Coasts Case Studies

Hurricane Sandy

- October 2012

- modern example of coastal flooding

- low air pressure caused rise in sea level that coincided with spring tide and high tide, created by storm waves

- 24 states were affected, creating a cost of $60 billion

- 300 deaths in the USA and Caribbean

- resulted in extreme coastal erosion and heavily saturated ground

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Depositional Features

SPIT - Dawlish Warren, Devon. Located at the mouth of the Exe estuary and has existed since the 16th century. 500m wide, extends 2km into the estuary. A saltmarsh has developed behind the spit, creating a wide intertidal bay.

TOMBOLO - Chesil Beach, Devon. A pebble and shingle tombolo that connects the Isle of Portland to the mainland of Dorset. 18 miles long, making it the largest in the UK.

BAR - Slapton Sands, Devon. Slapton Key is a lagoon that has formed behind the 2.5km bar.

CUSPATE FORELAND - Dungeness, Kent. Migration of shingle ridges as wind directions have changed over time and is the result of two different LSDs. Shelters a low-lying area known as Romney Marsh.

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Purbeckian Coastline

- East facing is discordant so the geology is perpendicular to the coastline, leading to the formation of bays (Swanage Bay - made from wealden beds) and headlands (Peveril Point - made from Purbeckian limestone). 

- South facing is concordant so the geology runs in paralell lines to the coastline. This means erosion tends to happen at fault lines, creating coves (Lulworth Cove).

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Natural Defence Barriers

CORAL REEF - The Great Barrier Reef, Australia. Off the coast of Queensland in the Coral Sea, it is the largest coral reef in the World. Generates $5-6 million australian dollars from 2 million visitors a year however it is dying due to increased carbon and water pollution. Solutions have included;

- making it a UNESCO World Heritage Site, creating a charity to raise money for it (Great Barrier Reef Foundation) and the Australian Government has pledged to spend £600 million to improve the water quality around the reef, as well as decreasing the subsidy to the fossil fuel industry.

MANGROVE SWAMPS; The Sundarban Islands, Bangladesh. UNESCO World Heritage Site and largest carbon sink in the Indian sub-continent. Sparsely populated mangrove forest in the Bay of Bengal, is a place of sanctuary the endangered Bengal Tiger and Indian Python.

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Changes in Landscape over Millennia

- due to isostatic readjusment of the land

SUBMERGENCE - Rias (Kingsbridge Estuary, Devon) and fjords (Sogne Fjord, Norway). Sogne Fjord is 198km long and 1.3km deep

EMERGENCE - raised beaches and fossil cliff lines. Kings Cave, Scotland (located on the Isle of Arran) has a raised beach 8m above sea level which progresses 30m back and shows evidence of marine processes/erosion. There are also fossil cliff lines on the Isle of Arran.

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Changes in Landscape in Seconds

MASS MOVEMENT - Cliff collapse at Hive Beach in 2012. 400 tonnes of rock fell over a 20m stretch, 1 fatality.

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Impacts of coastal processes on human activity

POSITIVE - John O' Groats, Scotland. Orcas, grey seals and Atlantics puffins can all be seen while the erosional features of the coast (John O' Groats stacks) and the Northern most point are also factors that aid its tourism. The Scottish Coast also uses the sea for tidal power in Pentland Firth waters which gives it an economic benefit through renewable energy as well as fishing - a high proportion of the 481,000 tonnes plus of fish landed in 2014 (with a value of over £514 million) came through the ports of north-east Scotland.

NEGATIVE - Happisburgh, Norfolk. Realignment and managed retreat plans mean only the most important settlements are protected leading to a loss of land, infrastructure and community in more isolated areas.

MANAGEMENT - Lyme Regis, Dorset. Soft permeable rock requires support, UNESCO World Heritage Site. The Cobb leads to sediment starvation as it disrupts LSD. The tourism industry of £42 million and 900 jobs. The £30 million plan focuses on stabilising the land (Cobb road strengthened), protecting the foreshore (old rock armour extended), replenishing the beach and cost to benefit anaylsis (6:1).

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Impacts of human activity on coastal processes

POSITIVE - Medmerry, Sussex. Largest managed realignment of open coast in Europe. Completed in 2013, worth £28 million and built 7km of new flood embankment. Sustainable flood risk management and involvment of communities were both focused on.

NEGATIVE - Great Yarmouth, Norfolk. 10 billion tonnes of material are dredged which has created fears that this is increasing coastal erosion - the Barnet Sands have virtually disappeared which acted as a natural barrier for the coastline.

MANAGEMENT - The Zandmotor, Holland. 12 million m3 of Dutch coast is being replenished each year. The Zandmotor is rising up to 5m above sea level. Material is dumped in one go to avoid disruption of the seabed and is allowed to be distributed by natural processes so that the coastline can form its own equilbrium.

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