From Hydraulic Heads to Dollars and Decision: It's Time to Integrate Groundwater in Coastal Risk Assessment

Sea level rise presents a range of hazards, including rising groundwater tables, salinization, and subsurface flooding, which threaten subsurface infrastructure in coastal communities. Groundwater shoaling inundates basements, tunnels, and utility networks, and mobilizes contaminants, while salinization accelerates corrosion and deteriorates water quality. Hydrogeologic studies increasingly assess these hazards, but few consider exposure and vulnerability to evaluate the overall risk, which is critical for adaptation planning. This commentary offers a perspective on the need to develop subsurface risk assessment tools for coastal zones by building on existing groundwater hydrology knowledge and adapting current risk analysis frameworks for coastal communities. We highlight essential data sets, infrastructure needs, and interdisciplinary collaborations required to implement these frameworks. Finally, we outline a path forward that includes (a) well‐defined, local‐scale risk analyses of specific infrastructure categories, (b) scale up through the creation of accessible, web‐based coastal groundwater observatories and shared monitoring networks, and (c) advances toward the long‐term development of digital twins that integrate real‐time sensing, satellite data, and machine learning to anticipate subsurface hazards at regional scale. All require sustained interdisciplinary collaboration among academia, government institutions, and coastal communities.