BAR. A submerged or emerged embankment of sand, gravel, or other unconsoli- 

 dated material built on the sea floor in shallow water by waves and 

 currents. (See Figures A-2 and A-9.) See BAYMOUTH BAR, CUSPATE BAR. 



BARRIER BEACH. A bar essentially parallel to the shore, the crest of which is 

 above normal high water level. (See Figure A-9.) Also called OFFSHORE 

 BARRIER and BARRIER ISLAND. 



BARRIER LAGOON. A bay roughly parallel to the coast and separated from the 

 open ocean by barrier islands. Also, the body of water encircled by coral 

 islands and reefs, in which case it may be called an atoll lagoon. 



BARRIER REEF. A coral reef parallel to and separated from the coast by a 

 lagoon that is too deep for coral growth. Generally, barrier reefs follow 

 the coasts for long distances and are cut through at irregular intervals 

 by channels or passes. 



BASIN, BOAT. A naturally or artificially enclosed or nearly enclosed harbor 

 area for small craft. 



BATHYMETRY. The measurement of depths of water in oceans, seas, and lakes; 

 also information derived from such measurements. 



BAY. A recess in the shore or an inlet of a sea between two capes or head- 

 lands, not so large as a gulf but larger than a cove. (See Figure A-9.) 

 See also BIGHT, EMBAYMENT. 



BAYMOUTH BAR. A bar extending partly or entirely across the mouth of a bay 

 (see Figure A-9). 



BAYOU. A minor sluggish waterway or estuarial creek, tributary to, or 

 connecting, other streams or bodies of water, whose course is usually 

 through lowlands or swamps. Sometimes called SLOUGH. 



BEACH. The zone of unconsolidated material that extends landward from the low 

 water line to the place where there is marked change in material or 

 physiographic form, or to the line of permanent vegetation (usually the 

 effective limit of storm waves). The seaward limit of a beach — unless 

 otherwise specified — is the mean low water line. A beach includes FORE- 

 SHORE and BACKSHORE. See also SHORE. (See Figure A-1.) 



BEACH ACCRETION. See ACCRETION. 



BEACH BERM. A nearly horizontal part of the beach or backshore formed by the 

 deposit of material by wave action. Some beaches have no berms, others 

 have one or several. (See Figure A-1.) 



BEACH CUSP. See CUSP. 



BEACH EROSION. The carrying away of beach materials by wave action, tidal 

 currents, littoral currents, or wind. 



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