APPENDIX C: MITIGATION ALTERNATIVES
FLOODPLAIN REGULATIONS Flood damage prevention ordinances establish standards for new construction or substantial improvements to minimize flood related damages. These ordinances are required to meet NFIP minimum standards for communities to participate and comply with the NFIP. The North Carolina state model ordinance recommends a two foot freeboard. Vegetation along a stream bank is extremely beneficial for the health of the stream. Trees and other plants have an extensive root system that strengthen stream banks and help prevent erosion. Vegetation that has sprouted up near streams should remain undisturbed unless removing it will significantly reduce a threat of flooding, or further destruction of the stream channel. North Carolina regulations prohibit the removal of vegetation within 50 feet of all streams in the Wake County area. These are known as the Neuse River Riparian Buffer Rules and the North Carolina Division of Water Resources should be consulted before any activities are undertaken in these areas. All communities enforce reconstruction regulations to ensure that mitigation is integrated into recovery. Requiring permits for building repairs and conducting inspections are vital activities to ensure that damaged structures are safe for people to reenter and repair. There is a special requirement to do this in floodplains, regardless of the type of disaster or the cause of damage. The NFIP requires that local officials enforce the substantial damage regulations. These rules require that if the cost to repair a building in the mapped floodplain equals or exceeds 50% of the building's market value, the building must be retrofitted to meet the standards of a new building in the floodplain. STORMWATER MANAGEMENT REGULATIONS Stormwater runoff is increased when natural ground cover is replaced by urban development. Development in the watershed that drains to a river can aggravate downstream flooding, overload the community's drainage system, cause erosion, and impair water quality. There are three ways to prevent flooding problems caused by stormwater runoff: 1) Regulating development in the floodplain to ensure that it will be protected from flooding and that it won't divert floodwaters onto other properties; 2) Regulating all development to ensure that the post-development peak runoff will not be greater than it was under pre-development conditions; and 3) Set construction standards so buildings are protected from shallow water. REDUCING FUTURE FLOOD LOSSES Zoning and comprehensive planning can work together to reduce future flood losses by directing development away from hazard prone areas. Creating or maintaining open space is the primary way to reduce future flood losses. Planning for open space must also be supplemented with development regulations to ensure that stormwater runoff is managed, and that development is protected from flooding. Future flood losses will be reduced through the implementation of the building code, flood damage prevention ordinances, and stormwater management ordinances. Enforcement of freeboard requirements will provide an extra level of protection for buildings. Stormwater management and the requirement that post-development runoff cannot exceed pre- development conditions is one way to prevent future flood losses. Retention and detention requirements also help to reduce future flood losses.
WSP June 2024 Page C.4
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
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