基于GIS的伊通河流域农业非点源污染风险评估

针对伊通河流域农业活动带来的水体污染及水土流失等环境问题,在分析农业非点源污染影响因子的基础上,选择了土地利用类型、土壤孔隙度、年降水量及氮磷排放量等影响因子,建立了农业非点源污染风险评估指标体系,并应用GIS技术,通过工程图绘制和叠加分析,采用幂法计算各因子权值,确定了风险等级指数,最后划分了农业非点源污染风险分区。研究结果表明:在沿河地区和相对发达的城市周边地区,受水田耕作和畜牧饲养等因素影响,农业非点源污染风险较高;在较偏远地区与林区,农业非点源污染风险相对较低。

GIS-Based Risk Assessment of Agricultural Non-Point Source Pollution of Yitong River Basin

In view of existing environmental problems such as water pollution and soil erosion caused by agricultural activities in Yitong River basin,based on the analysis of influence factors of non-point source pollution,the paper chose the affecting factors of land use type,soil porosity,annual precipitation and discharge of nitrogen and phosphorus,and established a risk assessment system for agricultural non-point source pollution.It determined the risk rating indexes by using GIS technology and through engineering drawing and overlay analysis,then divided the risk zoning of agricultural non-point source pollution.The outcomes show that: a) due to the factors of paddy fields and animal husbandry,it has a higher risk of agricultural non-point source pollution along the river and the surrounding areas of relatively developed cities and;b) the risk is relatively lower in the more remote and forest regions.