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46 Cards in this Set
- Front
- Back
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What is mechanical weathering? |
When rock is broken down with no change to its chemical composition |
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Describe freeze thaw weathering |
Water gets into rocks through cracks Water freezes and expands putting pressure on the rock Water thaws and releases pressure Constant freeze thaw breaks up rock |
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What is chemical weathering? |
Rainwater with co2 dissolved in becomes weak carbonic acid Carbonic acid reacts with calcium carbonate in chalk and limestone and dissolves rock |
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What is mass movement? |
Mass movement is the shifting of rocks or loose material down a slope causing the cliff to retreat rapidly. Happens often when rock full of water which acts as a lubricant |
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Describe the two types of mass movement |
Slides- Material moves in a straight line Slumps- Material moves with rotation |
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What are the 4 processes of coastal erosion? |
Hydraulic power- Waves crash against rock compressing air into cracks putting pressure on the rock and widening cracks which then break off Abrasion- Eroded particles in water rub against rock and wear away small pieces Attrition- Eroded particles smash into each other and get smaller and rounded off Solution- Carbonic acid in seawater dissolves chalk and limestone |
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How are wave cut platforms formed? |
Lots of erosion at foot of cliff Wave cut notch is formed Rocks above wave cut notch are unstable and collapse Collapsed material is washed away and leaves wave cut platform Repetition of this causes cliff to retreat leaving a wave cut platform |
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How are headlands and bays formed? |
Bands of more and less resistant rock across the coast are eroded at different speeds Headlands form from the more resistant rock which erodes slower Bays formed from the softer rock which erodes quicker |
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How are caves arches and stacks formed? |
Headlands made out of more resistant rocks have weaknesses and cracks Waves erode headland with hydraulic power and abrasion Cracks in rocks are enlarged Enlargement of cracks forms cave Cave gets deeper until it breaks through headland to form arch Rock supporting arch eroded until it collapses leaving a stack- an isolated rock separate from headland |
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Describe the 4 types of transportation along the coast |
Traction- Large particles are rolled along the sea bed by the force of the water Saltation- Pebble sized particles bounced along by force of the water Suspension- Small particles are carried along in the water Solution- Soluble material carried along whilst dissolved in the water |
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What is deposition? |
Where material being carried along by the coast is dropped |
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Which areas have the most deposition? |
Areas with lots of material transported into the area or areas with high erosion further up the coast |
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Describe the kind of waves that would build up a coast |
Constructive waves Low energy Low frequency of 6-8 waves a minute Swash more powerful than backwash meaning material is deposited on beach |
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How are beaches formed and where are they found? |
Formed by constructive waves depositing material and found between low and high water marks |
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Describe a sand and a shingle beach |
Sand- Flat and wide as sand particles are small so a weak backwash from constructive waves can still move them back down the beach to create a long gentle slope Shingle- Steep and narrow as shingle is large and heavy so weak backwash can't carry it back down beach so it builds up to create a steep slope |
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Describe the formation of spits and bars |
Spits- form at sharp bend in coast where long-shore drift carries sand particles past bend and deposits them in the sea. Strong wind can bend spit end creatinga recurved end. Sheltered area behind spit is protected from waves and lots of deposition occurs so plants can grow there. Sheltered area often becomes a marsh or mud flat Bars- Formed when spit attaches two headlands. Bar creates a lagoon behind it |
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How would you see stacks, cliffs, wave cut platforms, beaches and spits on a map? |
Stack- Seen as little white blobs in the sea Cliffs- Little black lines Wave cut platform- Bumpy edges along coast Beaches- Pale yellow for sand beach and yellow with speckles for a shingle beach Spits- Beaches that go out to sea |
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What two things are causing rising sea levels and how much do they rise by each year? |
Melting ice causes water stored in ice to return to the oceans Hotter oceans causes water to expand through thermoexpansion increasing the volume |
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What are the economic effects of coastal flooding? |
Repairing damage from floods is expensive Loss of tourism from coastal attractions being flooded or floods putting off tourists Salty seawater can kill crops and reduce soil fertility for years |
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What are the social effects of coastal flooding? |
Deaths Contaminated water supplies Homes destroyed Loss of jobs |
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What are the environmental affects of coastal flooding? |
High salt content in seawater can kill vegetation and force of water can uproot plants Large volume of fast moving water can increase erosion |
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What are the political effects of coastal flooding? |
Policies made to reduce the impacts and likelihood of future flooding like building defences of managing flood areas |
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Why is London at risk from coastal floods? |
Major city with large tidal river flowing through Population of over 9 million Heavy rainfall causes river channel levels to increase Many homes and businesses by river bank |
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What were the effects of a previous flood on London? |
31st Jan 1953 Hundreds killed and thousands evacuated Millions of pounds of damage |
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Describe the social, economic and environmental effects of floods in London |
Economic- £80 billion of property and 26 underground stations at risk and tourists may be put off Social- 1.3 million people at risk, 400 schools and 16 hospitals as well as a power station and an airport Environmental- New habitats made on flood plain |
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What measures have been taken to protect London? |
Thames barrier opened in 1982 and can close 8 barriers to stop tidal surges and protect London and is closed 5-6 times a year. Without London would flood 183m of floodwall built. But now some removed to allow water to flood onto flood plain |
