【作者】 于栋；

【导师】 李发文；

【作者基本信息】 天津大学 ， 水利工程， 2018， 硕士

【摘要】 永定河流域地处京畿重地,是全国的政治文化中心,水资源保障形势受到国家的高度重视。水网肩负着实现区域发展的重任,同时作为区域的基础设施,其对人类生活和社会的发展具有重要意义。水网的结构深刻地影响着水资源循环和水资源的调节。本文在分析永定河流域水网格局的基础上,分别对水网水资源可达性、滨水区可达性、水系连通性及重要节点进行了评价研究。主要研究内容及成果如下:(1)选用分维数、河网密度、河道坡度、弯曲度对永定河流域水网结构特征进行分析,发现永定河流域西南部和东北部水系发育程度较高,西北部和东南部水系发育程度较差,并验证了降雨量与水系发育程度间的关系。永定河流域的河道坡度介于0~0.55之间,河流弯曲度介于1~3.75之间。采用Strahler分级法和Shreve累积分级法对永定河流域的水系进行分级,并基于Strahler分级结果,对永定河流域的分叉比、河长比进行分析,发现永定河流域发展程度较低。(2)同一流域的水资源可达性存在一定的空间差异,传统的水资源评价方法不能反映可达性的空间差异性。本文基于格元变量Length、Runoff和Viewshed,以标准化的变量累积分布值表征其对应的水资源可达性,应用Copula函数将各变量的累积概率分布连接起来构建联合分布,以联合概率分布表征各格元的水资源可达性,构建了栅格尺度的水资源可达性评价模型——LRV。应用LRV模型评价永定河流域的水资源可达性,选用T Copula函数作为各变量的联合分布函数,得到永定河流域的水资源可达性分布格局。(3)采用滨水区可达性计算模型即潜能模型计算永定河流域滨水区的可达性。应用人口密度、滨水区综合质量、阻力成本三个指标综合评价滨水区的可达性。针对山区河流的特点,对滨水区综合质量评价模型进行改进,加入河道坡度、水系形态这两个指标,更加全面地衡量滨水区的休闲资源特征。应用滨水区可达性评价模型评价永定河流域各县区滨水区的可达性,得到各县区居民到各滨水区的平均可达性由大到小排序为:尚义县、阳原县、怀仁县、怀来县、大同县、宣化县、天镇县、阳高县、北京城区、山阴县、应县、蔚县、兴和县、大同城区、崇礼县、丰镇市、怀安县、涿鹿县、朔州城区。各滨水区可达性呈现从水域向外围不断减小的特点。(4)选择结构连通性和纵向连通性表征永定河流域的连通性特征,运用区域景观廊道连通分析方法对永定河流域的结构连通性进行评价,得到其水系环度α为-0.25,节点连接率β为0.50,水系连通度γ为0.17,表明永定河流域水网的成环水平、连接水平、连通水平均较差;基于永定河流域拦河建筑物现状,运用阻隔系数法,对流域干支流的纵向连通性进行评价,得到永定河流域的纵向连通性指数为0.87,其评价等级为差等。由此可见,永定河流域整体的连通状况较差,其洪水防御功能、水量调配作用和水体自净能力较弱。基于CDI指数,发现鄂卜坪水库对水系连通性影响最为显著,卢沟桥枢纽对水系连通性的影响最为微小。(5)本文从局部属性、传播属性、全局属性和网络位置四个维度分别选取了度中心、介数中心、接近中心和改进K-核分解这四个指标,并结合层次分析法,得到永定河流域111个节点的重要度综合评价值:流域边缘各节点重要度较低,节点越靠近中心位置,连通能力越强,其重要度越高。重要度较高的节点大部分集中于流域东北部。更多还原

