Rivers And Coasts Flashcards

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1
Q

Describe the hydrological cycle?

A
  • Water evaporates from the sea and the land- evaporation is when water is heated by the sun and turns into water vapour.
  • Transpiration is the evaporation of water from plants. Evapotranspiration is both evaporation and transpiration happening together.
  • Water vapour is moved inland by winds. Water vapour then condenses to form clouds and then falls over the land as precipitation.
  • Water moves from one place to another in many ways called transfers.
  • Water can be stored in the land.
  • The water eventually ends up in the sea where it evaporates and goes round in the cycle again…
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2
Q

Infiltration?

A

Is when water soaks into the soil.

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3
Q

Percolation?

A

Is when water moves vertically down through soil and rock.

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4
Q

Through flow?

A

Is when water in the soil flows downhill.

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5
Q

Groundwater flow?

A

Is when water in rock flows downhill.

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6
Q

Surface runoff?

A

When water flows overground.

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7
Q

Channel flow?

A

Is the flow of water in a river.

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8
Q

Channel storage?

A

Is when water is held in a river.

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9
Q

Groundwater storage?

A

Is when water is stored underground in soil and rock. A rock that stores water is called an aquifer.

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10
Q

Interception storage?

A

Is when water lands on things like plant leaves and doesn’t hit the ground.

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11
Q

Surface storage?

A

Is when water is held in things like lakes,reservoirs and puddles.

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12
Q

Drainage basins?

A
  • Part of the hydrological cycle that happens on land goes on in drainage basins.
  • Drainage basins are open systems.
  • There are inputs of water to drainage basins.
  • Water flows through them and is stored in them.
  • There are outputs of water from drainage basins.
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13
Q

Features of drainage basins?

A
  • Drainage basins are separated by a bounty called a watershed.
  • They’re ridges of high land- water falling either side of these ridges will go into different drainage basins.
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14
Q

Tributary?

A

A smaller river that joins a main river.

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15
Q

The source?

A

Is where a river starts usually an upland area.

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16
Q

Confluence?

A

A point where two rivers join.

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17
Q

The mouth?

A

Is where the river flows into the sea or a lake.

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18
Q

Mechanical weathering?

A

Is the breakdown of rock without changing its chemical composition.

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19
Q

Freeze thaw weathering?

A
  • It happens when the temperature alternates above and below 0 degrees Celsius.
  • Water gets into rock that has cracks.
  • When the water freezes it expands which puts pressure on the rock.
  • When water thaws it contracts which releases the pressure on the rock.
  • Repeated freezing and thawing widens the cracks and causes the rock to break up.
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20
Q

Chemical weathering?

A
  • Rainwater has carbon dioxide dissolved in it which makes it a weak carbonic acid.
  • Carbonic acid reacts with rock that contains calcium carbonate so the rocks are dissolved by the rainwater.
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21
Q

Biological weathering?

A

Is the breakdown of rocks by living things.

Plant roots break down rocks by growing into cracks on their surfaces and pushing them apart.

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22
Q

What is a course?

A

The path of a river as it flows downhill is called its course.

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23
Q

Upper,middle and lower course?

A

Rivers have an upper course (closest to the source of the river)

A middle course and a lower course (closest to the mouth of the river)

24
Q

How do rivers erode materials?

A

They erode the landscape - wear it down then transport the material to somewhere else where it’s deposited.

25
Q

The shape of a valley?

A

The shape of the valley and channel changes along the river depending on whether erosion or deposition is having the most impact.

26
Q

Long profile of river?

A

The long profile of a river shows you how the gradient changes over the different courses.

27
Q

Cross profile?

A

The cross profile shows you what a cross section of the river looks like.

28
Q

Upper course?

A
  • Steep gradient
  • V shaped valley, steep sides.
  • Narrow shallow channel.
29
Q

Middle course?

A
  • Medium gradient.
  • Gently sloping valley sides.
  • Wider deeper channel.
30
Q

Lower course?

A
  • Gentle gradient.
  • Very wide almost flat valley.
  • Very wide and deep channel.
31
Q

Hydraulic action?

A

Waves crash against rock and compress the air in the cracks. This puts pressure on the rock.

Repeated compression widens the cracks and makes bits of the rock break off.

32
Q

Corrasion?

A

Eroded rocks picked up by the river scrape and rub against the channel wearing it away.

Most erosion happens by corrosion.

33
Q

Attrition?

A

Eroded rocks picked up by the river smash into each other and break into smaller fragments.

Their edges also get rounded off as they rub together.

34
Q

Corrosion?

A

Weak carbonic acid in seawater dissolves rocks like chalk.

35
Q

Transportation?

A

The material a river has eroded is transported downstream. There are 4 processes of transportation;

  • Traction
  • Suspension
  • Saltation
  • Solution
36
Q

Traction?

