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OCR for page 148
B Glossary AAER" Average annual erosion rate. ACCRETION" May be either natural or artificial. Natural accre- tion is the buildup of land, solely by the action of the forces of nature, on a beach by deposition of water or airborne material. Artificial accretion is a similar buildup of land by human ac- tions, such as accretion formed by a groin, breakwater, or beach fill deposited by mechanical means. A-ZONEb Flood hazard zone that corresponds to the 100-year floodplain; also known as Special Flood Hazard Area. BEACH NOURISHMENTa The process of replenishing a beach. It may be brought about naturally by Tongshore transport or artificially by deposition of dredged materials. BREAKWATERa A structure protecting a shore area, harbor, an- chorage, or basin from waves. COASTLINEa (~) Technically, the line that forms the boundary between the coast and the shore. (2) Commonly, the line that forms the boundary between the land and the water. NOTE: Definitions are from the Shore Protection Manual, Volume II, 1984. bFEMA definitions. CNRC committee definition. 148

OCR for page 148
APPENDIX B 149 CUSPa One of a series of low mounds of beach material separated by crescen~shaped troughs spaced at more or less regular inter- vals along the beach face. DOWNDRIFTa The direction of predominant movement of littoral materials. OZONE An area along the coast where waves and other forces are anticipated to cause significant erosion within the next 60 years and may result in the damage or Toss of buildings and infrastructure. FIRM Flood insurance rate maps. GRABENa A relatively long, narrow area of the earth's crust that has subsided between two bordering faults. In practice it can be one fault. GROINa A shore protection structure built (usually perpendicular to the shoreline) to trap littoral drift or retard erosion of the shore. JETTYa A structure extending into a body of water, designed to prevent shoaling of a channel by littoral materials and to direct and confine the stream or tidal flow. Jetties are built at the mouths of rivers or tidal inlets to help deepen and stabilize a channel. LITTORALa Of or pertaining to a shore, especially of the sea. LITTORAI~ DRIFTa The sedimentary material moved in the lit- toral zone under the influence of waves and currents. LITTORAL TRANSPORTa The movement of littoral drift in the littoral zone by waves and currents. Includes movement parallel and perpendicular to the shore. MEAN HIGH WATERa The average height of the high waters over a 19-year period. PERCHED BEACHa A beach or fillet of sand retained above the otherwise normal profile level by a submerged dike. PLANFORMa The outline or shape of a body of water as deter- mined by the stillwater line. NOTE: Definitions are from the Shore Protection Manual, Volume II, 1984. bFEMA definitions. CNRC committee definition.

OCR for page 148
150 APPENDIX B POCKET BEACH A beach, usually small, in a coastal reentrant or between two littoral barriers. REVETMENTa A facing of stone, concrete, etc., built to protect a scarp, embankment, or shore structure against erosion by wave action or currents. SAND WAVEa A large wavelike sediment feature composed of sand in very shallow water. Wave length may reach 100 meters; am- plitude Is about 0.5 meter. SCARPa An almost vertical slope along the beach caused by erm sion by wave action. It may vary in height from a few centimeters to a meter or so, depending on wave action and the nature and composition of the beach. SEAWALLa A structure separating land and water areas, primarily designed to prevent erosion and other damage from wave actions. SHOREa The narrow strip of land in immediate contact with the sea, including the zone between high and low water lines. A shore of unconsolidated material usually is called a beach. SHORELINEa The intersection of a specified plane of water with the shore or beach. The line delineating the shoreline on natural ocean service nautical charts and surveys approximates the mean high water line. UPDRIFTa The direction opposite that of the predominant move- ment of littoral materials. V-ZONEb Flood hazard zone that corresponds to the Midyear floodplain that is subject to high velocity wave action from coastal storms or seismic sources; also know as Coastal High Hazard Area. WIND TIDEa The vertical rise in the stillwater level on the leeward side of a body of water caused by wind stresses on the surface of the water. NOTE: Definitions are from the Shore Protection Manual, Volume II, 1984. bFEMA definitions. CNRC committee definition.