Flood Mitigation Best Practices

When a community is looking for ways to assist citizens and mitigate flood losses, the products produced by the Flood Mitigation Program can help.


Traditional Regulatory Products include the Flood Insurance Rate Maps and the Flood Insurance Study (FIS) Report.  These products provide a wealth of useful information. 

For example, the report contains information on the principal flood problems for the study area.  Information included is from past events that have occurred.  For many years, South Carolina experienced a pattern of below-normal rainfall.  For floodplain Managers and Emergency Managers that began working in these positions during these drier than normal years; this information provided a historical perspective that assisted them in understanding the flood risk of the citizens in their community.  This information has also been used to enhance the flood portion of local hazard mitigation plans and focus mitigation efforts.

Within the FIS report, profiles are available for any stream that was studied by detailed methods. These profiles provide not only the 1% annual chance flood elevation, also known as the Base Flood Elevation, but the 0.2%, 2%, 4% and 10% annual chance flood elevations.  Many communities have used this information for grants involving critical facilities that are required to be elevated to the 0.2% chance flood elevation.


The Flood Insurance Rate Maps (FIRM) are typically thought of as a product to determine if flood insurance will be required or not.  While that is true, they provide much more information.  The FIRMs indicate the areas subject to a 1% chance of flood event being equaled or exceeded in any given year. This area called the Special Flood Hazard Area (SFHA), ties directly to the regulations that are adopted in the community's local flood damage prevention ordinance.  These ordinances govern how development occurs inside of the SFHA.  Many communities also use them to guide long-range planning and establish mitigation focus areas.

Flood Risk products are products that are non-regulatory in nature.  They are not intended to regulate the SFHA but rather enhance the communication resources available to the local governments.  In many cases, they give a visual representation of flood risk that makes it easier for citizens to understand.  Communities use these products to explain changes in the SFHA when new maps are getting ready to go effective.  Also, as part of a local floodplain managers job, they provide flood zone determinations for citizens.  These products have allowed floodplain managers in many communities to be able to provide additional information regarding flood risk for the area of inquiry.  The most common information provided from the Flood Risk products during these types of inquires is the percent annual chance of flooding and the percent chance of flooding over 30 years.