1. UNIT 2: NATURAL ENVIRONMENT
COASTAL LANDSCAPES
UNIT 2: NATURAL ENVIRONMENT
RIVER LANDSCAPES
COASTAL LANDFORMS
HEADLANDS AND BAYS
Rocks of varying resistance lie at right angles to the sea.
Softer rock is eroded more quickly forming bays.
More resistant rock is eroded less quickly forming headlands protruding into the sea.
As the sea erodes the bays back the headlands are exposed to greater levels of erosion from the sea and are eroded more quickly.
CLIFFS AND WAVE-CUT PLATFORMS
The sea erodes the base of he cliff using abrasion and hydraulic action.
It undercuts the cliff forming a wave-cut notch with an overhang above.
Erosion continues, the overhang grows - falling into the sea under its own weight.
The repeated collapse of the cliff causes it to retreat, becoming higher and steeper.
This forms a rock, wave-cut platform which is visible at low tide.
As the width of the platform increases and so the rate of erosion slows down.
CAVES, ARCHES, STACKS & STUMPS
Formed in rocks with a fault or line of weakness.
Hydraulic action widens the fault forming a cave.
On headlands, caves form on both sides and erode through to form an arch.
The bottom of the arch continues to be eroded.
This causes the top of the arch to collapse leaving a column of rock - a stack.
Continued erosion an weathering leads to the formation of a stump.
SPITS AND BARS
Longshore drift transports material along the beach.
This movement continues even where there is a change in the direction of the coastline, creating an extension of the coastline out into the sea -a spit.
The wind and sea currents may curve the end of the spit.
On the land side, silt is deposited and salt marshes form.
If a spit develops across two headlands it is known as a bar.
BEACHES
Area of land between low tide and storm tide.
Formed by constructive waves, often in bays as a result of deposited material.
Sometimes found on straight stretches of coastline where longshore drift occurs.
Types of Erosion
Hydraulic Action
Pressure of water pushed against cracks in bed/banks.
Abrasion
Particles thrown against river bed/banks.
Solution
Chemical reaction between rock and river water (when slightly acidic).
Attrition
Wearing away of rocks as they knock into one another.
HOW DOES A RIVER CHANGE FROM SOURCE TO MOUTH?
UPPER COURSE
MIDDLE COURSE
LOWER COURSE
Vertical Erosion
V Shaped valley
Narrow channel
Shallow river
Slow flowing
Lateral erosion
U shaped valley
Wider channel
Deeper river
Faster flowing
Mostly deposition
Broad valley
Wide channel
Deep river
Fast flowing
DRAINAGE BASIN
The land that is drained by a river system is called a
Watershed
The boundary of a drainage basin. It separates one drainage basin from another and is usually high land, such as hills and ridges.
Confluence
A point where two streams or rivers meet.
Tributary
A stream or small river that joins a larger stream or river.
Source
The starting point of a stream or river, often a spring or a lake.
Mouth
The point where a river leaves its drainage basin as it flows into the sea.
Types of Weathering
Physical
(Freeze/Thaw)
Water gets into cracks in rock / Freezes (at night) / Expands / Widens crack.
Chemical
Rainwater containing weak acids reacts with rock / Rock breaks up and disintegrates.
Biological
Seeds fall into cracks and grow / The roots break up rock.
Mass Movement
Slumping
(Rotational Slipping)
Common of banks of rivers / Dry weather, clay cracks / Rainwater fills cracks / Rock becomes saturated (and so weakened) / Gravity pulls rock down slope.
LARGE AREA OF LAND. LEAVES A CURVED SURFACE.
Soil Creep
Water gets in soil / Gravity pulls water slowly downhill.
SLOW DOWNHILL MOVEMENT. LEAVES RIPPLES (TERRACETTES) ON THE LANDSCAPE.
RIVER LANDFORMS
V-SHAPED VALLEY
The river is small with lots of water in contact with the bed / banks.
The river flows slowly and only has enough energy to erode downwards.
This forms a v-shaped valley.
The river flows around the valley sides (spurs) instead of eroding them.
These resistant rocks are known as interlocking spurs.
WATERFALL
A river flows over more resistant and then less resistant rock.
The weaker rock is eroded and develops a step on the riverbed.
The river gains velocity as it falls over the step and erosion increases.
As the river erodes downwards and backwards an overhang (of resistant rock) is formed.
Eventually this becomes too heavy and collapses into the plunge pool below.
Over time this process continue and the waterfall retreats.
MEANDER
River flows fastest on the outside of a bend because it is deepest (reducing friction).
This results in a greater level of erosion – forming a steep bank known as a RIVER CLIFF.
