Landforms and Coast Flashcards
Swash
The act of the waves crashing up against the beach
Backswash
The act of waves pulling away from the beach transporting sediment
Fetch
Distance travelled between waves
What is solution
Weak acids in the water eventually erode the soluble rock at the coast over time
Attrition
Sediments and rocks in the water are thrown against the coast eventually wearing it down over time
Abrasion
When rocks and pebbles grind against the coast wearing it down like sandpaper
Hydraulic action
Water crashes against the coast seeping through the cracks causing the air to break the rock.
How is a bay formed
When softer rocks are eroded causing a curve in-between two headlands
What’s a spit
Long narrow finger of sand or shingle pointing out into the sea from the shore
Direction of Longshore drift
Direction of longshore drift depends on the angle of the wind
Prevailing wind
Opposite angle of where the wind is blowing
Process which sediment is transported along a coast
Longshore drift
Deposition
When waves drop the sediment they are carrying either due to a loss of energy or a change in direction
Arch, Stack, Stump
- Waves at the bottom of the cliffs force a crack into the cliff
- The crack eventually widens into a cave
- Erosion from both sides of the cave erode the cave completely causing an arch
- The arch collapses due to weathering and forms a stack
- The Stack is then eroded a way therefore forming a stump
Beaches
- Pebbles and rock is eroded down into fine grains of sand
- The sediments are transported by constructive waves which have a stronger swash than backwash therefore it doesn’t bring back the sediment.
- These are transported into the bays and a beach is formed
Bays
- Bays are formed when softer rock such as clay is eroded away in-between two sections of hard rock (headlands)
Solution (Transportation)
When pebbles and rocks are dissolved in the sea water and are carried a long the waves
Suspension
When small rocks and grains are suspended in the flow of water
Saltation
When small pieces of shingle and pebbles are bounced a long the sea bed
Traction
Where pebbles and larger rocks are carried down the sea bed
Sea Wall
Advantages - Effective at protecting the cliff base
- Normally have promenades so people can walk along them
Disadvantages - Still able to be eroded by the waves
- Expensive
Rock Armor
Advantages - Cheaper and easier to maintain than a sea wall
- Can be used for fishing
Disadvantages - Looks unusual and can ruin the aesthetic
- Can be hard to be transported
Gabions
Advantages - Cheap
- Absorbs the wave energy
Disadvantages - Not very strong
-Looks unnatual
Groynes
Advantages - Builds a beach therefore increasing tourism
-Helps stop the transport of sediment by longshore drift
Disadvantages - Looks ugly
- Starves the beach further down
of sediment therefore increasing erosion
Beach Nourishment
Advantages - Blends in to the beach
Disadvantages - Needs to be replaced frequently
- Sand needs to be brought in from elsewhere
Reprofilling
Helps abort wave energy
Cheap
Only works when eave energy is low
Needs to be replaced constantly
Managed retreat
Advantages - Cheap
-Creates salt marshes
Disadvantages - Land is lost
-Landowners need to be compensated can be from 5000-10000
