Rivers

Question 1

What is hydraulic action?

Answer 1

The force of water compresses air into the river bank. When this pressure builds up, the bank is weakened and wears away.

Question 2

What is abrasion?

Answer 2

Rocks carried by the river rub and scrape against the river bed and river banks, wearing them down.

Question 3

What is attrition?

Answer 3

Rocks carried by the river rub and crash against each other which breaks them into smaller pieces.

Question 4

What is solution?

Answer 4

Acidic water dissolves certain types of rocks on the river bed and banks (limestone)

Question 5

What is river discharge?

Answer 5

Amount of water in a river at a given time.

Question 6

What is a river’s load?

Answer 6

Materials carried by the river (they can be all different shapes and sizes)

Question 7

What is traction?

Answer 7

Large boulders and rocks are rolled along the river bed by the force of the water at times of high discharge.

Question 8

What is saltation?

Answer 8

Small rocks and sand are bounced along the river bed.

Question 9

What is suspension?

Answer 9

Fine clay and sand particles are carried along the river, even at low discharge.

Question 10

What is solution?

Answer 10

Minerals dissolve in the water (calcium carbonate). This requires little energy.

Question 11

What is the valley like in the upper, middle and lower course?

Answer 11

upper- steep valley sides
middle- flatter valley sides
lower- flat valley sides

Question 12

What is the channel like in the upper, middle and lower course?

Answer 12

upper- narrow and shallow channel
middle- wider and deeper channel
lower- widest and deepest channel

Question 13

What landforms are there in the upper course of a river?

Answer 13

V shaped valley, marshy land, rapids, High Force waterfall (River Tees)

Question 14

What landforms are there in the middle course of the river?

Answer 14

Floodplains, meanders, slip off slopes, river cliffs

Question 15

What landforms are there in the lower course of the river?

Answer 15

Mudflats, meanders

Question 16

What processes occur in the upper course and what is the size of the load?

Answer 16

Large angular bedload
-low velocity
-vertical erosion
-traction
-saltation

Question 17

What processes occur in the middle course and what is the size of the load?

Answer 17

smaller less angular bedload
-faster velocity
-hydraulic action
-attrition
-lateral erosion dominates

Question 18

What processes occur in the lower course and what is the size of the load?

Answer 18

Small bedload
deposition
suspension

Question 19

when/ why do rivers deposit sediment?

Answer 19

velocity of the water slows, decreasing the energy of the water. the heaviest material is dropped first

Question 20

what are the erosional landforms?

Answer 20

waterfalls, interlocking spurs, gorges

Question 21

what is a floodplain?

Answer 21

the land covered in water when a river bursts its banks

Question 22

how do floodplains form?

Answer 22

erosion removes interlocking spurs, creating wide flat land either side of the river

Question 23

what is a levee?

Answer 23

small build ups on river banks

Question 24

how do levees form?

Answer 24

when a river floods, it deposits the heaviest of its load. after many floods, the levees rise to raise the river bank –>flooding is less likely

Question 25

what is an estuary?

Answer 25

the tidal mouth of a river meets the sea

Question 26

how do estuaries form?

Answer 26

wide banks of deposited mud are exposed at low tide, which are important for wildlife

Question 27

how does precipitation increase flood risk?

Answer 27

torrential rainstorms can lead to sudden flash floods

Question 28

how does rock type increase flood risk?

Answer 28

impermeable rocks (clay) do not allow water to pass through them, so water flows over the land into the river

Question 29

how does relief increase flood risk?

Answer 29

steeper relief allows water to run over the land quickly so there is no time for it to seep into the soil --->more water enters the channel

Question 30

how does agriculture increase flood risk?

Answer 30

soil can be left exposed when unused so more surface run off occurs

Question 31

how does urbanisation increase flood risk?

Answer 31

often, new roads etc are built on impermeable rock (tarmac), so more surface run off into drains and therefore rivers occurs

Question 32

how does deforestation increase flood risk?

Answer 32

trees can't intake water, and less interception

Question 33

what is a dam? (hard engineering)

Answer 33

a large concrete barrier built across a river to hold back its flow

Question 34

what are some benefits of dams?

Answer 34

reduces flood risk, allows for hydroelectric power, allows for leisure activities

Question 35

what are some costs of dams?

Answer 35

they are ugly, expensive and disrupts natural fish life

Question 36

what is channel straightening? - hard engineering

Answer 36

a meandering section of a river is engineered to create a widened, straightened and deepened course to carry more water

Question 37

what is a benefit of channel straightening?

Answer 37

river flows faster, gravel removes friction

Question 38

what is a cost of channel straightening?

Answer 38

it disrupts wildlife

Question 39

what are embankments?- hard engineering

Answer 39

raised river banks, which allow more water to be contained in the channel

Question 40

what is a benefit of embankments?

Answer 40

the river can carry more water before it floods

Question 41

what is a cost of embankments?

Answer 41

they are costly, disrupt views and access to the river, soil fertility is reduced

Question 42

what is flood relief? - hard engineering

Answer 42

another channel is built to move water away from human settlements

Question 43

what is a benefit of flood relief?

Answer 43

removes water from settlements at times of high discharge

Question 44

what is a cost of flood relief?

Answer 44

disrupts surrounding areas of the channel

Question 45

what are flood warnings? - soft engineering

Answer 45

the environmental energy monitor rivers and send warnings via radio tv etc

Question 46

what is an advantage of flood warnings?

Answer 46

people have time to save possessions, or protect their property

Question 47

what is a disadvantage of flood warnings?

Answer 47

some people cannot access the warnings, flash floods may happen too quick for a warning, does not stop the flood from actually happening

Question 48

what is floodplain zoning?- soft engineering

Answer 48

only certain land uses are allowed on floodplains

Question 49

what is an advantage of floodplain zoning?

Answer 49

valuable buildings are at less of a risk of flooding, less damage

Question 50

what is a disadvantage of floodplain zoning?

Answer 50

some land uses cannot be changed

Question 51

what is a benefit of aforestation?

Answer 51

more interception and water taken in from photosynthesis

Question 52

what is a cost of aforestation?

Answer 52

takes long for trees to grow

Question 53

what is river restoration?

Answer 53

reverting a river to how it was before channel straightening

Question 54

what is our example of a flood management scheme?

Answer 54

Jubilee River

Question 55

what type of flood relief scheme is the jubilee river?

Answer 55

a flood relief channel

Question 56

what is an economic effect of the jubilee river?

Answer 56

business insurance costs for Wraysbury in 2014 was £500 million

Question 57

what is a social effect of the jubilee river?

Answer 57

some properties are protected but not others, eg 3000 affluent properties in Eton are protected, but settlements in Wraysbury aren't

Question 58

what is an environmental effect of the jubilee river?

Answer 58

algae collects behind weirs where river flow slows

Question 59

how many km is the jubilee river?

Answer 59

12km

Question 60

how many hectares of reed bed were created as part of the growth corridor in the jubilee river?

Answer 60

38

Question 61

how many businesses and houses were protected by the jubilee river?

Answer 61

500 businesses, 3000 homes