Water on the land Flashcards
How many people died in the Pakistan floodings of 2010? How many were affected?
1,600 people died. 14 million were affected.
Which area in Pakistan was affected the worst during the 2010 floodings?
Swat Valley.
Why was there a slow response to the Pakistan floodings of 2010? (2 reasons)
- The global community was suffering from donor fatigue due to the recent Haiti earthquake
- The government of Pakistan had an uncoordinated response.
What are the four methods of transportation in a river?
Traction, saltation, suspension and solution.
What shape is the cross profile of the upper course?
A ‘V’ shape.
What is a drainage basin?
An area which ,if water is precipitated into, drains into a specific river.
What is a tributary?
A smaller river that joins a larger one within the same drainage basin.
What is a confluence?
The point at which two rivers join.
What is a watershed?
The boundary between two drainage basins, usually marked by highlands.
What is the source of a river?
Where a a river begins.
What is the mouth of a river?
Where a river meets with the ocean.
What is the catchment area?
The area within a drainage basin.
How do types of erosion differ in different courses?
Higher courses have more vertical erosion. Lower courses have more lateral erosion.
What is alluvium?
The sediment deposited by rivers.
What is a levee?
A bank formed by alluvium deposited through periodic flooding.
What is a delta?
When the mouth of a river deposits alluvium faster than the sea can remove it, forming a landmass.
What are the three types of delta?
- Fan-shaped: when the land around the river mouth arches and the river splits many times, creating a fan effect.
- Cuspate: the land around the mouth forms an arrow-head shape.
- Bird’s foot: The river splits on the way to the sea, each part of the river juts out into the sea, rather like a bird’s foot.
What is infiltration?
Water entering the ground.
What is surface runoff?
Water on the surface of the land.
What is afforestation?
Deliberately planting trees to decrease surface runoff.
What is a meander?
A bend in a river.
How do oxbow lakes form?
- In a meander, the river flows the fastest on the outer bend and slowest on the inner bend.
- This causes erosion in the outer bend and deposition in the inner bend.
- This exaggerates the shape of the meander until the meander connects in the middle, isolating a horseshoe shape from the current.
- This creates a straight river and a stagnant horseshoe shape, which is the oxbow lake.
What unit measures river discharge in a hydrograph?
Cumecs, or cubic metres per second.
What is lag time and how does it influence river discharge?
Lag time is how long it takes from water to end up in the rivers after being precipitated. The shorter the lag time the greater the river discharge.
What factors effect river discharge? (4 physical 2 human)
Physical:
-Rainfall
-Temperature
-Relief (Speed of surface runoff, influenced by gradient of land and rock type)
-Rock type (impermeable/non-porous or permeable/porous)
Human:
-Urbanisation (tarmac and concrete are impermeable)
-Drains and sewers (they go into the river)
What are examples of permeable and impermeable rock?
Chalk is permeable; granite is impermeable.
How much damage and deaths did the Boscastle floods cause?
£15 million in damage and no deaths.
What are 6 reasons that the Boscastle floods happened?
- The local area was saturated by weeks of rainfall
- There was a confluence of 3 rivers (Jordan, Valency and Paradise)
- Steep V shaped valleys increased runoff
- 15mm of rain fell in 15 minutes at Lesnewth (near Boscastle)
- The underlying rock was impermeable
- Car parks either side of the Valency river increased surface runoff
What were some of the effects of the Boscastle floodings? (4 effects)
- Alluvium and debris were left even after the flood.
- The visitor centre collapsed
- Tourism reduced
- Destroyed infrastucture
What were some of the responses to the Boscastle floodings?
- RAF helicopters from Chivenor saved 150 people
- Falmouth coast guard mobilised
- Temporary accomodation was set up in the Boscastle football pitch
- Within 6 months utilities were fixed and everyone could go home.
What hard and soft engineering strategies were used in Boscastle after the floods?
- Dams and Reservoirs (can regulate the volume of a river)
- Straightening (can make water in a river move away quicker)
- Afforestation (can reduce surface runoff)
- Flood plain zoning (allows some parts to be flooded and manages where buildings are built)
What is 1 reason that water consumption in the UK has increased?
Washing machine and dishwasher use has increased from 66% in 1972 to 94% today.
What is water stress?
When the demand for water outweighs supply.
What is the name of a reservoir involved in a water transfer scheme in England? How much did it cost?
The Kielder water reservoir in Northumberland, £167 million.
What are three issues with the Kielder water reservoir?
- Habitats and farmland was lost in the making
- People had to be relocated
- Construction cost was £167 million
What are three benefits of the Kielder water reservoir in Northumberland?
- It generates hydro-electric power
- Water is transferred from low water stress areas to high water stress areas.
- It manages the flow of the River Tyne
