EM 1110-2-1100 (Change 1)
31 Jul 03
Usage note: CAPITALIZATION within a definition indicates that the term is defined elsewhere in the
glossary. Figure numbers refer to the main text of the Coastal Engineering Manual.
A
ABRASION
The mechanical wearing away by rock material transported by wind or water
ABRASION PLATFORM
A rock or clay platform which has been worn by the processes of abrasion.
A device used in wave buoys for measuring acceleration.
ACCRETION
May be either natural or artificial. Natural accretion 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 reason of
an act of man, such as the accretion formed by a GROIN, BREAKWATER, or beach fill deposited by mechanical means.
Also AGGRADATION.
ACTIVE MARGIN
A margin of a continental plate consisting of a continental shelf and slope, and an oceanic trench or basin.
ADJUSTABLE GROIN
A GROIN whose permeability can be changed, usually with gates or removable sections.
ADVANCE (of a beach)
(1) A continuing seaward movement of the shoreline. (2) A net seaward movement of the shoreline over a specified
time. Also PROGRESSION.
ADVECTION
Changes in a sea water property (salinity, temperature, oxygen content, etc.) that take place in the presence of
currents. Also, changes in atmospheric properties in the earth's atmosphere.
AEOLIAN
See EOLIAN.
AGE, WAVE
The ratio of wave velocity to wind velocity (in wave forecasting theory).
AGGRADATION
See ACCRETION.
ALIGNMENT
The course along which the center line of a channel, canal or drain is located.
ALLUVIAL DEPOSITS
Detrital material which is transported by a river and deposited usually temporarily at points along the flood plain
of a river. Commonly composed of sands and gravels.
ALLUVIAL PLANE
A plain bordering a river, formed by the deposition of material eroded from areas of higher elevation.
ALLUVIUM
Soil (sand, mud, or similar detrital material) deposited by streams, or the deposits formed.
Appendix A Glossary of Coastal Terminology
A-1
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