This document discusses various types of coastal erosion and protection methods. It describes the characteristics and impacts of constructive and destructive waves. It also explains various coastal landforms that form from erosion like cliffs, arches and stacks. Additionally, it outlines different coastal management techniques like riprap, seawalls, beach replenishment and managed retreat. The advantages and disadvantages of each protection strategy are provided.

1. By Badir

2. Characteristics:
 Backwash is much stronger than its
swash, therefore it carries sediment away
from the shore.
 The break frequently, between ten to fifteen
every minute.
 High in porportion to their length.
 There are generally found in steep beaches

3. These types of wave are responsible for coastal
erosion.

4. Characteristics:
 The swash is more powerful than the
backwash, therefore it deposits sediment on
the beach.
 The break infrequently at rate of ten or
fewer per minute.
 They are long in relation to their height.
 They are usually found on gently sloping
beaches.

5. This type of wave is responsible for
depostition.

6. Hydraulic action: Pressure of water being
thrown onto a cliff.
Corrasion/Abrasion: Sand and pebbles scrape
are thrown against the cliff and they scrape
it therefore causing erosion.
Corrosion: A chemical rection between the ock
and the salt and the other acids in seawater.
Eg Limestone.
Attrition: When boulders and rock bang into
eachother it causes them to lose parts of the
rock because they are being chipped off.

7. Physical weathering: (Freeze Thaw) This is
when water gets into cracks in the rock.
When the temperature falls below 0 degrees
it freezes, therefore the water will expand
as it turns to ice. As a result this would add
pressure to the surrounding rocks and causing
them to break off.

8. Chemical Weathering: Rain water contains
weak acids (Sulfur dioxide and Nitrogen
oxide) these can react with certain rocks.
The carbonates in limestone are dissolved by
these acid and this causes the rock to break
up and disintegrate.

9. Biological Weathering: This is the action of
plans on animals on land. When seeds fall
into cracks and grow the roots of the plant
put pressure on the rock and therefore break
the rock. Burrowing animals such as rabbits
can also be responsible for further damage to
the rocks.

10. Basically the movement of material down a
slope due to the pull of gravity.
Slumping: During dry weather the clay
contracts and cracks, when it rains water
gets into the cracks and rock absorbs it until
it is saturated. This weakens the rock and
due to the pull of gravity it slips down the
slope in a rotational movement. This is most
common on the coast.

11. Soil creep: This is the slowest downhill
movement of material. It happens when
water on the slope is frozen therefore it
expands causing the material to stick out at
an angle. Then when it is warmer it turns
back into water but due to the pull of gravity
it falls at a 90 degree angle. This leaves
terracetts behind

12. On coastlines where the resistance of rocks varies.
The headlands are the ones that stick out onto the
sea since they are more resistant therefore it is
takes longer for it to be eroded. However the bay
is made of a less resistant rock therefore it erodes
more easily. After a while when the bay has
retreated back the waves would be breaking on
the headlands first therefore they would now be
experiencing a lot more force therefore they erode
quickly now.

14. When the force of the sea attacks the base of a cliff
(Hydraulic action and abrasion) it undercuts the cliff
forming a wave cut notch. Above this an overhand
has been formed after a long period of time due to
the weight and pull of gravity the overhang will fall
(sometimes due to weathering also) . As this process
repeats itself the cliff will retreat. The rocks will fall
into the sea creating a platform, overtime the width of
the platform increases therefore the power at which
the waves hit the cliff decreases.

16. These are formed in rocks that a have a fault
or line of weakness. The fault will be
exploited due to the sea (hydraulic action).
Over a certain period of time the fault will
widen to form a cave. After continuous
erosion caves from both side meet forming
an arch. The sea will continue to erode the
bottom of the arch, and weathering will
weaken the rock. Over time the rock will fall
down due to gravity and its weight. This
leaves a column of rock called a stack.
Continued weathering and erosion will
develop the stack into a stump.

