Coasts Flashcards
Define coast
Where the land meets the sea
What factors effect the rate of erosion?
Tide Current Weather Soft rock and hard rock Sea defences People Beach Rock structure
Benefits that coasts bring us…
Fishing
Docks - Trade
Money
Jobs
Problems that coasts cause…
Erosion of land, pollution, danger
Overcrowding
Litter
Flooding
How does weathering create land forms on the coast? [5]
Waves attack the base of the cliff
Abrasion corrosion attrition and hydraulic action all contribute towards this erosion
Eventually the cliff becomes unstable and collapses
Further cliff retreat will form a wave-cut platform
What is a wave cut notch?
A small crack in the bottom of the coastlines rock wall
What is a wave cut platform?
An area of land in front of the cliff edge that has been eroded and left a beach platform
How is a stump created?
Weathering causes a small FAULT in the headland to be formed
The waves attach this weakness and will eventually form a cave. The cave then develops into an arch due to erosion from the waves
Then the resistant rock that supports the arch will eventually collapse and a stack will be left
Finally the stack will get undercut causing it to be unstable and collapse leaving a small stump behind
How is a bay formed?
Hard rock surrounds soft rock
The soft rock becomes eroded and gets eroded inwards
Thus creating a bay
How does a wave form?
In the beginning wind builds up the force of a wave
The wave then travels along the surface of the water
When it gets closer towards the beach friction is built up between the base of the wave and the sea bed causing ripples to develop into waves
The wave that is formed will topple over once it has reached land
The water going up the beach is known as swash
The water going back out to sea is known as backwash
Define fetch
The stretch of open water over which the wind blows
The longer the fetch the more powerful the wave can become
Define swash
The water that rushes up the beach
Define backwash
The water that travels up then down the beach
What is a constructive wave?
A wave that builds up a beach by having a strong swash (transporting material along/up the beach) and a weak backwash
What is destructive wave?
A wave that effectively ‘destroys’ a beach by having a tall height in proportion to its length meaning that it has a weak swash but strong backwash
Explain Long Shore Drift…
Long shore drift occurs when the wind approaches the beach at a 45* angle
The wind pushes the water up and down the beach
The water travels up the beach (swash) and deposits material in the process
Backwash occurs when the water travels back down the beach which pulls material down and away from the beach
What are three factors that are needed/contribute towards the development of spits and bars?
Strong long shore drift
Large amounts of sediment
A change in the direction of the coastline
How does a spit develop?
Long shore drift transports material beyond the change in the coastline
The spit is formed when the material is deposited in front of the change in the coastline
Over time the spit will grow in length and may develop into a hook depending on the wind direction in the area
Waves cannot get behind the spit and thus creating a sheltered area in which silt is deposited which forms a salt marsh
How does a bar develop?
When a bay has been formed and a strong long shore drift is present a bar can form connecting the two sets of hard rock surrounding the bay
The formation of a bar is the same as the formation of a spit, only it connects two land sectors together
How does a Tombolo form?
A tombolo is simply when a spit develops into a bar and connect to land masses together creating a ‘bridge’ between them
What are some economic effects of coastal erosion?
Land is eroded which decreases land value
Jobs can be lost if businesses fall off the cliff
People’s house values drop due to the possible/inevitable erosion
Expensive/impossible to get insurance
Properties that are destroyed cost money to clear
What are some social effect of coastal erosion?
People’s house values drop
People are forced to move
Expensive/impossible to get insurance due to possible/inevitable erosion
Loss of homes
What are some environmental effects of costal erosion?
Loss of land
Eroded land becomes an eye sore
