Brainscape's Knowledge GenomeTM

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


See full index

AS Geography > Unit 1: Rivers, floods and management > Flashcards

Unit 1: Rivers, floods and management Flashcards

You may prefer our related Brainscape-certified flashcards:
U.S. Geography flashcards World Geography flashcards
1
Q

What are drainage basins separated by?

A

Watersheds

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

What are the inputs, outputs, stores and transfers in the drainage basin?

A

Inputs: Precipitation, solar energy
Outputs: Evaporation, transpiration, discharge
Stores: Puddles, rivers, lakes, soil, groundwater storage
Transfers: Infiltration, percolation, run off, throughflow

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

What are the 6 features of the drainage basin?

A 
Main river channel 
Source
Tributaries
Confluence
Watershed 
River mouth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name factors affecting the amount of infiltration:

A
  • Intensity of precipitation
  • Type of slope
  • Nature of the soil
  • Depth of the water table
  • Time
  • Climate
  • Vegetation cover
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What’s the interception store?

A

Where water is caught/intercepted by vegetation-stored temporarily

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

What’s infiltration rate?

A

The speed at which water enters into the soil- measured by the depth of the water layer (in mm) that can enter the soil in one hour

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

Name some human factors affecting infiltration:

A
  • Urbanisation
  • Deforestation
  • Afforestation
  • Agricultural land use
  • Water resource
  • Land use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name some human factors affecting interception:

A
  • Deforestation
  • Urbanisation
  • Afforestation
  • Agricultural land use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What’s the water balance (budget)?

A

The difference between the inputs and outputs in a drainage basin.

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

What does the water budget model show?

A

The balance between the precipitation and evapotranspiration in any given month

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

What is river discharge and what is the equation for it?

A

The volume of water passing a given point at a given time, measured in cubic metres per second

Velocity (m/s) x cross sectional area (metres squared)

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

What does a storm hydrograph show?

A

How a river responds to a period of rainfall

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

What are the physical factors affecting river discharge?

A

Rainfall
Temperature
Relief
Rock Type

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

What are the human factors affecting river discharge?

A

Urbanisation
Deforestation
Afforestation

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

What are the 3 river processes?

A

Erosion
Deposition
Transportation

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

What is the equation for energy?

A

Discharge + height above sea level + gradient

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

What are the 4 types of erosion?

A

Hydraulic action
Abrasion
Attrition
Corrosion

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

What are the 4 types of transportation?

A

Traction
Saltation
Suspension
Solution

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

What is the Hjulstrom curve?

A

A graph to show the relationship between velocity and competence

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

What’s river competence?

A

The size of the sediment a river can transport

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

Deposition occurs when:

A
  • Less discharge
  • Less velocity
  • Shallow water occurs
  • Sediment capacity increases
  • River overflows
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of landforms are in the upper course?

A 
V-shaped valleys 
Rapids
Waterfalls
Braided streams 
Potholes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What landforms are in the middle course?

A

Meanders

Oxbow lakes

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

What landforms are found in the lower course?

A

Floodplains
Levees
Deltas

25
Q

What are the velocity variables for high velocity?

A
  • High discharge
  • high hydraulic radius
  • Low wetted perimeter
  • Increase in gradient
  • Centripetal force
26
Q

What’s velocity determined by?

A

Channel shape
Roughness of channel bed/banks
Channel slope

27
Q

What’s channel efficiency measured by?

A

It’s hydraulic radius

28
Q

What’s the hydraulic radius equation?

A

Cross sectional area ÷ wetted perimeter

29
Q

What’s the equation for cross sectional area?

A

Channel width x channel depth

30
Q

What’s the wetted perimeter?

A

The total length of the bed and banks in contact with the water

31
Q

What is velocity like at baseflow and bankfull conditions?

A

Baseflow: greater frictional drag so lower velocity
Bankfull: high velocity

32
Q

How does channel roughness/bedload impact wetted perimeter (WP), hydraulic radius (HR) and velocity (V)?

A

Large angular bedload: greater WP,lower HR and lower V

Smoother bed: Higher V, greater HR

33
Q

How are rapids created?

A

Where there is a sudden increase in gradient or where there is an area of large highly angular bedload- increases turbulence and erosion

34
Q

How are waterfalls and gorges created?

