Coastal Landscapes Flashcards
How do waves form
Wind blowing over the sea.
Constructive waves
Spills, strong swash, beach sediment gain.
Destructive waves
Plunge, weak swash, strong backwash, beach sediment loss.
Mechanical weathering
break up of rocks
Chemical weathering
Caused by chemical changes, acid rain.
Biological weathering
Animals like rabbits, burrowing.
Examples of types of weathering processes
Freeze-thaw-mechanical, carbonation-chemical.
What is mass movement
Downward movement or sliding of material under the influence of gravity.
What solution erosion
the dissolving of soluble chemicals in rocks,
What is corrasion erosion
Fragments of rock are picked up and hurled by the sea at a cliff. The rocks act like tools scraping and gouging to erode the rock.
What is abrasion erosion
Sandpaper effect of pepples grinding over a rocky platform making it smooth.
what is attrition erosion
Rock fragments carried by sea knock against each other and become more rounded and smoother.
What is hydraulic power erosion
Power of waves as they smash into a cliff. Trapped air slowly causes the rock to crack.
Solution transportation
Dissolved chemicals carried.
Suspension transportation
Particles carried suspended within the water.
Saltation tranpsortation
Bouncing motion
Traction transportation
Rolled along the sea bed
Longshore drift
Waves arrive at the coast at an angle, sediment moved up with swash at an angle and carried back with backwash, straight with gravity. Crating zig-zag pattern.
What is a wave-cut platform
Cliff collapsed, cliff gradually retreat leaving wave-cut platform usually smooth because of abrasion.
Caves,…….
Notch is formed, which is widened into a cave, waves make cave larger until it cuts through headland making an arch, the arch is eroded and the roof collapses leaving a stack, stack eroded into a stump.
How do sand dunes form
Embryo dunes form around obstacles like wood and rocks, These form for dunes and yellow dunes, Marram grass is adapted to windy exposed conditions and has long roots to find water.
How does a spit form
Longshore drift transports sand along the coast, changing in the shape of the coastline, spit grows out into the sea, spit exposed to changes in wind and wave direction- curved end, saltmarsh forms in sheltered water behind spit.
What is a bar
Longshore drift causes spit to grow across a bay, trapping lake behind it, this is a bar.
Groynes
Timber built out to sea from the coast. 150,000 each 200m, create a wider beach, not too expensive, unnatural, starve beaches further along the coast.
Sea wall
Concrete or rock barrier. effective, has a walkway, unnatural, expensive.
Rock armour
Piles of large boulders dumped at foot of a cliff. cheap used for fishing, expensive to transport, unnatural.
Gabions
Wire cages filled with rocks, cheap, improved drainage, look unattractive, cages only last 5-10 years.
cons of hard engineering
expensive and involve high maintenance costs, interfere with natural coastal processes, look unnatural.
Beach nourishment
The addition of sand or shingle to an existing beach to make it higher or wider. Relatively cheap, blends in with the environment, needs constant maintenance.
Dune regeneration
Sand dunes are effective buffers to the seas but are easily damaged, fences are used to keep people off. cheap, damaged by storms, time-consuming.
Dune fencing
Fences constructed on sandy beaches along the seaward face of existing dunes to encourage more dunes to form. minimal impact on natural systems controls public access to eco-systems, can become easily broken.
What is managed retreat
deliberate policy of allowing the sea top flood or erode an area of relatively low-value land. Cretes a large salt marsh to form a natural buffer to the sea, help protect surrounding farmland, new wildlife habitats.
