Coasts Flashcards
Swash
The movement of waves up the beach
Backwash
The movement of waves back towards the sea at the angle of 90 degrees.
Constructive waves
Add material to the beach because they have a strong swash than backwash
Destructive waves
Remove material from the beach because they have a stronger backwash than swash.
Abrasion
Breakdown of the coast by rocks hitting it and wearing it away.
Hydraulic action
Erosion of the coast through the force of wave water against the shore.
Attrition
Erosion of coastal sediment as it is knocked together. This gradually makes it rounder and smaller.
Solution
Chemical erosion of coastlines using the slightly acidic nature of some sea water.
Freeze-Thaw
A type of weathering caused by water filling a crack in the coast, freezing (which causes it to expand), melting, allowing more water into the larger crack. This process repeats until the rock fragment breaks away.
Mass Movements
Large amounts of a cliff face being removed at once. Types include: Landslides, rockfalls and slumps.
Longshore Drift
A method of coastal transportation driven by the direction of the waves. Material is moved along the coast in the direction determined by the prevailing wind.
Prevailing wind
The most common wind direction in a place (South Westerly for the UK)
Hold the line
An approach to coastal management where a decision is made to keep defending the coast in its current position.
Managed retreat (realignment)
An approach to coastal management where a portion of the coast is allowed to be flooded in order to protect more valuable areas.(Soft engineering)
Beach Nourishment
A soft engineering approach where material is added to the beach to absorb wave energy and reduce erosion.
Groynes
A hard engineering strategy where fences are built at right angles to the sea to prevent longshore drift. This slows down erosion by building up a beach which absorbs wave energy.
Sea walls
A hard engineering approach using concrete walls to reflect wave energy and prevent coastal flooding. The most expensive method of coastal management.
Fetch
The distance the wind can travel over the ocean to form waves. The longer this distance the larger the wave.
Wave cut platform
Erosional feature found at the base of a cliff. If shows the base of the former cliff after is retreats following erosion between the high and low water lines.
Sand dune
A wind formed depositional landform found at the back of a beach. Material is blown towards them and stops when it hits an obstacle of existing dune.
Spit
A depositional landform created when longshore drift continues beyond a bend in the coastline. Deposition causes the feature to build over time.
Bar
A depositional landform formed when a spit extends across a bay. The formation is very similar to a spit, Behind a bar you will often find a lagoon.
Headland
An area of hard rock which sticks out into the sea. It is created by the soft rock beside it eroding backwards at a faster rate.
Bay
An often horse-shoe shaped inlet at the coast. They are found in areas of soft rock which erode at a faster rate than the hard rock beside them.
