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

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.