Coastal Resilience, Flood Risk Management, and Groundwater Sustainability under Global Climate Change: An Ecohydrological Approach

Abstract

Flooding, a prevalent consequence of climate change, poses significant threats to coastal zones, ecosystems, and groundwater resources. This paper investigates the efficacy of ecohydrological adaptation strategies in enhancing coastal resilience, flood response, and groundwater sustainability. By comparing existing ecohydrological restoration in the Mississippi River Delta, Ganges-Brahmaputra Delta, and the Netherlands, this study finds that ecohydrological strategies including wetland rehabilitation, Managed Aquifer Recharge (MAR), and mangrove preservation—outperform traditional engineered solutions in terms of sustainability, cost-effectiveness, and ecological value. Specifically, in the Mississippi River Delta, ecohydrological strategies reduced annual flood damage costs from $500 million to $300 million, a 40% decrease, and reduced flood frequency from 3 events per year to 1.5. In the Ganges-Brahmaputra Delta, these strategies decreased flood costs from $800 million to $450 million and reduced flood frequency from 4 events per year to 2. In the Netherlands, ecohydrological approaches lowered flood damage costs from $600 million to $350 million and cut flood frequency in half, from 2 events per year to 1. Additionally, ecohydrological measures effectively reduced groundwater salinity and increased recharge rates; in the Mississippi River Delta, groundwater salinity was reduced from 1500 ppm to 800 ppm, and recharge rates doubled from 50 mm/year to 120 mm/year. These results indicate that ecohydrological adaptation tools are viable and sustainable options for coastal adaptation, confirming the need for policy-driven coastal ecosystem-based adaptation and integrated governance.