- Created by: chelseagiles00
- Created on: 05-05-17 16:39
Weather and Climate
Related Case Study:
Climate and Anticyclones
- High air pressure > Air is sinking > Clouds can't form > Dry
- Low air pressure > Air is rising > Clouds can form > Wet
- A slow moving weather system caused by high pressure of 1016mb.
- Low wind speeds (shown on a weather map by the isobars being spread out).
- In summer it brings high temperatures and the opposite for winter.
- Drought and water shortages.
- More forest fires in summer as vegetation dries out.
- There may be a hose pipe ban.
- There may be water rationing.
- In the winter, local councils will grit the roads if it will be below 0'C.
- Those involved in outdoor activities will gain.
- Tourist related businesses will gain in summer.
- The elderly and those with health problems are more at risk in extreme hot or cold weather.
- Warm and cold air meet at the front and then the warm air forces its way into the cold air.
- Two lots of rain.
- A lot of cloud on and near the fronts.
- High wind speeds.
- Flooding if the depression brings a lot of rain.
- In winter, it may bring snow if the temperatures are low enough.
- Structural damages due to high wind speeds.
- The Environment Agency issues flood warnings.
- Schools may be forced to close.
- Football matches may have to abandon matches.
- The Environment Agency is responsible for monitering rivers.
- Commuters may have to change their journey plans.
- Parents may have to arrange child care at short notice.
Tropical Storms e.g. Hurricanes
- Very low pressure weather systems.
- Strong winds.
- Heavy rainfall.
Tropical depressions have winds less than 38mph, Tropical storms have winds between 39-73mph and hurricanes have winds over 74mph.
- Recorded on the Saffir - Simpson scale.
How do hurricanes form?:
- Low pressure area.
- Warm water.
- Coriolis Force.
- The atmosphere.
- The wind.
- It was formed over the Bahamas on 23rd August 2005.
- Crossed Florida as a small hurricane.
- Strengthened rapidly over the Gulf of Mexico.
- Second landfall on the 29th August 2005 in Louisiana.
- The storm broke up on the 31st August 2005.
- The city of New Orleans, in Louisiana.
- Alabama was also affected.
- Sea temperature of 27'C.
- 1800 people died.
- The costs are estimates at $75 billion.
- 1 million people were evacuated from New Orleans.
- 80% of New Orleans were submerged under 6ft of water.
- 9000 people took shelter in the Superdome.
- The government were criticised for not helping the people of New Orleans quickly enough.
Related Case Study:
Amazon Rainforest / Bramcote Woods
Key Services and Management
- Maintaining a steady supply of clean water to rivers.
- Preventing soil erosion.
- Reducing the risk of river floods.
- Providing natural meterials such as timber for building, or plants for medicine use.
- Providing food stuffs such as honey, fruit and nuts.
How can ecosystems be managed sustainably?
- Allowing access to parts of an ecosystem and protecting the rest.
- Encouraging responsible use of an ecosystem - Sign posts, Bins, Fences, Paths.
- Encouraging activities that use the wood in a non-harmful way.
- Replanting trees that are removed.
Human Impacts in the Wood - Bramcote
Different Groups of People:
The wood is managed by Broxtowe Council. People who use the wood are:
- People walking their dog.
- People keeping fit.
- Mountain bikers.
- Local school children taking a short cut.
- Horse riders.
- Soil erosion from people walking and mountain biking.
- Litter and vandalism.
- Tree planting at the top of the hill.
Related Case Study:
Location and Causes
The Sahel is located in the southern region of the Sahara Desert, Africa.
Causes of desertification:
- An increase in population --> Deforestation --> Overcultivation --> Loose top soil blown away or eroded by rainfall ..
- An increase in population --> An increase in cattle --> Overgrazing --> Less vegetation --> Loose top soil blown away or eroded by rainfall ..
Human Causes and Solutions:
- Deforestation = Afforestation.
- Overcultivation = Educate the farmers to use the land in a productuve way.
- Overgrazing = Plant acacia trees for use as food for the animals.
- Over use of fertilisers = Use genetically modified crops.
- Lack of irrigation = Build terraces on the land to help conserve water.
- Poverty/Civil War = Build stone lines across fields.
Causes and Groups of People
Physical Causes and Solutions:
- Climate change and drought = Irrigation schemes or dams.
- Variations in seasonal rainfall = Storing water during rainy seasons and plant more drought tolerant crops (GMC)
- High pressure systems = None
Groups of People:
- The people who live in the Sahel region struggle to survive. Many face starvation or malnutrition.
- The United Narions has a convention to tackle the problems of desertification.
River Processes and Landforms
Related Case Study:
River Trent and Flood Defences in Duffield
Related Case Study:
The Dorset Coast
Location and Landforms
Dorset is a county in South West England on the English Channel coast.
- Old Harry is an example of a stack.
- Durdle Door is an example of an arch.
- Swanage Bay is an example of a bay between two headlands.
- Kimmeridge is an example of a wave-cut platform.
Headlands and Bays - Erosional Landforms:
- This type of coastline is called discordant.
- This coastline is eroded by abrasion and hydraulic action.
- Soft rock is eroded quicker to create bays.
