Unit 4 - River Processes and Pressures

Question 1

Name three landforms formed in the upper course

Answer 1

Waterfalls, V shaped Valleys, gorges

Question 2

Name three landforms formed in the middle course

Answer 2

Meanders, oxbow lake, river beach

Question 3

Need two landforms formed in the lower course

Answer 3

Floodplains, deltas

Question 4

What is the river profile

Answer 4

A graph that shows how the weather changes during its journey

Question 5

What happens during the upper course

Answer 5

There is the river’s source in highland areas as there is more rainfall. The river runs downstream cutting its valley by vertical erosion. The Valleyside it’s a steep and is usually large rocks on the river bed.

Question 6

What happens during the middle course

Answer 6

Less vertical erosion and more lateral or erosion. Wider and deeper. More lateral erosion where the river cuts meanders

Question 7

What happens in the lower course

Answer 7

Gentle gradient and the channel is wider. Tributaries s, surface run-off and groundwater have increased the volume of the river

Question 8

Describe what the river profile looks like

Answer 8

Height on the Y axis. The length of the river from the source along the X axes with a plotted line from top left to bottom right showing the river

Question 9

What is the Bradshaw model

Answer 9

A diagram showing how characteristics of a river change from upstream to downstream. Triangles are used to show this as they either start wider or narrow and end with the opposite

Question 10

What is transportation

Answer 10

Rivers move material, Load, downstream from its source to its mouth. There are four types of transportation methods

Question 11

What is erosion

Answer 11

Rivers wear away their load and the bed and banks of the river channel. There are four processes

Question 12

What are the four types of transportation

Answer 12

Traction, saltation, suspension, solution

Question 13

What happens during traction

Answer 13

Large stones are dragged or rolled

Question 14

What happens during saltation

Answer 14

Smaller stones are picked up and then dropped or bounced

Question 15

What happens during suspension

Answer 15

Tiny particles of sediment are carried in the rivers current

Question 16

What happens during solution

Answer 16

Dissolved chemicals are carried along in the solution, invisible to the eye

Question 17

What are the four types of erosion

Answer 17

Attrition, abrasion, solution and hydraulic action

Question 18

What is attrition

Answer 18

Rocks and stones where each other away as they knock together

Question 19

What is abrasion

Answer 19

Sand and pebbles are dragged along the river bed, or knock into it by saltation wearing away the bed

Question 20

What is solution in erosion

Answer 20

Alkaline rocks such as limestone are dissolved by acidic rainwater

Question 21

What is hydraulic action

Answer 21

Fast flowing water is forced into cracks breaking up the bank overtime

Question 22

How are a waterfalls and gorges formed

Answer 22

1. There must be a layer of hard rock on top of soft rock and the river must cross it
2. The soft rock gets eroded faster by the river. This forms a ledge undercut and overhang and a plunge pool at the bottom
3. The ledge collapses as it wasn’t supported into the plunge pool
4. This repeats making the waterfall retreat leaving a gorge

Question 23

How is a V shaped valley formed

Answer 23

The river erodes vertically making the valley like a V.
The steep valley sides are attacked by weathering processes like freeze thaw
The valley sides weaken making them collapse
River valleys may have interlocking spurs, slivers of land that interlock. These are more resistant so it is left behind and the river moves between them

Question 24

What is velocity

Answer 24

The speed of the river, measured in metres per second

Question 25

What is discharge

Answer 25

The volume of water flowing in a river, measured in cubic metres per second

Question 26

How does a meander form

Answer 26

The weather is naturally curved slightly which means the water flows at different speeds in different parts. On the outer edge of a curve it is fastest so it erodes the edge. On the inner edge, it is slow so sediment builds up.

Question 27

What happens at the outer edge of a river

Answer 27

It is fast flowing so it is eroded. This forms an undercut or a river cliff

Question 28

What happens at the inner edge of a river

Answer 28

It is slow flowing so sediment carried from the outer edge is the positive here which forms a slip off slope

Question 29

What are the three types of flow in a river

Answer 29

Inside flow, outside flow or thalweg, helicoidal flow

Question 30

What is an oxbow lake

Answer 30

When a loop of a meander is left and split from the river

Question 31

How an oxbow lake formed

Answer 31

The outside of the meander bend which is the neck is eroded more It is continued to be eroded until only a thin piece of land separates the two channels The river floods over the neck where it is eroded and the Ariver takes the easier course.

Question 32

What is a floodplain

Answer 32

A flat area of land that the river spills onto when it bursts its banks

Question 33

What is a levee

Answer 33

A small raised area of land on the banks of the river made up of sediment. It can be natural or man-made

Question 34

What is a river delta

Answer 34

When the river deposits its material faster than the sea can remove it

Question 35

What is estuary

Answer 35

It appears where the river meets the sea

Question 36

How is a levee formed

Answer 36

During a flood sediment builds up along the banks small ridge. This then continues to grow as more floods happen

Question 37

What are the three types of deltas

Answer 37

Fan shaped Cuspate Birds foot

Question 38

What is a fan shaped delta

Answer 38

The river splits into many smaller ones to create a fan effect as the river mouth arches out into the Sea

Question 39

What is a cuspate Delta

Answer 39

The land around the mouth juts out like an Arrow into the sea

Question 40

What is a birds foot delta

Answer 40

The river splits on the way to the sea and each part juts out into the Sea

Question 41

Give an example of a fan shaped delta

Answer 41

The Niger delta

Question 42

Give an example of a cuspate Delta

Answer 42

The Ebro Delta

Question 43

Give an example of a birds foot delta

Answer 43

The Mississippi Delta

Question 44

How is a river delta formed

Answer 44

When the river meets slower water, like the sea or a lake, it loses power as it slows down so the sediment being carried is deposited forming the deltas.

Question 45

What are water stores

Answer 45

Different places where bodies of water are stored

Question 46

What is most of the earths water

Answer 46

Salt water

Question 47

What is interception

Answer 47

Water being prevented from reaching the surface by trees or grass

Question 48

What is infiltration

Answer 48

Water sinking into the soil from the ground surface

Question 49

What is groundwater flow and through flow.

Answer 49

Groundwater flow is flowing through the rock layer and through flow is flowing through the soil layer

Question 50

What is percolation

Answer 50

Water seeping deeper below the surface

Question 51

What is transpiration

Answer 51

Water lost through pores in vegetation

Question 52

What is the lag time

Answer 52

The peak flow of water time - the peak amount of rainfall

Question 53

Give three points of a short lag time

Answer 53

Intense rainfall, urban area, high drainage density

Question 54

Give three points of a long lag time

Answer 54

Gentle Valleyside, forest, low drainage density

Question 55

What is antecedent rainfall

Answer 55

The amount of moisture already in the ground before a rainstorm

Question 56

Three causes that make hydrographs look different

Answer 56

Antecedent rainfall, geology, vegetation