coasts

Question 1

Hydraulic action

Answer 1

lots of sea water crashes against the land and air and water are trapped and compressed in rock surface cracks
when the sea moves away again the air expands explosively weakening the rocks, enlarging the cracks and breaking pieces off

Question 2

Corrasion or abrasion

Answer 2

is very effective and is caused by broken rock fragments battering the land cliffs etc and breaking off other piece of rock

Question 3

Attrition

Answer 3

attrition occurs when rock fragments find each other down in to smaller and smoother pebbles shingle and finally sand which is later deposited as beaches

Question 4

Corrosion

Answer 4

involves chemical action of sea on rock. Weak acids and and salts in seawater can dissolve some rock types e.g. limestone

Question 5

Wave pounding

Answer 5

the battering action of the weight of funding waves

Question 6

Groynes

Answer 6

Grounds are wooden structures placed at right angles to the coast where longshore drift occurs. They reduce movement of material along the coast and hold the beach in place protecting the shore from further erosion.

Question 7

Sea walls

Answer 7

Sea walls reduce erosion and protect against flooding in lowland areas. The problem is that they deflect (not absorb) the waves. This means the protective beach gets washed away. The waves also erode the wall itself which can collapse.
They are expensive to build.

Question 8

Revetments

Answer 8

Revetments are like slatted barriers which are built where a sea wall is too expensive e.g. out of towns . They break the wave force trapping beach material benign then and protecting the cliff base - they are more effective than sea walls but look ugly and don’t give full protection

Question 9

Gabions

Answer 9

Gabon are steel mesh cages containing boulders built on the cliff face or along a beach. The rocks absorb some of the wave energy and cut down erosion - they are cheap but ugly

Question 10

Armour Blocks

Answer 10

Armour blocks are large boulders pile on teachers where erosion is likely. They are cheap but ugly and they can be moved by strong waves.

Question 11

points about sea defences

Answer 11

Hard engineering style sea defences are not sustainable in the long term. They are extremely expensive, ugly, need constant maintenance and often cause problems further down the coast.
None of the methods of sea defences are perfect but they have their merits

Question 12

hard engineering

Answer 12

groynes, sea walls, revetments, gabions and armour blocks

Question 13

soft engineering (sustainable methods)

Answer 13

Soft engineering approaches try to fit in with the natural coastal processes and protect habitats - e.g. beach nourishment, shoreline vegetations, dine stabilisation, manage retreat, set backs

Question 14

beach nourishment

Answer 14

beach nourishment is the term for adding more mud or sand to the beach. The beach is an excellent natural flood defence so by replacing all the sediment that’s eroded you avoid a big flood problem. The problem is how to get the sediment without causing environment damage somewhere else. It is also pretty expensive and needs to be done again and again.

Question 15

shoreline vegetation

Answer 15

planting things like marsh beds on the shoreline bind the beach sediment together, slowing erosion. It also encourages shoreline habitats to develop

Question 16

dune stabilisation

Answer 16

Dunes (big sand mountains) are an excellent defence against storm floods. Sediment is added and erosion is reduce by footpath control and marram grass planned . This supports the dune ecosystem.

Question 17

Managed retreat

Answer 17

instead of continually pumping money in to fighting a losing battle, managed retreat is about slowing coastal erosion but not trying to stop it. Eventually buildings will have to be moved or lost to the sea, but this can often be cheaper than investing in constant coastal control.

Question 18

set backs

Answer 18

set backs - mean building houses set back form the coasts edge.

Question 19

think about how coastlines can be protected - include examples of hard engineering and soft (sustainable) and say why they are good or bad

Answer 19

Hard - groynes, sea walls, revetments, gabions and armour blocks
Soft - beach nourishment, shoreline vegetations, dune stabilisation, manage retreat, set backs

Question 20

features of coastal erosion

Answer 20

cliffs 
headlands 
caves 
arches 
stacks