长江经济带城市洪涝脆弱性评估——以南京、武汉和成都为例

在全球气候变暖和海平面上升的背景下,随着城市化水平的不断提高,城市系统面临洪涝灾害的风险形势也更加严峻。构建长江经济带城市洪涝脆弱性评估模型,采用熵权法确定权重,运用模糊集对分析法判断样本所属等级,对南京、武汉和成都的城市洪涝脆弱性进行评估。结果表明:2012—2016年,南京市平均洪涝脆弱度最低,受低人口密度、建成区高绿化率以及较高经济密度作用,洪涝脆弱性整体呈下降趋势;武汉市平均洪涝脆弱度最高,由于人口密度过高、建成区绿化率过低导致洪涝脆弱性呈现恶化态势;成都市平均洪涝脆弱度位于中等,受人口密度下降、经济密度和排水管道密度上升的影响,洪涝脆弱性呈下降趋势;提出了大力发展当地经济、合理调整城市化速度、兴修排水基本设施等降低长江经济带城市洪涝脆弱性的建议。

Assessment of vulnerability to urban floods in Yangtze River Economic Belt: Taking Nanjing, Wuhan and Chengdu as examples

Under the background of global warming and rising of sea level, the risk of flood disasters in an urban system becomes severe with the continuous development of urbanization. An evaluation model for the vulnerability of urban foods in Yangtze River Economic Belt is established. Taking Nanjing, Wuhan and Chengdu as examples, the entropy weight method is used to determine the corresponding weight of each index, and the fuzzy set pair analysis method is used to judge the grade of the sample. The results show that in the five years from 2012 to 2016, the average vulnerability index of Nanjing is the lowest, and it totally has a decrease tendency due to the effects of low population density, high green areas and high economic density. The average vulnerability index of Wuhan is the highest, and its vulnerability is worsening due to high population density and low greening rates in built-up areas. The average vulnerability index of Chengdu is medium, and its vulnerability has a decrease tendency due to the impact of declining population density, increasing economic density and increasing density of drainage pipes. Some suggestions are put forward for reducing the vulnerability of urban floods in Yangtze River Economic Belt as follows: development of the local economy, rational adjustment of the speed of urbanization, and construction of drainage infrastructures.