On the insider of the bend, water is slower (because it is shallower) and deposits material.
This forms a gently-sloping bank known as a SLIP-OFF SLOPE.
OXBOW LAKE
The outside bends of a meander erode most quickly.
This causes the neck of the meander to narrow.
Eventually the neck erodes through completely forming a new, straight river channel.
Deposition at the neck seals off the original bend forming an oxbow lake.
Gradually, the lake dries up leaving an oxbow scar.
FLOODPLAIN & LEVEES
When a river floods the flood water spreads out on the valley either side.
As it slows down it deposits its load.
This creates a wide, flat area made up of fine material known as a FLOODPLAIN.
At the same time, the largest material carried by the river is deposited along its banks closest to the river.
This creates natural embankments of sediment either side of the river known as LEVEES.
FACTORS AFFECTING CLIFF RECESSION
Fetch – Longer the fetch, the stronger the waves.
Steepness of beach – Gently sloping beach – gentle waves. Steeper beach = stronger waves.
Rock type – resistant rocks (granite) erode more slowly than less-resistant rocks (clay).
Steepness of cliff – steeper cliffs = more mass movement and so greater retreat.
EFFECTS OF CLIFF / COAST RECESSION
HAPPISBURGH: 25 properties and the village’s lifeboat launching station washed away. The main area of concern now is Beach Road which terminates in the sea. The houses were worth £80,000 when the coast was being defended, but are now valued at just £1. In the next 100 years 1,000 homes, 3.5Km of road and 7 golf courses will be lost to the sea.
DAWLISH: The main railway line runs along the coast to Dawlish, when the sea is rough trains are cancelled or delayed, with 160 passengers being stranded for 4 hours on one occasion as the train’s electrics where affected. The annual building and repair bill is £400,000. If this main line is washed away the economy in the area will suffer.
PREDICTION AND PREVENTION OF THE EFFECTS OF COASTAL FLOODING
Met Office – predicts likelihood of a coastal flood. Gives info. to public through weather forecasts and news broadcasts. This includes giving them a flood hotline number.
Environment Agency – website has information on likelihood of a flood. This is identified as different warning codes.
This tells people what to expect and how to react. Monitors sea conditions 24 hrs per day / 365 days per year.
Building design / control – Before houses can be built the LA has to give planning permission. This is not granted in flood-risk areas. From 2010 all houses in flood-risk areas must be flood-resistant.
CAUSES OF RIVER FLOODING
URBANISATION – Concrete is impermeable.so water flows to storm drains more quickly.
DEFORESTATION – Less interception. Water flows more quickly to river.
TEMPERATURE RISE – Ice/snow rapidly melts overwhelming river.
GEOLOGY – Impermeable bedrock doesn’t allow infiltration and so increases surface runoff.
EFFECTS OF RIVER FLOODING
USA 2006: 200,000 people evacuated from homes in NE Pennsylvania. Roads closed / destroyed.
MEXICO 2007: 70% of state of Tabasco under water with 100% of crops destroyed.
INDIA 2008: Affected more than 2.2 million people in 1,000 villages. Roads and railways submerged. Floodwater caused the course of the river to change – flowing 120km east of original course.
HARD ENGINEERING
SOFT ENGINEERING
Sea Wall – Usually made of concrete. Reflects and absorbs wave energy. Very visible = people feel safe but are ugly and expensive.
Beach Replenishment – placing sand/pebbles on the beach. Looks natural and is cheap. Requires constant upkeep.
Groynes – Usually made of wood. Stretches from coastline to sea. Prevents longshore drift. Effective for many years but unattractive and make it difficult to walk along beach.
Cliff regrading – Cliffs cut back and given gentle slope to stop slumping. Natural. Will encourage wildlife. Houses may need demolishing.
HOW IS THE COAST MANAGED IN WALTON-ON-THE-NAZE?
1977 – Seawall built in the south to protect houses on Sunny Point Road (worth an average £400,000).
Groynes used to address longshore drift and cliff regraded with drainage channels installed to prevent slumping (cliffs made from London clay which slumps easily).
1998 – Council paid £167,000 for 300 tonnes of Leicester granite to protect the Tower.
1999 – Beach replenished in front of cliffs.
HARD ENGINEERING
SOFT ENGINEERING
Embankments – Raised banks along the river. Raise level of banks and reduce erosion (if concrete). Ugly.
Afforestation – trees planted near river to intercept rainfall.
Channelisation – Widening or deepening the river allowing it to carry more water. Long lasting. Expensive.
Warning systems – A network of sirens to give early warning. Cheap but can be vandalised.
