高度城镇化背景下珠三角地区城市洪涝风险变化特征

Variation characteristics of urban flood risk in the Pearl River Delta under dense urbanization

为分析城镇化进程中珠三角地区城市洪涝风险变化特征,选用极端降雨量、暴雨频次、地面高程、坡度、人口密度、GDP、土地利用类型共7个指标构建指标体系,对珠三角地区城镇化前后城市洪涝灾害风险变化进行研究分析。结果表明:城镇化进程中珠三角高度城镇化地区极端降雨量和暴雨频次增加导致其危险性等级升高,珠三角地区原本高易损性地区基本没有发生变化,但有向外扩张的趋势,高度城镇化背景下珠三角地区洪涝风险等级结构发生了改变,低风险区占比显著降低,高风险区占比明显增加,其主要原因是高度城镇化地区的高风险区面积增多。

In order to analyze the change characteristics of urban flood risk in the Pearl River Delta region during the process of urbanization,an index system was constructed with seven indicators including extreme rainfall,rainstorm frequency,ground elevation,ground slope,population density,GDP and land use type.The changes of urban flood risk before and after urbanization in the Pearl River Delta region were studied and analyzed.The results show that in the process of urbanization the increase of extreme rainfall and storm frequency in the highly urbanized area of the Pearl River Delta region lead to the increase of its risk level,and the original high vulnerability areas have not changed basically,but has a tendency to outward expansion,under the background of highly urbanization the flood risk grade structure in the Pearl River Delta region has changed,and the proportion of low risk areas has significantly decreased,while that of high risk areas has significantly increased.The main reason is that the area of high risk areas in highly urbanized areas has increased.