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COASTS - Coggle Diagram
COASTS
Dunes
Embryo: Earliest form, sand stuck behind some litter or a twig
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Fore Dune, pionner plants start to reduce erosion
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Mature Dunes are the oldest, and have trees
PROCESSES
SUB-ARIEAL
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Biological
roots can break a part chucks of rock, but can also hold them together
Phsyscal
Freeze-thaw involves water getting in cracks, expaning , then when they melt, they break the rock appart
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CASE STUDIES
ODISHA ICZN
Facts: 480 km of coast in india, near bay of bengal, cyclone territory, 1/3rd of coastline is eroding, Chilika bird sanctum. 35% limestone, clay, and other not-resistant to erosion rock. salinisation risking the removal of rice farms.
Reliance / addaption
Due to salinization occurring, the federal government has encouraged farmers to farm poultry, cattle and aquaculture.
In an attempt to remove workers from the primary sector, rugs and textiles are being made. as well as in the tourism area, due to Chilika lake and temples
40 Cyclone shelters each containing enough space for a thousand residents, have been implemented across Odisha.
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Holderness Coast
Terminal Groyne syndrome: groynes can reflect the power of the waves , but they are redirected south of Mappleton, causing mass erosion
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The holderness coast is between Hull and Scarborough, 61 km long, nd has seen massive erosion. the shoreline has retreated 4km over the past 2000 years, and only 3 out of the 8 coastal settlements have sea defences. 10m / yr 2.4km^2 land lost per year.
DEFENCES
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HARD ENGINEERING
Man made defences for the coasts, used for Hold the Line approaches
Examples
Sea wall: costly but effective at reflecting energy of the waves away from the infrastructure. Apparently it does not look nice to most people, but i don't care.
Rock armor as seen in Lyme Regis and West Bay, they are relatively cheap and acts as a sacrificial line reducing the effectiveness of storm surges and backwash
Groynes are easy to make, cheap and the most cost effective, as they prevent longshore drift allowing beaches to retain their sediments. However they can cause beaches down wind to starve.
LANDFORMS
Headlands
A crack in the headland expands making a Cave. once 2 cave from either side meet, they become an Arch. when the bridge of the arch collapses, the headland retreats and causes a Stack to form. overtime, marine process will cause 'timber' to happen, and the Stump is all that remains.
Depositional
Bars & Lagoons form when the spit reaches the other headland, and the water behind it then becomes a lagoon.
Tombolos, wither a spit connects to an island, or the shadow of the island will be a location where accumulation of sediment will occur.
Spits are when longshore drift moves sediment and there is a change in coastal shape, causing a branch of sediment to 'grow' and the change in prevailing wind causes the spit to bend
Salt Marshes form in the protected area of spits, acculation of sediment occur casing land to be exposed during low tide.
MANAGEMENT
Integrated Coastal Zone Management (iczm). It is a large area of coast that is managed by one scheme, and allows there to be no location that is negatively affected by the actions of another section. It is more than just sea defences, and focuses on the people, and quest for sustainability
Shoreline Management Plan (SMP) It is a national approach to sections of a coastline. It requires weighing up the pros and cons in a cost benefit analysis, and allows the EA to know where to allocate funds. there are 22 of them protecting England.
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managed retreat: allow net erosion to occur, but at a controlled rate
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