妫水河流域农业非点源污染负荷估算与分析

本文利用改进的输出系数模型对妫水河流域农业非点源污染负荷进行了估算,并且分别通过三分法,即分区、分类、分期的方法对结果进行了分析。结果表明:(1)2017年妫水河流域农业非点源污染物TN和TP的负荷量分别为1 402 214.9 kg/a,279 629.1 kg/a;(2)流域内各乡镇TN和TP的负荷量差异较大,旧县镇、永宁镇所贡献的TN、TP负荷量最多且单位负荷强度最大,属于重点治理区域;(3)流域内对TN的贡献最大的污染源为农业种植,对TP的贡献最大的污染源为农村生活污染,这两个污染源属于优先控制的污染源;(4)TN、TP负荷与降雨量呈现正相关关系,降雨冲刷是导致的污染物负荷增加的一个主要因素。农业非点源污染的三分研究结果为妫水河流域非点源污染治理与农业结构调整提供了科学依据。

Estimation and analysis of agricultural non-point source pollution load in Guishui River Watershed

The agricultural non-point source pollution load in Guishui River Watershed is estimated herein with the improved export coefficient model，and then the result is analyzed with the tripartition method，i. e. the method of zoning，classifying and staging. The result shows that ( 1) the loads of the agricultural non-point source pollutants TN and TP in Guishui River Watershedare 1 402 214. 9 kg /a and 279 629. 1 kg /a respectively in 2017; ( 2) the differences of the loads of TN and TP among all the townships within the watershedarelager; in which the loads of TN and TPcontributed by Jiuxian Town and Yongning Town are the most with the maximum unit load intensity，thus the regions belong to the key control areas; ( 3) the pollution source with the greatest contribution to TN in the watershed is the agricultural pollution，while the pollution source with the greatest contribution to TP is the rural domestic pollution; thus both the pollution sources belong to the pollution sources necessary to be preferentially controlled; ( 4) TN and TP loads are positively correlated with rainfall，whilethe rainfall erosion is one of the major factorsfor the increase of pollutant load. The result from the study made with the tripartition method provides a scientific basis for the control of the agricultural non-point source pollution and the adjustment of the agricultural structure within Guishui River Watershed.