基于图论边连通度的平原水网区水系连通性定量评价

Connectivity Evaluation Technology for Plain River Network Regions based on Edge Connectivity from Graph Theory

河湖水系保持连通是流域内河流与湖泊、河道与河漫滩之间物质流、能量流、信息流和物种流保持畅通的基本条件,也是优化水资源配置战略格局、提高水利保障能力、促进水生态文明建设的有效举措。利用GIS平台和图论理论,研究河湖水系的系统性连通程度定量评价技术,以胶东地区为例,分析了胶东调水东线工程和引黄济青工程实施后山东半岛东部地区水网连通情况。结果表明,胶东调水东线工程实施后连通度可提高50%。此方法可为平原水网区水生态保护与修复、河湖水系连通规划及闸坝调度方案优化等提供技术支持。

The connectedness of river-lake systems promotes the flow of material,energy and information and supports species diversity in river-lake and river-floodplain systems. Identifiying and evaluating the connectedness is important for optimizing water allocation,improving water conservation and promoting awareness of the water environment. Quantitative evaluation of river-lake connectivity using GIS and graph theory was the subject of this study.Modeling an aquatic system involves several steps. A digital map of the system is extracted and key elements,including water channels,lakes and reservoirs,sluices and dams and the operating modes of sluices and dams are gaphically modeled. An adjacency matrix for the graphical model is then constructed and the connectivity of the river-lake water system is calculated using the matrix analysis tool of MATLAB. A case study of the river-lake system in the Jiaodong area was carried out using the quantitative evaluation system and connectivity of the river-lake system under three conditions was analyzed：（ 1） the original connectivity,（ 2） connectivity after implementation of the water diversion project from the Yellow River into Qingdao and（ 3） connectivity after the implementation of Jiaodong water diversion project. The calculated connectivities under the three conditions were 2,2 and 3 respectively,and the results indicate that connectivity increased by 50% after the implementation of the Jiaodong water diversion project. The water diversion project from the Yellow River into Qingdao and the Jiaodong water diversion project directly influenced the connectivity of the water network in the eastern Shandong Peninsula. Newly established pump stations connected previously separated rivers and lakes,forming new water channels and increasing connectivity of the entire river-lake system. This evaluation method provides technical support for protecting water resources and restoring river networks in plain regions,planning river-lake connectivity and optimizing sluice and dam operations.