基于图论的河道-滩区系统连通性评价方法

Evaluation method for river floodplain system connectivity based on graph theory

河道-滩区系统的连通性是维持河流生态系统健康的重要因素。基于图论连通度理论,将河道-滩区系统中的水流通道、鬃岗地形、小型封闭水域和牛轭湖等微地貌单元概化为图模型,并利用ArcGIS平台和DEM模型实现其表述。在此基础上,建立图的邻接矩阵,进行连通性分析和水流通道连通度计算,实现了河道-滩区系统连通程度分析的定量化。以瓯江丽水河段的河道-滩区系统为例,进行了一定水位条件下的连通状况模拟和连通程度定量分析。案例分析结果表明:通过确定关键性水流通道和水流通道汇合点,可对河流生态修复工程设计方案进行优化;利用本文所提出的方法对河道-滩区系统的连通性进行定量评价是有效可行的。该方法可用于河流健康评估、河流生态修复工程优化、河湖水网连通程度的定量分析等。

Connectivity of river system is an important factor to maintain the health of river ecosystem.Based on the concept of connectivity in graph theory,micro-geomorphic units such as flow channel in river-floodplain system,topography of hogback,small closed water and oxbow lake are generalized with graph model and realized by ArcGIS platform and DEM model.On this basis,the adjacency matrix of the graph model has been built,and the analysis and calculation of connectivity were carried out to realize the quantitative analysis of connectivity property in river-floodplain system.Taking the river-floodplain system in Lishui Reach of the Oujiang River as a pilot research case,the connectivity at a certain water level was simulated and analyzed quantitatively.The result indicates that making certain key flow channel and confluent point of flow channels can optimize the scheme of river restoration project,the method proposed here is effective and feasible in evaluating the river-floodplain system connectivity.The evaluation method can be utilized in the fileds of river health assessment,river restoration projects optimization and river-lake water network connectivity analysis.