1.3 River Landscapes Flashcards

1
Q

Define Ribbon Lake

A

Large, narrow lake, occupying a v-shaped valley

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2
Q

Define V-Shaped Valley

A

A valley formed where a glacier used to be

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3
Q

Define Meltwater

A

River which form when glaciers melt

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4
Q

Define Moraine

A

A mass of rocks/ sediment carried and deposited by a glacier

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5
Q

Define Hydraulic Action

A

Water is forced into cracks in the rock and air is forced out explosively, breaking off pieces of the banks

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6
Q

Define Abrasion

A

This is when pebbles grind along a rock platform, much like sandpaper. Over time the rock becomes smooth.

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7
Q

Define Attrition

A

This is when rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.

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8
Q

Define Corrosion

A

When acid rain causes chemical weathering

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9
Q

Define Chemical Weathering

A

Acids in seawater slowly dissolve rocks

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10
Q

Define Biological Weathering

A

Roots of growing plants and burrowing animals or nesting birds can cause rocks to weather

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11
Q

Define Mechanical Weathering

A

Caused by repeated freezing and thawing of water in a crack or hole in the rock.

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12
Q

What is deposition?

A

When sediment, usually carried by waves is laid down or deposited

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13
Q

When does deposition occur?

A

When their is not enough energy to carry sediment any further

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14
Q

Define Source

A

The beginning of the river

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15
Q

Define Confluence

A

Where 2 rivers meet

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16
Q

Define Watershed

A

An area of highland between two drainage basins

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17
Q

Define Mouth

A

Where a river flows into a lake or the sea

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18
Q

Define Tributary

A

A small river/ stream that flows into a larger river

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19
Q

Drainage Basin

A

The area drained by a river and its tributaries

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20
Q

How does the channels shape change through the course of a river?

A

The channel becomes larger the further down the river it is.

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21
Q

How does the gradient change through a river course?

A

Decreases. The gradient starts very steep but the steepness evens out as it reaches the lower course.

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22
Q

How does the discharge change through a river course?

A

It increases as it goes down the river.

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23
Q

How does the velocity change through a river course?

A

It increases due to less friction.

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24
Q

How does the sediment size change through a river course?

A

The sediments erode one another getting smaller through the river course.

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25
Q

Describe how a plunge-pool forms

A

When hard rockets on top of soft rock, the waves erode at the soft rock creating an undercut. Hydraulic action and abrasion then deepen this into a plunge-pool.

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26
Q

What is likely to occur if you have an overhang?

A

The overhang is likely to collapse

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27
Q

On which side of a bend does water travel faster?

A

Outside

28
Q

What forms on the outside bends of rivers?

A

River Cliffs

29
Q

What forms on the inside bends of rivers?

A
Point Bar 
(Slip-off Slope)
30
Q

Describe levees

A

A natural (or artificial) wall that increases the height of a river bank to prevent flooding.

31
Q

Describe Channelisation

A

Widening or deepening the river to increase the discharge

32
Q

Describe Flood Relief Channels

A

Channels made to relieve a river from high discharge

33
Q

Describe Dams and Reservoirs

A

Large (usually artificial) lakes used to collect water and store it.

34
Q

Describe Washlands

A

Areas of land near a river allowed to flood to take stress of off other areas

35
Q

Describe River Restoration

A

The process of restoring a river to improve natural process

36
Q

Describe Floodplain Zoning

A

This involves placing restrictions on land usage in the areas surrounding a river.

37
Q

Describe Vertical Erosion

A

Erosion of the bed

38
Q

Describe Lateral Erosion

A

Erosion of the sides

39
Q

Describe the formation of Oxbow Lakes

A

As a Meander becomes deeper and deeper, the river may meet itself and then find another path, this leaves an oxbow lake

40
Q

Describe Meanders

A

As river rushes around bends, the outside is eroded more than the inside, this causes bends called meander

41
Q

What is the Tees-Exe line?

A

A line which separates highland and lowland Britain

42
Q

Describe a River Profile

A

Altitude decreases as the river gets further from the source

43
Q

How does depth change down the river?

A

Gets deeper down the river

44
Q

How does valley profile change down a river?

A

In the upper course it is narrow and steep, it gets wider and the banks slope more further down the river

45
Q

What is the shape and size of sediment in the upper course?

A

Angular Boulders

46
Q

What is the shape and size of sediment in the middle course?

A

Rounded Rocks

47
Q

What is the shape and size of sediment in the lower course?

A

Smooth, Round Pebbles

48
Q

What are the three sections a river can be broken down into?

A

Upper Course
Middle Course
Lower Course

49
Q

What features are present in the upper course?

A

Waterfalls
Gorges
Interlocking Spurs
V-shaped valley

50
Q

What features are present in the middle course?

A

Meanders
Floodplain
Gentle Slopes

51
Q

What features are present in the lower course?

A
Meanders
Floodplain
Estuary
Levees
Ox-bow Lake
52
Q

What features are present in the mouth of a river?

A

Deltas

53
Q

What model shows us how features of a river change across the profile?

A

Bradshaw Model

54
Q

Define Irrigation

A

A method in which a controlled amount of water is supplied to plants at regular intervals for agriculture

55
Q

Define Saturated

A

Holding as much water or moisture as can be absorbed

56
Q

What are 6 physical causes of flooding in the UK?

A
Impermeable Rock
Steep Valley Sides
Hot, Dry Weather
Ploughing Slopes
Deforestation
Dams Burst
57
Q

How do impermeable rocks contribute to flooding?

A

Water does not soak into the ground, causing more surface run-off

58
Q

How do steep valley sides contribute to flooding?

A

More water runs down to the river, increasing discharge so that less is needed to cause the flood

59
Q

How does hot, dry weather contribute to flooding?

A

Means that the soil becomes hard and water cannot soak in

60
Q

How do dam bursts contribute to flooding?

A

Greatly increases discharge and water in the area

61
Q

How does deforestation contribute to flooding?

A

Water is not soaked up by roots and therefore the soil is more quickly saturated, once soil is saturated, there is greater surface run-off

62
Q

How does ploughing contribute to flooding?

A

Soil can hold less water

63
Q

What do hydrographs show?

A

How a river responds to a storm event

They show the relationship between rainfall and river discharge

64
Q

Define the rising limb on a hydrograph

A

Line representing the rapid rise in water after a period of intense rainfall

65
Q

Define the falling limb on a hydrograph

A

Represents the reduction in the amount of rainfall reaching the river channel

66
Q

What is lag time? (Hydrographs)

A

The difference between the heaviest rainfall and the point at which the river contains the largest amount of water

67
Q

What factors influence lag time?

A

Size of a drainage basin
Vegetation
Velley side steepness
Soil Type