【Abstract】 The Yongdinghe River Basin is located in the capital vicinity.As the political and cultural center of the country,its situation of water resources security has been paid more attention by academia and the country.River network shoulders the important task of regional development,and as a regional infrastructure,it is of great significance to human life and social development.The structure of river network has a profound impact on the circulation of water resources and regulation function of river network.In this paper,based on the analysis of river network pattern of Yongdinghe River Basin,the water resources accessibility,waterfront accessibility,drainage connectivity and node importance are evaluated and studied.The main research contents and achievements are as follows:(1)Fractal dimension,river network density,channel gradient and curvature were selected to analyze the structure characteristics of river network in Yongdinghe River Basin.It was found that the southwest and northeast of Yongdinghe River Basin developed well,while the northwest and southeast of Yongdinghe River Basin developed poorly,and the relationship between rainfall and river development degree was verified.The river slope in Yongdinghe river basin was between 0~0.55 and river curvature was between 1~3.75.Strahler classification method and Shreve cumulative classification method were used to classify the river level of Yongdinghe River Basin.Based on the classification results of Strahler classification method,the bifurcation ratio and river length ratio of Yongdinghe River Basin were analyzed,and it was found that the development degree of Yongdinghe River Basin was low.(2)There are some spatial differences in the accessibility of water resources in a basin,which cannot be reflected by traditional water resources assessment methods.Based on the Length,Runoff and Viewshed value of each water consumption grid,this paper characterized the corresponding water accessibility with standardized accumulative probability distribution of the three variables.The Copula function was used to connect the accumulative probability distributions of the three variables to construct a joint distribution.Then,the joint probability distribution was used to characterize the water accessibility of all water consumption grids and a grid-scale water accessibility evaluation model-LRV was constructed.This paper chose Yongdinghe River Basin as a case to evaluate the water accessibility by the LRV model.The T Copula function was chosen as the joint distribution function to obtain the water accessibility distribution pattern of the Yongdinghe River Basin.(3)The riverfront accessibility of the Yongdinghe river was calculated by using the potential model.The accessibility of waterfront was evaluated comprehensively by three indexes: population density,accessibility quality of riverfront and resistance cost.According to the characteristics of mountain rivers,the quality evaluation model of riverfront was improved,and the river slope and river shape were added to measure the leisure resources of riverfront.Applying the model to evaluate the accessibility of riverfront in each county of Yongdinghe River Basin,the average accessibility of the riverfront in each county was ranked as follows: Shangyi County,Yangyuan County,Huairen County,Huailai County,Datong County,Xuanhua County,Tianzhen County,Yanggao County,Beijing City,Shanyin County,Ying County,Wei County,Xinghe County,Datong City,Chongli County,Fengzhen City,Huai’an County,Zhuolu County,Shuozhou City.The accessibility of each riverfront was decreasing from the riverfront to the periphery.(4)Structural connectivity and vertical connectivity were selected to characterize the connectivity characteristic of the Yongdinghe River Basin.The structural connectivity of the Yongdinghe River Basin was evaluated by the connectivity analysis method of landscape corridor.The results showed that the river network of Yongdinghe River Basin had a ring degree of-0.25,a node connectivity of-0.50 and a river connectivity of-0.17,indicating that the river network of Yongdinghe River Basin had a poor level of ring formation,connection and connectivity.Based on the current situation of the river barrage,the longitudinal connectivity of the river was evaluated by the barrier coefficient method.The longitudinal connectivity index of the Yongdinghe River Basin was 0.87,and the longitudinal connectivity was poor.Therefore,the overall connectivity of the Yongdinghe River Basin was poor,and its flood prevention function,water allocation function and water self-purification capacity were weak.(5)From the four dimensions of local attribute,propagation attribute,global attribute and network location,this paper selected the degree center,intermediate center,proximity center and improved K-nuclear decomposition,and combined with the analytic hierarchy process,the comprehensive evaluation value of the importance of 111 nodes in the Yongdinghe River Basin was obtained.The importance of the nodes at the edge of the basin was low.The closer the nodes were to the center,the stronger the connectivity was,and the higher the importance was.Most of the nodes with high importance were concentrated in the northeastern of the basin.更多还原