Coasts as a system

Systems approach to coasts

-Geological systems has inputs, stores transfers and outputs striving to be in dynamic equilibrium

-The coast can be both open and closed

-open as it receives inputs from lithosphere,atmosphere,hydrosphere,biosphere and cryosphere

-During reasearch and coastline management is closed

In puts into the coast

-Sediment carried by rivers/waves

-Wind generated waves

-Precipitation

-Outputs in a coast

-Eroded material taken out to sea

-Ocean currents

-Evaporation

Stores in a coast system

-Beaches

-Cliffs

-Dunes

Transfers in a coastal system

-Transportation processes

-LSD

-Mass movement

-Wind blowing sand

Give 2 positive feedback loops of the coast

• As waves erode the cliff, material is released-This material abrades the cliff resulting in more cliff erosion

• Groyns placed to trap sediment-deprivation down the coast of beach replenishes-exacerbates the rate of erosion

Give an example of a negative feedback loop of the coast

Beach is in dynamic equilibrium-sediment eroded from beach during a storm-sediment deposited offshore forming an offshore bar-waves now break before reaching beach reducing erosion-when storm passes waves move sediment from offshore bar back to beach

Coastal zones-Backshore

The area between high water mark and the landward limit of marine activity

Changes normally only take place here during storm activity

Coastal zones-Foreshore

-The area lying between the HWM and LWM

-It is the most important zone for marine processes in times not influenced by storm activity

Coastal zones-Inshore

-The area between the LWM and the point where waves cease to have any influence on the land beneath them