基于水流阻力与图论的河网连通性评价

河网连通是区域防洪、供水和生态安全的重要基础。基于图论将河网概化为图模型,考虑不同类型河道输水能力差异,以河道水流阻力倒数表征水流通畅度,并以河道水流通畅度为权值,借助ArcGIS平台建立河网图模型加权邻接矩阵,再利用MATLAB工具进行顶点水流通畅度计算和河网连通度分析,从而实现对河网连通性的定量化分析。以太湖流域嘉兴平原河网为例,进行河道疏浚前后的河网连通程度定量评价,结果表明河道疏浚后河网连通度明显增加。

Evaluation of river network connectivity based on hydraulic resistance and graph theory

River network connectivity is an important parameter for consideration in the context of regional flood control, water supply and ecological security. Based on graph theory, the natural river network might be represented by a graph model. Taking into account the variability in delivery capacity of different channel types, the hydraulic conductivity (or the reciprocal of the hydraulic resistance) is used to describe the degree of patency within a river channel. Using the ArcGIS platform with the degree of patency as a weighted factor, the graph model can then be represented by a weighted adjacency matrix. Using MATLAB, the degree of patency within a river channel can be estimated, and the connectivity in river channel networks can also be calculated. The quantitative analysis of river network connectivity can thus be achieved. The proposed approach has been tested on a river network of the Jiaxing Plain in the Taihu Lake Basin. The result shows that the river network connectivity is improved significantly after dredging. The study provides a useful tool for evaluating the river network connectivity.