以淮河流域为例,选取降水、土地利用、经济、人口等指标作为淮河流域暴雨洪涝灾害风险指标,利用信息熵改进的层次分析法确定淮河流域暴雨洪涝的风险评估指标权重,并应用于县域尺度淮河流域暴雨洪涝灾害风险评价.结果表明:(1)淮河流域暴雨洪涝灾害风险空间分布整体呈现南部高、北部低,东西高、中部次之的形态.(2)改进的层次分析法得到的高风险区比传统方法的面积减少,市县个数下降,而次高风险区、中风险区、次低以及低风险区面积比之传统方法均有增加.同时风险平均值升高,导致受灾程度可能加大.(3)改进方法得到的岳西县风险等级由高风险区降为次高风险区,低于金寨县风险等级.宿州市风险等级由次高风险区降为中风险区,较灵璧、泗县风险低,与实际情况更为相符,提高了淮河流域暴雨洪涝灾害风险评价精度.
Taking Huaihe river basin as example,the precipitation,land utilization,economy and population were selected as rainstorm and flood risk indexes and their importance was determined by modified Analytic Hierarchy Process (AHP) based on comentropy.The application of improved AHP in the county-scale rainstorm and flood risk shows that (1) The spatial distribution of rainstorm and flood risk in Huaihe river basin appears high in the south but low in the north; high in the east and west and followed by the middle.(2) The area of high risk regions and the number of cities and counties in this region evaluated by the modified AHP all decreases compared with traditional methods,but the area of the secondary high risk regions,medium risk regions,secondary low risk and low risk regions all increase.Meanwhile,the rising of the average risk possibility may lead to the increasing of disaster degree.(3) The risk grade deduced by the improved method in Yuexi county is lower than that in Jinzhai county.In Suzhou,the risk grade descends from secondary high risk to medium risk,which is lower than that in Lingbi and Sixian and is more consistent with actual situation.Therefore,it is concluded that the modified AHP improves the precision of rainstorm and flood risk assessment in Huaihe river basion.