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Swash and backwash operate to move material
along the beach.
Groyne at Walton-on-the -Naze
2
lessons
A spit growing out into deep water
The spit is trying to join Hengistbury Head to Mudeford across Christchurch Bay
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Longshore
drift
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page
9 draw the diagram at the top of the page, on longshore
drift, and explain how this process operates.
Use the graphic opposite, or you could use the graphic from
Georesources on longshore drift.
groynes
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What job is
the groyne doing in the photo opposite?
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Make a sketch
of the photograph opposite. On it you should label; sandy beach,
shingle beach, wave breaking at an angle, heavy wooden
posts, iron band to hold post top, iron bracket, heavy timbers
between posts, groyne, discoloured by marine creatures.
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How would
you set up a piece of fieldwork to prove longshore drift?
... see the photo left. What would you measure and how
would you record your results.
spits
When the
coastline changes direction, the beach that is being moved by
longshore drift just keeps going! It builds out to sea, or
across a river mouth, even into quite deep water. At its end the
waves bend around and curve its tip (making it recurved), and
inshore of the spit salt marshes start to build up.
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On page 11 the graphic at the top of the page has labels 7-10 devoted to the formation of spits. Draw a sketch of photo B from page 11 and use labels 7-10 to explain its formation. Also answer qn.3 page 11 on your sketch.
Spurn Head on multimap
Orfordness on multimap
and
Shingle Street
Hurst Castle spit on multimap
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Use one of
the above links to get a map/photo of a spit. Sketch its shape
and label its named features, and show the direction of
longshore drift and any salt marshes present.
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Complete the longshore drift and spit
sheet in the explanation boxes .. this features a map of Spurn Head.
Spurn Head photos on this site
You
could also use a shot of Spurn
Head
from Fortune City, which has a site
devoted to the Holderness coast of Yorkshire.
^ This
photograph, of Orfordness is from
norfolkskyview.flier,
where there are a number of good aerial
shots of East Anglia, can be used to illustrate how spits
develop. This feature dominates the Suffolk coastline from
Aldeburgh southwards.
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