Brainscape's Knowledge GenomeTM

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


See full index

Real geo > Untitled Deck > Flashcards

Untitled Deck Flashcards

1
Q

What is erosion?

A

Erosion is the wearing down of surfaces.

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

What are the four erosion processes that change the shape of the river channel?

A

Hydraulic action, Abrasion, Attrition, Corrosion (solution).

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

What is hydraulic action?

A

The force of the water which removes material from the bed and banks of the river.

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

What is abrasion?

A

When the materials carried by the river scrape away the banks and bed.

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

What is attrition?

A

When the material being carried by the river hits each other the pieces become rounder and smaller.

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

What is corrosion (solution)?

A

When rocks are dissolved in slightly acidic water.

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

What are the types of erosion?

A

Vertical erosion and Lateral erosion.

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

What is vertical erosion?

A

Vertical erosion is dominant in the upper course of rivers. It increases the depth of the river and valley, as the river erodes downwards.

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

What is lateral erosion?

A

Lateral erosion is dominant in the middle and lower course of rivers. It increases the width of the river and valley as it erodes sideways.

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

What are the four processes of transportation?

A

Traction, Saltation, Suspension, Solution.

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

What is traction?

A

Occurs when larger rocks and materials are rolled along the riverbed.

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

What is saltation?

A

Smaller material which can be lifted by the water

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

What is suspension?

A

Lighter material carried within the river flow.

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

What is solution in transportation?

A

When materials are dissolved in the river water.

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

What is deposition?

A

When a river does not have enough energy to carry materials it drops them.

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

What are the causes of reduced energy leading to deposition?

A

Reduced discharge due to a lack of precipitation or abstraction upstream, Decreased gradient, Slower flow on the inside of a river bend or where the river is shallower, When the river enters a sea/ocean or lake.

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

What is the bedload?

A

The heaviest material is deposited first.

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

What are lighter materials deposited by rivers called?

A

Gravel, sand and silt are known as alluvium and they are carried further downstream.

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

What happens to dissolved materials in rivers?

A

They are carried out to sea.

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

“What summarises the changes in a river as it moves downstream?,The Bradshaw model.
“What are river characteristics based on profiles?

A

All rivers have long and cross-profiles. Each river’s long and cross profiles are unique but they do have some characteristics in common.

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

“What does a long profile of a river show?,The changes in the river gradient from the source to the mouth.
“What are the characteristics of a typical long profile?”,”The source is usually in an upland area

A

The upper course of the river includes steep areas with uneven surfaces

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

What is a cross profile of a river?

A

The cross-sections from one bank to another.

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

What are the characteristics of the upper course of a river?

A

Shallow, Steep valley sides, Narrow, Low velocity, Large bedload, Rough channel bed, High levels of friction, Vertical erosion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the characteristics of the middle course of a river?

A

Deeper than upper course channel, Gentle valley sides, Wider than upper course channel, Greater velocity than upper course channel, Material in river decreases in size, Smoother channel bed, Lower levels of friction than upper course channel, Lateral erosion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the characteristics of the lower course of a river?

A

Deeper than middle course channel, Flat floodplains, Wider than middle course channel, Greater velocity than the middle course channel (apart from as the river enters the mouth), Material carried mainly sediment and alluvium, Smooth channel bed, Lowest friction, Deposition is dominant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the landforms found in upland areas of rivers?

A

Waterfalls, Gorges, V-shaped valleys, Interlocking spurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How do waterfalls form?

A

Due to a drop in the river bed caused by changes in rock hardness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What erosional processes are key in forming waterfalls?

A

Hydraulic action and abrasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What happens to the soft rock beneath a waterfall?

A

It erodes quicker, undercutting hard rock and forming a plunge pool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What causes the overhang in waterfalls to collapse?

A

Erosion undercuts hard rock; it collapses into the plunge pool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How do gorges form?

A

Waterfall retreats upstream, leaving steep-sided valleys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What dominates erosion in V-shaped valleys?

A

Vertical erosion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What leads to the formation of V-shaped valleys?

A

Weathering and mass movement collapse valley sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Where do interlocking spurs form?

A

In the upper course of rivers, as the channel meanders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What process forms potholes in rivers?

A

Abrasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How are potholes created?

A

Sediment spins in dips, eroding circular hollows

37
Q

What features are common in lowland river areas?

A

Meanders, Ox-bow lakes, Floodplains, Levees

38
Q

What is the dominant erosion in lowland meanders?

