The Flood Insurance Rate Map and Flood Insurance Study (described in the Flood Insurance Rate Map section of these web pages) are used primarily for floodplain regulatory purposes by the Federal Emergency Management Agency (FEMA) and local communities managing their floodplain ordinances as part of the requirements of participating in the National Flood Insurance Program.
In addition to the Flood Insurance Rate Map and Flood Insurance Study, the Risk MAP project includes non-regulatory resources (referred to by FEMA as "products) intended to help community officials and citizens understand their flood risk and what may be done to help make their communities more resilient to flooding. These non-regulatory resources include a Flood Risk Report, a Flood Risk Map, and a Flood Risk Database.
The Flood Risk Report is a comprehensive watershed-based study containing specific flood risk information and explains the concept of flood risk in a community.
The Flood Risk Report for Loudoun County is available online (PDF) or by selecting the image of the report.
The Flood Risk Map is a countywide presentation illustrating overall flood risk identified and developed during the Risk MAP project.
Included are areas where new detailed studies have been performed, areas of mitigation interest, and the overall zones of flood risk.
The areas of mitigation interest include the 90-plus regulated dams in Loudoun County and essential facilities at risk of flooding. Select the map image to view the Flood Risk Map (PDF).
The Flood Risk Database includes Geographic Information System-based maps of depth of flooding, water elevation, percent annual chance of flooding at specific locations and percent chance of flooding at specific locations during a 30 year period (typical length of a mortgage loan). The image at right is an example map depicting the depth of water (in feet) at a specific location during a "1% annual chance" flood, commonly called a "100-year" flood.