HOW IS THE RIVER NENE MANAGED?
2002 – 450m clay flood embankment built in Weedon (raising level of banks by 6.8m).
2003 – Warning system upgraded in St. James area to give 2 hours’ notice.
£8 million defences built around Upton creating washland. Road protected by 2m high floodwall.

2. UNIT 2: NATURAL ENVIRONMENT
TECTONIC LANDSCAPES
UNIT 2: NATURAL ENVIRONMENT
A WASTEFUL WORLD
PLATE BOUNDARIES
CONVERGENT ‘DESTRUCTIVE’ (OCEANIC / CONTINENTAL):
Two plates come together. The heavier oceanic crust is subducted (goes underneath).
This creates a deep ocean trench.
Friction from subduction melts the oceanic crust and creates earthquakes.
The newly-melted material is lighter than the surrounding magma in the mantle and rises to the surface.
It forces its way to the surface through faults in the rock – creating explosive volcanoes.
CONVERGENT ‘COLLISION’ (CONTINENTAL / CONTINENTAL):
Two plates move together.
The collision of the two plates creates earthquakes.
As both plates are the same density neither will sink and so both push upwards forming fold mountains (e.g. Himalayas).
As no crust is created or destroyed, no volcanoes are formed.
DIVERGENT ‘CONSTRUCTIVE’:
Two plates move apart (most commonly underneath the ocean)
As the plates move faults are created at the boundary.
Magma rises to fill these faults (filling the gap).
This creates a ridge of new land.
Over time this may continue to grow, eventually rising above the surface of the water forming volcanic islands.
CONSERVATIVE:
Two plates move alongside each other.
This movement is not smooth and the plates stick, building up pressure.
When this pressure is released it creates an earthquake.
WHAT ARE THE DIFFERENCES BETWEEN HIC AND LIC WASTE PRODUCTON?
HIC’s produce MORE WASTE because of the consumer society that operates in these countries. People here have the ability to buy more products and generate more waste (throwing things away instead of repairing).
EXAMPLES of waste produced in HICs:
Excessive packaging – creates lots of paper/cardboard/plastic.
E-waste - as people discard electronic devices that work for an up to date model (e.g. mobile phones).
Non-biodegradable waste such as disposable nappies – people can afford these instead of traditional nappies that can be washed and re-used.
HOW IS WASTE RECYCLED AT A LOCAL SCALE? BRACKNELL FOREST COUNCIL
2 household waste recycling centres, with one way system and clear signage. This makes recycling quicker and easier for people so they are more likely to do it.
150 recycling sites at easy to reach places such as supermarkets. These are more local and easy to access so people are more likely to use them.
Alternate week waste collection (one week general waste, the next week recycling). Therefore, if people don’t recycle their bin overflows. Also useful for people who can’t drive.
WHERE DOES THIS WASTE GO TO? WHAT IS IT RECYCLED INTO?
Paper and cardboard – paper mill in Kent. Becomes new packaging.
Cans – Biffa waste management facility in Southampton. Used for new cans (aluminium) or cars (steel).
Plastic bottles – Bayliss recycling in Bristol. Become garden furniture, fleece jackets or new bottles.
HOTSPOTS
Some parts of the mantle are particularly hot (‘hotspots’).
If the crust above these areas is thin/weak this magma can rise through the crust forming a volcano.
Over time, these can grow and reach above the surface of the water forming a volcanic island.
As the plate moves, the original volcano moves away from the hotspot and becomes extinct. A new volcano forms in its place.
This creates a line of volcanoes known as an island arc.
HOW IS WASTE DISPOSED OF IN A HIC? GERMANY
LANDFILL (DOMESTIC WASTE):
Germany has 160 landfill sites for domestic waste (a huge drop on the figure in the past). Since 2005, all waste has had to be treated before it can be put into landfill. Problem with landfill = methane produced.
INCINERATION (DOMESTIC WASTE):
There are 68 incinerators in Germany. The owners of these plants receive money to incinerate the waste and income from the heat it gives off. These plants do release carbon dioxide that is harmful.
RECYCLING (DOMESTIC WASTE):
All products that can be recycled have the ‘Grune Punkt’ logo on them – they cost the average family an extra £100 - £200 a year with the cost of recycling added to the initial cost of the product making it expensive.
EXPORTING (NUCLEAR/TOXIC WASTE):
Until 2009 , Germany paid a lot of money to Britain and France to export nuclear waste. Facilities are being developed that will mean in the future all nuclear waste can be dealt with in Germany.
FOCUS / EPICENTRE
FOCUS: The point below the surface where the crust snaps leading to an earthquake.
