海岸侵蚀作用下海岸带地区极端风暴洪水风险评估 —以上海石化为例

海堤是海岸带地区社会经济活动的重要保护屏障。海岸侵蚀的加剧将导致海堤稳定性和安全性降低， 增加海岸带地 区遭受极端风暴洪水的风险， 进而影响到海岸带地区的安全。本文选择上海石化这一遭受海岸侵蚀较为严重的区域作为研究 区， 利用 GIS 分析了 1972—2020 年近岸海床侵蚀特征， 并基于 2000—2020 年-5 m 等深线变化评估了上海石化近岸海堤的 稳定性。结果表明： 1972—2020 年间上海石化前沿海床整体以侵蚀为主， 石化近岸东侧以及西侧局部的浅滩侵蚀明显， 城 市沙滩中段、第 6 次围堤处以及码头东岸海堤稳定性最低。基于上述研究结果， 考虑海堤稳定性薄弱段出现极端风暴洪水漫 堤或溃堤情景， 模拟并分析了上海石化 2010 年 、2030 年和2050 年遭受千年一遇极端风暴洪水的风险。结果显示： 在 2010 年基准年情景下， 受海岸侵蚀作用最明显的城市沙滩和第6 次围堤区域遭遇极端风暴洪水的风险最高， 到 2050 年， 当前稳 定性较好的海堤安全性也将大大降低， 与 2010 年相比， 上海石化近岸地区的直接经济损失将会增加近 3 倍。

Risk assessment of extreme storm flooding in coastal zones under coastal erosion : A case study in shanghai Petrochemical

Seawalls are the important protective barriers for social and economic activities in coastal areas. Coastal erosion can reduce the stability and safety of seawalls and increase the risk of extreme storm flooding. posing a severe threat to coastal areas. In this study. Shanghai petrochemical was selected as study area. which is suffering from serious coastal erosion. The erosion characteristics of the coastal seabed from 1972 to 2020 were analyzed using GIS. and the stability of Shanghai petrochemical seawall was evaluated based on the changes of -5 m contour from 2000 to 2020. The results show that the Shanghai petrochemical coastal bed was mainly eroded and the shoals on the east and west sides of the petrochemical coast were eroded severely. The middle section of the urban beach. the sixth dike and the seawall on the east shore of the dock have the lowest stability. Considering the scenarios of extreme storm flooding or bank breach in the weak section of the seawall. the risk of Shanghai petrochemical being exposed to the millennium extreme storm flooding in 2010. 2030 and 2050 was simulated and analyzed. The results indicate that under the 2010 base year scenario. the urban beaches and the 6th dike area that are most affected by coastal erosion have the highest extreme storm flood risk. By 2050. the current security status will also be greatly reduced. and the direct economic loss of shanghai petrochemical coastal areas will quadruple the 2010 level.