基于多指标综合的巢湖环湖区水系连通性评价

Evaluation of Water System Connectivity of the District around Chaohu Lake Based on Comprehensive Indexes

平原河网区河流水系密布,其水系连通性影响着流域河湖的蓄泄洪能力、水环境健康和水文过程。已有研究多基于水流阻力与图论、水文过程或基于水系格局的某些指标进行水系连通性评价,该文修正了基于水流阻力与图论的水系连通性计算方法,改进了基于水文过程的水文连通性计算公式,概括了表征河网连通程度的主要指标,得到水系格局连接度,在此基础上综合各指标构建指标体系,评价了巢湖环湖区5地区的水系连通性。结果表明,巢湖环湖区5地区中,肥西县的水系连通性最高,合肥市次之,肥东县最低。修正后的水系连通度能够更好地考虑到水流内部运输能力对水系连通性的影响,水文连通度反映了平原河网区水位对产流过程的影响,水系格局连接度则定量分析了河网的空间格局和地理连接,基于综合指标进行的水系连通性评价反映了巢湖环湖区5地区河网的实际状况,研究结果可以为平原河网区水系连通性研究提供参考。

Connectivity of river network influences the capacity of lake drainage storage, the health of water environment and watershed hydrological processes. Current studies evaluate water system connectivity by using some index based on water flow resistance and graph theory, hydrological process, or water system pattern. In this paper, the calculation method of water system connectivity based on water flow resistance and graph theory is modified, the calculation formula of hydrologic connectivity based on hydrological process is improved, and drainage pattern connected degree is obtained by summarizing the main indicator of river network connectivity. On this basis, index system is built to evaluate water system connectivity of the district around Chaohu Lake. The results show that among the 5 districts around Chaohu Lake, the river network connectivity of Feixi County is highest, followed by Hefei, and Feidong County is the lowest. The modified water system connected degree can better take into account the influence of the internal transport capacity of the water flow on the river system connectivity. Hydrologic connected degree reflects the characteristics of water level on runoff process of river network in plain areas. Water system pattern connected degree can quantitatively analyze the spatial pattern and geographical network connection of river network. The water system connectivity evaluation based on comprehensive indexes reflects the actual situation of river network of the 5 districts around Chaohu Lake. The research results can provide a reference for the water system connectivity research in plain river network region.