基于四维度模型的湖南省湘江流域洪涝灾害风险评估

当前极端气候事件频发，降水频次与强度剧增，致使区域洪涝风险提高。为了降低区域洪涝风险，从致灾因子危险性、孕灾环境敏感性、承灾体脆弱性和防灾减灾能力四维度分析洪涝灾害风险的形成机理，基于11项指标，综合运用ArcGIS地理信息软件与熵权法等数理统计方法客观赋权，对湖南省湘江流域的洪涝风险进行综合性评估，最终制作出区县尺度的洪涝风险分布图。结果表明：湘江流域中西部致灾因子危险性低，中游地区孕灾环境敏感性高；环长株潭地区与衡阳市的承灾体脆弱性较高，但前者凭借良好的经济基础，其防灾减灾能力相对较强；湘江流域洪涝风险分布从东北向西南呈增强趋势，高洪涝风险区位于长沙市、益阳市、衡阳市及永州市南部，不同地区洪涝风险的主导因子不同。研究结果较好地反映了多因子作用下地区洪涝风险的差异，可为区域防洪减灾提供支撑。

Assessment of flood disaster risk based on a four-dimensional model in Hunan section of the Xiangjiang River Basin

The frequent recurrence of climatic extreme events and the sharp increase in the frequency and intensity of precipitation have increased the risk of coastal flooding. To reduce regional flood risks, we analyzed the formation mechanism of flood risk in four dimensions: risk of contributing factors, sensitivity of breeding environment, vulnerability of hazard-bearing bodies and disaster prevention and mitigation capacity. Based on 11 indicies, the ArcGIS and entropy method were used to evaluate the flood risks in Hunan section of the Xiangjiang River Basin, then the final flood risk map was produced at the district and county scale. The results show that the risk of contributing factors is low in the central and western parts of the Xiangjiang River Basin, while the sensitivity of breeding environment in the central part is high; the vulnerability of hazard-bearing bodies is relatively high in the Changzhutan Rim and Hengyang City, but the former has a relatively high disaster prevention and mitigation capacity due to its good economic foundation; the distribution of flood risk in the Xiangjiang River Basin increases from northeast to southwest, with high flood risk areas in Changsha City, Yiyang City, Hengyang City and southern Yongzhou City. The different dominant factors in different regions reflect the differences in flood risks under the effect of multiple factors, the research results can provide a technical support for regional flood prevention and mitigation.