Coastal Landscapes and Processes Flashcards
Coastal erosion def?
Weathering?
Mass movement def?
Waves wearing away and removing sediment
Breakdown of rocks at the surface of the ground
Downslope movement of rocks from cliff due to gravity
3 Types of weathering and definitions
Mechanical (freeze-thaw)–>Repeated freezing and thawing expands cracks
Chemical (acid rain)–> Slightly acidic rain breaks down weak rocks
Biological–>Plants and animals can widen cracks / weaken rocks
4 Types of erosion and description
Hydraulic action–> water into cracks of cliff
Abrasion–> rocks thrown at cliff face
Attrition–> rocks bash into each other
Solution–> weak rocks being eroded by the salt
3 Types of mass movement and description
Slumping–> rotation of cliffs along a curved surface
Sliding–> movement of large rocks along a flat surface
Rock falls–> smaller pieces of a cliff falling
4 Types of transportation and description
Traction–> rolling
Saltation–> bouncing
Suspension–> floating
Solution–> dissolving
Fetch
The distance of open water the wave has travelled
Constructive wave characteristics
-Lower height
-Less energy
-Less frequent
-Strong swash, weak backwash
Destructive wave characteristics
-Taller height
-More energy
-More frequent
-Weak swash, strong backwash
Discordant coast definition
Bands of different types of rock perpendicular to the coastline
Concordant coastline definition
Bands of different types of rock parallel to the coastline
Joint
Vertical crack caused by sediment drying out or stress on the rock
Fault
Formed by stress or pressure on rock causing joint to move
3 Ways UK climate affects coastline
Storms, seasonality, prevailing wind direction
Storms
Seasonality
Prevailing wind direction
How they affect UK coastline?
Storms- Increase wave energy and erosion such as abrasion
Seasonality- More freezing temps, more mechanical weathering
Prevailing wind direction- Longer fetch, stronger wind, more powerful waves
How is a wave-cut platform formed?
Wave hits the base of cliff, forms wave-cut notch. Notch gets bigger, overhang collapses and cliff retreats.
How is a stump formed?
A crack in a cliff creates a weakness which is eroded to form a cave. Erosion continues until an arch is formed. Weathering from above and erosion causes the top to fall in, creating a stack. This is then eroded to form a stump.
How are headlands and bays formed?
On a discordant coastline bands of more and less resistant rock lie perpendicular to the coast. The less resistant rock is eroded at a faster rate on either side of the more resistant band of rock. This erodes at a slower rate so is left sticking out of the coastline creating a headland with a bay on either side.
What is longshore drift?
Swash depositing sediment on the beach in direction of prevailing wind. Backwash occurs perpendicular to the shore. Sediment moves down the beach.
3 Coastal deposition landforms
Spits, beaches and bars
5 erosional landforms
Wave cut platform, cave, arch, stack, stump
Spit definition
Long and narrow ridge of sediment with one end attached to land and the other sticking out into the sea
How is a spit formed?
Erosion- erosion at the coast, waves collect sediment
Transportation- longshore drift moves sediment along a coast
Deposition- change in coast direction or a river mouth causes sediment to be deposited in a spit
Bar definition
Ridge of sediment across the entrance of a bay or river mouth
How is a bar formed?
Erosion- erosion at the coast, waves collect sediment
Transportation- longshore drift moves sediment along the spit
Deposition- deposits sediment at end of spit, lengthens until it reaches land again
3 Ways humans use the coast, and their negative effects
Urbanisation-> Settlements near the coast, could be damaged
Industry-> Used for trade, disturb wildlife
Agriculture-> Fertile land used for farming, erosion destroys farmland, loss of money
Hard engineering definition?
4 types?
Man-made structures designed to stop erosion
Sea wall, rock armour, gabions, groynes
Soft engineering definition
3 types?
Sustainable, natural methods to reduce the rate of erosion
Managed retreat, dune nourishment, beach replenishment
Sea wall
Def, ad, dis
Concrete wall built at the foot of the cliff
Ad- effective, provides walkway
Dis- expensive, unnatural
Rock armour
Def, ad, dis
Large boulders placed at foot of the cliff
Ad- easy to maintain, quick to install
Dis- high transportation costs, doesn’t fit in natural landscape
Groynes
Def, ad, dis
Structures built at right angles to coast
Ad- quick to build, bigger beaches
Dis- unsightly, have further impacts down coast
Gabions
Def, ad, dis
Rocks in mesh cages
Ad- absorbs wave energy, cheap
Dis- unnatural, not very strong
Beach replenishment
Def, ad, dis
Sand added to a beach to make it wider
Ad- attracts tourists, cheap to maintain
Dis- causes disruption to beach users, needs constant maintenance
Dune stabilisation
Def, ad, dis
Planting shrubs and bushes to stabilise dunes
Ad- natural, cheap
Dis- takes time to grow, areas are fenced off
Managed retreat
Def, ad, dis
Controlled flooding of coastal areas
Ad- cheap, provides habitats for animals
Dis- owners need compensation, land is lost
