Culm - Single stem of grass.
Current - Flow of water in a given direction.
Current, Longshore - Current in the breaker zone moving essentially parallel to shore and usually caused
by waves breaking at an angle to shore. Also called alongshore current.
Deep Water - Area where surf ace waves are not influenced by the bottom. Generally, a point where the
depth is greater than one-half the surface wavelength.
Diffraction- Progressive reduction in wave height when a wave spreads into the shadow zone behind a
barrier after the wave has passed its end.
Diurnal - Period or cycle lasting approximately one day. A diurnal tide has one high and one low in each
cycle.
Downdrift - Direction of alongshore movement of littoral materials.
Dune - Hill, bank, bluff, ridge, or mound of loose, wind-blown material, usually sand.
Duration - Length of time the wind blows in nearly the same direction across a FETCH (generating area).
Ebb Tide - Part of the tidal cycle between high water and the next low. The falling tide.
Equilibrium - State of balance or equality of opposing forces.
Erosion - Wearing away of land by action of natural forces.
Fetch - Area where waves are generated by wind, which has steady direction and speed. Sometimes
called FETCH LENGTH.
Fetch Length - Horizontal direction (in the wind direction) over which a wind generates waves. In
sheltered waters, often the maximum distance that wind can blow across water.
Filter Cloth - Synthetic textile with openings for water to escape,
but which prevents passage of soil particles.
Flood Tide - Part of the tidal cycle between low water and the next high. The rising tide.
Glacial Till - Unstratified glacial drift consisting of unsorted clay, sand, gravel, and boulders,
intermingled.
Longshore - Parallel to and near the shoreline: same as ALONGSHORE.
Longshore Transport Rate - Rate of transport of littoral material parallel to shore.
Usually expressed in
cubic yards per year.
Low Tide - Minimum elevation reached by each falling tide.
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