The changing climate and anthropogenic activities raise the likelihood of damage due to compound flood hazards, triggered by the combined occurrence of extreme precipitation and storm surge during high tides and exacerbated by sea-level rise (SLR). Risk estimates associated with these extreme event scenarios are expected to be significantly higher than estimates derived from a standard evaluation of individual hazards. In this study, we present case studies of compound flood hazards affecting critical infrastructure (CI) in coastal Connecticut (USA). We based the analysis on actual and synthetic (considering future climate conditions for atmospheric forcing, sea-level rise, and forecasted hurricane tracks) hurricane events, represented by heavy precipitation and surge combined with tides and SLR conditions. We used the Hydrologic Engineering Center's River Analysis System (HEC-RAS), a two-dimensional hydrodynamic model, to simulate the combined coastal and riverine flooding of selected CI sites. We forced a distributed hydrological model (CREST-SVAS) with weather analysis data from the Weather Research and Forecasting (WRF) model for the synthetic events and from the National Land Data Assimilation System (NLDAS) for the actual events, to derive the upstream boundary condition (flood wave) of HEC-RAS. We extracted coastal tide and surge time series for each event from the National Oceanic and Atmospheric Administration (NOAA) to use as the downstream boundary condition of HEC-RAS. The significant outcome of this study represents the evaluation of changes in flood risk for the CI sites for the various compound scenarios (under current and future climate conditions). This approach offers an estimate of the potential impact of compound hazards relative to the 100-year flood maps produced by the Federal Emergency Management Agency (FEMA), which is vital to developing mitigation strategies. In a broader sense, this study provides a framework for assessing the risk factors of our modern infrastructure located in vulnerable coastal areas throughout the world.

中文翻译：

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考虑到当前和未来的气候，复合洪水事件对沿海关键基础设施的影响

气候变化和人为活动增加了由复合洪水灾害造成的破坏的可能性，这是由于涨潮期间极端降水和风暴潮的共同发生而引发的，并因海平面上升而加剧。与这些极端事件场景相关的风险估计预计将大大高于对单个危害的标准评估得出的估计。在这项研究中，我们介绍了影响美国康涅狄格州沿海重要基础设施（CI）的复合洪水灾害的案例研究。我们基于实际和综合（考虑到大气强迫，海平面上升和预测的飓风径迹的未来气候条件）飓风事件的分析，这些事件以强降水和潮汐以及潮汐和SLR条件为代表。我们使用了水文工程中心的河流分析系统（HEC-RAS）（一种二维水动力模型）来模拟所选CI地点的沿海和江河综合洪水。我们将分布式水文模型（CREST-SVAS）与来自天气研究和预报（WRF）模型的天气事件数据一起用于合成事件，并从国家土地数据同化系统（NLDAS）进行实际事件，以得出上游边界HEC-RAS的状况（洪水）。我们从国家海洋和大气管理局（NOAA）中提取了每个事件的沿海潮汐和潮汐时间序列，以用作HEC-RAS的下游边界条件。这项研究的重要成果代表了对于各种复合情景（在当前和未来的气候条件下）CI站点洪水风险变化的评估。这种方法相对于联邦紧急事务管理局（FEMA）制作的100年洪水地图，提供了复合危害的潜在影响的估算，这对于制定缓解策略至关重要。从更广泛的意义上讲，本研究提供了一个框架，用于评估位于世界各地脆弱沿海地区的现代基础设施的风险因素。