Water Lesson 7: Causes of Flooding

Question 1

Define a flood

Answer 1

When a river exceeds its bank full discharge

Question 2

Describe storms and flash flooding

Answer 2

Intense, torrential storms are often associated with the UK during summer months. Storms cause the capacity of the river to be overwhelmed quickly

Question 3

Example of storms and flash flooding

Answer 3

September 2016, flash flooding caused travel chaos as almost half a month’s worth of rain fell within hours in some places - UK

Question 4

Describe monsoon rainfall

Answer 4

This occurs across South and southeast Asia between May and September

Question 5

Example of monsoon rainfall

Answer 5

July 2016 the Philippines experienced heavy monsoon rains leading to flooding, landslides and evacuations in villages northwest of the capital Manila

Question 6

Describe snowmelt

Answer 6

Flooding can occur when this happens as the ground becomes saturated quickly.

Question 7

Example of snowmelt

Answer 7

Norfolk in 2013, very mild and wet weather caused rapid thawing, which combined at the same time as heavy rain, causing local floods

Question 8

When was Storm Desmond, UK?

Answer 8

5-6th December 2015

Question 9

Areas affected by Storm Desmond?

Answer 9

Cumbria, Northwest England

Question 10

How much rain fell in Honister Pass in 24hrs?

Answer 10

341.4mm

Question 11

When was the wettest 48hrs? How much rain fell?

Answer 11

Thirlmere
405mm

Question 12

How many died from storm Desmond?

Answer 12

2

Question 13

How many named storms in the UK in 2015/16?

Answer 13

4

Question 14

Causes of Storm Desmond?

Answer 14

-Very mild, moist air from the tropics pushed across to the UK
-Air quickly forced to rise over mountainous terrain, producing lots of rain - orographic rainfall
-The position of the jet stream – which are the driving force of the direction of depressions and speed of movement – remained over the northwest longer than usual

Question 15

Human causes of flooding in Cumbria from Desmond?

Answer 15

Changing land use
Mismanagement of rivers

Question 16

Describe land use in Cumbria

Answer 16

-Agricultural landscape managed by farmers
-Overgrazing leads to bare slopes as vegetation is removed. This leads to a reduced amount of interception and an increase in overland flow which means that lag times are reduced and a higher discharge peaks.
Soil is also trampled, reducing infiltration

Question 17

Describe mismanagement of rivers in Cumbria

Answer 17

Hard-engineering strategies have been common including raised riverbanks, pumping stations and diversion channels

Question 18

Which river in Cumbria rose by how much breaching its riverbank? Why?

Answer 18

River Greta in Keswick
Rose by 5.9m
No dredging - raised river bed

Question 19

Number of homes affected by Desmond?

Answer 19

5200

Question 20

Number of schools closed by Desmond?

Answer 20

40

Question 21

Insurance claims amounted to what?

Answer 21

£325 million

Question 22

Estimated cost of Desmond flooding?

Answer 22

£500 million

Question 23

Effect of Desmond on the environment?

Answer 23

Water pollution from debris and sewage
Destruction of habitats and increased erosion

Question 24

Location of storm Eva?

Answer 24

West Yorkshire and Lancashire - hit Manchester, Leeds and York heavily

Question 25

Number of properties flooded by Eva?

Answer 25

9000

Question 26

Number of homes with power cuts by Eva?

Answer 26

7574 homes

Question 27

What transport links were closed due to Eva?

Answer 27

Irish Ferries
M62
Rail services across the North

Question 28

Estimated cost of Eva?

Answer 28

£800 million

Question 29

Number of deaths from Eva?

Answer 29

1

Question 30

Effect on environment from Eva?

Answer 30

Habitats severely destroyed and increased erosion
Increased saturation of soil reducing infiltration

Question 31

Location of Storm Frank?

Answer 31

North-west Scotland and West of UK

Question 32

Number of properties evacuated by Frank?

Answer 32

300+

Question 33

What reduced the ability to rescue people by Frank?

Answer 33

Flooding combined with freezing temperatures and snow

Question 34

Transport routes closed by Frank?

Answer 34

A93 between Ballater to Braemar partly washed away down river Dee

Question 34

Transport routes closed by Frank?

Answer 34

A93 between Ballater to Braemar partly washed away down river Dee

Question 35

Which river changed its route from Frank?

Answer 35

River Quoich

Question 36

Number of wading birds around Braemar increased by what from Frank?

Answer 36

From 40 to 82 pairs

Question 37

Effect to environment from Frank?

Answer 37

Trees knocked down provided more dead wood and new habitats
Increase in wading birds

Question 38

Estimated cost of Frank?

Answer 38

£700-900 million

Question 39

How much did the UK gov give to Cumbria and Lancashire for recovery from Desmond?

Answer 39

£50 million

Question 40

Number of water pumps and length of flood barriers in response to Eva?

Answer 40

20 pumps and 2km of barriers

Question 41

Number of families into temporary accommodation?

Answer 41

300

Question 42

Average cost of domestic flood claims was?

Answer 42

£50 000

Question 43

Amount gov gave out for flood recovery?

Answer 43

£200 million

Question 44

Amount committed by gov for flood management projects over 6 years?

Answer 44

£2.3 billion

Question 45

Estimated total cost of floods by KPMG?

Answer 45

£5 billion