why do humans intervene in natural processes?
what are the problems with human intervention?
unsustainable and uneconomic
what is the England and Wales enviro agencies criteria for coastal protection?
what are the four options for coastal management
hold the line
advance the line
do nothing
managed realignment
hold the line
maintain existing coastal defences
advance the line
build new coastal defences further out to sea than existing ones
do nothing
allow nature to take its natural corse and deal with erosion and flooding as it comes.
managed realignment
allow the shoreline to move but manage retreat so it causes less damage. eg) change land use to flood farmland rather than town infrastructure.
what factors are responsible for a change in shoreline equilibrium? (5)
feedback loops
outputs modify the inputs/ processes = output cahnges
positive feedback (in terms of input and output)
outputs increase = inputs increase which causes a further increase in outputs
negative feedback (in terms of input and output)
output increases which slows the inputs and processes responsible for the increased output.
dynamic equilibrium
gradual shift in balance over a long period of time
metastable equilibrium
episodic shifts to a new equilibrium
steady state equilibrium
long term balance between inputs and outputs.
What is the SMP?
shoreline management plan
what are hard engineering strategies used for?
to intercept and impede marine and coastal processes
what are 5 examples of hard engineering strategies?
Groynes, sea walls, revetments, rip rap and offshore breakwater.
what are groynes?
they are wooden fenses built at 90* to trap sediment (LSD)
ADV of groynes
DIS of groynes
-staved beaches further down the coast of sediment = more erosion and flooding
ADV of sea walls
sea wall
large concrete wall that reflects wave energy back to sea ad protects against large waves with a recurved shape.
DIS of sea wall
- creates a strong backwash which erodes under the wall