3. Key Terms relating to coastal
management
• Advance the Line:
– A strategy to move the defence of an area seaward of its
position, e.g. land reclamation.
• Hold the line:
– A strategy to hold the current line of the coast. E.g. Beesands in
Devon.
• Do Nothing:
– Carry out no coastal defence activity except for safety measures.
E.g. moving static caravans away from cliff edge at …………., ……
• Retreat the line:
– A strategy to encourage the movement of the shoreline
landward of its present position in a managed or controlled
manner, hence the term ‘managed retreat’. E.g …………………….
4. • Soft Engineering
Makes use of natural systems, such as beaches or salt
marshes, to help with coastal defences,. The advantage of
soft systems is that they can absorb and adjust to wave and
tidal energy and have a more natural appearance.
• Hard Engineering
Involves building a physical structure, usually from rocks or
concrete, to protect the coast from the forces of natural. It is
used to reduce erosion and the risk of flooding.
Definitions
6. A. Soft Engineering
1. Beach Nourishment
• Sand and/or pebbles are brought in to
replace material that has eroded away.
• Natural looking
• Expensive and never ending!
8. 2. Beach Re-profiling
• Shape of beach
changed to
reduce the effects
of erosion.
• Cheap and simple
• Only works in low
energy
environment.
9.
10. 3. Dune regeneration
• Wooden structures erected to encourage sand
deposition and vegetation planted.
• Effective if managed properly.
• Only succeeds if public access is limited.
11.
12.
13.
14. 4. Offshore reefs
• Mining waste, old tyres and even old cars are
sunk and act like speed bumps in the sea.
• Cost effective and semi- natural.
• Largely untested and may have pollution
impacts.
17. B. Hard Engineering
1. Groynes
• Groynes are designed to slow down longshore
drift
• The Build up of sand reduces the wave energy
and thus protects the beach
• They are usually made of tropical hardwoods
which are more resistant to erosion.
• A few are made of concrete, steel or in more
recent times large rocks.
• They are built at right angles to the shore and
spaced about 50-100 metres apart. Groynes
may have a life of 15-20 years
18.
19. Terminal Groyne Effect
• Occurs when there are piecemeal protection
schemes.
• For instance a groyne field is built and
sediment builds up between the groynes
• The coastline continues to erode.
• On the downdrift side there is a sediment
deficit. The erosion of non protected side
continues
23. Gabions
• Small rocks, bound in place by cages
absorb the wave energy and reduce
erosion
• Cheap
24.
25. 4) Revetments
• Open structure of planks absorb wave
energy, but allow sand and shingle to build
up beyond
26.
27.
28. 5) Rock Armour / Rip Rap
• Large resistant rocks placed at base of cliff to
stop erosion.
• Help to absorb and dissipate wave energy.
• When resting on sand and shingle they may
be moved out of position by waves.
29.
30.
31.
32.
33.
34.
35.
36. Your turn!
• Now using p 241 in the text book complete
the hard engineering section of your A3 sheet.
