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<br />Mitigation Strategy Report <br />FEMA-1134-DR-NC <br /> <br />State of North Carolina <br />Division of Emergency Management <br /> <br />~ Elevation/Flood Proofing <br /> <br />Elevating buildings to the desired flood protection elevation is one of the most common retrofilling <br />techniques. The building is raised and set on a new or ex1ended foundation, such as piers, posts, <br />columns, piles, foundation walls, or properly compacted fill material. Virtually any structurally sound <br />building can be elevated, Properly done, eievating a house places the living area above all but <br />the most severe floods. The National Flood Insurance Program (NFIP) requires that the lowest floor <br />for all new construction and substantial improvements be elevated, at a minimum, to the Base Flood <br />Elevation (BFE), or 100 year flood level as identified on a community's Flood Insurance Rate Map <br />(FIRM) (see Appendix F). <br /> <br />Elevation is particularly applicable in areas that face moderate, intermittent flooding, A community <br />elevation project is typically less expensive and complicated than an acquisition/relocation effort. While <br />elevation does reduce the likelihood of sustaining flood damage, it does not, however, move people or <br />structures out of a flood hazard area. As a result, home owners must contend with flooded accessory <br />structures (unless they are elevated), cars, and adjacent infrastructure. In addition, home owners may <br />require costly emergency services to evacuate from rising flood waters. <br /> <br />Flood proofing is often used in conjunction with other hazard mitigation measures. Typically flood <br />proofing is utilized in areas of minorto moderate flooding. Flood proofing and retrofitting of businesses <br />or waste water treatment facilities, for example, offers a sound alternative to an otherwise expensive <br />relocation process. Flood proofing allows the structure to remain in its existing location while reducing <br />the likelihood of flood related damages. <br /> <br />Two possible approaches to non-residential flood mitigation include wet or dry flood proofing. Wet <br />flood proofing means modifying a building so that intruding floodwater will cause only minimal damage <br />to the building and its contents. Standard building materials below the flood protection level are repiaced <br />with water resistant materials. Floodwater is allowed into the building to counteract the water pressure <br />on outside walls. Wet flood proofed areas are often furnished with light, portable furniture that can be <br />moved before the onset of a flood. Equipment, such as furnaces, AC compressors, water heaters, <br />appliances, and bookcases, are permanently reinstalled upstairs or on elevated platforms. <br /> <br />Wet flood proofing is only suitable for pre-FIRM and post-FIRM accessory structures such as storage <br />sheds, detached garages, and farm storage buildings. In order to comply with the NFIP, wet flood <br />proofing cannot be used for buildings with confined animal feeding areas, dairy parlors, or machine <br />shops. Flood insurance rates, even with this type of flood proofing, are still based on the actual floor <br />level. <br /> <br />Dry flood proofing entails creating watertight structures to keep floodwater from entering. To ensure <br />compliance with flood prevention ordinances, the design must be certified by a professional engineer. <br />Walls can be coated with plastic or rubberized sheeting, and openings may be closed permanently or <br />temporarily sealed with removable shields. Dry flood proofing only provides effective protection against <br />minor flooding, depending on the type of construction. Once floodwater depths exceed 18 to 36 inches, <br />the walls of most sealed structures succumb to external water pressure. Despite their limitations, wet <br />and dry flood proofing techniques provide a measure of protection that may be effective and cost <br />beneficial for many non-residential structures. <br /> <br />~ Storm Drainage Improvements <br /> <br />Storm drainage improvements may reduce future flood impacts on the built environment by enabling <br />the timely diversion of water downstream. The flooding experienced by North Carolina riverine <br />communities prior to and during Hurricane Fran demonstrates the need to move water away from the <br />built environment (and the built envirOnment away from flood-prone areas). Numerous communities <br />faced severe flooding due to inadequately sized culverts, overgrown stream channels, and debris- <br /> <br />Page 6 <br />