A

Lateral erosion

39
Q

What is the result of erosion on the outside of meanders?

A

Riverbank collapse forming a river cliff

40
Q

Where does deposition occur in meanders?

A

On the inside of bends, forming slip-off slopes

41
Q

How does a meander migrate?

A

Erosion and deposition shift its position across the valley

42
Q

What leads to the formation of an oxbow lake?

A

Erosion cuts a meander neck; river flows straighter

43
Q

What causes a river to cut through a meander neck?

A

Flooding

44
Q

What happens after a meander is cut off?

A

Deposition isolates it, forming an oxbow lake

45
Q

What are floodplains?

A

Flat expanses on either side of a river

46
Q

What increases floodplain height over time?

A

Material deposition during floods

47
Q

What forms natural levees?

A

Heavy materials deposited nearest to the channel during floods

48
Q

What is necessary for deltas to form?

A

High sediment load and rapid drop in river velocity

49
Q

What processes aid delta formation?

A

Flocculation and bioconstruction

50
Q

What are examples of delta shapes?

A

Arcuate and bird’s foot

51
Q

What are the main river hazards?

A

The main river hazards are flooding and erosion.

52
Q

When do rivers flood?

A

Rivers flood when the water in them reaches bankfull discharge and then overspills across the floodplain.

53
Q

What are the two main causes of river flooding?

A
  1. If there is a period of heavy, torrential rain leading to high levels of overland flow because the water cannot infiltrate. 2. A prolonged period of steady rain means that the ground becomes saturated leading to high levels of overland flow because the water cannot infiltrate.
54
Q

What are the other natural causes of river flooding?

A

Landslides, Snow and ice melt, Storm surges push water up the river channel.

55
Q

What human activities increase the risk of river flooding?

A

Urbanisation, Deforestation, Building of bridges and dams, Human-induced climate change, Agriculture.

56
Q

What is the relationship between flooding and erosion?

A

Flooding often goes hand in hand with erosion of the banks as both result from increased discharge and velocity.

57
Q

What are the hazards of flooding and erosion?

A
  1. Flood waters may increase the spread of water-related diseases. 2. The water may act as a breeding ground for the animals that spread disease, for example, the mosquito. 3. The water may be contaminated by bacteria which can spread diseases such as cholera. 4. Deaths and injuries as floodplains are often densely populated due to the fertile soils. 5. Bridges and transport routes may be damaged or destroyed by the flood waters. 6. Erosion of the river banks leads to the loss of farmland, housing and transport routes. 7. Destruction of crops. 8. Increased insurance costs. 9. Lower house prices.
58
Q

What are the opportunities provided by rivers?

A
  1. The silt deposited during flooding is often rich in minerals and nutrients. 2. This makes it ideal for growing crops. 3. Rivers are a source of food. 4. The floodplains are flat land. 5. Construction and building of transport networks are easier. 6. Water can be used to irrigate farmland. 7. Leisure and tourism. 8. Generating electricity. 9. Transporting goods and people.
59
Q

What is Base Flow?

A

The normal level of river discharge.

60
Q

What is peak rainfall?

A

The highest level of rainfall during the storm.

61
Q

What is rising limb?

A

Shows the increase in river discharge.

62
Q

What is peak discharge?

A

Highest level of discharge.

63
Q

What is lagtime?

A

Time Difference between peak rainfall and peak discharge.

64
Q

What is recessional limb?

A

River discharge returning to normal base-flow.

65
Q

What is the purpose of flood prediction?

A

Prediction of flooding means that steps can be taken to manage flooding.

66
Q

What is a flood hydrograph and what does it show?

A

A flood hydrograph shows the changes in river discharge after a storm event. It displays data for a short period of time, usually 24 hours.

67
Q

What are the features of a flood hydrograph?

A

Base flow, Peak rainfall, Rising limb, Peak discharge, Lag time, Recessional limb.

68
Q

What is the key factor in assessing flood risk?

A

The time taken for the precipitation to reach the river from where it falls, known as the lag time.

69
Q

How does lag time affect flood risk?

A

Rivers with a short lag time and steep rising limb have a much greater risk of flooding because water reaches the river rapidly and it may not have the capacity to cope with the influx of water. Rivers with a long lag time and gentle rising limb have a lower flood risk as water reaches the river more slowly

70
Q

What factors influence lag time and flood risk?

A

Lag time depends on some human and physical factors, which lead to increased overland flow and shorten the lag time.

