flooding understanding the human dimension€¦ · 11/15/2007  · keeping the water away or...

Flooding – understanding the human dimension Professor Edmund Penning-Rowsell, Middlesex University

Somerset: Winter 2014

“Flooding” – 12 mentions

“Flooding” – 13 mentions

“Flooding” – 26 mentions !!

This is something you might just need to learn …..

So, listen carefully …..

Somerset: Winter 2014 Floods

Impacts Responses

Somerset: Winter 2014

Floods:

Physical drivers

Human dimensions

Management of floods and

flood risk

• Floods from rivers

• Floods from the sea

• Floods in cities from extreme rainfall

• Floods direct from the land: “surface water flooding”

Smalls floods

Big floods

Rare floods

Flash floods

Deep floods

High velocity floods

Contaminated

floodwaters

Damaging floods

(big impacts)

Disruptive floods

Dangerous floods

Types of Floods

£5,000

£22,000

£31,000

£38,000

£44,000

We know a great deal about the

economic damage caused by floods…. Impact 1

But the economic damage caused by

floods is only part of the story ….

Plus:

Impact 2

Evacuation:

50% of those

with flood water

> 30cm are not

back in their

homes inside 30

days

Impact 3: Immediate self-reported physical health effects (1998/2000)

Immediate physical health

effects

Percentage reporting the effect [N = 71]

Shock 58

Colds, coughs, ‘flu, sore throats

41

Headaches 30

From exposure to contaminants

22

Injuries due to over-exertion 17

Skin irritations 15 Injuries from being knocked over by flood waters

7

Other 15

None of the above 18

Floods and

health impacts:

a 4 year study

after the 1998

floods

Impact 3: Self-reported physical health effects in the aftermath of flooding

Physical health effects in

aftermath of flooding

Percentage reporting the

effect [N = 71]

Stiffness in joints 23

Respiratory illness 21

Gastro-intestinal illness 20 Weight loss 20

Skin irritations 16

Muscle cramps 16

High blood pressure 14

Sprains and strains 14

Cuts and bruises 11 Heart problems 6

Other 28

None of the above 36

Impact 3: Self-reported mental healtheffects of the flooding

Mental health effects ofthe flooding

Percentagereporting

[N = 71]

Anxiety when rains 80

Increased stress levels 67

Depression (mild to severe) 56

Sleeping problems 51

Lethargy/lack of energy 39

Flashbacks to the flood 36

Mood swings/bad moods 35

Difficulty concentrating on tasks 35

Increased tension in relationships 31

Panic attacks 27

Anger/tantrums 24

Increased use of alcohol/drugs 18

Nightmares 18

Thoughts of suicide 9

Other 6

None of the above 6

Flood

0 1 2 years

Psychological

impacts

Physical

impacts ??

Impact 3: Health and floods: The time

line of impacts

Up to

80%

< 60%

So what can we do to reduce the

flood risk? Types of responses

Engineering

measures:

Keeping the water

away or reducing

flood probability

Dams/reservoirs

Flood walls/levees

Flood gates

Dredging channels

By-pass channels

Non-engineering &

‘human’ measures

Reducing

vulnerability and

likely damages

Controlling floodplain

development

Warning systems

Emergency response

Insurance

So what can we do to reduce the

flood risk? Two specific responses

Engineering

measures:

Keeping the water

away or reducing

flood probability

Dams/reservoirs

Flood walls/levees

Flood gates

Dredging channels

By-pass channels (UK)

Non-engineering &

‘human’ measures

Reducing

vulnerability and

likely damages

Controlling floodplain

development

Warning systems

Emergency response

Insurance (Bangladesh)

The river Thames catchment

London

Floods

July 2007

rainfall: the

physical

driver of that

flood event

Surge tides

RESPONSE No. 1: The Maidenhead and the “Jubilee River” flood by-pass channel

The river Thames catchment

London

So what does a bypass

channel do?

1. Takes flood water from the main

channel, just like a by-pass road takes

road traffic around a town

2. Reduces flood risk from the main

channel in the towns: Maidenhead;

Windsor; Eton

3. Re-connects with the main channel

downstream

1

2

3 2

RESPONSE NO. 2

The Thames Barrier in

London

North

Sea

Surge tides

Raised gate

Raised gate

Thames Barrier closures each year:

the response to flood risk

Protecting 1.25 million people, 58 tube

stations, 16 hospitals, 8 power stations

and 400 schools, etc.

Global-mean sea-level rise IPCC Third Assessment Report AR5 (2013)

Representative Concentration Pathways

(RCPs) are four greenhouse gas concentration

(not emissions) trajectories adopted by the

IPCC for its fifth Assessment Report (AR5).