18. It is the movement of sand and pebbles down a
coastline. The direction of the prevailing
wind determines the angle at which the
swash will hit the beach. The backwash will
be perpendicular due to gravity. Due to this
process material is transported down the
beach. Long shore drift creates landforms
such as spits and bars

19. A beach is an area of land between the low
tide and storm tide marks, it is made up of
sand and pebbles. They are often formed in
bays where the swash is weak therefore
material is deposited.

20. A spit is a long narrow stretch of pebbles and
sand which is attached to land at one end. It
forms due to long shore drift. This is because
when the coastline ends, the sea deposits
the material it was transporting. If there is a
river estuary then the waves and river cause
a change in speed which cause both the river
and sea to deposit its material. Overtime the
material builds up and forms a spit. Salt
marshes are formed in the side of the spit
closer to the coast.

22. If a spit develops in a bay it may build across it
linking two headlands to form a bar. However
this is only possible if there is a beach with a
gentle slope and no river entering the sea.

23. The North Norfolk coast’s new shoreline
manage plan consists of a managed retreat
which means that 1000 homes, 1400 caravan
and chalet parks, six hotel and hotels, seven
historic building, 3.5km of road, seven golf
course holes and three community halls will
be lost to the sea over the next 100 year. The
government will save 41 million pounds by
not building coastal defenses. However the
estimated economic cost will be 100 million
pounds and 357 million pounds for tourism.

24. The met office predicts how likely a coastal
flood is to happen. Also the environment
agency has a website which warns people
when floods may happen.
www.Direct.gov.uk educates people on how to
protect homes from flooding and how to
react to a flood.
DEFRA provides money for coastal flooding
protection.
Also building design can help reduce effects of
coastal flooding.

25. Rip-rap: They are large rocks placed in front of
the cliff.
Advantages: Very cheap, effective for many
years, and reduce the energy of the waves.
Disadvantages: Can make the beach
inaccessible, unattractive and not effective
in storm conditions.

26. Recurved sea wall: Walls usally made with
concrete.
Advantages: Reflects and absorbs wave’s
energy, effective for many years and its very
visible therefore it makes residents feel safe.
Disadvantages: Ugly and makes tourists angry,
expensive to build

27. Groynes: Usually made from wood stretches
from the coastline into the sea.
Advantages: Prevents long shore drift (sand
builds up on one side of the groyne, it keeps
beaches in place for the tourist industry and
it is effective for many years.
Disadvantages: Unattractive and difficult to
walk over and it disrupts the natural process
of long shore drift which effects area down
the coast because they won’t have as much
sand.

29. Gabions: Wire cages filled with stone used to
reduce erosion.
Advantages: Cheaper than other forms of
coastal defence and the rock cages absorbs
the waves energy.
Disadvantages: Wire cages can break and they
are not as efficient as other forms of coastal
defence.

30. Offshore reef: Large concrete blocks and
natural boulders are sunk offshore to alter
wave direction and to dissipate the energy of
the waves.
Advantages: The waves lose energy when they
hit the offshore reefs therefore less erosive
power and they allow the build up of sand.
Disadvantages: May be removed by heavy
storms and difficult to install them.

32. Beach replenishment: The placing of sand and
pebbles on a beach.
Advantages: Looks natural, provides beaches
for the tourists, a beach is the best form of
natural defence because it dissipates wave
energy and its cheap.
Disadvantages: The scheme requires constant
maintenance, it can all be wash away very
quickly in less than a year and it creates a
loud nice as large lorries full of sand reularly
replenish beach.

33. Cliff regrading: The cliff is cut back and given
a new gentle slope to stop it slumping,
Advantages: It may be covered in ecomatting
to encourage vegetation growth and it is very
natural therefore it will encourage wildlife.
Disadvantages: It is not effective by itself it
will need extra defence at the bottom of the
cliff and some homes on the cliff may have
to be demolished.

34. Managed retreat: Allowing the sea to gradually
flood land or erode cliffs (North of Norfolk).
Advantages: Creates new habitats for plants
and birds and it is cheap.
Disadvantages: Upsetting for land owners who
lose land and it is difficult to estimate the
extent of sea movement especially with
rising sea levels.