Goegraphy Revision Notes
- Created by: Lauren
- Created on: 03-03-13 15:11
Types of Weathering
Weathering is the break down of rocks in the same place (situ)
Erosion- the break down of rocks and the subsequent removal of the material
Freezethaw- is a physical weathering where when water fills up in the cracks during the night the water freezes and expands.
Biological- To do with animals and plants that cause the rocks to weather
Chemical- is the down pour of acid rain that erodes the rocks. It is a chemical rewaction
Exfoliation- is a physical weathering and when the rock surface weakens and then it expands, the night colls rapidly down and the rocks stay like that.
Methods of Transportation
Erosion
Atrition- Where material is moved along the bed of a river , cthen collides with other material and breaks up into smaller and smaller pieces.
Corrasion- Fine material that rubs against the river bank. The bank is worn away, by a sort of sand papering action called abrasion.
Corrosion- Some rocks forming the banks and bed of a river are dissolved by acides in the water.
Hydraulic Action- The sheer force of the water hitting the banks of the river.
River Tees- Source to Mouth
Source is in the Midlands in Cumbria. They get a relief rainfall in Cumbria because its very high.
Then a v-shape valley going down the moutain. The rocks bedded in the stream are angler.
Resivours in the Upper Course. A build up of water. It is captured using the steep v-shape valleys.
20 cubic metres a secound- high force waterfall which is in the Upper Course.
At the begging of the middle Course, the land is flatter and crops can be grown on the land. The river brings lots of minerals and fertile soil.
The rocks are smoother and the lake is wider
Meanders can occur at any place in the river. Frequently in the middle course
Yarm was built right in the middle of a meanders. River channel is very deep and wide.
A Drainage Basin
A Drainage Basin- an area of land drained by a river and its tribuatry.
Watershed- The boundary of a drainage basin
Mouth- The end of a river where it enters the sea or lake
Channel-Where a river flows. It has a bed and 2 banks
Confluence- The point where 2 rivers meet
Features of a River
Upper Course
Steepsided valley
narrow river channel
large bedload from valleysides
Middle Course
Meanders and Oxbow lakes
Lower Course
Floodplains
Leeves
How we use rivers
1. For our water supply
2. For making electricity - building dams on fast flowing rivers and power stations pump water out of the river and boil to make steam
3. For Farming
4. For industry - many factories use water to wash things or to cool tanks where chemicals are reacting
5. For transport - boats
6. For leaisure and pleasure - fishing, swimming
7. As a dump- for drains and where the water gets cleaned up and put back into the river
...and how we abuse them- by putting posinous stuff down the drains and waste liquid from homes and farms contain nitrates and phosphates.
7 main causes of flooding
Climate- Heavy Rainfall
Human- Dam failure, Deforestation, Urbanisation
Physical- rapid snow melt, saturated ground. tidal surge
River Tees
The River Tees can be found in northern England. The source of the river is located at Cross Fell in the North Pennines, the river flows east for 85 miles until it reaches its mouth and flows into the North Sea between Hartlepool and Redcar near Middlesbrough.
As the river travels from source to mouth, it passes through different villages and towns with many thriving local businesses
The river continues to be enjoyed from people from all walks of life, with the improvement in water quality and surrounding environment being credited to hard work of many groups and local residents. As the river flows through Teesside the local population have reconnected with their local river as the overall improvements over the last decade have left them with a pleasant place to spend time with the full family.
Effects of Cumbria Floods
Some of the effects from the Cumbria Flooding
- 1,200 people were left without electricity.
- Many roads and bridges were closed
- Fire crews worked hard to pump water out of people's homes
- Cockermouth, at the confluence of the river Cocker and Derwent, suffered the worst flooding. Water was up to 2.5m in places
Responses to Flooding
Hard Management Schemes:
Using technology to try and stop flooding
Soft Manegment Schemes:
Works in the cunstrants of the natural environment
Strategys:
Flood Walls:
Advantages:
are effective when in use
Disadvantage:
Built around settlements and important location, also they are very expensive and don't look natural.
Flood Warnings:
Advantages:
It is the local radio and tv stations and have a much better prediciton and also they are not expensive.
Hard Management River Strategy Case Study
Name: The three Gorges dam
Location: China at Yichang on the River Yangtse
Size: 181m high and 2.3km wide
Cost: $25.5 billion
Area Flooded: 632km squared
Economic Benefit- flood control and a navagation and power generation.
Social Benefit- Decreases flooding and protects over 25,000 ha of farmland
Environmental Benefit- Increases depth by 110m and the disadvantage is that it gets heavily polluted from shipping and waste discharged from cities.
Some Defintions
Dredging- deeping the river channel by removing sand and silt
Estuary- the drowned river mouth in a lowland area
Flood Plain- the flat area of land on either side of a river in its lower course
Gabions- rocks set in wire cages to reduce erosion
Impermeable- does not allow water to pass through
Infiltration- the rate at which water may pass through soils or rocks
Reservoir- An artificial lake built to store water
River basin- the area of land drained by a river
Sustainable Development- new developments that do not destroy the environment but may improve it.
Kielder Water
Built in the 1900 to provdie water for the wollen trade
The scheme was approved by parliement in 1974
Work started in 1975
Took 2 years to fill in the valley
It cost £167M
Refurbised in 2005-2006
LArgest Reservoir in the Uk by capacity- 200 billion litres
27.5 mile Shoreine
10km long
Area 10 squared
Preventing Floods
1.Control the water levels- by building a dam and pumping stations
2. Build flood defences- build up the river banks to make embankments to keep water in, or build flood barriers around built-up areas to keep water out
3. MAke the river channel bigger- by dredging the river out
4. Improve street drainage- make sure that the street can cope with ehavy rainfall and that they are cleaned
5. Control land use around the river- stops people building on flood plains and to plant more trees in the drainage basin.
EFFECTS ON CUMBRIA FLOODING
Some of the effects from the Cumbria Flooding
- 1,200 people were left without electricity.
- Many roads and bridges were closed
- Fire crews worked hard to pump water out of people's homes
- Cockermouth, at the confluence of the river Cocker and Derwent, suffered the worst flooding. Water was up to 2.5m in places
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