Northeast Regional Ocean Council

Why is Coastal Hazards Resilience a NROC Priority?

Sea level rise is altering New England’s coastal shorelines through inundation and shoreline erosion. While erosion rates are reported as an annual rate of change, these annual rates actually map changes caused by aperiodic storms such as nor’easters and hurricanes. The region has been free of devastating hurricanes since the 1950’s. If a hurricane equivalent to the 1938 hurricane struck the New England coast in 2007, it would rank as the sixth costliest hurricane in U.S. history. New England hurricanes are often accompanied by significant rainfall and riverine flooding that has led to the construction of flood control dikes and levees. The level or protection afforded by these structures is expected to decrease and drainage problems behind dikes should increase as groundwater tables rise as a result of accelerated sea level rise. A number of scientists project that global climate change will increase the severity, if not the frequency, of hurricanes.

Recent polls demonstrate that coastal residents are unprepared for hurricanes and underestimate the risks they pose. Science-based forecasts for accelerated sea level rise over the next 100 years due to global warming are as high as 1.5 meters. Additional sea level rise is expected due to the melting of land-based glaciers in Greenland and Antarctica with suggestions that a 4-meter rise by 2100 is plausible unless significant steps are taken to reduce greenhouse gases. As sea level rise accelerates, shoreline erosion rates will accelerate. Several New England states have experienced significant abnormal inland flooding events (climate change forecasters predicted these types of changes for the region) that have lead to river flooding, loss of life and major damage to infrastructure. Backwater flooding from undersized culverts under roads causes some of this damage. In addition to roads, undersized culverts connecting embayments to the ocean through barrier beaches are locations where breaching may occur and induce inlet formation, inlet migration, and an ensuing loss of property and structures.

Data such as detailed terrestrial contour, shallow water bathymetry and mean high water positions to name a few, are universally needed throughout the region to support planning for storm surge, erosion and global warming-induced inundation (GWI). A companion to data is the need to develop user-friendly tools to access and analyze data and support management decisions and recommendations. Regional sediment management plans are lacking. Better models exist that would improve surge and storm forecasting (e.g., high resolution atmospheric) and the integration of atmospheric and ocean models/data will yield the most accurate forecasting.