coasts and rivers part 1 Flashcards
abrasion
a form of erosion where loose material and sediment ‘sandpapers’ the walls and floors of the river
attrition
rocks bang each other chipping away to make small and smoother rocks
hydraulic action
is the sheer force of water crashing against the coastline causing material to be dislodged and carried away by the sea
constructive waves characteristics
have stronger swashes than backwashes
backwashes are not strong enough to remove the sediment
low energy
begins to build up the coastline
far apart
destructive wave characteristics
weak swash
strong backwash
the strong waves removes sediment from the beach
steep
close together
sea walls disadvantages
can protect one area of the coasts but can increase erosion further down the coastline by disturbing the natural sediment movement
they can be visually intrusive which can spoil the natural beauty of the coastline
expensive to build and maintain-as sea levels rise, sea walls may need to rebuilt higher or more frequently making it more expensive
rock wall (rock armour) disadvantages
can interfere with natural processes like longshore drift leading to increased erosion in unprotected areas down the coast
often look out of place
makes access to the beach difficult as people might have to clamber on rocks or take a detour to get onto the beach
strong waves can cause the boulders to move causing them to have to be replaced
gabions disadvantages
they are weak than other management strategies which means they need regular maintenance
labour intensive
bulky and space-consuming
what are gabions?
are costal defences that consist of rocks and boulders encased in wired material
types of mass movement
rock falls
mudslide
landslide
slumping
beach nourishment
sediment can be put onto beaches
lorries dump thousands of tonnes of sand and shingle
widens the beach
does not stop erosion but slows it down but it is only a short term solution
relatively cheap
attractive
attracts tourists and local people as it provides a wider beach
concerned that the environment will get damaged
does not protect the whole beach
involves heavy machinery which can disrupt local tourism and businesses
beach reprofiling
change the shape of the coastline so it can absorb more wave energy
existing methods redistributed
relatively cheap
sustainable and natural looking
quick to implement
short term effectiveness
ongoing costs
disruption during work
limited protection
dune regeneration
is the artificial creation of new sand dunes or the restoration of existing sand dunes
act as a physical barrier
natural by most people
attractive amenity to the local people and tourists
may also increase biodiversity
easily damaged by storms
time consuming to plant the grass
doesn’t maintain the area
what is managed retreat?
it is a coastal management strategy that allows the shoreline to move inward instead of attempting to hold the line with structural engineering
