小清河流域非点源污染负荷与降水关系研究

流域非点源污染造成了严重的水环境问题,为准确核算典型流域非点源污染负荷及为流域水环境治理提供支持和依据,以山东省小清河流域为研究区,采用SWAT模型及相关分析方法,研究了流域总氮(TN)、总磷(TP)营养物输出负荷时空变化规律以及营养物输出负荷与降水间的关系。结果表明:SWAT模型对小清河流域非点源污染模拟具有较好的适用性。汛期(7—9月)营养物输出负荷最高,占全年比重的50%以上,而TN是其中主要非点源污染物。TN、TP输出负荷空间分布相似,负荷较高的区域都主要集中在流域南部;该区域TN、TP输出负荷分别在69.72～235.30 kg/hm~2和0.93～4.73 kg/hm~2范围内。不同的土地利用氮输出负荷较高的依次为林地、耕地和草地,磷输出负荷较高的依次为林地、草地和耕地。流域氮输出强度与降水相关性强的区域主要集中在流域中上游,而磷输出强度与降水相关性强的区域则主要集中在流域中游。

Study on relationship betweennon-point source pollution and precipitation in Xiaoqinghe River Watershed

Watershed non-point source pollution causes serious water environmental problems. In order to accurately calculate the non-point source pollution load of typical watershed to provide support and basis for water environment management of it，the spatio-temporal variation law of the nutrient output load from the total nitrogen ( TN) and the total phosphorus ( TP) as well as the relationship between the nutrient output load and precipitation are studied herein with the SWAT model and the related analysis methods by taking Xiaoqinghe River Watershed as the study area. The study result shows that the SWAT model has a better applicability for simulating the non-point source pollution within Xiaoqinghe River Watershed. During flood season ( July-September) ， the nutrient output load is the highest with the proportion of 50% of the whole year，in which TN is the main non-point source pollutant. The spatial ditributions of both TN and TP output loads are similar，the areas with higher loads are mainly concentrated in the southern part of the watershed，in which TN and TP output loads are within the ranges of 69. 72 ～ 235. 30 kg / hm2 and 0. 93 ～ 4. 73 kg / hm2 respectively. The higher nitrogen output loads of different land uses are forest land，cultivated land and grassland in turn，while the higher phosphorus output loads of different land uses are forest land，grassland and cultivated land in turn. The areas with strong correlation between the nitrogen output intensity and precipitation are mainly concentrated in the mid-upper reach of the watershed，while the areas with strong correlation between the phosphorus output intensity and precipitation are mainly concentrated in the mid-reach of the watershed.