D.C. Mun. Regs. tit. 20, r. 20-3199
When used in this chapter, the following words and phrases shall have the meaning ascribed:
Alteration of a Watercourse - an alteration of a watercourse includes, but is not limited to, any dam, impoundment, channel relocation, change in channel alignment, channelization, or change in cross-sectional area or capacity, which may alter, impede, retard or change the direction and/or velocity of the riverine flow of water during conditions of the base flood.
Base Flood - the flood having a one percent (1%) chance of being equaled or exceeded in any given year, also known as "the one-hundred (100) year flood."
Base Flood Elevation - the elevation of the base flood, including wave height, relative to the National Geodetic Vertical Datum (NGVD), North America Vertical Datum (NAVD) or other datum specified on the Flood Insurance Rate Map (FIRM).
Basement - the portion of a building having its floor subgrade (below ground level) on all sides.
Code Official - the officer or other designated authority charged with the administration and enforcement of the building codes, or a duly authorized representative, as designated by 12 DCMR A 103.1.
Construction - the construction, reconstruction, renovation, repair, extension, expansion, alteration, or relocation of a building structure.
DCRA - the Department of Consumer and Regulatory Affairs.
DDOE - the District Department of the Environment, also referred to as "Department."
Development - any manmade change to improved or unimproved real estate, including but not limited to: buildings or other structures, streets and other paving, utilities, filling, grading, excavation, mining, dredging, drilling operations, storage of equipment or materials, and the subdivision of land.
Department - the District Department of the Environment, also referred to as "DDOE."
Dry Floodproofing - a combination of design modifications that result in a building or structure, including the attendant utility and sanitary facilities, being water tight with walls substantially impermeable to the passage of water and with structural components have the capacity to resist loads as identified in ASCE 7 (see floodproofing).
Elevation Certificate - a certificate used to certify building and grade and other building information, and elevations to provide elevation information necessary to ensure compliance with this chapter, to determine the proper insurance premium rate, and to support a request for a Letter of Map Amendment (LOMA) or Letter of Map Revision based on Fill (LOMR-F).
Encroachment - the advancement or infringement of uses, fill, excavation, buildings, permanent structures or other development into a special flood hazard area which may impede or alter the flow capacity of a floodplain.
FEMA - theFederal Emergency Management Agency.
Flood or Flooding - a general and temporary condition of partial or complete inundation of normally dry land from:
Flood Insurance Rate Map (FIRM) - an official map of a community, on which the Federal Insurance Administrator has delineated both the special hazard areas and the risk premium zones applicable to the community.
Flood Insurance Study (FIS) - an official report including a Flood Insurance Rate Map by the Federal Insurance Administrator evaluating flood hazards and containing flood profiles and water surface elevations of the base flood.
Floodplain - a relatively flat or low land area which is subject to partial or complete inundation from an adjoining or nearby stream, river or watercourse; or any area subject to the usual and rapid accumulation of surface waters from any source.
Floodplain Administrator - the official or office charged with the administration and enforcement of this Chapter, for these purposes, DDOE.
Floodproofing - any combination of structural and non-structural additions, changes, adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures, and their contents.
Floodway - the channel or a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
Freeboard - a factor of safety usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, bridge openings, and the hydrological effect of urbanization of the watershed.
Historic Structure - any structure that is:
Land Disturbing Activity - any earth movement or land change which may result in soil erosion from water or wind and the movement of sediments in the District of Columbia, including, but not limited to, stripping, grading, excavating, transporting and filling of land, construction or demolition of buildings or structures.
Lowest Floor - the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, used solely for parking of vehicles, building access, or storage, in an area other than basement, is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this chapter.
Manufactured Home - a structure, transportable in one (1) or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For flood plain management purposes, the term "manufactured home" also includes park trailers, travel trailers, and other similar vehicles placed on a site for greater than one hundred and eighty (180) consecutive days.
Market Value - the price at which a property will change hands between a willing buyer and a willing seller, neither party being under compulsion to buy or sell and both having reasonable knowledge of relevant facts.
National Flood Insurance Program (NFIP) - a Federal program enabling property owners in participating communities to purchase insurance protection against losses from flooding. Participation in the NFIP is based on an agreement between local communities and the Federal Government that states if a community will adopt and enforce a floodplain management ordinance to reduce future flood risks to new construction and development in special flood hazard areas, the Federal Government will make flood insurance available within the community as a financial protection against flood losses.
New Construction/Date - for floodplain management purposes, structures for which the start of construction commenced on or after the effective date of the initial FIRM (i.e., November 15, 1985) and includes any subsequent improvements to such structures.
Obstruction - any wall, dam, wharf, embankment levee, dike, pile abutment, projection, excavation, channel, rectification, culvert, building, fence, stockpile, refuse, fill, structure, or matter in, along, across or projecting into any channel, watercourse, or flood-prone area, which may impede, retard, or change the direction of the flow of water either by itself or by catching or collecting debris carried by such water or is placed where the flow of the water might carry the same downstream to the damage of life and property.
Recreational Vehicle - a vehicle that is:
Regulatory Flood Elevation - the base flood elevation plus a freeboard safety factor of one and one-half feet (1-1/2 ft.).
Special Flood Hazard Area (SFHA) - the land in the floodplain within the community subject to a 1-percent (1%) chance or greater chance of flooding in any given year. The area may be designated in the FIRM as Zone A, A1-30, AE, A99, AR/A1-30, AR/AE, AR/AO, AR/AH, or AR/A.
Zone A - an area subject to inundation by the one (1)-percent (1%) chance or greater chance of flooding in any given year. Because detailed hydraulic analyses have not been performed, no base flood elevation or depths are shown.
Zone AE - an area subject to inundation by the one (1)-percent (1%) chance or greater chance of flooding in any given year determined by detailed methods. Base flood elevations are shown within these zones.
Zone X - an area identified in the FIRM and FIS as an area of moderate or minimal hazard from the principal source of flood in the area.
Start of Construction - the date of permit issuance for new construction and substantial improvements to existing structures, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement or other improvement is within one hundred eighty (180) days after the date of issuance. The actual start of construction means the first placement of permanent construction of a building (including a manufactured home) on a site, such as the pouring of a slab or footings, installation of pilings or construction of columns.
Structure - for floodplain management purposes, a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home or recreational vehicle that is on-site for more than one hundred eighty (180) days.
Subdivision - the division or redivision of a lot, tract, or parcel of land by any means into two (2) or more lots, tracts, parcels or other divisions of land including changes in existing lots lines.
Substantial Damage - damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed fifty percent (50%) of the market value of the structure before the damage occurred.
Substantial Improvement - any repair, reconstruction, rehabilitation, addition, or improvement of a building or structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure before the start of construction. If the structure has sustained substantial damage, any repairs are considered substantial improvement regardless of the actual repair work performed. The term does not, however, include either:
Violation - the failure of new construction or development to be fully compliant with requirements of this Chapter, the Construction Codes (DCMR Title 12), the District's Water Quality and Pollution Control Regulations (20 DCMR 500 et. seq.). A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this chapter is presumed to be in violation until such time as that documentation is provided.
Wet Floodproofing - floodproofing method that relies on the use of flood-damage-resistant materials and construction techniques to minimize flood damages to areas below the base flood elevation of a structure intentionally allowed to flood (see floodproofing).
Zone A - see Special Flood Hazard Area
Zone AE - see Special Flood Hazard Area
Zone X - see Special Flood Hazard Area
D.C. Mun. Regs. tit. 20, r. 20-3199