71
Q

What are the key points of flood management?

A
  1. The key cause of flooding is the amount and duration of precipitation, which cannot be altered. 2. Flood management methods aim to reduce the severity and/or impact of flooding. 3. There are two main categories of flood management: Hard engineering and Soft engineering.
72
Q

What is hard engineering in flood management?

A

Hard engineering involves building structures or changing the river channel to manage flooding.

73
Q

What is soft engineering in flood management?

A

Soft engineering works with natural processes of the river and surrounding environment. It is increasingly popular and is an example of mitigation, where schemes aim to minimise damage rather than trying to prevent the flooding.

74
Q

Human Factors which Increase the Risk of Flooding

A

Deforestation, Urbanisation, Agriculture, Climate change.

75
Q

Human and Physical Factors which Increase the Risk of Flooding: What is the impact of deforestation and urbanisation.

A

Deforestation
Lack of trees reduces interception and infiltration, increasing overland flow

Urbanisation
- Impermeable concrete and tarmac increase overland flow
- Water flows into the drains reaching the river rapidly

76
Q

Human and Physical Factors which Increase the Risk of Flooding: What is the impact of Agriculture and Climate Change

A

Agriculture: Bare soil and ploughing increase overland flow
Climate Change: Rising global temperatures may increase storm frequency and intensity

77
Q

Physical Factors which increase the risk of flooding.

A

Relief, Rock type, Soil, Weather, Seasonal Variations, Drainage Density, Vegetation.

78
Q

Physical Factors which increase the risk of flooding, explain the impact of relief and rock type.

A

Relief: Steep slopes reduce infiltration and increase overland flow

Rock Type: Impermeable rocks reduce percolation and increase overland flow

79
Q

Physical Factors which increase the risk of flooding, explain the impact of Soil & Weather

A

Soil

Frozen, saturated or compacted soil reduces infiltration and increases overland flow
Some soil types such as clay reduce infiltration and increase overland flow

Weather

Heavy or prolonged rainfall means that the rate at which water reaches the surface exceeds the infiltration rate leading to increased overland flow
After a period of snow rising temperatures can cause rapid melting which increases overland flow

80
Q

Physical Factors which increase the risk of flooding, explain the impact of Seasonal Variations & Drainage Density

A

Seasonal Variations

  • Flooding in Northern Europe tend to occur in the autumn and winter when rainfall is more frequent
  • In areas affected by monsoon much of the annual rainfall occurs in a few weeks saturating the ground and increasing overland flow
  • Higher temperatures in spring leads to snow melt in mountainous areas increasing overland flow

Drainage Density

Where drainage density is high there are many tributaries taking water to the main channel causing a rapid increase in discharge

81
Q

Physical Factors which increase the risk of flooding, explain the impact of vegetation.

A

Vegetation: Where there is little natural vegetation there is reduced interception leading to increased overland flow

82
Q

What are all the examples of hard engineering?

A

Dams and reservoirs
Embankments or levees
Straightened channels
Flood relief channels
Spillways or overflow channels

83
Q

What are all the examples of soft engineering?

A

River restoration
Wetland conservation
Catchment management plans
Flood plain zoning
Afforestation

84
Q

(1) Dams and Reservoirs
(2) Embankments or Levees

Hard Engineering Examples:

A

(1) Enable the amount of discharge downstream to be controlled.

(2) Increase the capacity of the river.

85
Q

(1) Straightened Channels
(2) Flood Relief Channels

Hard Engineering Examples:

A

(1) Mean that the river flows more quickly past vulnerable areas, reducing the risk of flooding.
(2) Allow some water to flow out of the main channel, reducing the discharge.

86
Q

Spillways or Overflow Channels

Hard Engineering Examples:

A

These take excess water away from the main channel.

87
Q

(1) River Restoration
(2) Wetland Conservation

Soft Engineering Examples:

A

(1) Supports the river by restoring it back to its original regime – putting meanders back in, stabilizing banks, and connecting to flood plains.

(2) These areas provide somewhere for excess water to go and slow the flow of the flood water.

88
Q

(1) Catchment Management Plans
(2) Flood Plain Zoning

Soft Engineering Examples:

A

(1) Assess the risk of flooding in an area and outline how this will be managed.

(2) Means that only certain land uses are allowed on the flood plain, reducing the risk.

89
Q

Afforestation

Soft Engineering Examples:

A

Involves the planting of vegetation and trees to increase interception and infiltration.

Real geo (6 decks)

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