A
  • Occurs where hard rock overlays soft rock
  • Soft rock is undercut by erosion (hydraulic action and abrasion)
  • Overhanging hard rock collapses
  • Deep plunge pool develops where soft rock was before
  • Waterfall retreats upstream
  • Steep sided cutting is left as the waterfall moves back- forming a gorge
35
Q

How are interlocking spurs created?

A

In areas f resistant rock, meandering streams and rivers will be incised into the landscape- forming interlocking spurs

36
Q

How are V-Shaped valleys created?

A
  • Vertical erosion in the river channel results in the formation of a V-shaped valley
  • Over time the sides of this valley are weakened by weathering processes and continued vertical erosion at the base
  • Mass movement of materials occurs down the valley sides, gradually creating the distinctive V-shape
  • This material is then gradually transported away by the river when it has enough energy
37
Q

How are potholes created?

A
  • Where there are depressions/fissures, large boulders may become trapped and swirled round by the current
  • In resistant rock, potholes require hundreds/thousands of years to form
38
Q

How are knickpoints created?

A
  • Each period of rejuventation that results in an incised valley floor, is marked by a knickpoint
  • Knickpoints are sudden increases in gradient and can be indentified as small waterfalls in the lower course
39
Q

What are incised meanders and how are they created?

A

Deeper meanders

Created by renewed energy from rejuvenation that increases vertical erosion

40
Q

What are ingrown meanders and how are they created?

A
  • Meanders with an asymmetric profile

- Created when incision is less rapid and lateral erosion is occuring

41
Q

What are entrenched meanders and how are they created?

A
  • Symmetrical cross profile due to rapid uplift

- Incision is rapid and vertical erosion dominates

42
Q

What are river terraces and how are they created?

A
  • When an old floodplain is left suspended at a higher level
  • Following rejuvenation, the river vertically incises into former valley. Several stages of rejuvenation can create several terraces (think steps)
43
Q

What is eustatic sea level change?

A

Caused by a change in the volume of sea water as ice caps and glaciers melt and freeze

44
Q

What is isostatic sea level change?

A

Caused by the uplift and subsidence of land (post glacial rebound)

45
Q

What are the causes of sea level rise?

A
  • Global warming
  • Sea absorbs high temps and expands
  • Ice sheets are melting faster than snow is replacing them
  • Land glaciers are melting
  • Post glacial rebound
46
Q

What is river rejuvenation?

A

When an increases in height above sea level increases the erosive power of the river. (Isostatic uplift or eustatic fall increases the height of the river above sea level)

47
Q

What are flood embankments/levees?

A

Raised banks on either side of the river designed to increase bankfull level

48
Q

What is afforestation?

A

Planting more trees to increase interception storage and reduce lag time

49
Q

What is channel enlargement?

A

Creating a bigger channel to higher the velocity, increase efficiency and the cross sectional area of the river

50
Q

What do sluice gates do?

A

Control the discharge of the river by opening and closing depending on catchment conditions

51
Q

What are flood relief channels?

A

Smaller, man made channels that take extra discharge to relieve the river

52
Q

What are storage reservoirs?

A

Areas that store excess water in the upper reaches of the river- expensive to build, but can provide a form of renewable energy

53
Q

What is contour ploughing?

A

Ploughing the earth so the plough channels do not run directly down slopes

54
Q

What is flood proofing?

A

Temporary or permanent methods that include flood proof ground walls, sandbags and sealed doors

55
Q

What is flood abatement?

A

Reduces the possibility of flooding by managing land use upstream- includes afforestation, contour ploughing and reducing the amount of bare earth

56
Q

What are intercepting channels?

A

Diverting the flow of the river away from settlements, agricultural land and important land uses

57
Q

What is the removal of settlements?

A

Involves moving built up areas off the flood plain - rarely used

58
Q

How do the factors affecting river discharge effect the storm hydrogaph?

A
  • Rainfall: higher peak discharge, shorter lag time, quick rising limb
  • Snow melt: steep rising limb
  • Porous soils/permeable rock: less steep, longer rising limb/lag time
  • Impermeable rock/frozen ground: steeper rising limb, peak discharge reached sooner, shorter lag time
  • Small drainage basin: short LT, steeper RL
  • Summer vegetation: slow response, peak discharge lower
  • Deforestation: faster response, high peak discharge

AS Geography (5 decks)

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