基于拓扑结构和空间网络结构的水系连通性评价

保持河湖水系连通是流域内物质流、能量流、信息流和物种流保持畅通的基本条件,河网水系连通性定量评价十分重要。利用图论理论、连通性指数和空间网络中心性评价指标,以湖北省大悟县滠水-刘家集河-上西大河片区为例,分析其水网连通情况。结果表明:①图论指标从整体上度量了水系网络的连接特征,研究区水系网络复杂程度一般;②水系网络连接度指标分析度量了各河链连接特征的重要程度,长度长或处于主干道的河链对水系网络整体连接特征的重要程度高;③水系网络的中心性分析能揭示汇点或是河链不同方面的重要程度,孤立的小的水系组分的中心性值易高。邻近中心性分析有助于发现水系中较主要的主干水系;中介中心性分析有助于发现水系中处于主要连通的汇点或河链;直线中心性能发现水系网络中较为曲折的河链。研究结果完善了水系连通性评价,对水系连通工程设计和河流健康治理工作具有一定参考价值。

Connectivity evaluation on water system based on topological structure and spatial network structure

Maintaining river-lake water system connectivity is the basic condition for the fluxion of material flow, energy flow, information flow and species flow in the basin and the quantitative evaluation of water system connectivity is very important. Taking the Sheshui River-Liujiaji River-Shangxida River area in Dawu County, Hubei Province as an example, this paper uses the theory of graph theory, the connectivity index and multiple centrality assessment model to analyze water network connectivity. The results showed that: (1) The graph theory index measures the connection characteristics of the water network as a whole, and the complexity of the water network in the study area is general; (2) The important degree of connectivity of each river chain are measured by the water network connectivity index, and the river chain with long length or in the artery is of great importance to the overall connection characteristics of water network; (3) The spatial centrality analysis of the water network can reveal the importance of different aspects of confluences or river chains. The centrality values of the isolated small water components are large. Closeness centrality analysis helps to discover the main trunk water system. Betweenness centrality analysis helps to find the confluences or river chains that are mainly connected in the water system. Straightness centrality helps to find the more tortuous river chains in the water network. The research results improve the evaluation of water system connectivity and have a certain reference value for water system connectivity engineering design and river health management.