Drainage basins of the UK

Question 1

Define drainage basin

Answer 1

Area of land drained by a river and it’s tributaries

Question 2

Define flow

Answer 2

Movement of water

Question 3

Define store

Answer 3

Place where water is stationary within the water cycle

Question 4

Define interception

Answer 4

When rainfall does not reach the ground as it is blocked by trees, buildings and so on

Question 5

Define Infiltration

Answer 5

Movement of water into the soil

Question 6

Define throughflow

Answer 6

Flow of water through the soil

Question 7

Define overland flow

Answer 7

Flow of water across the ground surface

Question 8

Define Groundwater flow

Answer 8

Flow of water through rocks

Question 9

Define transpiration

Answer 9

Water given off by plants

Question 10

Define stem flow

Answer 10

Movement of water hat has been intercepted down the stem or trunk of a plant

Question 11

Define Percolation

Answer 11

Movement of water from soil into the bedrock

Question 12

Explain why the speed varies due to the type and quantity of rainfall (3)

Answer 12

1. Rain moves quicker in heavy rainstorms
2. Raindrops are larger and fall in a shorter time period
3. This means less infiltration and more surface run off

Question 13

Explain why the speed varies due to the type and quantity of vegetation cover

Answer 13

more interception occurs in a woodland compared to a meadow

Question 14

Explain why the speed varies due to the size and shape of the drainage basin (2)

Answer 14

1. Round drainage basins lead to faster water movement compared to elongated ones
2. Larger basins have larger discharge

Question 15

Explain why the speed varies due to steepness of slopes

Answer 15

Greater surface run off and less infiltration

Question 16

Explain why the speed varies due to the geology and soil type within the drainage basin

Answer 16

Impermeable soil and rocks mean less infiltration or ground water flow and more surface run off

Question 17

Name 4 reasons why rivers flood

Answer 17

1. Climate
2. Vegetation
3. Geology
4. Urbanisation

Question 18

Why may climate increase the chance of a river flooding? (2)

Answer 18

1. Seasonal rainfall = saturated ground, more overland flow and higher river levels
2. Strom event = storm, high volume of rainfall in short time period, causes sudden rise in river levels, flash floods

Question 19

Why may vegetation increase the chance of a river flooding? (3)

Answer 19

1. Different vegetation intercepts different amounts of rainfall
2. This influences the speed the water reaches the drainage basins
3. Removal of vegetation = trees removed, water reach river channel quicker due to quicker saturation of soil

Question 20

Why may geology increase the chance of a river flooding? (3)

Answer 20

1. Porous rocks have large spaces which allows water through, reducing flood risk due to increased groundwater flow
2. Impermeable rocks have few spaces, little water passes through, creates more overland flow, higher flood risk
3. Rock may be well jointed, allows water to pass through lines of weakness

Question 21

Why may urbanisation increase the chance of a river flooding?

Answer 21

1. Expansion of towns/cities = ground covered by impermeable surface (tarmac), reduces amount of infiltrated water, causes more overland flow, high risk of flooding

Question 22

Define hydrograph

Answer 22

A line graph used to display discharge of a river over a period of time

Question 23

Define lag time

Answer 23

Time between the peak rainfall and peak discharge in a river

Question 24

Define rising limb

Answer 24

Part of hydrograph where the discharge of a river is increasing after a rainfall event

Question 25

What impact does urbanisation have on a hydrograph? (3)

Answer 25

1. Decreases lag time 2. Steep rising limb 3. High peak

Question 26

What impact does Porous rocks have on a hydrograph? (3)

Answer 26

1. Increases lag time 2. Gentle rising limb 3. Lower peak

Question 27

What impact does Impermeable rocks have on a hydrograph? (3)

Answer 27

1. Decreases lag time 2. Steep rising limb 3. High peak

Question 28

What impact does Broad-leaved trees have on a hydrograph? (3)

Answer 28

1. Increased lag time 2. Gentle rising limb 3. Lower peak

Question 29

Name an example of a flood

Answer 29

Somerset Levels 2013-14

Question 30

Name 5 physical causes of the Somerset Levels

Answer 30

1. Large area of flat land 2. 2 major rivers run through the area - Tone and Parrett 3. Prolonged heavy rainfall causing saturated ground 4. Silting up of the river channel therefore reducing capacity 5. High tidal range

Question 31

Name 2 human causes of the Somerset Levels

Answer 31

1. Reduction in frequency at which the rivers were dredged | 2. Building on the floodplain

Question 32

Name 7 effects of the Somerset Levels

Answer 32

1. Over 80 roads blocked 2. Children couldn't get to school, adults couldn't get to work 3. Villages were cut off 4. 600 homes were affected and people evacuated 5. Due to lack of grazing land farmers lost around £10m 6. Half of the business' in Somerset lost money 7. Cost of £19m to local government and emergency services

Question 33

Describe and name hard engineering strategies for river channel and drainage basin management (3)

Answer 33

1. Involve constructing defences to control natural processes 2. Often large scale, expensive and relatively effective 3. Examples = dams, gabions, dredging, flood relief channel and embankments

Question 34

Describe and name soft engineering strategies for a river channel and drainage basin management (5)

Answer 34

1. Work with environment rather than trying to control it 2. Often cheaper than hard engineering 3. Less impact on the environment 4. Can be less effective once river has flooded 5. Examples = restrict building on floodplains, afforestation, ecological flooding, warning systems

Question 35

Describe and name land-use zoning strategies for a river channel and drainage basin management (3)

Answer 35

1. Planning what the land is used for within river basin so less valuable land closer to a river 2. Housing put on higher ground away from river to lessen chance of being flooded 3. Method not always straightforward to carry out as many years ago housing were built close to rivers many years ago

Question 36

Name 2 conflicting views when considering the best way to manage the floodplains at Somerset Levels

Answer 36

1. Somerset Wildlife Trust 'We must allow the rivers to flood naturally. Some of the wetlands habitats are unique' 2. Royal Society for the Protection of Birds ' Dredging has an impact on the habitat in and around the river'

Question 37

Name 2 points of view in floodplain development conflict

Answer 37

1. Insurance Broker 'Over 80 new developments to be built on floodplains is a ridiculous amount, there should be non. If people don't want their homes to be flooded, don't build on floodplains' 2. Young family on low income 'We need more homes to be built so that the price of houses falls low enough for us to be able to afford them'