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COASTS (erosion ((cliffs and shore platforms - exposed rock surface with…
COASTS
erosion
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abrasion: sediments carried by waves are hurled against the coast, undercut cliffs
attrition: rock particles hit against one another, rounded rocks
solution: chemical reaction between rocks and sea water, disintegrating and weakening
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headlands and bays - alternating bands of less and more resistant rocks perpendicular to the coast, wave refraction
caves, arches, and stacks: headlands with exposed lines of weakness
deposition
TRANSPORT
beach drift: approach the coast at an angle, move perpendicularly down as backwash
longshore current: ocean currents that move parallel to the coast
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with decreasing wave energy, large sediments are deposited before smaller sediments
sheltered coasts: lower wave energy, constructive waves, finer sediments deposited
exposed coasts: higher wave energy to remove fine sediments, coarser beaches
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spits and tombolos: longshore drift continuing in the prevailing wind direction despite abrupt change in coastline
waves
constructive: low wave energy, strong swash and weak backwash ; depositional coast
destructive: high wave energy, weak swash and strong backwash ; erosional coast
factors: wind speed, wind duration, distance wind has travelled (fetch)
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measures
laws and regulation
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protect coastal resources - prevents commercial fishing, which deprives locals of income
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hard engineering measures
costly and require maintenance, only DCs
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adaptations
roots
aerial: take in oxygen during low-tide, when they are not submerged
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leaves
some species concentrate excess salt into older leaves which will decompose and form nutrients for the soil
as waves approach the coastline, they slow down due to friction
mangroves encourage sediment build-up in their roots, which prevents sedimentation in the sea, producing clearer waters for offshore coral reefs to photosynthesise
economic practicality
dependent on the uses of the coast, financial capacity of the country, existing environmental conditions and geology, scale and rate of coastal erosion