- Swanage Bay is made from clays and sands.
- Hard rock is left sticking into the sea as headlands.
Wave-cut Platforms and Cliff Recession - Erosional Landforms:
- Weather weakens the top of the cliff.
- The sea attacks the base of the cliff forming a wave-cut notch.
- The notch increases in size causing the cliff to collapse.
- The notch forms between the wave height at high and low tide.
- The backwash carries the rubble towards the sea forming a wave-cut platform.
- The process repeats and the cliff continues to recede.
Caves, Arches and Stacks - Erosional Landforms:
- These features are formed on cliffs or headlands that are made of hard rock.
- This hard rock is eroded by abrasion and hydraulic action.
- Old Harry is made from chalk.
- Durdle door is made from limestone.
- Sandbanks is an example of a spit.
- Chesil Beach is an example of a tombolo.
Landforms and Management
Spits, Bars and Tombolos - Depositional Landforms:
- Spits are created by deposition.
- They are formed where the prevailing wind blows at an angle to the coastline.
- A tombolo is a spit that has joined onto an island.
Why do coastal processes need to be managed?
- Increasing development of coastal areas including urban areas means there are more people at risk from coastal flooding.
- This risk is likely to increase in the future as climate change causes rising sea levels and an increase in the number of coastal storms.
- The value of coasts for leisure and recreation.
- Increased economic/transportation/industrial value in industries like oil refineries and ports.
- Increased environmental/nature conservation value of coastal wetlands
How are coastlines managed?
- Hold the existing defence line - To maintain or increase the level of protection provided by defences in their present location.
- Advance the existing defence line - Building new defences on the seaward side of the existing defence line to reclaim land.
- Managed realignment - Allowing the shoreline to position to move backwards (or forwards) in a controlled way.
- Do nothing - A decision to not invest in providing new or maintaining existing defences.
- Gabions - Hard engineering
- Sea walls - Hard engineering
- Rip rap - Hard engineering
- Groynes - Hard engineering
- Beach replenishment
- Revetments - Hard engineering
- Breakwaters - Hard engineering
Swanage Bay, Holderness Coast and Arguments
- Sea wall,
- Groynes and,
- Beach replenishment.
They have a hold the line policy.
- Concrete sea walls,
- Wooden groynes and,
- Rock armour.
Arguments For and Against Sea Defences:
- People have lived in these areas for generations.
- Houses, schools, roads, hotels, agricultural land will be lost.
- The cost is expensive.
- The land is not that valuable in some places.
Upper Course of a River
V-Shaped Valleys - Erosional Landform:
- Vertical Erosion - Results in a number of distinctive landforms including the steep sloping v-shaped valley through which the river flows in its upper course.
- Over time the sides of this valley are weakened by weathering processes.
- As the river flows through the valley it is forced to swing from side to side around more resistant rock outcrops (spurs).
Waterfalls - Erosional Landform:
- Waterfalls often form where hard rock lies over the top of a softer rock.
- The water drops over the edge and swirls around in the plunge pool which erodes the soft rock.
- The soft rock is eroded back.
- The hard rock is left to overhand.
- The position of the waterfall moves backwards (retreats).
- Over a long time this will carve out a deep sided velley called a gorge.
Middle Course of a River
Meanders - Erosional and Depositional Landforms:
- In the middle course, the river has more energy and a high volume of water.
- The gradient here is gentle and the lateral (sideways) erosion has widened the river channel.
- Outside of the bend = The force of the water erodes and undercuts the river bank on the outside of the bend where water flow has most energy due to decreased friction.
- Inside of the bend = The river's flow is slower so it has less energy. This means material is deposited, as there is more friction.
- On the outside bend, a steep bank called a river cliff is formed.
- On the inside, the build-up of deposited material creates a slip off slope.
Lower Course of a River and Flooding
Floodplains and Levees - Depositional Landforms:
- Levees are the higher banks that develop at the edge of the river.
A flood is a period of high river discharge or, alone the coast, an extremely high tide.
A hydrograph is a graph to show changes in discharge of a river over a period of time.
- Urban areas - Increases the risk of flooding due to being covered in impermeable surfaces.
- Deforestation - Increases flood risk because trees intercept some of the rain.
- Intensity of the rainfall - A heavy rainstorm will put a lot of water onto the land in a short period of time.
River Trent Floods of December 2012
- Farmers have removed trees in Derbyshire.
- High rainfall for many weeks - In Rolleston, they recieved 75mm in 24hrs.
- Impermeable surfaces in Derby and Burton on Trent.
- Notts County football match was cancelled.
- Trains were cancelled between Crewe and Derby.
- Toot Hill school in Bingham was closed.
- Fire crews were called out to rescue stranded animals.
- Dam Construction.
- River Engineering.
- Governments and developers often favour large hard enginerring options, such as dam building. Building a dam and a reservoir can generate income. Profits can be made from generating electricity or leisure revenue.
- Environemtal groups and local residents often prefer softer options, such as planting trees. Soft options cause little damage to the environment and do not involve the resettlement of communities.
- Effective flood management strategies should be economically, environmentally and socially sustainable. Sustainable strategies allow management without compromising the needs of future generations.