Water on The Land Flashcards

1
Q

What is a river’s course?

A

The path of the river as it flows downhill

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2
Q

Describe the valley and channel shape in the UPPER COURSE:

A

V-shaped valley, steep sides. Narrow, shallow channel

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3
Q

Describe the valley and channel shape in the MIDDLE COURSE:

A

Gently sloping valley sides. Wider, deeper channel

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4
Q

Describe the valley and channel shape in the LOWER COURSE:

A

Very wide, almost flat valley. Very wide, deep chanel

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5
Q

What effect does vertical erosion have?

A

It deepens the river valley and channel, making it V-shaped. Dominant in the upper course.

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6
Q

What effect does lateral erosion have?

A

Widens the river valley and channel. Dominant int he middle and lower course.

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7
Q

What are the 4 processes of erosion?

A

Hydraulic Action, Solution, Abrasion and Attrition

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8
Q

What are the 4 methods of transportation?

A

Traction, Solution, Saltation and Suspension

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9
Q

What is Hydraulic Action?

A

The force of the water breaks rocks and particles away from the river channel

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10
Q

What is Solution?

A

River water dissolves some times of rock, and carries the dissolved particles with it

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11
Q

What is Abrasion?

A

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

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12
Q

What is Attrition?

A

Eroded rocks picked up by the river smash into each other and break into smaller fragments. Their edges are also rounded off.

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13
Q

What is Traction?

A

Large particles like boulders re rolled along the river bed by the force of the water.

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14
Q

What is Saltation?

A

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

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15
Q

What is Suspension?

A

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

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16
Q

What is deposition?

A

When a river drops eroded material as it looses velocity and energy

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17
Q

What causes a river to slow down enough for deposition to occur?

A
  • The volume of water in the river decreases
  • The amount of eroded material in the river increases
  • The water is shallower
  • The river reaches its mouth
18
Q

What are meanders?

A

Large bends in the rivers middle or lower course

19
Q

What are the 2 main features of a meander bend?

A

River cliff and slip off slope

20
Q

How are the features of a meander formed?

A
  1. The current is faster on the OUTSIDE of the bend because the river channel is deeper there
  2. More erosion takes place on the outside of the bend, forming a river cliff
  3. The current is slower on the inside of the bend, because the water is shallower and slower
  4. More deposition occurs, forming a slip off slope
21
Q

Why does more erosion occur on the outside of a meander bend?

A

The river channel is deeper, so there is less friction to slow the water down and more erosion takes place via hydraulic action

22
Q

How are ox bow lakes formed?

A
  1. Erosion on the outside bends cause them to get closer, forming a neck of the meander
  2. The river breaks through the neck, usually during a flood
  3. The river flows it shortest course
  4. Depostion eventually cuts of the meander completely, and the ends of the oxbow lake will dry up over time
23
Q

Name 4 more river landforms:

A
  • Waterfalls
  • Gorges
  • Levees
  • Floodplains
24
Q

How are waterfalls formed?

A
  1. A band of hard rock and a bad of soft rock must lay parallel to each other for a waterfall to form
  2. The soft rock is eroded ore than the hard rock, creating a ‘step’ in the river
  3. The water flows over the step, leading to more erosion of the soft rock
  4. A steep drop is eventually created, and the hard rock is undercut by erosion
  5. The hard rock is unsupported and collapses. A plunge pool is also formed by erosion
  6. After more undercutting and more collapses, the waterfall retreats and a gorge is formed
25
Q

Where are waterfalls found?

A

In the upper course

26
Q

What do contour lines on a map tell you about a river?

A

Which direction it flows in

27
Q

What evidence could there be on a map to show a river is in its upper course?

A
  • Nearby high land
  • It crosses a lot of contour lines in a short distance, meaning it’s steep
  • The river is narrow
  • The contour lines are close together and the valley floor is narrow
28
Q

How is a waterfall marked on a map?

A

With a label, but the cliff symbol and close contours are evidence for one

29
Q

What evidence is there for a river in its lower course on a map?

A
  • Low nearby land
  • River only crosses a few contours
  • Joining a sea or lake
  • The river is wide (thick blue line)
  • The river meanders
30
Q

What is river discharge?

A

The volume of water flowing in a river

31
Q

What is discharge measured in?

A

Cumecs: m3/s

32
Q

What do hydrographs show?

A

How the discharge at a certain point in a river changes over time

33
Q

What is peak discharge?

A

The highest discharge in the period of time you’re looking at

34
Q

What is lag time?

A

The delay between peak rainfall and peak discharge

35
Q

What is a rising limb?

A

The increase in river discharge as rainwater flows into the river

36
Q

What is a falling limb?

A

The decrease in river discharge as the river returns to its normal level

37
Q

How is discharge affected by the amount and type of rainfall?

A

Lots of rain in short, heavy periods of rainfall means there’s more runoff. Lag time is decreased, so discharge increases

38
Q

How is discharge affected by temperature?

A

Hot, dry condition and cold, freezing conditions both result in hard ground - this increases runoff. Lag time is decreased, so discharge increases

39
Q

How is discharge affected by previous weather conditions?

A

After lots of rain, soil can become saturated, so can’t absorb any more water. Runoff will increase and lag time will decrease, so discharge increases

40
Q

How is discharge affected by rock type?

A

Water infiltrates through porous rocks and flows along cracks in previous rocks, so there isn’t much runoff. Lag time increased, so discharge decreases. Opposite for impermeable rock

41
Q

How is discharge affected by land use?

A

Urban areas have drainage systems and are covered with impermeable surfaces, increasing runoff. Lag time is decreased, so discharge increases

42
Q

How is discharge affected by relief?

A

Lots of runoff occurs on steep slops. Lag time decreased, discharge increased