EPICENTRE: The point on the surface directly above the focus (area where most damage is caused).
HOW ARE EARTHQUAKES MEASURED?
RICHTER SCALE
Measures earthquake magnitude using scientific equipment (seismometer) – and so objective. Logarithmic scale. Open ended scale.
MERCALLI SCALE
Measures earthquake’s intensity (the damage caused). Measured using people’s observations and so score varies depending on distance from epicentre. Scale from 1-12 (in Roman numerals).
ADVANTAGES / DISADVANTAGES OF RENEWABLE AND NON-RENEWABLE ENERGY
NON-RENEWABLE – COAL:
Advantages = Cheap to mine and easy to convert to energy by burning it. Disadvantages = Ugly waste heaps are left (the Aberfan disaster killed 116 children) and carbon dioxide is released.
RENEWABLE _ WIND:
Advantages = Wind is free, relatively cheap to build turbines, no greenhouse gases released. Disadvantages = can be ugly, noisy, disrupt bird movements.
WHY DOES GLOBAL ENERGY CONSUMPTION VARY?
The wealth of the USA allows it to provide the energy required of its population and their income means that they can afford to buy electrical equipment.
In Qatar there is availability of large supplies of oil – this has resulted in wealth for its citizens, but also plenty of resources to produce electricity.
WHY DO PEOPLE CONTINUE TO LIVE IN AREAS OF TECTONIC ACTIVITY?
EARTHQUAKES
Improved building design makes people feel safe.
People can’t afford to move away.
People don’t want to leave family behind.
VOLCANOES
Ash creates very fertile soil – and so is good for farmers e.g. Naples, Italy.
People feel ‘it will never happen to me’.
Volcanoes are tourist attractions – bringing money through jobs. E.g. Mt Etna
PREDICTION OF TECTONIC ACTIVITY
PREVENTION OF TECTONIC ACTIVITY
Volcanoes – Tiltmeters detect changes in slope of volcano; Measuring gas levels to see if sulphur increases; Seismometers measure small earthquakes before eruptions.
Earthquakes – Historical mapping; animal behaviour.
Earthquakes – Education: Japan, 1st Sep = Disaster Prevention Day . Schools and businesses practice evacuations.
Earthquakes – Building design: Yokohama Landmark Tower is tallest building in Japan. Has flexible structure to absorb earthquakes.
Volcanoes: 1996, Italian army detonated 7000kg of mining explosives to successfully block a lava flow from Mount Etna reaching villages. Large volumes of water sprayed on lava to disrupt the flow.
HOW IS ENERGY WASTED DOMESTICALLY AND INDUSTRIALLY?
Carbon Footprint = ‘The amount of CO₂ released into the atmosphere as a result of the activities of an individual or group’.
DOMESTICALLY:
- Poor insulation (20% heat escapes through windows).
- Electrical appliances left on standby.
- Lights left on (not in room).
INDUSTRIALLY:
- Offices leaving electricals on overnight (e.g. PCs).
- Iron and steel industry, £1 in every £12 spent on fuel is wasted.
Carbon Footprint = Amount of CO2 required by an individual / group to sustain their day-to-day activities. (A measure of impact on the environment).
HOW CAN WE SOLVE THE PROBLEM OF ENERGY WASTAGE IN THE UK?
NATIONAL SCALE:
Government policy providing grants for energy efficient measures (£2,500 a household) and removing planning permission for energy efficient measures (solar panels and wind turbines) for homeowners.
LOCAL SCALE:
Oldham City Council is upgrading its social priority housing to make it more energy efficient – cavity wall insulation / double glazing. It also has info on its website to reduce energy use and gives all households two energy saving light bulbs.
DOMESTIC SCALE:
Fitting loft insulation saves £180-£220 in energy costs and around 1 tonne of CO2 a year. Draught proofing windows and doors saves £20 and around 150kg of CO2 a year.
CAUSES OF THE HAITI EARTHQUAKE
EFFECTS OF THE HAITI EARTHQUAKE
Conservative plate boundary (Caribbean and North American plates). Plates are sliding past one another.
Two major fault lines run through Haiti; the earthquake near Port-au-Prince occurred along the Enriquilla-Plantain Garden Fault.
Over time, pressure had built due to plates being locked for 250 years .
The focus was shallow at 6.3 miles below the surface.
3 million people affected = over 220,000 deaths and 300,000 injured.
1.3 million made homeless and 30,000 commercial buildings were destroyed affecting the economy.
Emergency services struggled to respond as several hospitals collapsed. Difficulties in aid reaching the country caused by damage to the port and airport in the capital.
Deforestation of hills around Port-au-Prince resulting in landslides.