1.1.1 - the operation of the coast as a system Flashcards
what is the coastal spatial boundary?
the distance between how far inland and how far out to see a coast goes
what are some processes that bring sediment into a coastal system (inputs)?
rivers, longshore drift, beach feeding
what are some processes that bring sediment out of a coastal system (outputs)?
storms, flocculation, beach dredging
what is beach dredging?
scooping of sediment out of a seabed or beach
what is a littoral cell/sediment cell?
coastal system in which all processes are equal, which are largely self-contained with smaller sub-cells within them
what is an example of a littoral cell?
st davids head
what does steady-state equilibrium mean?
morphology of the coast stays the same and follows its expected long-term pattern
what does meta-stable equilibrium mean?
the coastal system switches between two equilibriums, typically after a storm event.
what does dynamic equilibrium mean?
coastal system is constantly changing but no net change overall
what is positive feedback on a coastal system?
exacerbates a change in the coastal system, allowing for more future change (e.g. new equilibrium is found)
what is negative feedback on a costal system?
reduces the effects of change; like a sand dune preventing erosion of the coast
what are the cliff sub-system inputs?
- subaerial processes of weathering
- atmospheric process of wind erosion
- a transfer of cliff mass movement of falls, slips and slumps and an
output of sediment at the base of the cliff which is either deposited or is transported by marine processes
what are the beach sub-system inputs?
- sediment from longshore drift, the cliff and offshore
- transfer of longshore drift
- destructive waves carrying
sediment offshore.
what are the three supplies of sediment?
- cliffs
- rivers
- dunes
