平原河网水系测度与演化机制研究- - 以杭嘉湖区为例

Due to unique structure characteristic of river system and dramatically affected by human activities in plain river network regions, the research of measure, change mechanism and its hydrological effects have become one of the focus and difficult in current hydrology, geography, and other fields. As the study area in Hangzhou-Jiaxing-Huzhou plain river network region, firstly, this project establishes study methodology. Through mathematical analysis and empirical analysis too many of the existing methods, the optimize methods of river system structure will be establishment. Based on hydraulic resistance and graph theory, Connectivity evaluation for river channel network will be establishment. Based on the level difference of adjacent stations, hydrologic connectivity evaluation method of river system will be established. Secondly, this project wills analysis the temporal and spatial changes of river system / water level. From the river system / water level data of 1960s to the present of the study area, river system structure, river network connectivity, multi-scale water level characteristics, index of hydrological alternation, hydrologic connectivity of river system, and regulation and storage capacity of river system will be analyzed. Thirdly, combine the land use and socio-economic data study area, the change mechanism of river system will be analysis of the study area, and then the hydrological effects of the changes of river system will be analyzes. Based on these, the relational model of river system and hydrological changes of different types of river system of Hangzhou-Jiaxing-Huzhou plain regions will be explored. The findings of the project will provide data support to the sustainable development of the regions from the management, repair, planning, and flood control of river system in the changes environment. The project also provides a useful reference for the research of river system of other plain river network region.

由于水系结构独特性及受人类活动影响强烈性，平原河网区水系测度、变化及其水文效应研究成为当前水文学、地理学等领域研究热点和难点之一。本项目以杭嘉湖平原区为实证区域，首先建立水系研究方法体系：通过计量分析和实证分析对已有的众多水系结构研究方法进行梳理并建立水系结构优化指标体系，基于水流阻力和图论建立平原水系网络连通性评价方法，基于相邻站点水位差建立水系水文连通性评价方法；其次分析水系/水位时空变化，由20世纪60年代至今的水系/水位数据对研究区水系水系结构、水系网络连通性、多尺度水位特征、水文变异指标、水系水文连通性、水系调蓄能力进行分析；第三结合研究区土地利用和社会经济数据，分析研究区水系变化机制，进而分析研究区水系变化的水文效应；并探讨杭嘉湖平原区不同水系类型区水系与水文变化的关系模型。本项目研究结果可为水系管理、修复、规划和变化环境下的防洪排涝等区域可持续发展提供借鉴。

区域河网水系的改变增加了洪涝等极端事件的强度和发生概率，城市化为代表的人类活动对河流水系的影响研究已经在地貌学界、水文学界得到越来越多的关注。平原河网区地处流域下游，地势平缓，河网密集，连续降水易形成排水不畅导致洪涝。近年来由于极端降水造成的洪涝事件频繁发生。同时，平原区也是人口密集，经济发达的地区。一旦遭受洪涝，极易造成巨大的损失。因此，平原河网区的水系结构/格局特征的定量化，水系结构的时空变化，是目前亟待需要开展的研究。.本项目以杭嘉湖平原区为例，通过计量分析和实证分析对已有的众多水系结构研究方法进行梳理，建立了水系结构/连通评价方法体系。基于水流阻力和图论建立了平原水系网络连通性评价方法，基于相邻站点水位差建立水系水文连通性评价方法；其次分析水系/水位 时空变化，由 20 世纪 60 年代至今的水系/水位数据对研究区水系水系结构、水系网络连通 性、多尺度水位特征、水文变异指标、水系水文连通性、水系调蓄能力进行分析；第三，结合研究区土地利用和社会经济数据，分析了研究区水系变化机制，进而分析研究区水系变化的水文效应；并探讨杭嘉湖平原区不同水系类型区水系与水文变化的关系模型。本项目研究结果可为水系管理、修复、规划和变化环境下的防洪排涝等区域可持续发展提供借鉴。