A Coastal Flood Stage to Define Existing and Future Sea-Level Hazards

This paper explores the possible definition of a generic coastal flood stage (FS), an elevation at which significant flooding of local infrastructure is initiated, for regional or nationwide use in flood hazard analysis. By using monthly National Oceanic and Atmospheric Administration tidal gauge data from several coastal locations, a coastal FS based on the statistics of extreme high water events is proposed. This statistical FS is then compared to moderate and major FSs established by the National Weather Service with good agreement. Once adopted, the FS serves as a less ambiguous reference elevation or threshold to which the flooding potential of future storm events and sea-level rise can be compared and allows for consistent comparison between different sites.