辽河源头区流域农业非点源污染风险评价与关键源区识别

Critical Source Area Identification and Risk Assessment of Agricultural Non-Point Source Pollution of the Source Areas of Liaohe River Watershed

在农业非点源污染研究中,确定农业非点源污染的关键源区是开展有针对性研究和控制农业非点源污染的首要问题之一。采用GIS和地统计学为技术手段,在综合分析辽河源头区流域农业非点源风险的源因子和迁移因子的基础上,筛选出影响辽河源头区流域非点源污染的主要因子,建立识别辽河源头区流域农业非点源污染风险程度的指标体系,确定权重并划分因子等级,生成指标体系中各因子的30 m×30 m栅格图,,采用多因子综合分析法计算非点源污染风险等级,对农业非点源污染风险进行定量化评价,确定流域内非点源污染发生风险高的区域为关键源区,并针对关键源区内最易产生污染物的地段和部位提出反映辽河源头区非点源污染特征的管理控制措施。结果表明:流域中农业非点源污染高风险区即关键源区占全流域面积的21.77%,主要集中在辽河源头区东北部、中部以及东南部丘陵区,大部分为流域中的农田和坡耕地区域,其人口密度、畜禽养殖量以及施肥量都偏高。

The primary issue of efficiently controlling and managing agricultural non-point source pollu-tion is how to identify critical source areas or the sensitive regions of pollutants in agricultural lands .In this pa-per,under GIS and geostatistics technical means ,based on comprehensive analysis of the source factors and the migration of agricultural non-point sources of risk factors ,the authors identify the impact of non-point source pollution factor ,establish the index system to identify agricultural non-point source pollution risk .The study chose 30 m×30 m grid unit to generate the identification system ,determine the factor weights ,used multifactor analysis to calculate the non-point source pollution risk index of each factor and carried out its quantitative e-valuation .Critical source areas were areas whose risk of non-point source pollution is high .Management control measures reflecting the characteristics of non-point source pollion in the Liaohe River headwaters area were proposed.The results show that：the high risk areas of agricultural non-point source pollution in the watershed or the critical source areas occupies 21.77%of the total drainage area .The critical source areas compose of farmland and sloping land area mainly concentrate in the northeasted ,middle and southern parts of Liaohe Riv-er head waters .The population density ,the amount of livestock and poultry as well as fertilizer levels in these aress are relatively high .