Coast: Igcse Geography

Tuesday, 28 March 2017

COAST IGCSE Geography

- Cost are important • Tourism • sport (i.e surfing) • ecosystem • fishing • oil and gas reserves (found under oceans) • housing (choose to live near coast) • Industry (easy to trade) • transport (of goods and services) • Walkers (people enjoy walking along coasts) - why under threat • global warming • Pollution • litter • overfishing • Erosion • tropical storms • Privatisation (being privately owned) - waves depend on: 1. Strength of the wind 2. length of time that the wind blows 3. Distance of sea that the wind has to cross Fetch: the distance the wind blows over the surface of water 1

Tuesday, 28 March 2017

- 4 types of erosion • hydraulic action: weight of waves compress air in cracks • Corrosion: dissolving rock by acids in sea water, carried away by solution • Corrasion(abrasion): particles carried by waves hit against cliff=sand paper action • Attrition: particles carried by the waves crash against cliff, eroding cliffs

- type of waves • Destructive (weak swash, strong backwash; shorter wavelength; higher in amplitude; higher frequency), erode and transport material away from beaches

• Constructive (strong swash, weak backwash; longer wavelength; lower in amplitude, less frequent), deposits material

- Bay and headlands - *differentiated erosion*-key term include in both headland and bay formations • Bay (usually found between two headlands): formed by differentiated erosion, less resistant rocks erode rapidly by sea through hydraulic action/abrasion, etc. Hard rocks erode more slowly than soft rocks • Headlands: same as above. when soft resistant rocks are eroded, hard resistant rocks are left to form headlands

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Wave cut platform

*need to know how to try the diagram above and also need to know how to identify the features on the pic above 1.formed when high tide and strong sea attacks and erodes the bottom of the cliff 2

Tuesday, 28 March 2017 =wave cut notch 2. When wave cut notch gets bigger, weight of rock above increase and eventually it cannot support its weight and collapse 3. repeating and resulting a retreat of coastline

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Caves, arches, stacks and stump (usually found on headlands) 1. waves always find weaknesses in headlands and start attacking it 2. overtime, crack may turn into a cave 3. cave will get bigger and cut all the way through the headland making an arch 4. arch gets bigger and the weight of arch roof collapse=stack 5. stack is then eroded by sea and weathered form the air=stump

- Longshore drift (transportation) Define: process of waves moving and transporting material along the coastline 1. wave approach coast at an angle parallel to the direction of the prevailing wind 2. Swash of the materials carry beach material at an angle 3. backwash then flows back to the sea at a straight line at 90° 4. transport material sideways along the coast , occurs in a zigzag *need to know how to draw diagram

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Tuesday, 28 March 2017

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Depositional landforms

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SPIT: (formed near mouths of rives where coastline changes direction creating protection) long stretch of sand connected to mainland but stretching out into the sea

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when the direction of the coast changes longshore drift continues into the sea and material is deposited instead of transported

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If deposition is greater than erosion, a sit will build up overtime (similar to sand dunes)

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BARS: out that connects two headbands or run across face of a small bay

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MARSH: low energy ecosystem that develops behind a spit (have some salt resistant vegetation

- SAND DUNES (conditions): wind blow sand deposition by wind, sand dunes build overtime (formed by dry sand being blown up the beach)

- 1. strong wind - 2. Supply of wind - 3. obstacles (marram grass as it has wide spreading roots to trap sand) - BEACH: accumulation of sand between lowest and highest tides

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Tuesday, 28 March 2017

- Receive material from longshore drift and constructive waves - SALT MARSH: found behind spits and low energy coastlines - Deposition exceeds erosion - salt resistant vegetation (halophytic)

CASE STUDY (7 mark) COASTAL MANAGEMENT: Happisburgh, southeastern coast of england average rate of erosion: 5-8m per year reasons: soft glacial sands, gravels which is less resistant to wave energy long fetch of wind exposed to North sea Impact: 27 houses lost to sea and loss of farmland since 1986 Coastal defences/management (hard engineering vs soft strategies)

- Aim: stop erosion, reduce wave energy, reflect wave energy and absorb wave energy

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Tuesday, 28 March 2017

- HARD: • Groynes: stop longshore drift transporting away beach material (effective but need replacement and look ugly)

• sea wall: made out of concrete times to absorb waves energy(effective but ugly)

• rock amour (granite) - SOFT: • dune stabilisation: planting vegetation (i,e marram grass making them more stable and reducing the moisture content as marina grass has wide spreading roots and they will have water uptake)

• cliff regarding: making cliffs less steep (steep cliffs are unstable because of undercutting)

• beach nourishment: adding more sand to beach • managed retreat (changing some inland ecosystems by adding salt water) CORAL REEFS

- Conditions: tropical sea conditions, warm water clear water no pollution, sunlight, water less than 60m deep

- Three types: • Fringing: circle coastline and islands • Barrier: separated from island by deep lagoon • Atoll: submerged CASE STUDY (7 mark) CORAL REEFS: great barrier reef 3000km long and up to 52m wide, located in Australia in the tropics BENEFITS

- support 25% marine species

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Tuesday, 28 March 2017

- Protect coastline from erosion - form natural barrier against tropical storm - Contribute to material formations of beaches - Tourism industry: 2 million tourists - provide fishing ground - great barrier reed marine park authority THREATS

- coral bleaching occurred in 1996, 2002 and 2006 - Overfishing led to population explosion o starfish (predator of coral reefs) - water pollution in agriculture in Queensland - marie trading - Deforestation - Global warming CORAL REEF MANAGEMENT

- Conservation zones - fish stocks - Sewage outlets - Banning the dropping of anchors - reduce use of fertilisers - educate people about coral reefs TROPICAL STORMS: super typhoon Haiyan December 2012 affected central Philippines 5-6m high storm surge 6500 confirmed deaths , 1000 missing 7

Tuesday, 28 March 2017 destroyed hectares of sugar and rice vegetation which greatly impacted Philippines’ economic development as they strongly rely on food production to sustain life

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