Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Geography > Rivers > Flashcards

Rivers Flashcards

(78 cards)

Start Studying
1
Q

What is river discharge?

A

The volume of water going through a point in the river. Measured in cumecs. Can either show annual flow or storm event.

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

What effects the rate of erosion.

A

Height above sea level, volume of water in the river, gradient of channel.

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

What is the capacity of a river?

A

The total load of a river at a particular time or location.

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

What is calibre?

A

The size of a pebble of particle.

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

What is the competence?

A

The size of the largest sediment particle that can be carried by the river at a particular point or location.

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

What does the hjulstrom curve show?

A

Shows the relationship between river velocity and competence.
Also shows the processes of erosion, deposition and transport.

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

What is the hydrological cycle.

A

The circulation of water between the oceans atmosphere and land. It’s a closed system.

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

What is fall/ settling velocity?

A

The average velocity at which grains are too heavy to be carried at the current velocity so are deposited.

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

Types of erosion?

A 
Hydraulic action- pressure and force of water
Attrition- smash, rounded off, smaller 
Abrasion- rub, scrape 
Solution- dissolving   
Cavitation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Depositional land forms?

A

Delta’s
Braided channels
Floodplain
Levees

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

What is brackish water?

A

When salt and fresh water mix.

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

What is alluvial deposit?

A

Fine sediment deposit.

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

Types of transportation?

A

Traction- boulders
Suspension- silt
Solution- limestone
Saltation- cobbles

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

What factors increase downstream?

A 
Discharge 
Channel width
Channel depth
Average velocity 
Load capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What factors decrease downstream?

A

Calibre
Roughness
Gradient

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

Pothole formation?

A

Small circular hollows in river bed.
Turbulent swirls- eddies
Abrasion on bedload
Scrape out holes

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

How do Rapids form?

A

Bands of resistant and less resistant rock on bed of river, soft rock gets eroded leaving ridges of hard rock which cause the water to be turbulent and its erosive power increases

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

Describe interlocking Spurs?

A

They form when the river winds around protrusions which appear to interlock when viewed looking upto a valley.

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

Three features of river rejuvenation?

A

Incised meanders
Nick points
River terraces

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

What is river rejuvenation?

A

Isostatic or eustatic change to cause base level to decrease.
Rivers gravitational potential energy is increased.
River wants to get back to graded profile. Vertical erosion dominant to regrade itself.

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

Term to describe a rivers perfect profile?

A

Graded profile

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

Word to describe fine sediment?

A

Alluvium

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

Formation of V shaped valley?

A

Bolders and cobbles can only be transported by traction and saltation- erode bed- intensive vertical erosion
Steep sides

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

First 3 steps of waterfall formation?

