伊犁河流域暴雨洪水灾害风险精细化特征和区划研究

Study on fine characteristics and regionalization of rainstorm and flood disaster risk in Yili River Basin

摘要:

本文基于高分辨率的小时降水强度和频次、地形、植被指数(NDVI)以及社会经济数据,集成GIS与层次分析法(AHP)等方法,分析洪水灾害致灾因子危险性、孕灾环境敏感性和承灾体易损性的基础上,综合给出了伊犁河流域的暴雨洪水灾害风险精细化特征并进行风险区划。结果显示：1)伊犁河流域洪水灾害高风险区域(风险性指数≥3.96)所占面积比例最大,约为40.74%,中风险区域占比面积为27%,高风险和低风险区域占比面积分别为25.04%、5.76%,而极低风险区域面积比例最少,约1.617%。2)洪水灾害危险性、敏感性、易损性、风险性等级均呈现出由西北部向东南部递减的变化特征。降水强度和频次、NDVI及社会经济发展等是决定伊犁河流域洪水灾害风险程度的关键因素,在防灾减灾规划设计中需重点关注。洪水灾害风险程度为高和极高的区域主要集中在伊犁河流域北部山区的西段和东段、南部山区,即霍尔果斯市、霍城县、伊宁县、尼勒克县东部、新源县和昭苏县,与历史灾情分布相符合。

Abstract:

Based on the high-resolution hourly precipitation intensity and frequency, topography, vegetation index (NDVI) and socio-economic data, integrated GIS and analytic hierarchy Process (AHP) and other methods, this paper analyzes the risk of flood disaster causing factors, disaster-induced environmental sensitivity and the vulnerability of disaster bearing bodies. The detailed characteristics of rainstorm and flood disaster risk in Yili River basin are given and risk zoning is carried out. The results showed as follows: 1) In the Ili River Basin, the area of high risk area (risk index ≥3.96) accounted for the largest proportion, about 40.74%, the area of medium risk area accounted for 27%, the area of high risk area and low risk area accounted for 25.04% and 5.76%, respectively, while the area of very low risk area accounted for the least, about 1.617%. 2) The flood hazard, sensitivity, vulnerability and risk levels all showed a decreasing trend from northwest to southeast. Precipitation intensity and frequency, NDVI and social and economic development are the key factors that determine the degree of flood risk in the Ili River basin, which should be paid attention to in disaster prevention and reduction planning and design. The areas with high and extremely high flood risk are mainly concentrated in the western and eastern sections of the northern mountainous area of the Ili River basin and the southern mountainous area, that is, Horgos City, Huocheng County, Yining County, eastern Nilek County, Xinyuan County and Zhaosu County, which is consistent with the historical disaster distribution.