Coastal Systems Flashcards
Landform
A feature created by natural Processes.
Landscape
all visible features in an area.
Characteristic Landscape
The combination of related landforms in an area.
Coastal Landscape
Occur on the interface between land and the sea.
Landforms are created by
Weathering
Erosion
Transportation
Deposition
natural system
Simplifying the complexity of our world so we can understand it.
Coasts as a system
In a state of dynamic equilibrium if the inputs and outputs are balanced.
An open system, but closed as a sediment cell
Positive feedback
System experiences further change away from equilibrium.
Examples Of Positive feedback
portlock in somerset, Shingle ridge was breached, Flooding land behind, Regular flooding, Widened breach, Land behind now a salt marsh.
Systems Model
Components of an aspect of geography and how the stores are linked through flows.
Exist within a boundary.
Involve energy and/or matter flowing between stores.
Negative Feedback
Stabilises system, reducing impact of change, maintaining dynamic equilibrium.
Example of negative feedback.
If beach is eroded during a storm,
Sediment might form an offshore bar, waves will break on bar,dissipating energy, reducing erosion on the beach, after storm sediment back to the beach.
The littoral zone
A series of sub-zones to represent the features of the wider coastline from sea to land.
Sub-zones of the littoral zone
Offshore, Nearshore, foreshore, backshore
Inputs and outputs of the littoral zone
Sediment is the key input and output of the system.
Determined by the action of waves,currents,wind and deposition
High energy coasts
Characterised by Destructive waves, long fetches, high rates of erosion, Landforms of erosion.
Low energy Coasts
Characterised by
Constructive waves, shorter fetches, higher rates of deposition, Landforms of deposition.
Waves
Two types of waves
constructive and destructive.
Constructive
Happens at low frequency
Long and low
Form gently sloping beaches
Deposit material due to backwash being less powerful than swash.
Destructive
Responsible for erosional processes
Happens at high frequency.
Steep and high
Remove material from coasts because swash is less powerful than the backwash.
Currents
Currents are the movement of surface water in the oceans.
Types of currents
Longshore
Rip
Global Ocean Circulation
Longshore Currents
When a flow of water runs parallel to the shoreline. Where waves approach at an angle.
Rip Currents
Strong currents which flow away from the shoreline.
Global Ocean Circulation Currents
Upwelling is movment of cold water from the deep ocean to the surface.
Tides
Water is pulled towards the moon,Bringing a high tide on each side of the earth.
Follow the moon as it orbits the earth.
Tides are also influenced by the shape of the seabed, the Coriolis force and nearby landmasses
Spring tide
When the moon and sun and earth a spring tide occurs. Highest tide.
Neap Tide.
When the moon and sun are perpendicular.
Tidal Range
The difference in height between high and low tide.
Why do they varies
Over time due to differences in heights of tides
Why is it Important
Erosion and deposition will occur in this zone.
Tidal Surges
Occur when storms bring much higher water levels than usual.
Why ?
This is often due to the low-pressure conditions created by atmospheric depressions.
Processes of Erosion
Erosion is the wearing away of rock.
Attrition
Where peices