A

Change in gradient
Resistant rock underlain by less resistant bed
Less resistant bed is undercut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Second 3 steps of waterfall formation?
Plunge pool forms, vertical erosion Overhang collapses Waterfall retreats upstream, gorge sometimes formed
26
Precipitation?
All forms of moisture that reach the earths surface
27
Evaporation?
The transformation of water droplets into water vapour due to heat
28
Evapotranspiration?
The loss of water from a drainage basin into the atmosphere from the leaves of plants
29
Surface storage
The total volume of water held on the earths surface in lakes, ponds and puddles
30
Groundwater storage
The storage of water underground in rock strata
31
Infiltration?
The downwards movement of water into the soil surface
32
Percolation?
The gravity flow of water within soil and through permeable rock
33
Through flow
The movement of water downslope within the soil layer
34
Groundwater flow?
The deeper downward movement of water through underlying rock strata
35
Dynamic equilibrium?
Rivers changing to reach a balanced state.
36
Velocity definition?
The speed in a specific direction at which a body of water moves
37
Interception?
The prevention of water reaching the earths surface by trees and plants
38
Another term for drainage basin?
Catchment area
39
Watershed?
A boundary between two drainage basins
40
What is vegetation storage?
Water that has been taken up by plants
41
What are rocks that hold water?
Aquifers
42
What is the water balance?
Shows the balance between inputs and outputs. Affects how much water is stored in the basin Used to show seasonal patterns
43
What happens to the water balance during wet seasons?
Precipitation exceeds evapotranspiration. | Water surplus- ground stores fill - more run off & increased discharge
44
What happens in drier season?
Precipitation is lower than evapotranspiration. Ground stores are depleted. End of dry season there is a deficit but ground stores are recharged next wet season.
45
What is a hydrograph?
Graphs to show the discharge at a certain point of the river. Storm hydrograph shows this following a storm event
46
Lag time?
Delay between peak rainfall and peak discharge.
47
What does a shorter lag time mean?
Will increase peak discharge as more water will enter the river during a shorter period of time.
48
Drainage basin characteristics to affect lag time?
Gradient Size shape Number of tributaries
49
What is a hydrograph with a steep rising limb?
Flashy
50
Rising limb?
Part of the graph leading up to peak discharge. Shows the increase in discharge as rain water flows into river
51
Other factors affecting lag time?
``` Saturated soil Rock type- aquifers Soil type- sandy or clay Vegetation- deciduous trees Precipitation- rainfall and snow Temperature ```
52
Human factors affecting lag time?
Urbanisation Impermeable surfaces- concrete Drainage systems- pipe flow
53
What is bed load?
Material transported by traction and saltation.
54
Why do silt and clay require a higher velocity to erode?
As they stick together so are harder to dislodge.
55
What is the critical erosion velocity curve?
The minimum velocity required to erode and transport material of different calibre.
56
What is the other curve of the hjulström curve?
Mean settling velocity curve
57
What is the long profile?
A diagram to show how a river changes from source to mouth by showing the height of the river above base level.
58
Base level?
The highest point a river can erode to - sea level
59
Upper course?
Most gpe Steep gradient High channel roughness- turbulence Vertical erosion dominant
60
Why does velocity increase downstream?
GPE is converted to kinetic energy. | Channel is smoother so less friction.
61
What is the wetted perimeter?
The total length of the banks and bed in contact with water
62
What does a small hydraulic radius mean?
That a river is less efficient. More friction so more energy loss. Reduced velocity
63
What can increase wetted perimeter?
Channel roughness | Protrusions and angular boulders
64
How to work out hydraulic radius?
Cross section divided by wetted perimeter
65
Why does calibre decrease downstream?
Lots of attrition in middle stage.
66
Why are lower stage valleys wide with gentle sloping sides?
Increased floodplain due to deposition.
67
Magnitude?
Size of flood
68
Term to describe how often a specific level of flood will occur?
Recurrence interval
69
Hard engineering?
Dams Levees Channel straightening Diversion spillways
70
Soft engineering strategies?
Land use zoning Afforestation Wetland creation River restoration
71
Floodplain formation?
Water overspills from bank and floods the flat land Floodwater is shallow and has extensive wetted perimeter Alluvium is deposited
72
Levees formation
River floods Coarser material deposited closest to banks Builds up overtime
73
Braided channel formation?
Coarsest material dropped Blocks main channel Channel no longer competent to transport material Channel Subdivides into a series of converging and diverging channel to seek easier a route
74
When may river velocity drop?
Discharge decreases At mouth as sea absorbs energy Increased friction
75
Delta formation?
Energy decreases Sediment deposited at mouth River braids into distributaries to reach the sea
76
First 3 steps of meander formation?
River takes most efficient route Riffles reduce hydraulic radius Alternatively water flows over pools
77
Last three steps of meander formation?
Water will swing to avoid riffles- increases turbulace Helicoidal flow transports eroded material from outside and deposits inside Water travels fastest on outer bend
78
Oxbow lake formation?
Sinuosity of meander increase. Neck of start and end of bend get narrower. Flood event- river breaks through Straight path current more dominant Meander cut off

Geography (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions