基于复杂网络和网络流的河段重要度分析方法及应用

River Reach Importance Analysis Method and Its Application Using Complex Network with Network Flow

河网水系的连通状况与区域水资源配置、用水安全保障、旱涝灾害防御及水生态健康息息相关。将河网水系的交汇点和河段抽象为由节点和边组成的无向图,以河道断面面积作为边权值来表征相邻节点对的过水能力,采用最大流/最小割计算得到河网源汇节点之间最大过水能力和过水瓶颈河段,对过水瓶颈河段进行基于不同边权值增量的最大流模拟并计算得到最佳边权值增量,同时提出以清淤、疏浚为背景基于过水瓶颈河段出现频次的河段重要度分析方法,并与河网水系自然状态下的基于河段移除法的河段重要度分析进行对比。结果表明,支流因过水能力较小易成为河网排涝的过水瓶颈河段,宜优先增加其断面面积,从而加大河网过水能力,而主干河道对河网的连通性影响较大,应予以重点保护与保留。

Kiver water network connectivity is closely associated to regional water resource allocation and security of water supply,and it is also important to prevent drought and flood disaster and establish healthy water ecology.It is considered as an undirected graph with multiple interconnected elements which represent rivers by links and junctions by graph nodes.Simplified river cross-section area regarded as edge weight is utilized to estimate maximum flow capacity between any two nodes and river reaches with constrained capacity with algorithm of Max-Flow/Min-Cut.With edge weight of constrained reaches effected by given cross-section change,this study intends to simulate maximum flow variation to find rational river cross-section area added.The proposed approach has been used to evaluate importance of river reach under background of dredging.Another approach is used to assessment the importance of river reach for water network connectivity as a comparison.The result shows that it is easier to reach flow saturation for branch streams,should give a priority dredging to increasing maximum flow capacity of water network.Meanwhile,it should be protected and retained for the main streams because they are more important to water connectivity.