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Where is holderness? |
Northeast England in Yorkshire south of Bridington and north of Easlington. Holderness coast is 61km long from flanborough head to spurn head which is a spit |
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Why is erosion happening so much along the holdernesss coast? |
Erosion along the coast is causing cliffs to collapse. 1.8m eroded on average per year and up to 10m in places Cliffs made from boulder clay an easily eroded type of rock which slumps when wet to cause cliffs to collapse Beaches naturally narrow so can't slow down waves Prevailing wind comes from north east in Arctic ocean and increases power in waves as they travel so waves are very erosive Groynes make beaches narrower elsewhere |
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What impacts does the eroding coastline have on lives? |
Homes near cliff at risk of collapsing into sea Property prices dropped Some roads such as southfeild lane closed between Skipton and Ulrome Buisnesses at risk Caravan park looses 10 pitches per year Gas terminal 25m away from sea at Easlington supplies 25% of british gas supply 80000m2 of farmland lost per year |
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What is an environmental impact of coastal erosion |
Habitats lost to erosion and some SSIs at risk. Lagoons in Easlington seperated from sea with a bar which, if eroded, would destroy the lagoon |
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Give 3 hard and three soft coastal management strategies |
Hard- Sea wall, rock armour, sea wall Soft- Beach nourishment, dune regeneration, marsh regeneration, managed retreat |
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Describe a sea wall and give benefits and disdvantages |
Wall made out of hard material like concrete to reflect waves back to sea. Prevents erosion and also acts as a flood barrier Creates strong backwash which erodes under wall. Expensive to maintain |
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Describe rock armour and give advantages and disadvantages |
Boulders piled up along coast Cheap, absorbs waves energy to reduce erosion and flooding Boulders moved by strong waves so need to be replaced |
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Describe groynes and give advantages and disadvantages |
Wooden or stone fences at right angle to coast which trap material transported by LSD Make beaches wider to slow waves and protect the coast from erosion and flooding and are cheap Starve beaches further down coast and make them narrow causing more erosion |
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Describe beach nourishment and give advantages and disadvantages |
Sand and shingle from elsewhere added to beach Wide beaches slow waves giving greater protection from erosion and flooding Taking material from bed can kill organisms and it's expensive as it must be repaced |
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Describe dune regeneration and give advantages and disadantages |
Creating or repairing dunes by planting vegetation to stabilise soil Provides barrier between land and sea and absorbs enerhy from waves. Planting vegitation cheap. Nourishment expensive. Only protects small area |
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Describe marsh regeneration and give benefits and disadvantages |
Planting vegetation in mudflats Vegetation stabilised flat and reduces speed of waves to prevent flooding and erosion. Creates new habitats Expensive. Not good where there's lots of erosion as marsh can't be established |
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Describe managed retreat and give benefits and disadvantages |
Removing existing defences and allowing land behind to flood Cheap, land becomes new habitat as a marshland and flooding and erosion is reduced behind marsh People disagree over what land can flood |
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Describe the flood defences Along the Holderness coast |
Flanborough Head- Protected by 4.7km of sea walls and wooden groynes Hornsea- Sea wall, wooden groynes and rock armour to protect village Withersea- Groynes to creates wider beaches and roclk armour in front of a damaged sea wall Spurn head- Eastern side protected by groynes and rock armour which also protects humbar estuary |
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What are some problems with the coastal defences along the Holderness coast |
Groynes protect locally but narrow beaches down the coast increasing erosion and Cowden farm which is south of mappleton is at risk of falling into sea Without defences material is transported south into humbar estuary but with defences trapping material there is less water in water meaning it's not slowed down increasing the risk of flooding Rate of material along linconshire cost increased Spurn head may be eroded away as less material added to it ~Bays forming between protected areas making them into headlands which erode qiucker |
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Describe the development of a sand dune and the dune characteristics at each stage |
Embryo dune- windy salty no moisture, humus or nutrients. Sea rockets grow Foredune/ yellow dune- Very little moisture and nutrients and humus. Marram grass grows Grey dune- More moisture and nutrients. lots of vegetation. Gorse, brambles, insects, bees and small birds and lizards live Dune slack- Water table reaches surface. Frogs, dragonflies, fish, willow and bulrushes live Mature dune- Deep rich soil with lots of humus, moisture and nutrients. Oaks, pines, foxes, squirrels and badgers live |
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What is studland bay? |
Bay in dorset Mostly sheltered freom erosive waves except south end Sandy beaches, foredunes and heathland behind Heathland is a SSSI and a nature reserve Popular tourist attraction |
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What are some reptiles, birds, fish and plants that live in Studland bay? |
Reptiles- Adders, grass snakes, sand lizards and slow worms Birds- Dartford warbler, shelducks and grebes Plants- Marram grass, sea rocket, heather, lyme grass Fish- Seahorse (Studland bay only breeding ground in UK for spiny seahorse) |
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What are some adaptations organisms in studland bay have? |
Marram grass- Folded leaves help to retain moisture and long roots help take up moisture and stabilise them in sand Lyme grass- Waxy leaves help reduce water lost to transpiration Grebe- feet far back to make them streamlined so they can dive underwater for fish Snakes and lizards- thick scaly skin reduces water loss and protects them from rough undergrowth |
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What does environmental management do? |
Ensure the environment is conserved but can also be used for other activities |
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What does the national trust do to manage Studland bay |
Add boardwalks to protect sand dunes Fence off some dunes and marram grass planted to stabilise them Info signs tell visitors why habitat is important and how to enjoy it without damaging it Education about dangers of fires on the heathland and provides fire beaters after fire in 2008 destroyed 6 acres of heathland Boats told not to drop anchor after anchors destroyed seagrass where protected seahorses live |