A

Large particles like boulders are pushed along the river bed by the force of the water.

37
Q

Saltation?

A

Pebble sized particles are bounced along the river bed by the force of the water.

38
Q

Suspension?

A

Small particles like silt and clay are carried along by the water.

39
Q

Solution?

A

Soluble materials dissolve in the water and are carried along.

40
Q

Deposition?

A

Is when a river drops the eroded material its transporting.

It happens when the river slows down (loses velocity)

41
Q

Reasons for deposition?

A
  • The volume of water in the river falls.
  • The amount of eroded material in the water increases.
  • The water is shallower.
  • The river reaches its mouth.
42
Q

Waterfalls?

A
  • Waterfalls form where a river flows over an area of hard rock followed by an area of softer rock.
  • The softer rock is eroded more than the hard rock creating a “step” in the river.
  • As water goes over the step it erodes more and more of the softer rock.
  • A steep drop is eventually created which is called a waterfall.
  • The hard rock is eventually undercut by erosion. It becomes unsupported and collapses.
  • The collapsed rocks are swirled around at the foot of the waterfall. Where they erode the softer rock by corrasion.
  • This creates a deep plunge pool.
  • Over time more undercutting causes more collapses. The waterfall will retreat, leaving behind a steep sided gorge.
43
Q

Interlocking Spurs?

A
  • In the upper course of a river most of the erosion is vertically downwards. This creates steep sided, V shaped valleys.
  • The rivers aren’t powerful enough to erode laterally (sideways) - they have to wind around the high hillsides that stick out into their paths on either side.
  • The hillsides that interlock with each other as the river winds around them are called interlocking Spurs.
44
Q

Meanders?

A

In their middle and lower courses rivers develop meanders;

  • The current is faster on the outside of the bend because the river channel is deeper. As there’s less friction to slow the water down, so it has more energy.
  • So more erosion takes place on the outside of the bend forming river cliffs.
  • The current is slower on the inside of the bend because the river channel is shallower. As there’s more friction to slow the water down, so it has less energy.
  • So eroded material is deposited on the inside of the bend forming slip off slopes.
45
Q

Ox-box lakes?

A

Meanders get larger over time they eventually turn into ox- bow lake.

  • Erosion causes the outside bends to get closer.
  • Until there’s only a small bit of land left between the bends (called the neck)
  • The river breaks through this land, usually during a flood.
  • And the river flows along the shortest course.
  • Deposition eventually cuts off the meander.
  • Forming an ox-bow lake.
46
Q

Flood plains?

A
  • The flood plain is the wide valley floor on either side of a river which occasionally gets flooded.
  • When a river floods onto the flood plain the water slows down and deposits the eroded material that it’s transporting.
  • This builds up the flood plain.
  • Meanders migrate across the flood plain making it wider.
  • The deposition that happens on the slip off slopes of meanders also build up the flood plain.
47
Q

Levees?

A
  • They are natural embankments along the edges of a river channel.
  • During a flood eroded material is deposited over the whole flood plain.
  • The heaviest material is deposited closest to the river channel because it gets dropped first when the river slows down.
  • Over time the deposited material builds up creating levees along the edges of the channel.
48
Q

Deltas?

A
  • Rivers are forced to slow down when they meet the sea or a lake.
  • This causes them to deposit the material that they’re carrying.
  • If the sea doesn’t wash away the material it builds up and the channel gets blocked.
  • This forces the channel to split up into lots of smaller rivers called distributaries.
  • Eventually, the material builds up so much, that low lying areas of land called deltas are formed.
  • There are three types of deltas.
49
Q

Arcuate?

A

They have a rounded shape and lots of distributaries.

50
Q

Cuspate?

A

They have a triangular shape and few distributaries.

51
Q

Birds Foot?

A

They are shaped like a birds foot.

52
Q

Contour lines on maps?

A
  • Contour lines are the orange lines drawn all over maps.
  • They tell you about the height of the land (in metres) by the numbers marked on them
  • And the steepness of the land by how close together they are. (The closer they are the steeper the slope)
53
Q

Evidence for waterfall?

A

Waterfalls are marked on maps, but the symbol for a cliff (black blocky line) and the close contour lines are evidence for a waterfall.

54
Q

Evidence for a rivers upper course?

A
  • The nearby land is high (712m).
  • The river crosses lots of contour lines, in a short distance which means it’s steep.
  • The river is narrow (thin blue line)
  • Contour lines are close together and the valley floor is narrow.
  • This means the river is a steep sided V shape valley.
55
Q

The hydrological cycle?

A
  • It has different parts- the sea,land and the atmosphere.
  • Water flows between the different parts in various ways, and is also stored on the land.
  • It is a closed system. This means there’s no inputs or outputs.