coastal management Flashcards
what is erosion
removal of rock and sand particles as a result of wind and wave action
issues in coastal environments
- development
- rivers/lagoons
- erosion
- pollution
- population growth
- introduced plants
- tourism
what are the four types of coastal erosion
hydraulic action
corrosion abrasion
corrosion solution
attrition
what is hydraulic action
when a wave hits a headland, the trapped air is compressed which weaken the cliff
what is corrosion- abrasion
bits if rock and sand in waves grind down cliff surfaces
what is corrosion (solution)
acids contained in sea water dissolve some rock types
what is attrition
waves smash rocks into smaller particles to use in abrasion
how are sea cliffs formed
large waves break and cut the foot of the cliff causing wave cut notches
these notches enlarge until the cliff collapses
how are headlands and bays formed?
the sea erodes a section of the coast
the soft rock erodes quicker causing bays to form and the hard rock is left forming headlands
how do caves, arches, stacks and blowholes form?
caves occur when waves force their way into cracks in a cliff
arches occur when the cave breaks through to the other side
stacks are formed when the arch becomes bigger and breaks at the top leaving a column
blowholes form when cracks in the rock create a gap right through to the top
what is a crest?
peak of the wave
what is a trough?
bottom of the wave
what is the fetch
distance wind travels over the ocean to form waves
what is the size of a wave influenced by:
wind strength
wind duration
wind speed
what is swash
when the water is washed up the beach
what is backwash
when the water runs back down the beach
what is the difference between constructive and destructive waves
destructive waves make the beach steeper we they drag sand down the beach
constructive waves push sand up the beach
which waves have strong backwash and weak swash
destructive waves
which waves have weak backwash and strong swash
constructive waves
what is longshore drift
where the swash carries the material up the beach at an angle and the backwash travels back in a straight line
this continually transports materials along the coast
occurs in a zig zag
what is deposition
happens when the swash is stronger the the backwash
when waves lose energy and drops any particles it’s been carrying
name 5 depositional features
beach spits and bars tombolo storm bay/ sand bank sand dunes
what is coastal management
the controlled retreat of the coastline
what is the difference between soft engineering and hard engineering
soft- less expensive and more sustainable
hard- expensive, unsustainable
why do we need coastal management
to prevent beaches from eroding away and disappearing as this occurs naturally
what are some effects of costal erosion
- loss of land
- loss of infrastructure
- loss of property
- economic loss- tourism
name some hard engineering approaches
groynes sea wall rock bars rock gabions metal pilling rip rap revetments
name some soft engineering approaches
sand pumped
replanting grass
boardwalks
mangrove trees
