Interactive Floodplain Mapping Tools
Loudoun County staff developed two interactive mapping programs that allowed users to access information online to see how the floodplains were changing at the parcel scale as the Risk MAP project progressed. The first online mapping program showed the “Preliminary” Flood Insurance Rate Map (FIRM), which allowed users to locate their property to see if there was floodplain on the property and if there was a change to FEMA’s Special Flood Hazard Area since it was last mapped. The image (above right) provides an example view from the Preliminary FIRM Interactive Mapping Program. This program was helpful during the Preliminary mapping stage of the project since property owners could see what was planned for the updated FIRM and submit information if they thought the preliminary map was incorrect. (Additional information about contesting the preliminary map data is available in the “Appeals Process” section.)
After the Appeals Process was completed, FEMA finalized the new floodplain data and the map became the “Pending” FIRM. Because the Preliminary FIRM had been superseded by the Pending FIRM, the original mapping tool was replaced by a new mapping program.
The new mapping program (image at right) showed the Proposed Loudoun County Floodplain Overlay District (FOD) Major and Minor Floodplains compared to the existing County FOD Major and Minor Floodplains. The proposed FOD was based on FEMA’s finalized (Pending) FIRM and Flood Insurance Study. The new mapping program was available online for viewing leading up to the Board of Supervisors potential adoption of FEMA’s Pending FIRM and the County’s revised FOD. The Board approved adoption of FEMA’s new FIRM and the County’s revised FOD on February 7, 2017. The county’s new FOD became effective on February 16, 2017 and FEMA’s new FIRM became effective on February 17, 2017. This second interactive mapping program was taken offline after the new maps were adopted and became effective because the information, as presented, was no longer accurate.
More information about the amendments to the county's Flood Overlay District is online here