Learn about the acronyms and terms through our

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.

The hard copy maps are also available in the Planning or Natural Resources Division offices at
141 Keyes Road
Concord, MA 01742

The office hours are 8:30 a.m. to 4:30 p.m. Monday through Friday, and staff will be available to help you interpret the maps as needed. 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

FEMA applies rigorous standards to develop Flood Insurance Rate Maps (FIRMs) and uses the most accurate hazard information available. However, limitations in the scale or topographic detail of the source maps used to prepare a FIRM may cause small elevated areas to be included in a Special Flood Hazard Area (SFHA). SFHAs are high-risk areas subject to inundation by the base (1-percent-annual-chance) flood. They are also known as 1-percent-annual-chance floodplains, base floodplains, or 100-year floodplains.

To change the flood hazard designation for properties in these areas, FEMA has established the Letter Of Map Amendment (LOMA) process for properties on naturally high ground and the Letter Of Map Revision-Fill (LOMR-F) process for properties elevated by the placement of fill. LOMAs and LOMR-Fs are letter determinations that officially amend an effective FIRM. They can establish that a property is not in an SFHA and, by doing so, remove the Federal flood insurance requirement. For more information, please see the