Building toward a dynamic national coastal flood map that includes sea level rise and storms

With 700 million people living in the coastal zone worldwide, episodic storms, chronic beach erosion, and cliff failures pose a significant hazard to coastal communities and associated infrastructure, hazards that will be amplified by continued sea level rise and population growth in the coming decades. Yet despite projections that across the United States over $1 trillion in property will be at risk of daily flooding by 2100, there exist only regional studies that consider the full exposure of the coastal zone due to flooding from both sea level rise and storms. Prior work in California suggests that when considering dynamic water levels and the morphological response of the coast over the 21^st century, the population at risk of flooding can triple over static approaches. Therefore, it is imperative that we develop a scientifically defensible, nationally-consistent approach to deliver user-friendly tools that communicate the full extent of coastal risk over the next century, supporting effective local and regional planning, management and policy. The USGS Coastal and Marine Hazards and Resources Program has been developing coastal hazards products for decades across a range of coastal settings, including low-lying dune-backed coasts, active tectonic margins, permafrost coasts, and coral reef-lined islands and atolls. However, coastal hazards models that comprehensively assess the exposure of the coastal zone to climate change have only been applied at the regional level (e.g., www.usgs.gov/cosmos), and such computationally expensive approaches are not practical for a national scale application. Here we will discuss the lessons learned from our regional flood-hazard modeling research along the Gulf Coast, East Coast, West Coast, Alaska and Pacific Islands, including the development of partner-driven products and scientific outreach. Further, we will discuss the path forward, including crucial data sets, modeling approaches, and partner needs, as we begin to develop the framework to deliver a national coastal flood map that accounts for dynamic water levels incorporating sea level rise, tides, storm surge and waves.