EM 1110-2-1100 (Change 1)
31 Jul 03
BERM BREAKWATER
Rubble mound structure with horizontal berm of armor stones at about sea level, which is allowed to be (re)shaped
by the waves.
BERM CREST
The seaward limit of a BERM. Also called BERM EDGE. (See Figure A-1)
BIGHT
A bend in a coastline forming an open BAY. A BAY formed by such a bend.
BIOTURBATION
The disturbance of sediment bedding by the activities of burrowing organisms.
BIRDFOOT DELTA
A river DELTA formed by many levee-bordered DISTRIBUTARIES extending seaward and resembling in plan the
outstretched claws of a bird. Example: Mississippi River delta.
BLANKET (FOUNDATION or BEDDING)
A layer or layers of graded fine stones underlying a BREAKWATER, GROIN or rock embankment to prevent the
natural bed material from being washed away.
BLOWN SANDS
See EOLIAN SANDS.
BLOWOUT
A depression on the land surface caused by wind erosion.
BLUFF
A high, steep bank or cliff.
BOG
A wet, spongy, poorly drained area which is usually rich in very specialized plants, contains a high percentage of
organic remnants and residues and frequently is associated with a spring, seepage area, or other subsurface water source. A
bog sometimes represents the final stage of the natural processes of eutrophication by which lakes and other bodies of water
are very slowly transformed into land areas.
BOIL
An upward flow of water in a sandy formation due to an unbalanced hydrostatic pressure resulting from a rise in a
nearby stream, or from removing the overburden in making excavations.
BOLD COAST
A prominent landmass that rises steeply from the sea.
BORE
A very rapid rise of the tide in which the advancing water presents an abrupt front of considerable height. In
shallow estuaries where the range of tide is large, the high water is propagated inward faster than the low water because of the
greater depth at high water. If the high water overtakes the low water, an abrupt front is presented, with the high-water crest
finally falling forward as the tide continues to advance. Also EAGER.
BOTTOM (nature of)
The composition or character of the bed of an ocean or other body of water (e.g., clay, coral, gravel, mud, ooze,
pebbles, rock, shell, shingle, hard, or soft). (See Figure A-1)
A-10
Appendix A Glossary of Coastal Terminology
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