Wave Erosion

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Wave Erosion

• This slide show explains how waves can straighten
  a coastline.

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(No Transcript)
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Headland
Wave Fronts
Wind Direction
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Orthogonalsimaginary lines that divide a wave
into equal segments of energy. Perpendicular to
wave crests. (Broken lines above.) On an
unrefracted wave these are equal in width, eg.,
the outer most wave in the diagram.
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The amount of energy contained in a wave between
any two orthogonals is assumed to be constant
regardless of refraction. Note that a point of
land refracts the waves in such a way that energy
is focussed on the point. An embayment has the
opposite effect.
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A
B
There is an equal amount of energy in A as there
is in B but the actual length of coastline is
much more for A than it is for B. Therefore, the
wave energy per unit of coastline is greater in B
than A.
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Eroded materials carried to bays
The net effect of this is that erosion is greater
on headlands. Combined with longshore drift and
beach drift, which carry eroded sediments into
the embayments where they get deposited,
coastlines tend to be straightened by wave action
regardless of the direction of the waves in the
open ocean.