Coasts: Why are coastal landscapes different and what processes cause these differences Flashcards
What is the littoral zone?
The area from the shoreline from the sea to the land, which is where waves, currents and tides move sediment around.
What are the four subzones of the littoral zone?
- Backshore
- Foreshore
- Nearshore
- Offshore
What is the Offshore?
The area of deeper water beyond the point at which waves begin to break.
What is the Nearshore?
The area of shallow water beyond the low tide mark. Friction between seabed & waves distort the waves making them break.
What is the Foreshore?
The area between the hide tide and the low tide mark.
What is the Backshore?
The part of the beach lying between the beach face and the coastline.
What is the Breaker/Surf zone?
Where waves break as a consequence of depth limitations and surf (foamy bubbly surface) onshore as waves bore (change in depth)
What are berms?
Terrace of a beach that has formed in the backshore, above the water level at high tide.
What is meant by dynamic equilibrium?
refers to the maintenance of a balance in a natural system, despite it being in a constant state of change.
Inputs: natural processes examples
- Sediments from the sea
- Weathering & mass movement occuring on the backshore
- Constructive and deconstructive waves casing deposition and erosion
- Longshore Drift
Inputs: Human activity examples
- Dredging of rivers to make them deeper for shipping
- dredging of offshore areas to get sand and gravel for construction
- The building of coastal defences against erosion and flooding
What are some characteristics of a high-energy coastline?
- More powerful (destructive) waves
- Long fetches (generate larger waves)
- Erosion and transport processes
- Cliffs, wave-cut platforms, arches, sea caves, stacks
- Exposed to largest waves
- Rocky landscape
- Highland and lowland coasts
What are some characteristics of a low-energy coastline?
- Less powerful (constructive) waves
- Short fetches (generate smaller waves)
- Rate of deposition exceeds erosion
- Beaches, spits, salt marshes, sand dunes, bars, mudflats
- Sheltered from large waves
- Lowland coasts
Is the coast an open or closed system? And what does it mean?
Open system, meaning it receives inputs from outside the system and transfers outputs away from the coast and into other systems.
Examples of outputs:
- Evapouration
- Sediment transfer
Examples of transfers:
- Wind-blown sand
- Mass movement processes (landslide)
- Longshore drift
- Weathering
- Erosion