Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IGCSEs > Geography 🌍 | The flood of knowledge πŸ’§ | Deck 2 > Flashcards

Geography 🌍 | The flood of knowledge πŸ’§ | Deck 2 Flashcards

1
Q

Define percolation

A

The seeping of water through porous rock.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define throughflow

A

Unsaturated flow of water through soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define interception.

A

The rainfall intercepted by vegetation, absorbed by roots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define infiltration

A

The process where water on the ground enters soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define depression (rainfall).

A

An area of low pressure that creates a lot of rainfall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define saturated (rivers).

A

Soil full with water, usually around a river that can’t let any more infiltrate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What’s the difference between arable farming and pastoral farming?

A

Arable farming is the farming of crops and pastoral farming is that of cattle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the physical factors causing flooding?

A

Geology, relief, and precipitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the human factors causing flooding?

A

Agriculture, deforestation, urbanisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does geology impact flooding in mountains?

A

Mountains, mostly impermeable rock such as slate, has high flood risk as rainwater cannot infiltrate or percolate through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does geology impact flooding in low lying areas?

A

Soil is more compacted (as it is clay) which makes it harder for water to infiltrate it, increasing flood risk.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the relief?

A

The heights and slope of the land.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does relief impact flooding in areas with steep sides?

A

A floodplain with too steep of a surface leads to surface runoff occurring on the side without time to infiltrate the soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does relief impact flooding in low lying, flat flood planes?

A

If the flood plain is too flat, there is not enough gradient to remove the water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do sudden bursts of heavy rain impact flooding?

A

When rain suddenly appears, drought often bakes soil hard, leading to surface runoff and increase in discharge. Flash floods occur.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does prolonged rainfall impact flooding?

A

Antecedent rainfall saturates soil, which can lead to flooding as the soil is saturated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does precipitation impact flooding from change in season?

A

Snow can melt, leading to a release in stored water flowing over the ground as surface runoff, or certain seasons can have more rainfall or increase transpiration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why did a change in agriculture techniques after world war 1 impact flooding?

A

After WW1, hedges were ripped out and replaced with huge fields for mechanical arable farming, which reduced interception.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How did our increase in arable farming increase flooding?

A

With arable farming, soil is left bare and lost of nutrition in winter after being harvested, meaning there is less interception of water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does the way we create furrows impact flooding?

A

We plough fields up and downhill towards the river to create channels for water to flow down easier. However, this increases the soil that ends up in the river, raising their beds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does deforestation increase flooding?

A

It reduces interception, increases discharge as soil is saturated quickly, and builds up beds with soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Up to what percent of precipitation does a forest use up?

A

40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does urbanization impact flood risk?

A
  • Cities have few natural areas to store excess water
  • Drains increase discharge
  • Tarmac and concrete are impermeable and increase flood risk.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a hydrograph?

A

A graph plotting river discharge after a storm.

25
Q

Define lag time.

A

The difference between time of peak discharge and peak rainfall.

26
Q

What is the discharge measured in?

A

Cumecs.

27
Q

How does lag time impact flood risk?

A

The shorter the lag time, the higher the flood risk, as it shows how much time water has to infiltrate soil

28
Q

What is hard engineering?

A

When manmade structures are used to prevent or control natural processes from taking place.

29
Q

What is soft engineering?

A

Involving adapting to a river and working with natural processes.

30
Q

What are the hard engineering methods?

A

Dams, channel straightening, embankments, flood relief channels.

31
Q

What are dams?

A

Large concrete barriers across a river, water gradually released downstream in a controlled manner.

32
Q

What is a resevoir?

A

The artificial lake behind a dam where water is held.

33
Q

What are the advantages of dams?

A
  • Reservoirs are attractive to tourists
  • Areas around reservoirs can be planted with forests
  • Dams provide drinking water
  • Hydroelectric power
34
Q

What are the disadvantages of dams?

A
  • To create a dam an area of the valley has to be flooded, displacing families
  • Dams are the most expensive method
  • Downstream soils can become less fertile due to flack of alluvium from floods
  • Fish are disrupted from migrating
35
Q

What is channel straightening?

