CZM developed the Sea Level Rise and Coastal Flooding Viewer to support the assessment of coastal flooding vulnerability and risk for community facilities and infrastructure, consistent with Governor Baker’s Executive Order 569. This viewer includes interactive maps of flooding extents and water level elevations associated with sea level rise scenarios, current coastal flood zones, and hurricane surge modeled by the National Oceanic and Atmospheric Administration (NOAA), Federal Emergency Management Agency (FEMA), and U.S. Army Corps of Engineers (USACE).
How to Use the Viewer
The following community facilities and infrastructure were mapped: airports, community health centers, commuter rail and subway stations, electrical generation facilities, fire stations, harbormaster's offices, hospitals, landfills, libraries, long-term care residences, police stations, port facilities, prisons, public colleges and universities, public water supply sources, schools (pre-K through high school), town/city halls, wastewater treatment plants, and water supply protection areas. Public facilities and infrastructure located inland of mapped coastal flooding areas are not included in the viewer.
The online viewer includes these sections:
- Intro - The first tab provides an overview of the tool and a link to a technical report (PDF, 272 KB) with additional information, including how the maps were produced and a complete list of the community facilities and infrastructure.
- Sea Level Rise - This tab shows NOAA’s prediction of coastal flooding above Mean Higher High Water (MHHW, the average height of daily highest tide) with six increasing levels of sea level rise up to six feet. This map does not account for storm surge, waves, erosion, and other dynamic factors. See the Sea Level Rise Scenario figure (PDF, 155 KB) for a visual representation of the information depicted on the map. See CZM’s Sea Level Rise Guidance (PDF, 3 MB) for more information on sea level rise rates and projections, as well as general advice in the selection and application of scenarios for coastal vulnerability assessments.
- FEMA Coastal Flood Zones - This tab displays coastal areas with a 1% annual chance of flooding (A and V zones). These high-risk flood zones are determined by FEMA using historical data for storm tides and frequency. This map does not account for sea level rise.
- Hurricane Surge - The final tab includes four worst-case scenarios of storm surge based on thousands of modeled combinations of hurricane intensity (Category 1-4), forward speed, track or direction, and other factors not including sea level rise. NOAA’s National Hurricane Center, in partnership with the USACE, uses the Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model to calculate the storm surge heights and map coastal areas with the highest degree of exposure.
With the viewer, users can zoom in to an area of interest and then switch tabs to compare coastal flood data.
The community facilities and infrastructure mapped in the viewer are identified with an icon and facility outline. Clicking on the icon opens a pop-up box with the facility name, type, and town or city. Within the “Sea Level Rise” and “Hurricane Surge” tabs, the facility pop-up boxes also contain water levels. In the “FEMA Coastal Flood Zones” tab, water levels are included with the flood zone labels on the map.
The viewer and technical report are designed as a general vulnerability assessment and planning tool. This product should not be used for legal, engineering, or surveying purposes. Site-specific assessments of elevations or boundaries (parcel, structure, or other) should be made by a certified survey professional.
Coastal Shoreline and Floodplain Management
Mapping and Data