襄阳市河湖水系空间格局演变评估分析

An Analysis of the Characteristics and the Evaluation Indexes of Evolution of Spatial Pattern of River-lake System in Xiangyang City

河湖水系是水资源的载体,其演变将对自然生态环境和区域经济社会发展带来影响,研究河湖水系演变特征可为流域水资源的科学管理及河湖水系的均衡管控提供依据。以襄阳市为研究区,采用GIS和RS方法,基于河湖水系空间格局内涵,构建了包含水系数量、水系结构和水系连通3个方面的河湖水系空间格局演变评价指标体系,分析了全市新中国成立以来河湖水系空间格局的变化特征。结果表明:自1950年以来,河湖水系无论在数量、结构还是连通方面都发生了一定变化,河网密度及河网发育系数呈增加的趋势,水面率及主干河流面积长度在1996年最大,节点连接率及水系连通度均呈减小的趋势;人类活动是近年来河湖水系空间格局变化的主导因素,且其变化与不同时期经济社会发展需求密不可分,人类活动程度加强,水系结构趋于简单,连通性趋于下降。

River and lake networks are the carrier of water resources, and its evolution will impact the ecological environment and the devel- opment of economy and society. Understanding the changing features of the spatial pattern of river and lake system better can provide refer- ences for the scientific management of the basin water resources and balance the control of river and lake water system. By using geographic information system （GIS） and remote sensing （RS） technologies, the evaluation index system of evolution of spatial pattern of fiver-lake sys- tem in Xiangyang City, including quantity features, structure features and connectivity features, was established based on the connotation of fiver-lake system, and the characteristics of the spatial pattern of river and lake network for the period 1950-2015 were analyzed. The results show that there is a huge number of crisscrossing rivers and the river system is well developed. The fiver network presents five vertical and five horizontal distributions. Since 1950, the river and lake systems in terms of quantity, structure or communication have undergone certain changes; fiver density and river development coefficient have increased, water surface ratio and main fiver area length ratio were the largest in 1996, while the indexes of river connectivity included 13 and Y index decreased. Human activity is the dominant factor that changes spatial pattern of river and lake water system in the recent years, and the change is inseparable from the needs of economic and social development in different periods.