Coasts Flashcards
Name the 3 processes within the coastal system
Erosion, deposition, transportation
Outputs of the coastal system
Crack, cave, arch, stack, stump Cliffs Headlands and bays Spits Bars and tombolos Sand dunes Wave cut notches Beaches Wave cut platforms
What is a sediment cell?
A well defined boundary in which sediment can be transported around and form a depositional landform
How does a high energy coastline differ from a low energy coastline?
High energy = lots of inputs, processes and outputs (destructive waves)
Low energy = not as much (constructive waves)
What 3 factors acquire the energy of a wave?
- The strength of the wind
- The length of time the wind is blowing
- The fetch (the distance of which the wind blows over)
Give me 6 features of constructive waves
Low energy, frequency, steepness and in proportion to length. Strong swash and weak backwash
Give me 6 features of destructive waves
High energy and frequency, steep gradient waves, tall waves with short wavelength, weak swash, strong backwash (beach erosion)
Name 3 types of soft engineering
Coastal zoning (marsh creation)
Dune regeneration
Beach nourishment
When would you use coastal zoning?
When the land has not already been developed as the land behind it has no economic value, meaning no need for expenses on coastal management
What is the role of beach nourishment
To replace the beach or cliff material that has been removed by erosion or LSD. It increases the size of beaches meaning that when waves come up the beach, they have no energy left to erode.
What is the role of dune regenerations ?
Involves creating new sand dunes or stabilising existing dunes so that they can act as a barrier between the land and the sea, absorbing storm and wave energy.
Give 4 advantages of beach nourishment
Sustainable, tourists, cheap, doesn’t change the natural environment
4 disadvantages of beach nourishment
High maintenance
Have to close beach
Disturb marine life
3 advantages of dune regeneration
Sustainable
Cheap
Creates habitats
A disadvantage of dune regeneration
Can be wiped out in storm surges or strong winds
3 advantages of coastal zoning
Costs nothing
Looks nice
Good environment
3 disadvantages of coastal zoning
Erosion continues
Cant use the land
Individual complaints - someone’s house may have to go
Why is soft engineering sustainable when hard engineering isn’t?
Although hard engineering by outcome is stopping erosion, it is not sustainable because you can’t physically stop erosion. Yet soft engineering reduces the impact of erosion
Why do spring and neap tide occur?
Spring tide happens when the gravitational pull from both the sun and the moon is aligned and therefore there is a compensatory bulge and tide is at its highest. Neap tide happens when the sun and the moon form a right angle which means there is less gravitational pull and there is the lowest tide range.
When does a storm surge occur?
When the tide is unusually high (higher than spring tide) due to storm conditions when the wind is so powerful
What is our case study for mass movement
Holbeck hall
What is sub-aerial weathering?
Weathering that takes place lower down the cliff, creating weak points for erosion to compress into the cliff and erode it more efficiently
What are the 3 sections in long profile of a beach
Nearshore, foreshore, backstory
Name the features of the beach in order from the backshore to the nearshore
Storm beach, berms, cusps, runnels, ripples.
What is a spit
A long narrow ridge of sand an shingle which is projected into the sea from the coastline. Behind it salt marshes can form.
What is our case study of a spit?
Spurn head at Holderness Coast
What is stopping the spit from continually growing until it reaches another headland or island?
A river estuary (current)
What is a salt marsh?
A low energy zone formed behind a spit, where deposition occurs.
How is a bar formed?
The same way as a spit, except it continues the process until it joins another headland. Or it can be formed by an offshore glacial deposit, where roll-over has caused material to be transported landward.
How is a tombolo formed?
Same as a spit, it just continues until it reaches an island.
Name the 4 types of transportation
Traction, saltation, suspension, solution
What are the new dunes called at the front of the beach?
Embryo / foredunes
What are the 4 factors needed to form a sand dune?
Sand
Wind
Plants
An obstacle to trap the sand
Why is the biggest dune called?
Yellow dune
Give 1 marine, atmospheric and human imput of the coastal system
Wave, tides or salt spray
Air pressure, sun, precipitation, wind speed
Pollution, recreation, settlement, defences
What is isostatic change?
The rise of land masses that were previously covered by ice sheets during the last ice age. This causes some land to be rising whilst others sinking. Sea level rise is localised and dependent on the change in the land
What is eustatic change?
Worldwide changes in sea level caused by glacial and interglacial periods.
What are the 2 factors that cause eustatic change?
Thermal expansion
Ice caps melting
What is thermal expansion ?
When water expands due to global warming
How is a fjord formed?
In mountainous areas, within U shaped valleys that have been carved by abrasion, there would have been a glacier connecting the high cliffs, as they melt, the water as well as the sea fills the valley floor
How is a ria formed?
During the last ice age when the sea level was lower. Now as sea levels rise, the valley now cuts below present sea level. After the ice melted etc, the valleys drowned leaving rias.
What is our case study for coastal flooding?
Hurricane Katrina in New Orleans
What’s our example for sea level rise?
The Maldives.