Hurricane Sandy is a vivid reminder that coastal communities are vulnerable to the risk of damage from storms and flooding. Sea level rise increases the frequency and severity of coastal flooding in human and natural systems, even if storm patterns remain the same. FEMA has provided information about risk based on current conditions, including the new Advisory Base Flood Elevation maps (ABFEs) for the Sandy-affected areas. Addressing flood risk based on current conditions has immediate, short-term benefits to communities, but does not adequately account for increasing flood risk resulting from sea level rise.
Post-Sandy recovery provides an opportunity to reduce vulnerability and increase resilience further into the future by incorporating sea level rise information into decisions about how and where to rebuild or start new development. Using the best available science and data, federal agencies have therefore worked together to develop tools to help government officials, planners, and the public understand these future risks and use information about future sea level rise in planning decisions.
The map products display what the future 100-year floodplain boundaries could look like with sea level rise, but they do not indicate site-specific projected 100-year flood elevations.
The map products display what the future 100-year floodplain boundaries could look like with sea level rise, but they do not indicate site-specific projected 100-year flood elevations.
The NOAA Coastal Services Center, in partnership with FEMA and the U.S. Army Corps of Engineers, has created a set of map services to provide guidance to communities, residents, and other stakeholders for considering risks from future sea level rise in planning for reconstruction following Hurricane Sandy.
The map services provided here integrate FEMA's new ABFE maps with information on future sea level rise from two different peer-reviewed sources:
- A NOAA-led interagency report prepared as input to the National Climate Assessment, Global Sea Level Rise Scenarios for the United States National Climate Assessment. Scientists from multiple federal agencies and academic institutions synthesized the best available science to create a set of scenarios of global mean sea level rise through 2100. This team considered both ocean warming and melting of mountain glaciers and ice sheets. For all areas in NJ and NY outside the five boroughs, the maps use these global scenarios combined with the FEMA ABFEs.
- The 2010 New York City Panel on Climate Change report published by the New York Academy of Sciences in Climate Change Adaptation in New York City: Building a Risk Management Response. Experts convened by Mayor Michael Bloomberg’s Office of Long Term Planning and Sustainability developed regional sea level rise scenarios for the five boroughs in New York City. These scenarios include sea level rise from both ocean warming and ice sheet melt, and factor in local conditions such as vertical land movement and regional climate variations. For all areas inside the five boroughs of NYC, the maps use these scenarios combined with the FEMA ABFEs.
These maps show the horizontal expansion of the floodplain associated with a future increase in sea level in 2050 and 2100, highlighting areas that will be at risk in the future to flood inundation from the 1% annual chance flood event.
To help users obtain projected 100-year flood elevations for specific sites, USACE has adapted their existing “sea level rise” calculator in order to find ABFE+SLR elevations for any or all of the above SLR scenarios at 5-year intervals, up to 2100.
The U.S. Army Corps of Engineers, in partnership with FEMA and NOAA, has modified its existing Sea-Level Change Calculator to integrate FEMA’s new ABFE elevation data with the same two peer-reviewed sources of information on future sea level rise used in the NOAA maps and described above.
The Corps calculator tool complements the NOAA maps by providing site-specific detail on flood elevations during the 1% annual chance flood events for 5-year intervals from 2010 to 2100. Such information can be used by floodplain managers, professional engineers, and surveyors, in conjunction with other local information, for developing additional safety margins above the ABFEs.
Included with the calculator tool are simplified tables of future flood elevations above the ABFEs in NY and NJ under the different sea level rise scenarios.
Please contact your local floodplain manager for assistance in interpreting this information. Professional engineers and surveyors can assist in translating this information for recovery planning. Click on the buttons below to read more about the following questions:
