小流域非点源污染模拟与生态修复影响评价

Non-point Source Pollution Simulation and Eco-remediation Impact Assessment in Small Watershed

[目的]基于各流域场次降雨径流过程和非点源污染负荷模拟分析,评价小流域生态建设对密云水库流域水文过程和污染防控效果影响,为水源地保护、流域山水林田湖一体化修复和生态环境建设提供科学依据。[方法]以北京市重要饮用水源地密云水库上游蛇鱼川小流域为研究对象,利用EcoHAT-LCM模型和传统大尺度非点源污染模型相结合的模式进行模拟分析,并设置情景,分析评价小流域生态建设效果。[结果]随着场次雨量的增加,吸附态N,P负荷占污染负荷总量的比重在逐渐增加,溶解态N,P负荷占污染负荷总量的比重在逐渐减少。小流域内居民点具有小城镇级别的垃圾处理率和垃圾入网率时,农村生活N,P污染负荷可以削减28%;减少经济林的现有施肥量,农业生产活动的N,P污染负荷能够削减43.9%和48.9%。[结论]研究区域不同频次暴雨对吸附态N,P负荷的影响大于对溶解态N,P负荷的影响。生态修复措施对N,P污染负荷削减作用显著。

[Objective]Based on the simulation analysis of rainfall-runoff process and non-point source pollution load in each basin,the impacts of ecological construction in small watershed on the hydrological process and pollution control effect of Miyun Reservoir watershed were eraluated in order to provide scientific basis for water source protection,integrated restoration of mountain,water,forest,field and lake in watershed and ecological environment construction.[Methods]Taking the Sheyuchuan small watershed upstream of Miyun Reservoir,an important drinking water source in Beijing,as the research object,the model of combining EcoHAT-LCM model with traditional large-scale non-point source pollution model were used to simulate and analyze the ecological construction effect of the small watershed.[Results]With the increase of rainfall,the proportion of adsorbed N and P load to the total pollution load increased gradually,while that of dissolved N and P load to the total pollution load decreased gradually.When the residential areas in small watersheds had small town-level garbage disposal rate and garbage access rate,the pollution load of N and P in rural life could be reduced by 28%,and the existing fertilizer application in economic forests could be reduced by 43.9%and 48.9%in agricultural production activities.[Conclusion]The influence of different frequency rainstorm on adsorbed N,P load is greater than that on dissolved N,P load in the study area.The ecological restoration measures had a significant effect on the reduction of pollution load of non-point source N and P.