Impact of compound flood event on coastal critical infrastructures considering current and future climate

• Published in: Natural hazards and earth system sciences Vol. 21; no. 2; pp. 587 - 605
• Main Authors: Khanam, Mariam, Sofia, Giulia, Koukoula, Marika, Lazin, Rehenuma, Nikolopoulos, Efthymios I., Shen, Xinyi, Anagnostou, Emmanouil N.
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 11.02.2021; Copernicus Publications
• Subjects: 100 year floods; Analysis; Anthropogenic factors; Atmospheric forcing; Boundary conditions; Case studies; Climate; Climate change; Climatic conditions; Coastal flooding; Coastal zone; Coasts; Critical infrastructure; Data assimilation; Data collection; Emergency management; Emergency preparedness; Environmental risk; Evaluation; Extreme weather; Flood damage; Flood hazards; Flood management; Flood mapping; Flood risk; Flood waves; Flooding; Floods; Future climates; Hazards; Heavy precipitation; High tide; Human influences; Hurricane tracking; Hurricane tracks; Hurricanes; Hydrodynamic models; Hydrodynamics; Hydrologic analysis; Hydrologic models; Hydrology; Infrastructure; Infrastructure (Economics); Mathematical models; Medical research; Medicine, Experimental; Meteorological research; Mitigation; Precipitation; Risk analysis; Risk assessment; Risk factors; Rivers; Sea level; Sea level forecasting; Sea level rise; Simulation; Storm damage; Storm surges; Storms; Stress concentration; Tides; Two dimensional analysis; Two dimensional models; Watersheds; Weather; Weather analysis; Weather forecasting; United States > US; Connecticut
• DOI: 10.5194/nhess-21-587-2021
• ISSN: 1684-9981; 1561-8633

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.