Technical Bulletin 10 (TB 10) provides guidance on the National Flood Insurance Program (NFIP) requirements related to determining that buildings constructed on fill will be reasonably safe from flooding during the occurrence of the base flood. Guidance is provided for the placement of fill and the parameters for the design and construction of buildings on filled land that has been removed from the Special Flood Hazard Area (SFHA) through the flood map revision process managed by the Federal Emergency Management Agency (FEMA). The SFHA is identified as Zone A (A, AE, A1-30, AH, AO, A99, and AR) and Zone V (V, VE, V1-30, and VO) on a community’s Flood Insurance Rate Map (FIRM) prepared by FEMA.
“development” means: … any manmade change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operation or storage of equipment or materials.
“reasonably safe from flooding” means: … base flood waters will not inundate the land or damage structures to be removed from the SFHA and that any subsurface waters related to the base flood will not damage existing or proposed buildings.
As a condition for NFIP participating, FEMA requires that county officials review all permit applications to determine whether the proposed building sites will reasonably safe from flooding (44CFR60.3(a)(3)). If a proposed building site is in a flood-prone area, all new construction and substantial improvements shall comply with applicable local floodplain development regulations.
When permitted under applicable federal, state, and local laws, ordinances, and regulations, earthen fill is sometimes placed to reduce flood risk to structures located in Zone A. In Zone V, fill for the purpose of elevating buildings is not permitted, and use of fill for other purposes is limited because fill may obstruct the flow of floodwater and divert waves. Under certain conditions, when structural fill (also called engineered fill) is placed to raise the surface of the ground to or above the base flood elevation (BFE), property owners and developers may submit requests to FEMA to revise FIRMs to remove filled land from the SFHA.
When a revision is warranted, after reviewing an application, FEMA may revise a FIRM by issuing a Letter of Map Revision Based on Fill (LOMR-F). The NFIP requirements include, as part of the LOMR-F application, that written assurance from the participating community include a determination that the site (filled area) and any existing, proposed or future development (buildings and structures on the filled land) to be removed from the SFHA are or will be “reasonably safe from flooding” as defined in Title 44 of the Code of Federal Regulations (CFR) Part 65, Section 2 (see definition referenced above).
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