Department of Civil and Environmental Engineering, Princeton University, USA.
Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, China.
Sci Total Environ. 2018 Jan 1;610-611:1251-1261. doi: 10.1016/j.scitotenv.2017.07.229. Epub 2017 Aug 30.
Coastal flood protection measures have been widely implemented to improve flood resilience. However, protection levels vary among coastal megacities globally. This study compares the distinct flood protection standards for two coastal megacities, New York City and Shanghai, and investigates potential influences such as risk factors and past flood events. Extreme value analysis reveals that, compared to NYC, Shanghai faces a significantly higher flood hazard. Flood inundation analysis indicates that Shanghai has a higher exposure to extreme flooding. Meanwhile, Shanghai's urban development, population, and economy have increased much faster than NYC's over the last three decades. These risk factors provide part of the explanation for the implementation of a relatively high level of protection (e.g. reinforced concrete sea-wall designed for a 200-year flood return level) in Shanghai and low protection (e.g. vertical brick and stone walls and sand dunes) in NYC. However, individual extreme flood events (typhoons in 1962, 1974, and 1981) seem to have had a greater impact on flood protection decision-making in Shanghai, while NYC responded significantly less to past events (with the exception of Hurricane Sandy). Climate change, sea level rise, and ongoing coastal development are rapidly changing the hazard and risk calculus for both cities and both would benefit from a more systematic and dynamic approach to coastal protection.
沿海地区已广泛采取防洪措施以提高防洪能力。然而，全球沿海特大城市的防护水平存在差异。本研究比较了两个沿海特大城市纽约市和上海市的独特防洪标准，并调查了风险因素和过去洪灾等潜在影响。极值分析表明，与纽约市相比，上海市面临着更高的洪水灾害风险。洪水泛滥分析表明，上海更容易受到极端洪水的影响。同时，过去三十年来，上海的城市发展、人口和经济增长速度均明显快于纽约市。这些风险因素部分解释了为何上海实施了相对较高水平的保护（例如，设计用于 200 年一遇洪水位的钢筋混凝土海堤），而纽约市的保护水平较低（例如，垂直砖石墙和沙丘）。然而，个别极端洪水事件（1962 年、1974 年和 1981 年的台风）似乎对上海的防洪决策产生了更大的影响，而纽约市对过去的事件反应相对较小（除了桑迪飓风）。气候变化、海平面上升和正在进行的沿海开发正在迅速改变这两个城市的灾害和风险计算，两者都将受益于更系统和动态的沿海保护方法。