A

Cutting through meanders to create straighter channels to speed up water flow, sometimes lined with concrete.

36
Q

How does channel straightening decrease flood risk?

A

Water quickly leaves the area and there is less friction with the bed and banks.

37
Q

What are the advantages of channel straightening?

A
  • Reduces flood risk
  • Improves navigations
  • Increases homeowner confidence
38
Q

What are the disadvantages of channel straightening?

A
  • Downstream, floods increase as water reaches a meandering section and sudden velocity decrease sediments the channel
  • Concrete and straightness is unattractive
  • Expensive to straighten
  • Increases pollution as land from agrochemical runoff cannot drain easily.
39
Q

What are embankments?

A

Artificially raised banks to increase capacity to reduce floodrisk with impermeable soil, often concrete.

40
Q

What are the advantages of embankments?

A
  • Flood safety due to larger capacity. The raised banks are less likely to burst
  • Earthen embankments provide habitats for river bank animals such as water voles kingfishers..
  • Cheap in comparison
  • Often allows for walking routes
41
Q

What are the disadvantages of embankments?

A
  • Deprive access to the river for fishing and boating
  • False sense of security for flood risk
  • High maintenance costs as they need monitoring
  • Earthen ones are erosion prone which increases downstream sediment and dredging cost.
  • If broken by a flood, water lies on the land for a long time.
42
Q

What are flood relief channels?

A

Artificially constructed channel as a backup for frequently flooding rivers. This goes around urban areas parallel to the river.

43
Q

What are sluice gates?

A

Gates in flood relief channels that open in high flow.

44
Q

What are the advantages of flood relief channels?

A
  • Removes flood risk from designated area. Exeters relief channels protect 3000 properties
  • More secure for businesses
  • Calm water for recreation
  • Some have artificial reed beds and grass covered concrete sides which provides new habitats
45
Q

What are the disadvantages of flood relief channels?

A
  • People south of the relief channel have to be moved
  • Downstream settlements have increased flooding as the merging of relief channel and main river swells it.
  • Ethical concern on who we are prioritising
  • Expensive and need maintenance
46
Q

What are the methods of soft engineering?

A

Floodplain zoning, flood warnings, aforestation, river restoration.

47
Q

What is floodplain zoning?

A

When land in a river valley is used in such a way to reduce the impact of flooding

48
Q

What are the advantages of floodplain zoning?

A
  • Only administrative, low costs
  • Provides welcome green space in towns
  • Tradition water meadows by a river protected from development
  • Impermeable surfaces decrease by restricting building on active flood plain.
49
Q

What are the disadvantages of floodplain zoning?

A
  • Habitats are destroyed as building on other green sites increases
  • Limited impact where towns have already spread over the flood plain
  • Tough to get planning permission or extend homes
  • Housing crisis
50
Q

How do flood warning systems work?

A

The environmental agency works with emergency services, armed forces, and voluntary groups to carry out action plans at areas of risk.

51
Q

What are the advantages of flood warnings?

A
  • Cheap
  • People feel secure
  • Ensures safety without costly hard engineering
  • People can protect their valuables.
52
Q

What are the disadvantages of flood warnings?

A
  • Education needed
  • People need access to media
  • Doesn’t help those in flood prone areas
  • Distressing
53
Q

What are the advantages of aforestation for flood prevention?

A
  • Reduces surface runoff
  • Absorbs carbon dioxide
  • Adds landscape variety and habitats
54
Q

What are the disadvantages to aforestation as a flood prevention technique?

A
  • Loss of potential grazing where there are trees
  • Being wooded rather than open looks artificial
  • Many must be planted for good impact.
55
Q

What is river restoration?

A

Removing hard engineering to restore back to natural channel

56
Q

What are the advantages of river restoration?

A
  • Aesthetically pleasing
  • Increases tourism
  • New wetland habitats
  • Increased water storage and reduced downstream flood risk
57
Q

What are the disadvantages of river restoration?

A
  • Expensive
  • Loss of agricultural land
  • Flooding
  • Not most effective or practical
58
Q

What is dredging?

A

The digging of the river bed to increase volume of water that can be held.

IGCSEs (68 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions