Abstract: A river network diagram model is constructed for the main rivers and man-made canals to analyze the connectivity of the Luoyang River network under the background of urbanization. Connectivity is evaluated by the five element connection number and calculated using a coupling model of the set pair analysis and graph theory, revealing its value of 1.34 for the Luoyang river network. In the graph model, each of the six canals connecting the river channels are removed separately, and accordingly six connecting schemes are formulated with connectivity values of 1.06, 1.25, 1.23, 1.29, 1.19, and 1.27, respectively. The results show the influence of the six canals on the connectivity of the network can be ranked,from strong to weak: Yellow-to-Luo water diverting canal, connecting canal of Yi River and Luo River, Yellow-to-Chanhe water diverting canal, Zhenhe-to-Jianhe water diverting canal, Zhongzhou Canal, Luohe-to-Yihe water diverting canal. This coupling model realizes a comprehensive evaluation of functional connectivity and structural connectivity. And it can improve, through analysis of the connectivity factors using the set pair potential of five element subtraction, the connectivity of a water system in terms of water volume, reservoir operation capacity, river bank ecology, water quality, etc.

Key words: river network, connectivity, graph theory, set pair analysis, man-made canal