Coastal Systems and Landscapes: Systems and processes Flashcards
Define fetch:
The distance the wind blows
What is a sediment cell?
The largely self-contained stretch of a coastline.
Define backshore:
The part of the beach lying between the beach face and the coastline.
Define foreshore:
The area between the high tide mark and low tide mark.
What are constructive waves?
Waves that deposit material and built up the beach.
What is wave height?
The difference between the elevations of a crest and a neighbouring trough.
What are destructive waves?
Waves that take back material and destroy the beach.
What is wave frequency?
The number of waves produced each second.
What is hydraulic action?
Sheer force of the waves
Define solution:
Chemical makeup of the water
How does chemical weathering occur in a coastline?
- Rainwater is a low-concentration acid
- Over time rock will be dissolved
How does biological weathering occur in a coastline?
- Roots enter and grow in a crack in the cliff
- Rock breaks off
How does mechanical weathering occur in a coastline?
- Freeze-thaw
- Water enters crack in cliff
- Water freezes, widening the crack
- Ice melts, deepening the crack
- Process is a loop
What is a sediment budget?
A coastal management tool used to analyse the different inputs and outputs within a coastal system.
What is a longshore current?
Current that flows parallel to the shore within the zone of breaking waves.
What is a low energy coast?
A coastline where wave energy is low and the rate of exposition exceeds the rate of erosion
What is a high energy coast?
Coastline where strong, steady prevailing winds create high energy waves and the rate of erosion is faster than the rate of depostion
What is upwelling?
Movement of cold water from deep in the ocean towards the surface
What are rip currents?
Strong currents moving away from the shoreline
What are the features of a destructive wave?
- High wave height
- Steep form
- High frequency
What are the features of a constructive wave?
- Low wave height
- Low frequency
- Long wavelength
Why do constructive waves have a weak backwash?
Water rapidly looses volume and energy as it comes up through the beach material, so it has an insufficient force to pull sediment out.
Constructive waves have a ______ wave frequency.
Low
What is backwash?
The action of water receding back down the beach towards the sea.
What is swash?
The rush of water up a beach after a wave breaks
What is a crest?
The highest point (top part) of a wave.
Define mass movement:
The downslope movement of material, such as mud, rock or soil.
What is attrition?
Material in the water hitting each other.
What is abrasion?
When material is picked up and thrown against the cliffs.
Define solution:
Chemical makeup of the water
What is hydraulic action?
Sheer force of the waves
What are destructive waves?
Waves that take back material and destroy the beach.
What are the 4 sources of energy in coastal environments?
- Wind
- Waves
- Tides
- Currents
What is the wavelength of constructive waves?
Up to 100m.
Constructive waves have a ______ wave height.
Low
What is the wave frequency of constructive waves?
6-8 per minute.
Destructive waves have a ______ wave height.
High
What is the frequency of destructive waves?
10-14 per minute.
What is a sea current?
The permanent or seasonal movement of surface water in the seas and oceans.
