Concord River Watershed - Preliminary Flood Map Updates 2013
Please note: the information contained herein is meant solely to provide guidance to property owners based on preliminary mapping and studies provided by FEMA to the Town of Concord. For more specific information, please consult the lists of additional links and additional contacts above.
INTERACTIVE MAPPING TOOL: FIND YOUR PROPERTY
(click icon to enter site, then click on each data layer for more information)
How can I view the new maps?
The maps are available in three formats on this webpage:
1. The most user-friendly option is the INTERACTIVE MAPPING TOOL that allows a property owner to search for his/her address and see how it will be impacted by the updated flood information.
2. There is a link above to the actual .pdf files (Maps - Large .pdf Files), where you can download the maps. But beware - each map is about 20 MBs. First check the Index (Index1B) to find out which panel your property is on.
3. If you prefer not to download the maps, you can link to them via the STARR Team website link above - LINKS to PRELIMINARY MAPS. However, the STARR Team website link contains all the maps for the Concord HUC8 Watershed, not just for the Town of Concord. For a list of the map panels that contain portions of the Town of Concord, see CONCORD MAP PANEL #S above.
Weren't the Town's flood maps just updated in 2010?
Yes. In June 2010, all communities in Middlesex County received updated Flood Insurance Rate Maps (FIRMs) and a Flood Insurance Study (FIS) report from FEMA. These maps became effective in June 2010 and were the first set of digital maps for Middlesex County. Another important change that occurred with the 2010 maps was the shift from the National Geodetic Vertical Datum (NGVD) of 1929 to the North American Vertical Datum (NAVD) of 1988. A vertical datum is a set of constants that defines a system of comparison of elevations; it is important because all elevations need to be referenced to the same system. Datums are updated periodically to reflect geologic changes to the surface of the earth, and as technology and scientific assumptions improve. The 2010 and 2013 maps are based on the new vertical datum: NAVD 88.
Why are the maps being updated again?
Many flood hazards identified in Middlesex County are from the 1970's, 1980's and 1990's. FEMA strives to improve its risk identification and continually evaluates and incorporates new approaches where and when necessary. The new Preliminary maps that were issued on January 10, 2013 incorporate updated engineering analyses and data within the Concord River Watershed. Only those FIRM panels with updated flood hazard information have been revised.
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 Concord's Interactive Mapping Program (see link above). The hard copy maps are also available in the Natural Resources Division Office at 141 Keyes Road, Concord, MA. 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.
What if I do not agree with the new mapping?
Communities in Middlesex County will have a 90-day Appeal Period during which technical information or comments are solicited on the proposed flood hazard determinations shown on the Preliminary FIRM, and where applicable, the FIS report. Appeals must be backed by scientific data that is more technical and accurate than FEMA's base data.