EM 1110-2-1100 (Change 1)
31 Jul 03
CONTINENTAL SHELF
(1) The zone bordering a continent extending from the line of permanent immersion to the depth, usually about 100
m to 200 m, where there is a marked or rather steep descent toward the great depths of the ocean. (2) The area under active
littoral processes during the HOLOCENE period. (3) The region of the oceanic bottom that extends outward from the
shoreline with an average slope of less than 1:100, to a line where the gradient begins to exceed 1:40 (the CONTINENTAL
SLOPE).
CONTINENTAL SLOPE
The declivity from the offshore border of the CONTINENTAL SHELF to oceanic depths. It is characterized by a
marked increase in slope.
CONTOUR
A line on a map or chart representing points of equal elevation with relation to a DATUM. It is called an
ISOBATH when connecting points of equal depth below a datum. Also called DEPTH CONTOUR.
CONTROLLING DEPTH
The least depth in the navigable parts of a waterway, governing the maximum draft of vessels that can enter.
CONVERGENCE
(1) In refraction phenomena, the decreasing of the distance between orthogonals in the direction of wave travel.
Denotes an area of increasing wave height and energy concentration. (2) In wind-setup phenomena, the increase in setup
observed over that which would occur in an equivalent rectangular basin of uniform depth, caused by changes in planform or
depth; also the decrease in basin width or depth causing such increase in setup.
CORAL
(1) (Biology) Marine coelenterates (Madreporaria), solitary or colonial, which form a hard external covering of
calcium compounds or other materials. The corals which form large REEFS are limited to warm, shallow waters, while those
forming solitary, minute growths may be found in colder waters to great depths. (2) (Geology) The concretion of coral
polyps, composed almost wholly of calcium carbonate, forming reefs and tree-like and globular masses. May also include
calcareous algae and other organisms producing calcareous secretions, such as bryozoans and hydrozoans.
CORAL REEF
A coral-algal mound or ridge of in-place coral colonies and skeletal fragments, carbonate sand, and organically-
secreted calcium carbonate. A coral reef is built up around a wave-resistant framework, usually of older coral colonies.
CORE
(1) A cylindrical sample extracted from a beach or seabed to investigate the types and depths of sediment layers.
(2) An inner, often much less permeable portion of a BREAKWATER or BARRIER BEACH
CORIOLIS EFFECT
Force due to the Earth's rotation, capable of generating currents. It causes moving bodies to be deflected to the right
in the Northern Hemisphere and to the left in the Southern Hemisphere. The "force" is proportional to the speed and latitude
of the moving object. It is zero at the equator and maximum at the poles.
COVE
A small, sheltered recess in a COAST, often inside a larger EMBAYMENT.
COVER LAYER
The outer layer used in a rubble system as protection against external hydraulic loads
CREEK
(1) A stream, less predominant than a river, and generally tributary to a river. (2) A small tidal channel through a
coastal MARSH.
Appendix A Glossary of Coastal Terminology
A-17
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