Concord River Watershed – Flood Map Updates
What data was used in determining the revisions?
For many flooding sources throughout the Concord River Watershed, the Special Flood Hazard Areas (SFHAs) and Base Flood Elevations (BFEs) were produced using new hydrologic and hydraulic analyses as well as 2-foot topographic data obtained through Light Detection and Ranging (LiDAR). In areas where there were no new studies or information, the current effective digital SFHA was incorporated into the new base map.
What does this mean for property owners?
Impacts to property owners will vary. The best way to determine whether your property and/or structure is in a SFHA, and if there has been a change to the SFHA or BFE in your area, is to consult the Town of Carlisle’s website on which the digital maps for Carlisle, including some areas of abutting towns, have been placed (see link above).
How can I view the new maps?
To determine whether your property is in or near a mapped Flood Hazard zone, go to Concord_Flood_Risk_Map.pdf. The highlighted/shaded areas on that map, which includes Carlisle as well as other towns in the Concord River Watershed are considered within the flood risk areas. The areas in Carlisle are associated with Meadow River Branch, Pages Brook, Pages Brook Branch, Spencer Brook and the Concord River. If you find you are in or near one of these areas, there are different maps to review: A). FEMA Depth Grid Maps, showing the flood areas, B). FEMA Change Since
Last FIRM (CSLF), providing an overlay of the proposed mapping against the previously mapped flood maps dating from about 1988, and C). the FIRMS (Flood Insurance Rate Map, which provides information on details of study areas.
There are 10 maps covering all of Carlisle and beyond. A simple, locally produced map (“Index Map”) showing the ID numbers for each panel covering Carlisle is provided to assist your search for the map with the area where your property exists. Once you have located your area, keep track of the last four numbers in the panel number as the other three maps will have the same number.