Water On The Land Flashcards
Water On Land
What is a drainage basin?
Imaginary area of land that water collects into.
Water On Land
What is the mouth?
Where river meets sea
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What is the source?
Where river begins - usually in mountains or at high altitude
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What is water surplus?
Having more water than is needed - amount exceeds demand.
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What is water deficit?
Not having enough water to meet demand.
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What is a confluence?
Point at which two rivers or streams join.
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What is attrition?
Rocks and stones knock into each other and wear away.
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What is traction?
Big boulders and stones are rolled and dragged along river bed.
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What is transportation?
When a river moves sediment from one position to another through the force of flowing water
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What is deposition?
When a river drops sediment due to an insufficient amount of energy to carry material
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What is erosion?
The wearing away of moving rocks.
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What is a tributary?
A stream or smaller river which joins a larger stream or river.
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What is a watershed?
Edge of highland surrounding a drainage basin. Marks boundary between two drainage basins.
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What is a meander?
A large bend in river caused by both erosion and deposition.
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What is a floodplain?
Wide valley floor on either side of river which gets flooded.
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What is a levee?
Natural embankments along river edge which builds up when material is deposited as velocity decreases.
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How are levees formed?
During flood material is deposited over floodplain with heaviest sediment deposited first, closest to channel. Material builds up to form levees along channel edge.
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What is abrasion?
Pebbles are dragged along and knock into the river bed, wearing away the channel.
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What is hydraulic action?
Pressure builds up from fast flowing water in cracks, breaking the channel.
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What is suspension?
Very small particles are carried in river and suspended in water - making it look muddy.
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What is saltation?
Small stones and pebbles are bounced along in flowing water.
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What is weathering?
Erosion of rocks in situ
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What are the positive economic impacts of a dam/reservoir?
Income generated for local community at each step of project. Provides new infrastructure for water and electricity.
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What are the positive social impacts of a dam/reservoir?
Supplies clean water - provision of electricity encourages industrial development.
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What is solution?
Water dissolves minerals from the river bed and this breaks up the channel.
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What are aquifers?
Pourous rocks underground which store water - accounts for 25% of UK’s water supply.
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What is hard engineering?
Uses construction techniques and materials such as steel and concrete to prevent flooding
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What is soft engineering?
involves adapting to flood risks and allowing natural processes to deal with rain water.
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How does the direction of erosion change at each stage of the river?
In upper course, vertical occurs most. Becomes lateral in middle course and both are present in lower course.
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How are ox-bow lakes formed?
From meanders. Meander gets larger over time until neck gets very narrow. Water cuts through to find fastest route and deposition cuts off meander.
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What is precipitation?
Any moisture that falls from sky e.g. rain/snow
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What is channel flow?
Water travelling in rivers/streams
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What is surface run-off?
(overland flow) Water travels across surface of Earth
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What is infiltration?
When water travels from surface to underground
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What is through flow?
Movement of water through unsaturated ground
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What is groundwater flow?
Movement of water through saturated ground
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What is ground water storage?
Water that is stored in saturated ground
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What are inputs?
When water is added to a system
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What are transfers?
When water moves within a system
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What is interception?
When objects stop precipitation reaching ground below
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What is soil-moisture storage?
Water stored below the ground in unsaturated ground
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What is surface storage?
Any water held on surface e.g. lakes/pond - some may be temporary (puddles)
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What are outputs?
When water exits a system
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What is evaporation?
Liquid water from surface stores and rivers turn into water vapour
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What is transpiration?
Liquid water evaporating from vegetation
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What is evapo-transpiration?
Evaporation and transpiration collectively known
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What is river discharge?
Most rivers enter sea and discharge river’s flow into sea
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What is biological weathering?
animals and plants cause breaking down of rocks
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What is chemical weathering?
rocks break down if they come into contact with slightly acidic rain
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What is freeze-thaw weathering?
happens when water freezes in rock. Expands and causes rock to split or break up
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What is saltation?
small stones and pebbles bounced along in flowing water
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What is traction?
big boulders and stones rolled and dragged along river bed
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What is suspension (transportation)?
very small particles carried in river and suspended in water (making it look muddy)
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What is solution (transportation)?
when minerals are dissolved in river water
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What are the 4 reasons for deposition?
