Estuarine Hurricane Wind Can Amplify Flood Hazard in Converging Coastal Systems
Integrated high-resolution atmospheric, fluvial, and coastal modeling demonstrated the role of the landfalling wind field in locally amplifying flood water levels. Integrated high-resolution atmospheric, fluvial, and coastal modeling demonstrated the role of the landfalling wind field in locally amplifying flood water levels.
Photo by U.S. Department of Agriculture via Flickr
Coastal areas face a significant challenge from hurricanes, which can cause severe flooding. Our research focuses on how hurricane landfalling winds in shallow and converging estuaries (e.g., the Delaware Bay) can make this flooding worse. We find that when a hurricane's wind direction aligns with the surge direction, it can push more water into these narrow, shallow areas and create higher flood levels. This can lead to much more severe flooding than expected in places like Delaware Bay. Understanding this dynamic helps us better predict and prepare for future floods, as climate change may increase hurricane activity in the mid-Atlantic. We also demonstrate that a physically consistent and integrated modeling framework is critical for accurately resolving the tide, wind, and surge dynamics, thereby improving the coastal hazard projections and flood risk mitigation for future climates.
Our research explores how hurricane landfalling winds can worsen flooding in tidal estuaries like Delaware Bay. This is crucial because more hurricanes are expected to hit the U.S. East Coast due to climate change, threatening millions of people. Our study is the first to focus on how local winds in estuaries, where storm surges from the open ocean and the fluvial river discharge interact, can amplify extreme flood water levels. We used integrated atmospheric, fluvial, and coastal models to simulate these conditions, offering new insights into flood hazards. This work aids in better predicting flooding in the future, enhancing our ability to assess risks and strengthen flood resilience and mitigation strategies.
Our research investigates how hurricane landfalling wind fields can intensify storm surges in shallow, converging coastal systems, specifically focusing on the Delaware Bay and River. Using an integrated modeling approach, we combine an earth system model (E3SM), a hydrology model (DHSVM), and a hydrodynamic model (FVCOM) to simulate hurricane-induced coastal flooding. Our findings reveal that the direction of estuarine winds significantly impacts flood levels. Inland-directed hurricane tracks, which make landfall before reaching the mid-Atlantic coast, result in higher surges within the estuary than shore-parallel tracks. This is primarily due to the alignment of estuarine winds with surge propagation, which amplifies flooding in the bay and river system.
Our study underscores the importance of considering local wind dynamics using physics-based atmospheric models (like E3SM) in flood hazard modeling, as these factors can lead to substantial increases in water levels, even when offshore surges are not extreme. This research highlights the need for higher-resolution and physics-based models to accurately predict future flood risks in estuarine environments. By improving our understanding of these dynamics, we can enhance flood risk assessment, aiding in better preparation and response strategies for coastal regions vulnerable to hurricanes.