Flashcards in Chapter 3 - Coastal Systems & Landscapes - Complete Deck (121)
What are the 5 inputs into the coastal system?
- Wave refraction
- Sea currents
What are the 2 outputs from the coastal system?
- Sediment removal
What are the 4 processes in the coastal system?
- Erosional landforms
- Longshore drift
What are the 2 stores in the coastal system?
- Beach (Landscape)
What are the 4 factors which keep beaches in dynamic equilibrium?
- The supply of sand.
- The energy of the waves.
- Changes in the sea- level.
- The location of the shoreline.
What is the sand supply in dynamic equilibrium?
Input and output of sand into the beach must be equal.
Sand is food for beaches and gives shorelines protection from waves.
Being starved of sand can cause higher rates of erosion.
What is the waves in dynamic equilibrium?
The erosion action of a wave is greatest when the wave is high. The angle at which they strike a beach and how much sand they are carrying can also influence the rate of erosion.
Define the 4 causes of sea level change?
- Tectonic plate activity
- Thermal expansion (50% responsible)
What is the location of the shoreline in dynamic equilibrium?
Shorelines move back and forth between storms and their location can either increase or decrease erosion rates.
Define how the wind is created?
- Created by air moving from areas of high pressure to low pressure.
- Strong winds generate powerful waves, has prevailing winds causing higher-energy waves.
Define how waves are created?
- Waves created by wind blowing over surface - circular motion.
- The effect of a wave on the shore depends on its height.
Define constructive waves?
They are created in calm weather and are less powerful than destructive waves.
Define destructive waves?
Are created in storm conditions. They are created from big, strong waves when the wind is powerful and has been blowing for a long time.
Are the regular rise and fall of sea levels, the gravitational pull of the moon and sun cause the tides.
General flow of water in one direction - caused by wind, water temperature or salinity.
Define high energy coast?
- Receive high inputs of energy from large powerful waves.
- Caused by strong winds, long fetches and steeply shelving offshore zones.
Define low energy coast?
- Receive low inputs of energy from small gentle waves.
- Caused by gentle winds, short fetches and gently sloping offshore zones.
Define sediment budget?
The amount of sediment that enters and exits.
More enters then positive sediment budget
More exits then negative sediment budget
Define sediment cells (littoral cells)?
Coastline between two headlands which is a closed system.
Movement of sediment is contained in cell.
11 cells in England & Wales
Waves pick up small rocks and throw them at the cliff, breaking off more rocks.
This is when pebbles grind along with a rock platform, much like sandpaper. Over time the rock becomes smoother and worn.
Define hydraulic action?
This is the sheer power of the waves as they smash against the cliff, the air becomes trapped in the cracks in the rock and causes the rock to break apart.
As waves recede, the compressed air expands violently, again exerting pressure on the rock and causing pieces to break off.
Define wave quarrying?
When high energy, tall waves hit the cliff face they have the power to enlarge joints and remove chunks of rock in one go through vibration.
minerals are dissolved in the water and carried along in solution. Suspension - fine light material is carried along in the water. Saltation - small pebbles and stones are bounced along the river bed.
When rocks that the river is carrying knock against each other, they break apart to become smaller and more rounded.
Define the 5 transportation processes?
- Longshore drift
Define SOLUTION as a transportation process?
- Substances that are dissolved get carried along in the water.
Define SALTATION as a transportation process?
- The force of the water causes pebbles & gravel to bounce along the sea bed.
Define SUSPENSION as a transportation process?
very fine material, like silt & clay particles, is whipped up by turbulence and carried along in the water.