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FEMA FIRM Maps and Information for Buzzards Bay

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The Planning for a Shifting Shoreline Action Plan in the Buzzards Bay Comprehensive Conservation and Management Plan focuses on planning for storm damage and rising sea levels along the coast to protect living resource and water quality. The Goals of this action plan are:

• Protect public health and safety from problems associated with higher waters and shifting shorelines.
• Reduce the public financial burden caused by the destruction of or damage to coastal property.
• Plan for the loss of buffering wetlands and shifting sand formations.

A key element for implementing this action plan is a good understanding the location of the 100-year floodplain (Federal Emergency Management Agency, or FEMA maps), barrier beaches, and areas of high erosion. This page provides maps and key links to this information.

Property owners and engineers should consult original source FEMA National Flood Insurance Rate Maps (FIRMs) to definitively identify flood plain boundaries. The maps and links below provide good estimates of those boundaries. More information about the FIRMs can be found on the FEMA fact sheets page.

Because of the approximate nature of even the original FIRMs, property owners sometimes conduct their own studies to identify flood plain elevations. (Visit FEMA page: How To Request a Flood Hazard Determination Review from FEMA.

In the sections below, we provide some useful tools help interested parties identify flood plains, including the most recent updated information for Bristol County.

Updated FEMA FIRM maps for Buzzards Bay Communities

In 2009, FEMA updated its FIRM maps for Bristol County. If you want to look at a broader area and use features available on Google Earth, in the box to the right we provide FEMA created shapefiles as Google Earth-readable kmz files to make maps of larger areas that can be customized.

Draft hard copy maps for Barnstable and Plymouth County have been released to municipalities, but have not been finalized, so digital copies are not yet available. In 2010, Plymouth and Barnstable County final maps and digital shapefiles should become available. To check the status of this effort, go to this FEMA Multi-Year Flood Hazard Identification Plan (MHIP) site and this Flood Mapping Information page. To download maps or digital GIS data, visit the FEMA Map Service Center (choose "flood maps" for pdf maps or "DFIRM databases" for GIS files). Here is a Fairhaven, MA FIRM map, illustrating their new format.

These two images show revisions in FEMA flood zones (red= velocity zone, blue = 100-year flood plain) at a site along Nasketucket Bay in Fairhaven.

Link to MassGIS FIRM maps shapefile coverage. (currently only old data posted)

2009_fema_floodzones_bristol_county.zip (7.5 MB zipped shapefile, download by BBNEP, right click to download)

Hurricane Surge Inundation Maps

The US Army Corps of Engineers, as part of its Hurricane Evacuation Studies for New England, produced Hurricane Surge Inundation Maps for New England, also known as "SLOSH" maps. Hurricane surge elevations were determined by the National Hurricane Center using the SLOSH model (Sea, Lake and Overland Surge from Hurricanes), and assume peak hurricane surge arrives at either mean tide or mean high tide, as indicated at the bottom of the maps. The hurricane surge inundation areas shown on the maps depict the inundation that can be expected to result from a worst-case combination of hurricane landfall location, forward speed, and direction for each hurricane category. Ground elevation data was obtained from the USGS National Elevation Data Set. Gis Data for these maps can be obtained at this data link. An explanation of the Slosh map methodology and technical findings is contained in this ACOE SE MA hurricane Inundation technical report. FEMA put together this training package to explain how SLOSH data can be used.

LIDAR Data

FEMA hired the FIRM Camp Dresser and McKee to collect and evaluate LIDAR (Light Detection and Ranging) data for portions of Bristol and Plymouth Counties along Buzzards Bay. The effort is documented in this 2008 report, Flood Mapping Activities for Plymouth and Bristol Counties, Massachusetts (29 MB). Task Order 18 Activity 1--Topographic Data Development / Acquisition Summary Report. Contract No. EME-2003-CO-0340 Task Order T018. Prepared for: FEMA Region I, February 2008. The LIDAR data was collected in November and December of 2007 by Sanborn Mapping Company. CDM developed a bare earth TIN (Triangular Irregular Network) Digital Elevation Models based on this data, which was used as the basis for this coverage. In an evaluation of the study area, CDM determined that the root-mean square average difference in elevation for 48 surveyed points as compared to the LIDAR TIN data was 0.52 feet, and this met the FEMA minimum accuracy requirement of 1.2 feet. They concluded, "based on this analysis, this LIDAR data is acceptable for use in H&H analyses [hydrologic and hydraulic] and flood zone mapping." Elevations are NAVD 88 feet. They also prepared 2-foot elevation contours based on this LIDAR data. The Buzzards Bay NEP can provide this data to interested municipal officials and engineers (email us).

Although the absolute elevation accuracy averaged only half a foot for the study area, the relative precision of the LIDAR data is less than one inch over small areas. This means that the TIN data can be used to create very narrow elevation contours for a particular site, and this data can be used to evaluate stormwater flow paths. This application is illustrated by the map to the right showing one-half foot contours at piers along the New Bedford waterfront.

FEMA LIDAR coverages (TIN model and 2 ft contours) available from the BBNEP along Buzzards Bay (left, click map to enlarge) and in the Hull Weymouth, area (right, click to enlarge).

Options to obtain data from the BBNEP

For the entire set of TIN files, point files, and 2 foot contours, send us a portable external drive with at least 50GB capacity, and we will mail it back. If you need just one tile, we will email a link. If you just need two foot contours, download the shape files below (email us if you need more information.)



fema_09_bristol_2ftlidar.zip (2 ft contours derived from Lidar, 101 MB zipped shapefile, right click to download)

fema_09_plymouth_sw_2ftlidar.zip (2 ft contours derived from Lidar, 81 MB zipped shapefile, right click to download)

fema_09_plymouth_so_2ftlidar.zip (2 ft contours derived from Lidar, 59 MB zipped shapefile, right click to download)

fema_09_plymouth_no_2ftlidar.shp.zip (Weymouth, Hull, Cohasset area, 2 ft contours derived from Lidar, 26 MB zipped shapefile, right click to download)

Bare Earth Digital Elevation Models

Upon request, we can also provide bare-earth Digital Elevation Model TINS (DEMs). We also have "first return" and "last return" raw data for those who want to experiment with these coverages. Some of these coverages are quite large, and some individual tiles exceed 100MB. To use these files requires ARCMap or other comparable software. Want to test out a LIDAR TIN file in ArcMAP? Try these files that we have already posted on our website:

(Right click to download these files to avoid timeout errors.)
tnz_7602640.zip (Quicksand Pond, Westport, 26 MB)
tnz_8102680.zip (New Bedford Harbor, 22 MB)
tnz_8102685.zip (New Bedford Harbor, 43 MB)
tnz_8152680.zip (New Bedford Harbor, 32 MB)
tnz_8152685.zip (New Bedford Harbor, 15 MB)
tnz_8202685.zip (New Bedford Harbor, 7 MB)
tnz_8202690.zip (New Bedford Harbor, 40 MB)
tnz_8402700.zip (Eel Pond in Mattapoisett, MA27 MB)

Raw data for tile 8402700:first-return-8402700.xyz.zip (20 MB)   last-return-8402700.xyz.zip (20 MB)   mass-points-8402700.zip(2.3 MB)

tnz_8452700.zip (area of Mattapoisett, 40 MB)
tnz_9002735.zip (Little Buttermilk Bay in Bourne, 25 MB)
tnz_9002740.zip (Little Buttermilk Bay in Bourne, 8 MB)

email to request a specific DEM tile.

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