3. Wave Formation
Frictional
force between the wind and the
sea surface
Transfers circular motion to the water
In open water we get swells
As swells approach the shore waves are
formed
Waves break when the depth of the
water is less than the wave height
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6. Type of waves
Two types
Constructive – These build
beaches by depositing sand,
shingles and pebbles
Destructive
– These remove
material from the shore
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8. Characteristics - destructive
Backwash
>
is greater than the swash
Backwash > Swash
9 per minute
Short
wave lengths
Plunge
against the shore
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10. Characteristics - constructive
Swash
<
is greater than the Backwash
Swash > Backwash
9 waves per minute
long
Spill
wave lengths
onto the shore
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13. Wave Erosion
Hydraulic
alone
Attrition
– Load knock against each other
Abrasion
shore
Solution
the rock
Action – force of the water
or Corrasion – Load erodes the
– Sea water disolves minerals in
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15. Wave Transportation
The
movement of material can be either
of three ways: in, out and along
In, deposition of material to form beaches
Out, removal of material from the shore out
to sea by the undertow
Along the shore is called longshore drift
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17. The effect of Groynes /
Groines along a beach
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18. Wave Deposition
Deposition
is the laying down of
transported material
Constructive waves and gently sloping
shorelines are associated with deposition
Where rivers discharge into the sea
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20. Types of Coastal features
Erosional
– those produced by erosion
Examples: cliff, notch, wave-cut
platform, headland and bay, caves,
arches, stacks and blowholes
Depositional
– those produced by
deposition
Examples: beaches, spit, tombolo
and bars
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26. Wave Refraction
The change in the direction of
the waves as they approach the
shore, converging on headlands
and diverging as they approach
the bay
Stronger on the headlands
Weaker in the bay
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31. Depositional Features
What
are the two main conditions which
lead to the formation of depositional
features?
Constructive waves and gently sloping
shorelines are associated with deposition
Where rivers discharge into the sea
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33. A Beach
A
beach is a depositional feature. What
material is laid down to form a beach?
What is a bay-head beach?
Draw
a diagram to illustrate a beach.
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34. Other Depositional features
Spit
Bar
Tombolo
Draw
well labelled diagrams of the
features identified above.
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42. thanks
Physical
Geography in Diagrams
– R B Bunnett
Dale
Franklin – for the teaching concepts
and the initial powe-rpoint.
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