coastal erosian Flashcards
(15 cards)
describe two characteristics of constructive waves
stronger swash than backwash
small, less energy, less frequent than destructive waves
what is coastal deposition
formed as a result of LSD
beach material is transported along the coast by waves, shaping the shoreline
identify landforms P,Q,R
P- Cliff
Q- beach
R- wave cut platform
headlands and bays z,x
z-headland
x-bay
low tide
wave cut platforms, waves erode cliff
the beach is visible
you can see the wave cut platforms
the waves done reach the cliff the beach looks wet and has a darker colour
how does longshore drift occur
waves approach the beach at an angle controlled by pervailing wind, materials are moved up the beach in a zig zag pattern, in the swash and then the material is carried directly down the beach in the backwash
why coastal erosion is faster on some coasts then other
the structure of the rocks e.g. holes and layers
acid in rain water wearing down
the bigger the fetch the bigger the waves
tropical storms = more waves
if the coast has sea walls, groins or any sort of human intervention it can affect how fast the coast erodes
what are three pieces of evidence that costal erosion has occured
there is a wave cut notch that has even eroded from hydraulic action and abrasion
there are salt marshes, bays and headlands
there is a wave cut platform from the cliff collapsing because it was not stable
describe the main features of a spit
spits form when the coastline changes direction
longshore drift carries materials in the same direction
sand and shingles is built up to form a spit
end of spit curves due to wave refraction or wind
what is a swash
wave crashing against the shore
what is a backwash
waves coming back into the ocean
holderness coast case study
The Holderness Coast erodes at an average rate of 1-2 meters per year, mainly due to its soft boulder clay cliffs.
The cliffs are made of soft glacial till, which is easily eroded by hydraulic action, abrasion, and subaerial processes like rain and slumping.
Villages like Mappleton and Skipsea are at risk of disappearing due to coastal retreat, with homes and roads falling into the sea.
Defenses like groynes, sea walls, and riprap (rock armour) have been built in some areas (e.g., Mappleton) to slow erosion, but this can increase erosion further down the coast.
how much do groynes cost
Groynes – Around £5,000 to £10,000 each
how much does rock armour cost
rock armour – Around £1,000 to £3,000 per meter
how much do sea walls cost
Sea walls (e.g., Withernsea) – Can cost up to £5,000 per meter