- Reduction in gradient
- Reduction in volume of water
- Increased friction in river bed and bank causing water to slow down
- Adaptation of river for human use
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Where is sediment most likely deposited?
Inside bend of a meander and where river meets sea.
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What erosional features are found in the upper course?
Waterfalls/gorges.
Steep sided valleys.
Interlocking spurs.
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What erosional features are found in the middle course?
Meanders
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What erosional features are found in the lower course?
Flat land.
Ox-box lakes (meanders).
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What depositional features are found in the lower course?
Levees.
Floodplains.
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What depositional features are found in the upper course?
Large, angular sediment deposited
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What depositional features are found in the middle course?
Slip-off slopes on inside bend of meander
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How is a waterfall formed?
- River meets band of softer, less resistant rock, hydraulic action and abrasion creates plunge pool by eroding softer rock.
- Hydraulic action leaves undercut and harder, more resistant rock overhanging.
- Overhang collapses - transported away
- Process repeats and waterfall retreats upstream.
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What are some hard engineering techniques?
Building flood banks. Dams and reservoirs. Barriers. Flood walls. Straightening and deepening the river. Storage areas.
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What are some soft engineering techniques?
Flood proofing. Flood prediction and warning. Wash lands. Flood abatement. Flood plain zoning.
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What does building flood banks involve?
Raising banks of river, so it can hold more water
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What does building dams and reservoirs involve?
Trap store water and release it in a controlled way. It can generate electricity and be multipurpose.
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What does building barriers involve?
Barrier is raised when high tide or flooding is forecast.
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What does building flood walls involve?
Building them around settlements, industry or roads
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What does straightening and deepening the river involve?
Straighten channel to speed up flow, or line with concrete. Dredging makes river deeper - able to carry more water.
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What does building storage areas involve?
Water pumped out of river and stored in temporary lakes. Pumped back when water level in river has dropped.
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What is flood plain zoning?
Different uses are allowed depending on the river
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What is flood abatement?
Change land use upstream e.g. planting trees (aforestation)
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What are wash lands?
Parts of floodplain that are allowed to flood
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What does flood prediction and warning involve?
environmental agency monitor river levels and rainfall. Use information plus weather forecasts to predict flooding
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What does flood proofing involve?
Design new buildings, or alter existing ones, to reduce flood risk.
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What are the negatives of dam construction?
A danger of corruption with vast inwards investment. A large influx of non-local and/or foreign contract workers may introduce disease or encourage prostitution.
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What are the positives of dam construction?
May lead to investment in local companies and provide work for local people.
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What are the negative social impacts of dams?
Local population suffers massive displacement. Stagnant lake encourages spread of water-borne diseases.
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What are the negative environmental impacts of dams?
Rivers silt up. Stagnant lake disrupts local ecosystems
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What are the positive environmental impacts of dams?
Good design minimises ecological cost, but there will always be damage with projects of this size
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What are the negative economic impacts of dams?
Costs of compensation and construction sometimes outstrip projected budget. Income from water and electricity does not cover costs.
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What is a water transfer scheme?
where water is transferred from one area to another.
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When is a water transfer scheme needed?
to maintain river flow when river levels are low, to release extra water for home or industrial work and send water to places with demand/deficit.
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What is water supply like in the north and west of the UK?
lot of rainfall means a good supply of water - water surplus
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What is water supply like in the south east and midlands of the UK?
have high population density, which means a high demand for water - water deficit
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How much has water usage gone up in the last 25 years?
50%
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Why is the demand for water in the UK increasing?
- Increased population
- More needed for it/uses
- Changes in climate - less precipitation
- Guidelines to drink more
- People take it for granted and waste it i.e leave tap running
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How much water does the average single person consume?
165 litres per day
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How much water does an average family of 3 use?
About 150 litres each, per day.