24 C.F.R. § 55.2 Terminology.
Title 24 - Housing and Urban Development
(a) With the exception of those terms defined in paragraph (b) of this section, the terms used in this part shall follow the definitions contained in section 6 of Executive Order 11988 and in the Floodplain Management Guidelines for Implementing Executive Order 11988 (43 FR 6030, February 10, 1978) issued by the Water Resources Council; and the terms “criteria” and “Regular Program”, shall follow the definitions contained in FEMA regulations at 44 CFR 59.1. (b) The definitions of the following terms in Executive Order 11988 and related documents affecting this part are modified for purposes of this part: (1) Coastal high hazard area means the area subject to high velocity waters, including but not limited to hurricane wave wash or tsunamis. The area is designated on a Flood Insurance Rate Map (FIRM) under FEMA regulations as Zone V1–30, VE, or V. (FIRMs as well as Flood Hazard Boundary Maps (FHBM) shall also be relied on for the delineation of “100-year floodplains” (§55.2(b)(8)), “500-year floodplains” (§55.2(b)(3)), and “floodways” (§55.2(b)(4)). (2)(i) Critical action means any activity for which even a slight chance of flooding would be too great, because such flooding might result in loss of life, injury to persons, or damage to property. Critical actions include activities that create, maintain or extend the useful life of those structures or facilities that: (A) Produce, use or store highly volatile, flammable, explosive, toxic or water-reactive materials; (B) Provide essential and irreplaceable records or utility or emergency services that may become lost or inoperative during flood and storm events (e.g., data storage centers, generating plants, principal utility lines, emergency operations centers including fire and police stations, and roadways providing sole egress from flood-prone areas); or (C) Are likely to contain occupants who may not be sufficiently mobile to avoid loss of life or injury during flood or storm events, e.g., persons who reside in hospitals, nursing homes, convalescent homes, intermediate care facilities, board and care facilities, and retirement service centers. Housing for independent living for the elderly is not considered a critical action. (ii) Critical actions shall not be approved in floodways or coastal high hazard areas. (3) 500-year floodplain means the minimum floodplain of concern for Critical Actions and is the area subject to inundation from a flood having a 0.2 percent chance of occurring in any given year. (See §55.2(b)(1) for appropriate data sources.) (4) Floodway means that portion of the floodplain which is effective in carrying flow, where the flood hazard is generally the greatest, and where water depths and velocities are the highest. The term “floodway” as used here is consistent with “regulatory floodways” as identified by FEMA. (See §55.2(b)(1) for appropriate data sources.) (5) Functionally dependent use means a land use that must necessarily be conducted in close proximity to water (e.g., a dam, marina, port facility, water-front park, and many types of bridges). (6) High hazard area means a floodway or a coastal high hazard area. (7) 100-year floodplain means the floodplain of concern for this part and is the area subject to a one percent or greater chance of flooding in any given year. (See §55.2(b)(1) for appropriate data sources.) (8)(i) Substantial improvement means either: (A) Any repair, reconstruction, modernization or improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure either: (1) Before the improvement or repair is started; or (2) If the structure has been damaged, and is being restored, before the damage occurred; or (B) Any repair, reconstruction, modernization or improvement of a structure that results in an increase of more than twenty percent in the number of dwelling units in a residential project or in the average peak number of customers and employees likely to be on-site at any one time for a commercial or industrial project. (ii) Substantial improvement may not be defined to include either: (A) Any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications that is solely necessary to assure safe living conditions, or (B) Any alteration of a structure listed on the National Register of Historical Places or on a State Inventory of Historic Places. (iii) Structural repairs, reconstruction, or improvements not meeting this definition are considered “minor improvements”.
Title 24: Housing and Urban Development
PART 55—FLOODPLAIN MANAGEMENT
Subpart A—General
§ 55.2 Terminology.
