基于GIS/RS的衡阳盆地农村水资源系统脆弱性动态演变研究

Evaluation of the vulnerability of rural water resources system in Hengyang Basin based on GIS and RS

  • 摘要: 为研究衡阳盆地农村水资源系统脆弱性动态演变问题, 采用GIS/RS方法, 以衡阳盆地为研究对象, 构建由多年平均降水量、干旱指数(7—9月)、坡度指数、土壤蓄水能力指数、植被覆盖指数、土地利用指数、水源可获得性指数和人类活动指数8个指标组成的评价指标体系, 对1990—2010年衡阳盆地农村水资源系统脆弱性进行定量评价, 构建模型对其脆弱性指数的时空演变特征进行分析。结果表明: 1)衡阳盆地农村水资源系统脆弱性近20年内整体呈现“中高周低, 北强南弱”空间分布之势。2)研究期内, 脆弱性整体有所增强, 空间分异明显, 脆弱性增强区域呈条带状南北展布, 脆弱性减弱区域则呈团聚状分布在东西两翼。从各时段的变化来看, 脆弱性变化大体呈“首尾增长、中间下降”的规律。3)从全时段脆弱性指数变化来看, 衡山、衡阳和衡东3县农村水资源脆弱性增强明显, 耒阳和祁东2县(市)则以脆弱性减弱为主, 常宁和衡南2县(市)各种变化类型相对均衡。4)脆弱性指数变化的空间分异特征大致可以分为4种类型: 波动变化型, 先减弱、后强势增长型, 先增强、后强势减弱型和先强势减弱、后恢复性增长型。5)从不同时间变化趋势来看, 脆弱性以波动变化为主要类型, 其次是未变化类型, 单调增加、单调减少两种变化类型非常少。可见, 近20年来, 衡阳盆地水资源脆弱性强度整体有所增强, 脆弱性指数具有明显的时空分异特征。加强水资源系统的科学管理成为有关部门的紧迫任务。

     

    Abstract: In order to study the dynamic evolution of the vulnerability of rural water resources system in Hengyang Basin, an evaluation index system with 8 indicators was built. The indicators included average precipitation, drought index (July September), slope index, soil water storage index, vegetation index, land use index, water availability index and human activity index. The index-driven evaluation system was used to determine the vulnerability of rural water resources system in Hengyang Basin from 1990 to 2010. A mathematical model was constructed in GIS to analyze the spatial-temporal evolution and changing trends in rural water resources system vulnerability in Hengyang Basin in the last two decades. The model analyzed data were mainly from Remote Sensing (RS) satellites and processed on computer platform. After careful research and detailed analysis, the study concluded as follows: 1) In the last two decades, the vulnerability of rural water resources system in Hengyang Basin was low for the border regions, high for central regions, strong for the north and weak for the south of the basin. 2) In the last two decades, the vulnerability of rural water resources system in Hengyang Basin increased with an obvious spatial difference. The regions of enhanced vulnerability of water resources system were distributed mainly along the south and north while weakened regions of vulnerability of water resources system distributed mainly along the east and west. From the perspective of change in time, the vulnerability of rural water resources system in Hengyang Basin increased at the start and end of the study period, and weakened midway of the study period. 3) From the point of view of full time change, the vulnerability of rural water resources system in Hengyang Basin increased significantly in Hengshan, Hengyang and Hengdong Counties, weakened significantly in Leiyang and Qidong Counties, and had equilibrium distribution for different changes in the vulnerability of rural water resources system in Hengnan and Changning Counties. 4) The spatial differentiation characteristics of the change in vulnerability index was roughly classified into four types — fluctuating change, growing significantly after weakening, decreasing significantly after increasing and recovery growth after significant decrease. 5) From the trend of change in vulnerability in different years, the fluctuating change was the main type, followed by equilibrium state, and then the two types of increase (slow increase and slow decrease) were rare. In the last two decades, the overall intensity of the vulnerability of rural water resources in Hengyang Basin increased. Rural water resources vulnerability index had an obvious spatial and temporal variability. It was urgent to strengthen scientific management of water resources system in Hengyang Basin.

     

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