Coasts systems and landscapes Flashcards
What is a sediment cell?
A stretch of coastline bordered by two predominant headlands where sediment is contained.
There are 11 sediment cells around the UK and Wales, each is divided by a barrier.
What are shoreline management plans?
Drawn up for each cell so it can be managed in a practical and sustainable way.
- Sediment budges describes the balance between sediment being added and taken away.
How are wave cut notches and platform formed?
- Destructive waves hit the cliff face, causes marine erosion.
- Causes undercutting between high and low water marks.
- Creates a wave cut notch.
- Overhang becomes too heavy and eventually falls.
- Leads to a wave cut platform.
How are headlands and bays formed on a discordant coastline ?
- Waves begin to erode the cliff, erodes at different rates due to it being soft and hard rock facing the waves.
- Soft rock erodes the fastest so a bay is formed in the middle of the hard rock and headlands at each side facing out to sea.
Llandudno bay, North Wales
How are headlands and bays formed on a concordant coastline?
- Waves begin to erode at the hard rock which lays parallel to the oncoming waves.
- Once it breaks through it begins to erode the soft rock behind much quicker.
- This creates more of a cove with the two headlands facing towards each other.
Lulworth cove, Dorset
How are caves, arches, stacks and stumps formed?
- Waves erode the cliff which causes a crack to form, further erosion means this expands and widens into a cave.
- Sediment continually moved out due to erosion means this continues to widen until its an arch.
- Eventually it can no longer support the top so it collapses which is then a stack.
- As weathering continues it becomes a stump.
Old Harry, Dorset
How are spits formed?
- Formed on a drift-aligned beach where sediment is moved along by longshore drift.
- Sediment is moved along but there is a change in the direction of coastline.
- Sediment builds up along the estuary and a spit will form.
Blakeney point, North Norfolk
How are bars formed?
Submerged or exposed ridges of sand created by waves offshore from the coast between two headlands.
- Formed in the same way as a spit however joins the two headlands together.
Slapton, Devon
How are tombolos formed?
A beach/sink which has formed between an island and the mainland. Formed in the same way as spits and bars but the deposition occurs when the area is sheltered and the waves begin to lose energy.
Shetland to St Ninian’s
What are the two types of beaches?
- Swash-aligned beaches- waves hit beach head on.
2. Drift-aligned beaches- waves hit the beach at an angle.
What are the types of common landforms found on beaches?
- Storm beach- steep sediment above HWM.
- Berms- parallel ridges at breaking point of waves.
- Cusps- crescent shaped hollows.
- Sand ripples- ripples along the beach made when tide is in.
- Pools and runnels- pools on foreshore as tide retreats.
How are salt marshes formed?
- Usually formed behind a spit where the land is now protected from the tides.
- Mudflats begin to build up and pioneer species colonise area.
- Vegetation increases and mud levels are able to rise. No longer need to be halophytic plants.
- Creeks develop and salt water is drained to sea.
- Soil improves and new species develop this is vegetation succession.
Abbotts hall farm. Essex
How are sand dunes formed?
- Constructive waves build up the beach, and sediment is moved up the beach by saltation.
- An obstruction means it can’t go any further as its sheltered behind object. So sediment begins to build up.
- Becomes a fore-dune and vegetation begins to grow.
- Abiotic conditions change and it becomes a fixed dune sand less hardy species develop.
Blakeney point, North Norfolk
How are barrier islands formed?
Long narrow offshore deposit of sand and sediment that runs parallel to the coastline before they are stabilised they are barrier beaches.
Formed by:
Offshore bar-
- Builds on top of an already existing area of deposition, this then becomes stabilised.
Spits-
- Long spit breaks during storm so a long area of sediment is left separated from the mainland.
Sea level rise-
- Mainland beach ridge already exists but sea level rise means water forms lagoon between the beach and the ridge so forms barrier island.
Cape Lookout, USA