Surges would come

on top of this

Source: UKCIP02 Climate Change Scenarios (funded by DEFRA, produced by Tyndall and Hadley Centres for UKCIP)

The 5-year surge height increase (m) for the 2080s

Low emission scenario: climate change

Medium-high emission scenario

The 5-year surge height increase (m) for the 2080s

Source: UKCIP02 Climate Change Scenarios (funded by DEFRA, produced by Tyndall and Hadley Centres for UKCIP)

The 5-year surge height increase (m) for the 2080s

Source: UKCIP02 Climate Change Scenarios (funded by DEFRA, produced by Tyndall and Hadley Centres for UKCIP)

High emission scenario 1.4 metres surge

So: 0.2 + 1.4 = 1.6

metres. This is

getting serious….

Floods are dangerous: Glasgow 2002

Impact 4

‘Flume’ experiments: stunt

man and varying flood

depths and velocities:

standing; walking

across stream; walking

upstream

Courtesy BBC ‘999’

Floods are dangerous

‘Flume’ experiments: stunt

man and varying flood

depths and velocities:

standing; walking

across stream; walking

upstream

Courtesy BBC ‘999’ BBC 999 DVD

Velocity

Depth

Upstream

Test: Gate

opened

0.46m; man

fell over at

3.0m/sec and

0.25m depth.

Time

Stunt man: Walking upstream

Dummy run

3.0 m/sec

0.25m depth

Gate

open

0.46m

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 0.5 1 1.5 2 2.5 3 3.5

Velocity (m/sec)

De

pth

of f

loo

d w

ate

r (

m) Hazard zone

'Safe' zone

Standing and walking experiments: Summary results

Experimental

results

Jonkman, S.N. and Penning-Rowsell, E.C. (2008). Human Instability in Flood Flows. Journal of the

American Water Resources Association 44(4):1-11. DOI: 10.1111 ⁄ j.1752-1688.2008.00217.x

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 0.5 1 1.5 2 2.5 3 3.5

De

pth

of f

loo

d w

ate

r (

m)

Velocity (m/sec)

Hazard zone

'Safe' zone

Safer zone

Hazard zone

0

5000

10000

15000

20000

25000

30000

35000

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Ban

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Som

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Ban

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Inclusion criteria:

• 10 or more people reported killed

• 100 people reported affected

• A call for international assistance

• Declaration of a state of emergency

Floods are dangerous: just the last 25 years

Liv

es l

ost

in f

loo

ds

c. 30,000

deaths in

Venezuela

flash flood

(1999)

c. 30,000

deaths in

Venezuela

flash flood

(1999):

Rainfall =

91 cm (36

inches) in

2.1 days

Physical ...

Human …

Caraballeda, Vargas state, Venezuela

Bangladesh United Kingdom

Area 57,000 sqr miles 94,000 sqr miles

Population 160 million 65 million

People per sqr mile 2,800 690

Bangladesh: the flood-prone delta in the

catchments of the Ganges and Brahmaputra

Emergency response

Bangladesh

Drivers

Bangladesh

The summer monsoon Dhaka has 185

cm (73 in) of

rainfall between

May and

September.

Dhaka

The monsoon rain

36 cm

Impacts

RESPONSE:

embankments

RESPONSE:

embankments

Small scale regular

flooding in Bangladesh is

required to grow rice, so

natural flooding replaces

the requirement of

artificial irrigation.

Flood can remove salt

deposited on fields from

high rates of

evaporation, preventing

the land from becoming

infertile.

IMPACTS: POSITIVE

PHYSICAL : Tidal waves up to five

metres high and surges up

to 6 metres.

Breaching coastal and river

embankments, flooding low-

lying areas and causing

extensive physical damage

destruction.

On 15 November

2007, Cyclone Sidr

struck the south-

west coast of

Bangladesh with

winds up to 150

miles per hour.

Tropical

cyclones

IMPACTS: NEGATIVE

15 November 2007: Some 2.3

million households were affected

to some degree by Cyclone Sidr.

About one million were seriously

affected.

The number of deaths is

estimated at 3,406 … and over

55,000 people sustaining

physical injuries.:

Impacts

Impacts

RESPONSE: emergency response

Evacuation to ‘safe

havens’ in Cyclone

shelters

RESPONSE: cyclone shelters

RESPONSE: cyclone shelters

Evacuation to ‘safe

havens’ in Cyclone

shelters

’

Winnie-the-Pooh

bear story

IMPACT: Sheer panic!

RESPONSE: Message sent!

RESPONSE: Message received …

RESPONSE: Securing food supplies!

‘A Level’ fieldwork?

‘A Level’ fieldwork – in the rain ...??

RESPONSE:

Heading for home?

….. and living happily ever after?

Somerset: Winter 2014

Floods in catchments

Impacts Responses

Somerset: Winter 2014

Floods:

Physical drivers

Human dimensions

The end!