流域水生态健康评价——以北京市密云水库上游为例

Evaluation of water ecological health of watersheds:A case study of the upper Miyun Reservoir in Beijing

选取北京市重要的饮用水源密云水库上游西府营、安洲坝、对家河、西口外、六道河及菜食河等6条小流域,构建了涵盖生境结构、水体理化和水生生物等3大类10项指标的评价指标体系,运用基于熵值法的综合健康指数法对流域水体生态系统健康状况进行综合评价。结果表明:西府营、安洲坝、对家河流域的健康状态处于非常健康等级,西口外、六道河、菜食河流域的健康状态处于健康等级。6条小流域的健康状况差异显著,西府营、安洲坝、对家河、西口外的健康状况明显优于六道河和菜食河。贡献度评价分析中,景观破碎度和硝酸盐氮贡献度相对较高,平均值为18.61%、16.4%;植被覆盖度、总磷和总氮贡献度相对较低,平均值分别为5.05%、6.56%、4.43%。研究表明在流域内控制建设用地比例、提高河岸植被质量以及维护河道自然状态对提高河流健康的重要性,可为生态河流建设提供参考。

Six sub-watersheds from Xifuying,Anzhouba,Duijia River,Xikouwai,Liudao River,and Caishi River are served as crucial drinking water sources in Beijing.A comprehensive evaluation index system was established,comprising 10 indicators categorized into habitat structure,water body physicochemical properties,and aquatic organisms.Utilizing this comprehensive health index method based on entropy value,the water ecosystems health status within these watersheds was thoroughly assessed.The assessment revealed that the Xifuying,Anzhouba,and Duijia River watersheds exhibited very healthy conditions,while the Xikouwai,Liudao River,and Caishi River watersheds were classified as healthy.Significantly differing health statuses were observed among the six sub-watersheds,with Xifuying,Anzhouba,Duijia River,and Xikouwai performing notably better than Liudao River and Caishi River.In the contribution evaluation analysis,landscape fragmentation and nitrate nitrogen emerged as major contributors,with mean values of 18.61%and 16.4%,respectively.Conversely,the contributions of vegetation cover,total phosphorus,and total nitrogen were relatively lower,averaging 5.05%,6.56%,and 4.43%,respectively.This analysis underscored the significance of controlling the proportion of construction land in the watershed,enhancing riparian vegetation quality,and preserving the natural state of river channels to promote river health.