After Sandy: Rethinking Flood Risk Management in Asian Coastal Megacities
After Sandy: Rethinking Flood Risk Management in Asian Coastal Megacities
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DOI：
10.1061/(asce)nh.1527-6996.0000117
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发表时间：
2014-05
影响因子：
2.7
通讯作者：
F. Chan;N. Wright;Xiaotao Cheng;J. Griffiths
中科院分区：
文献类型：
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作者：
F. Chan;N. Wright;Xiaotao Cheng;J. Griffiths
2012年10月30日，热带风暴桑迪抵达美国东海岸，并在纽约市（NYC）的金融中心下曼哈顿地区产生了5.1米的风暴潮，这是自1851年以来的最高纪录（图1）[美国国家海洋和大气管理局（NOAA）2012]。全市共有40多人死亡，美国东北部与风暴有关的死亡人数达到63人。加勒比地区有69人死亡，这意味着风暴造成的伤亡总数为132人[英国广播公司（BBC）2012; Fischetti 2012]。公共交通系统被淹没，两个主要机场的跑道（约翰F。肯尼迪和纽瓦克）被洪水淹没并关闭，纽约证券交易所关闭2天。预测公司Equcat估计，损失总额可能超过850亿美元（路透社，2012 b）。路透社估计，仅在市中心和长岛之间的地区，损失就至少为180亿美元（路透社2012 a）。在此背景下，美国飓风、风暴潮、沿海洪水和大风造成的年均损失估计仅为100亿美元。虽然2005年桑迪的强度没有卡特里娜那么强，但桑迪影响的区域更大;美国国家航空航天局（NASA 2012年）报告卡特里娜飓风期间约500公里的距离有强风（大于65公里每小时），而桑迪以类似的强度盛行了1，500公里。这可能是桑迪比卡特里娜飓风在更大的沿海地区产生海浪的主要原因，并影响了东海岸超过12个州[中国中央电视台（CCTV）2012]。先前的研究（韦伯斯特等人，2005年）表明，气旋的频率和强度（即，飓风和台风）在过去50年中有所增加，由于气候变化，预计这一趋势在本世纪将继续上升。政府间气候变化专门委员会（IPCC 2012）还报告说，北方的主要热带风暴路径可能已经向极移动，这意味着产生大风和极端降雨的强烈风暴的可能性略有增加。风暴桑迪的影响反映了地球仪沿海大城市的脆弱性。这种脆弱性的存在是因为人类住区，包括财产和基础设施，大多位于与纽约市类似的低洼易发洪水地区。例如，华尔街的主要金融中心距离港口仅一英里。特大城市的公认定义是人口超过800万的城市（联合国，2010年）。纽约市有820万居民，其中约200万人居住在长岛或较小的岛屿和洪水易发地区。市政府意识到，不可能将这么多人和相关资产搬迁到危险区域之外，因此开始调整洪水管理战略，为气候变化做准备（纽约市政府，2012年）。自2010年以来，已经实施了适应做法，如评估激增风险、洪水风险绘图、预测各种气候情景的风险以及加强紧急疏散计划（Klima等人，2011年）。该市的风暴预警系统在风暴桑迪抵达前约41小时启动，当时市政府宣布关闭金融市场，并建议居民储备食物和水。建议使用沙袋防洪
The tropical storm, and for a time hurricane, named Sandy arrived on the U.S. east coast on October 30, 2012, and delivered a 5.1-m storm surge, the highest since 1851, to the heart of the country’s financial hub in the Lower Manhattan area of New York City (NYC) (Fig. 1) [National Oceanic and Atmospheric Administration (NOAA) 2012]. As a result, there were more than 40 fatalities across the city, and the storm-related death toll across the northeast United States reached 63. Sixty-nine deaths in the Caribbean region meant that the total number of casualties caused by the storm was 132 [British Broadcasting Corporation (BBC) 2012; Fischetti 2012]. Public transport systems were submerged, the runways of two major airports (John F. Kennedy and Newark) were flooded and closed, and the New York Stock Exchange was shut down for 2 days. The forecasting firm Equcat estimated the likely total cost of damages to be more than $85 billion (Reuters 2012b). Reuters estimated damage of at least $18 billion in the area between downtown and Long Island alone (Reuters 2012a). To put this in context, the average annual losses from cyclones, storm surges, coastal floods, and winds in the United States are estimated to be in the region of just $10 billion per year. Although the magnitude of Sandy was less intense than Katrina in 2005, Sandy affected a larger area; the National Aeronautics and Space Administration (NASA 2012) reported strong winds (greater than 65 km=h) for a distance of approximately 500 km during Hurricane Katrina, whereas Sandy prevailed for over 1,500 km at a similar intensity. This is possibly the main reason why Sandy generated sea surges over a larger coastal area than did Katrina, and affected more than 12 states on the east coast [China Central Television (CCTV) 2012]. Previous research (Webster et al. 2005) has indicated that the frequency and intensity of cyclones (i.e., hurricanes and typhoons) has increased in the past 50 years, and that the trend is expected to rise continuously this century because of climate change. The Intergovernmental Panel on Climate Change (IPCC 2012) also reported that it is likely that there has been a poleward shift in the main Northern Hemisphere extratropical storm tracks, which means that the potential for intense storms that produce significant wind and extreme rainfall is slightly increased. The impact of Storm Sandy reflects the vulnerability of coastal megacities across the globe. This vulnerability exists because human settlement, including properties and infrastructure, is located mostly in low-lying flood-prone areas similar to those of New York City. The major financial hub of Wall Street, for example, is just a mile away from the harbor. An accepted definition of a megacity is a city with a population of 8 million or more (United Nations 2010). NYC has 8.2 million inhabitants, approximately 2 million of whom live on Long Island or smaller islands and in flood-prone areas. The city government realized that it would be impossible to relocate this number of people and associated assets outside of the hazard areas, and has therefore started to adapt flood-management strategies in preparation for climate change (NYC Government 2012). Adaptation practices such as assessment of surge risk, flood-risk mapping, prediction of risks from various climate scenarios, and enhanced emergency evacuation plans have been implemented since 2010 (Klima et al. 2011). The city’s storm warning system was activated some 41 h before Storm Sandy arrived, at which point city authorities announced the closure of the financial markets and advised residents to stock up on food and water. Recommendations to employ sandbags for flood