, we divided their sources into three components： a domestic waste comportment, a fertilizer leaching compartment,and a livestock waste comportment. Using geographical information system（GIS） and statistical analysis of the agricultural data available in 2015, we examined the spatiotemporal variation of COD, total phosphorus, total nitrogen and ammonium in the basin.【Result】Pollution caused by the four contaminants was the most serious in the left control unit at the midstream, as well as the right and left control units at the downstream in the basin.Leaking from livestock waste was the key pollutant source.【Conclusion】Remediation aimed at ameliorating the nonpoint pollution should focus on the left sides at the midstream of the basin by reducing the leaking of the livestock wastes