coastal systems Flashcards
definition of a system
can be a process or a collection of processes which transfers sediment and other materials(inputs) into land forms (outputs)
what is a open system
both mass and energy are allowed to transfer across the system boundary. e.g the coast
what is a closed system
flow of energy can be transferred but no mass, there is always a fixed mass.
meaning of dynamic equilibrium at the coast
balanced state of a system when its outputs and inputs are equal
definition of an input
material or energy moving into the system from outside e.g precipitation
definition of an output
material or energy moving from the system to the outside . e.g ocean currents
definition of positive feedback
process in which an initial change will bring about an additional change in the same direction
example of positive feedback
- people walk over sand dunes, destroying vegetation such as marram grass, causing erosion
- damaging vegetation means more susceptible to erosion, increasing rate.
- sand dunes completely eroded so more of beach open to erosion.
definition of negative feedback
process in which initial change will bring about an additional change in the opposite direction.
example of negative feedback
constructive waves- strong swash brings sediment to gently sloping beaches and deposits the material.this leads to a steeper beach profile, which then causes destructive waves. the destructive waves have a stronger backwash, therefore they remove sediment from the beach and deposits it offshore, making the beach have a gentler profile once again, which encourages constructive waves.
definition of backshore
the area between the high water mark and the landward unit of marine activity
definition of foreshore
area lying between the high water mark and low water mark and is often seen as the most important area for marine activity.
definition of inshore
area in which activity is limited to the deposition of sediments
definition of offshore
area where the waves cease to have any influence on the land around them
