Top: Science: Environment: Coasts and Beaches: Terminology: W




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Water depth

Distance between the seabed and the still water level.


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Water level

The ELEVATION of a particular point or small patch on the surface of a body of water above a specific point or surface, averaged over a period of time sufficiently long to remove the effects of short period disturbances.


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Water line

(1) The juncture of land and sea. This line migrates, changing with the tide or other variation of the water level. Where waves are present on the BEACH, this line is also known as the limit of BACKRUSH.
(2) The common boundary between the water surface and any immersed structure.


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Water mark

A line or mark left on the shores of a body of water by the water as an indication of the water’s former ELEVATION.


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water, navigable

The waters which are or can be used as water highways for commerce.


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Water table

The upper surface of a zone of saturation, where the body of groundwater is not confined by an overlying impermeable formation. Where an overlying confining formation exists, the AQUIFER in question has no water table.


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Water type

A water having well-defined temperature, salinity and nutrient characteristics.


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Wave

(1) An oscillatory movement in a body of water manifested by an alternate rise and fall of the surface.
(2) A disturbance of the surface of a liquid body, as the ocean, in the form of a ridge, swell or hump.
(3) The term wave by itself usually refers to the term SURFACE GRAVITY WAVE (PROGRESSIVE). See also CAPILLARY WAVE, GRAVITY WAVE, PROGRESSIVE WAVE, STANDING WAVE, TIDE WAVE, TSUNAMI.


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Wave age

The ratio of wave velocity to wind velocity.


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Wave climate

Average condition of the WAVES at a place, over a period of years, as shown by height, period, direction, etc.


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Wave climate atlas

Series of maps showing the variability of wave conditions over a long COASTLINE.


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Wave crest

(1) The highest part of the wave.
(2) That part of the wave above still water level.


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Wave crest length

See CREST LENGTH.


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Wave-cut platform

A horizontal BENCH of rock formed beneath the surf zone as a COAST retreats because of wave EROSION.


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Wave delta

See DELTA.


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Wave direction

The direction from which the waves are coming.


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Wave drift

The small net forward displacement of water in the direction of the wave travel, particularly in waves of large AMPLITUDE, so that the orbits are not quite closed, and the water, while in the crests, moves slightly further forward than it moves backward while in the troughs. See also MASS TRANSPORT, SHOREWARD.


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Wave generation

Growth of wave energy by wind.


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Wave group

A series of waves in which the distance between crests, and the AMPLITUDE, vary only slightly.


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Wave height

The vertical distance between the crest (the high point of a wave) and the trough (the low point).


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Wave hindcast

The calculation from historic synoptic weather charts of the wave characteristics that probably occurred at some past time.


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Wave hollow

See WAVE TROUGH.


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Wave length

The distance, in meters, between equivalent points (CRESTS or TROUGHS) on waves.


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Wave period

(1) The time required for two successive wave crests to pass a fixed point.
(2) The time, in seconds, required for a wave crest to traverse a distance equal to one wave length.


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Wave propagation

The transmission of waves through water.


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Wave recorder

A meter which records either the surface time history of GRAVITY WAVES, or the subsurface pressure time history due to these waves.


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Wave refraction

See REFRACTION.


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Wave rose

Diagram showing the long-term distribution of wave height and direction.


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Wave set-up

ELEVATION of the still-water level due to breaking waves.


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Wave staff

An instrument consisting of a graduated vertical pole for measuring wave heights, and, by introducing a timing device, wave periods. The staff may support a strip or series of electrical contacts for activating a recorder.


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Wave steepness

The ratio of wave height to its length. Not the same thing as the slope between a wave crest and its adjacent trough.


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Wave train

A series of waves from the same direction.


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Wave transformation

Change in wave energy due to the action of physical processes.


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Wave trough

The lowest part of the wave form between crests. Also that part of a wave below STILL WATER LEVEL.


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Wave variability

(1) The variation of heights and periods between individual waves within a wave train. Wave trains are not composed of waves of equal heights and periods, but rather of heights and periods which vary in a statistical manner.
(2) The variability in direction of wave travel when leaving the GENERATING AREA.
(3) The variation in height along the crest.


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Wave velocity

Speed at which the individual wave form advances, defined as the wave length divided by the wave period (in meters per second). See CELERITY.


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Wave wash

The erosive action on shores or embankments caused by the lapping or breaking of waves.


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Weather shore

The land lying in the direction from which the wind is coming. The WINDWARD side.


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Weir

A low DAM or wall across a stream to raise the upstream water level. Termed fixed crest weir when uncontrolled.


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Well

A hole, generally cylindrical and usually walled or lined with pipe, that is dug or drilled into the ground to penetrate an AQUIFER below the zone of saturation.


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Well mixed estuary

In this circulation type, tidal fluctuations dominate, and the water column is mixed vertically.


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Wetlands

Lands whose saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities that live in the soil and on its surface (e.g. Mangrove forests).


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Whitecap

The white froth on crests of waves in a wind (caused by the wind blowing the crest forward and over).


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Wind current

A current created by the action of the wind. From theoretical considerations, currents produced by winds in the open sea will set to the right of the direction towards which the wind is blowing if in the Northern Hemisphere and to the left of this direction if in the Southern Hemisphere.


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Wind ripple

Small, low ridge of sand produced by the saltation of windblown sand.


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Wind rose

Diagram showing the long-term distribution of wind speed and direction.


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Wind sea

wave conditions directly attributable to recent winds, as opposed to swell.


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Wind setup

(1) The vertical rise in the stillwater level on the LEEWARD side of a body of water caused by wind stresses on the surface of the water.
(2) The difference in stillwater levels on the windward and the LEEWARD sides of a body of water caused by wind stresses on the surface of the water.
(3) synonymous with WIND TIDE and STORM SURGE. STORM SURGE is usually reserved for use on the OCEAN and large bodies of water. Wind setup is usually reserved for use on reservoirs and smaller bodies of water.


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Wind stress

The way in which wind transfers energy to the sea surface.


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Wind tide

The deviation from a still-water level surface ELEVATION caused by the transport of surface water by winds.


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Windward

The direction from which the wind is blowing.


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Wind waves

(1) waves formed and growing in height under the influence of wind.
(2) Loosely, any wave generated by wind.


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Witness mark

A material mark placed at a known distance and direction from a property corner, an instrument station or a survey station, as an aid in its recovery and identification.


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Witness post

See WITNESS MARK.



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