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17 Cards in this Set
- Front
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Weathering Processes & Mass Movement The Coastal Zone |
The coastline is shaped by different processes These processes are at direct result of MARINE PROCESSES: wave action, erosion, transportation and deposition of materials. They are aided by weathering of rocks exposed at coast and mass movement |
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4 Types of Mass movement The Coastal Zone |
Rock fall - fragments of rock break away from cliff, often due to freeze-thaw weathering Landslide - blocks of rock slide downhill Mudflow - saturated soil & weak rock flow downhill Rotational slip - slump of saturated soil & weak rock along a curved surface |
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Constructive & Destructive waves The Coastal Zone |
Constructive: swash stronger than backwash (carry large amounts sediment > construct the beach), arrive at <10 a minute, smaller in height, formed distant storms Destructive: backwash stronger than swash (removal sediment > destroy the beach), arrive at 10< a minute, larger in height, formed local storms. |
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5 Processes of Erosion The Coastal Zone |
Hydraulic action - sheer power of waves as they smash onto cliff, trapped air blast into holes & cracks, eventually causing rock break apart. Explosive force of trapped air called cavitation. Corrasion - fragments of rock picked up & hurled by the sea at cliff. Rocks act like erosive tools by scraping/gouging rock. Abrasion - 'sandpapering effect' pebbles grinding over rocky platform often causing it to become smooth. Solution - some rocks dissolved by seawater, particularly limestone & half which form cliffs. Attrition - where rock fragments carried by sea knock against each other, causing them to get smaller & rounder |
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4 Processes of Transportation The Coastal Zone |
Traction - large pebbles rolled along sea bed Saltation - 'hopping' of particles too heavy to be suspended Suspension - particles carried within water Solution - dissolved chemicals derived from limestone/chalk |
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Longshore Drift & Deposition The Coastal Zone |
1. Swash picks up sediment & travel up beach at an angle 2. Due to gravity, backwash carries material down perpendicular to coast. e.g prevailing winds in Britiain is from SW to material moved from W to E along south coast Deposition - occurs in areas where flow water slows down and sediment has to be deposited. Common in bays where energy of waves reduced on entering bay. Explains presence of beach in bays and explains the lack of beaches at headlands where wave energy much greater |
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Headlands & Bays The Coastal Zone |
Bays - broad inlet of the sea where the land curves inwards. Form when less resistant rock eroded first. There is deposition in bays, forming beaches. Headlands - a point of usually high land jutting out of the sea. Form when more resistant rock left sticking out but then erosion begins to take place at headland. |
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Wave-Cut Platforms & 4 Cliff Features The Coastal Zone |
Due to processes of erosions, wave-cut notch made at base of cliff & eventually the weight of cliff above too great so cliff collapses. This is cliff retreat. Area under wave-cut notch is wave-cut platform. Cliff features: Caves - (hydraulic action & corrasion) formed in weaknesses. Arches - form when a cave continually widened. Stacks - isolated portion of cliff, arch was too heavy so it eventually collapsed. Stumps - stack undercut & collapses to leave a stump, covered up at high tide. |
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Beaches, Spits & Bars The Coastal Zone |
Beaches - often formed in bays; energy of waves reduced as they slow down. Spits - formed longshore drift; sea relatively shallow & sheltered; prevailing winds; salt marsh (wildlife habitat) beings to grow behind spit; occasional strong winds from NE turn end of spit. Bars - a spit that has grown across a bay. |
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Reasons for Rising Sea Level The Coastal Zone |
- Glaciers & ice sheets are melting. - Global temps increase - sea water absorbs more heat & expands. - Affected by rate of global warming. |
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3 Types of Hard Engineering The Coastal Zone |
Sea wall - barrier to sea, placed at foot of cliffs/top of beach, curved face to reflect back waves, £6 per km (expensive), stops sea, can be unnatural, high maintenance. Groynes - wood/rock structures, prevent longshore d, £10,000 each, bigger beach, enhance tourist potential, starve beach down drift, unnatural. Rock Armour - pile of boulders at foot of cliff, absorb wave energy & protect cliffs, £1000-£4000 per metre, quite cheap, easy to maintain, can be expensive, don't fit in with local geology. |
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3 Types of Soft Engineering The Coastal Zone |
Beach nourishment - adding sediment to beach to make bigger, usually obtained locally, £3000 per metre, cheap, easy, increase tourist potential, need constant management. Dune Regen - effective defence but easily damaged by trampling marram grass can be grown to help dune develop, £2000 per 100m, maintains natural coastal environment, time consuming, can be damaged. Marsh Creation (managed retreat) - allow low-lying land to be flooded by sea, cheap, wildlife habitat, land lost. |
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Case Study: Hurst Castle Spit, Hampshire The Coastal Zone |
- 3km in length - Muddly, pebbly, salt marsh behind in sheltered water - Moving south-easterly |
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Case Study: Bangladesh (Impacts) The Coastal Zone Environmental and Economic |
Enviro: low lying country - flooding&cyclones, scientists predict sea could come inland, most vulnerable country to sea level in world, potentially 1.5m rise, rare species like Bengal Tiger & Wild Boar under threat, reduce freshwater availability, mangrove forests under threat. Eco: high unemployment, tourism could be lost, one of the poorest countries in world, decrease in nation's total economic activity, less of agricultural land, loss of infrastructure. |
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Case Study: Bangladesh (Impacts) The Coastal Zone Social and Political |
Social: densely populated, poor health; famine, cholera, diarrhoea (contaminated water), homelessness, communication loss.
Political: increased poverty, forced to seek aid from other countries, whether to spend money on food, health, water, depending on coast. Rural to urban migration pressure services, movement of people across borders, tension between India & Bangladesh government. |
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Case Study: Studland Bay Nature Reserve The Coastal Zone |
Located on the S coast of England near Bournemouth. 1.5m visit each year for it's beauty and rare species found there. The problem is that it's a very vulnerable eco-system: rare species are at risk, lots of tourists cause litter and create fire hazards (cigarettes). Marram grass holds the sand dunes together. |
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Case Study: Studland Bay Nature Reserve The Coastal Zone |
Solutions implemented to reduce damage: Vulnerable areas are fenced off. Guided walks allow people to enjoy it with damaging enviro. Limited car parking. Boardwalks. Fire beaters. Jet skis are not allowed to be launched. Dogs are prohibited during summer months on Knoll & Middle beach. Tourists educated about the enviro so they're encouraged to protect it. |
