南水北调中线水源地小流域面源污染生态阻控

Ecological control of non-point source pollution based on small watershed in the water source of the Middle Route of South-to-North Water Diversion Project

丹江口水库作为南水北调中线工程的水源地,水质保护极其重要,以小流域为单元建设面源污染生态阻控系统是控制库区氮磷输入的重要途径。结合丹江口库区现状,提出"控山""净水""护林""保田""治村"五位一体的小流域面源生态阻控总体思路,将汇水流域、汇水沟道、塘洼节点等区域的措施耦合衔接,功能上互补,形成生态阻控系统。小流域面源生态阻控技术的实施包括本底调查和问题识别、措施布局设计、工程建设和运行监测等步骤。该技术方法在丹江口库周的钱家沟小流域开展了应用实践,阻控系统建设完毕后的监测结果显示,小流域TN平均下降33.9%,TP平均下降49.1%,总体阻控效果较好,可为南水北调中线水源地小流域的面源治理提供参考。

Danjiangkou Reservoir,as the water source of the middle route project,water quality protection is very critical.The basic way to control the non-point source pollution is to build the ecological control system of non-point source pollution in the watershed unit.Based on the current situation of Danjiangkou reservoir area,the general idea of five-in-one ecological control for the non-point source control in the watershed unit:‘controlling mountains’,’purifying water’,‘protecting forests’,’protecting farmland’,‘governing villages’was put forward.The measures at catchment basin,catchment channel and pond node are connected and functionally complementary to form non-point source pollution control system in small watershed.The implementation of ecological control scheme of non-point source pollution includes background investigation,problem identification of small watershed,measures layout and design,project construction and operation monitoring.The application practice of technological approaches were carried out at Qianjiagou small watershed in Danjiangkou Reservoir,after the construction of the non-point source resistance control system,the total nitrogen and total phosphorus in the small watershed decreased by 33.9%and 49.1%on average.The overall resistance control effect of small watershed was good,which can provide reference for pollution control of nonpoint source in Danjiangkou Reservoir area.