基于磷负荷削减的沙河水库流域生态修复措施配置研究

水体磷浓度增加易导致水体中藻类大量繁殖等生态问题,磷负荷削减一直都是水环境治理的重点工作。以磷负荷削减为重点,以北京城市副中心上游沙河水库流域为研究对象,采用SWAT模型对4类24种源头控制—过程拦截生态修复措施进行分析模拟,评价生态修复措施对磷负荷的削减情况。结果表明：（1）对总磷的削减效率依次为退出畜禽养殖>分散污水处理>生态护岸>植草沟、植被缓冲带>城镇径流控制>节药节肥、林下结构提升,退出畜禽养殖、分散污水处理等源头控制措施效益十分显著。（2）针对农业面源污染,建议采取5 m宽生态沟渠,果园：过滤带面积比为10：1的植被过滤带,不使用除草剂,果园减少50%有机肥施用量,100%养殖废弃物资源化利用并减少30%污水量5项措施,削减农业生产过程产生的磷负荷;城镇建议采取提高20%透水铺装率和提升40%分散污染处理率2项措施;河道推荐采用高覆盖度生态护岸和布设5 m宽河道缓冲带。（3）空间上削减农业—城镇—河道磷负荷,要素上针对山水林田湖草生态要素进行系统治理,措施实施后总磷负荷削减率可达53%,总磷达到IV类标准的流域面积增加8.6%,效果尤为显著。研究成果为山水林田湖草系统治理措施布局提供了参考。

Study on Ecological Management Measures of Reducing Phosphorus Load in Shahe Reservoir Basin

The increase of phosphorus concentration in water is easy to made ecological problems such as the algae multiply greatly. Phosphorus load reduction has always been the key work of water environment treatment. Focusing on phosphorus load reduction and takes the Shahe reservoir basin upstream of Beijing Urban sub center as the research object, the SWAT model is used to analyze the effect of 24 items source control process interception ecological restoration measures of 4 categories on phosphorus load reduction. The results showed that: (1) The reduction efficiency of total phosphorus is in the order of withdrawing from livestock and poultry breeding> decentralized sewage treatment> ecological bank protection> grass ditch, vegetation buffer zone> urban runoff control> saving medicines and fertilizers, and improving the understory structure. The benefits of source control measures such as withdrawal from livestock and poultry breeding and decentralized sewage treatment are very significant. (2) It is recommended to adopt 5m wide ecological ditches, orchard: a vegetation filter belt with a filter belt area ratio of 10:1, no herbicides, a 50% reduction in the amount of organic fertilizer, a 100% resource utilization of aquaculture waste, and a 30% reduction in the amount of sewage measures to reduce the agricultural production process phosphorus load generated. Reduce the phosphorus load generated by urban non-point source pollution by increasing the pervious paving rate by 20% and increasing the dispersive pollution treatment rate by 40%. The river is recommended to adopt high-coverage ecological bank protection and 5m wide river buffer zone. (3) Reduce the phosphorus load of agriculture-towns-rivers in space, and systematically manage the major ecological elements of mountains-rivers-forests-farmlands-lakes-grasslands. After the measures are implemented, the total phosphorus load reduction rate can reach 53%, and the area of watersheds with total phosphorus reaching the IV standard will increase 8.6%, the effect is particularly remarkable.