Transcript Drivers of Flooding and Coastal Erosion Risk

Foresight Flood and Coastal
Defence Project
Government Office for Science
Department for Industry, Universities and Skills
Foresight project on Flooding and Coastal
Defence 2004
Colin Thorne
University of Nottingham
on behalf of the UK Foresight Team
Overview
• Context
• Project aims
• Methodology
• River, Coastal and Intra-urban Drivers
• Predicting Future Flood and Coastal Erosion Risks
(baseline case)
• Responses: Structural and nonstructural measures
• Costs and Affordability of Responses
• Take home messages
Foresight Project Aims
• Produce a long-term vision for future flood and
coastal risks and their management in the UK.
• Cover all aspects of flood & coastal erosion risk
for the whole UK, looking 30 – 100 years ahead.
• Provide a reliable evidence-base for decision
makers, using expert knowledge and high level
flood and erosion risk analyses.
• Supply the underpinning science for nationallevel policy making.
Methodology
The watershed and coastal flooding system
The urban flooding system
Foresight Futures 2020 +
UKCIP2002 climate change scenarios
Medium-high
emissions
Medium-low
emissions
High emissions
and
Low emissions
Low emissions
Drivers
Processes that change the state of the
system
Change in risk
System state variables
Sources
Pathways
Receptors
rainfall
sea level
storm
surges
wave
heights
etc.
urban surfaces
fields, drains
channels
flood storage
flood defences
floodplains
communities
homes
industries
Infrastructure
resources
ecosystems
• .
Responses
Interventions that change the state of the
system
System
analysis
Risk
Probability x
consequences
(economic, risk to
life, social, natural
environment etc)
Change in risk
Qualitative Analysis:
Flood Risk Drivers
Drivers of fluvial and coastal flooding
Driver group
Driver
SPR classification
Climate change
Precipitation
Source
Temperature
Source
Urbanisation
Pathway
Rural land management
Pathway
Agricultural impacts
Receptor
Environmental regulation
Pathway
River morphology and sediment supply
Pathway
River vegetation and conveyance
Pathway
Waves
Source
Surges
Source
Relative sea level rise
Source
Coastal morphology and sediment supply
Pathway
Stakeholder behaviour
Pathway
Public attitudes and expectations
Receptor
Buildings and contents
Receptor
Urban impacts
Receptor
Infrastructure impacts
Receptor
Social impacts
Receptor
Science, engineering and technology
Receptor
Catchment runoff
Fluvial Systems and
Processes
Coastal processes
Human behaviour
Socioeconomics
Drivers of
Flooding and
Coastal
Erosion Risk
“… phenomena
that change the state
of the flooding
system…”
Baseline ranking of
river and coastal
drivers
•
Socio-economic drivers
• Climate change
• Coastal drivers
• Environmental Regulation
• Big scenario differences
Drivers of intra-urban flood
risks
Plus……
• Stakeholder behaviour
• Urban planning policy
Ranking of intra-urban
scale drivers
•
Social impacts
• Asset deterioration
• Precipitation
• Environmental management
and regulation
• Buildings and contents
Quantitative Analysis
(Baseline Case)
Modeling: National quantitative risk
analysis:
Data used:
Risk
Assessment
for
Strategic
Planning
Rivers and coastlines
Floodplain mapping
Standard of protection
Condition of defences
Addresses of all
properties/people at risk
Flood damage by depth
Social vulnerability
Agricultural land grade
Calculating Flood Risk
Pathway
(e.g. beach, raised/non-raised
Receptor
defence and floodplain)
(e.g. people and property)
Source
(River or sea)
0
20
40
80
Kilometres
±
Definition
Dominant valley class
This map is reproduced from Ordnance Survey material
with the permission of Ordnance Survey on behalf of
the controller of Her Majesty's Stationary Office.
North-east
(c) Crown Copyright. Unauthorised reproduction
infringes Crown Copyright and may lead to prosecution
or civil proceedings.
North-west
Department of Trade and Industry. 100037208. 2003.
coastal
Coastal
Lowland (intermediate
/ shallow
valley slopes
lowland
(intermediate
/ shallow
valley
Upland (steep
valley
slopes)slopes
upland
(steep
valley
no defences
Midlands
East Anglia
Wales
Thames
Dominant Floodplain
Class (2002)
South-west
South-east
Flood Risk in 2050 and 2080 for ‘World Markets’
Present Day 2002
Pro bab ility of Inu ndatio n to a d epth
greater th an 0 .0m
Ne gligible
Low
M edium
High
World M arkets 2050's
World M arkets 2080's
Negligible Increase
Low Increase
Medium Increase
High Increase
Negligible Increase
Low Increase
Medium Increase
High Increase
Decrease
Decrease
Outside IFP
Outside IFP
Ve ry H igh
Outsi de IFP
Na tiona l E nte rpr ise 2 080's
Local St ewards hip 2080's
Glob al R e spon sib ility 20 80's
Negligible Increase
Low Increase
Medium Increase
High Increase
Negligible Increase
Low Increase
Medium Increase
High Increase
Negligible Increase
Low Increase
Medium Increase
High Increase
Decrease
Decrease
Decrease
Outside IFP
Outside IFP
Outside IFP
Expected annual damages: £ millions
(currently ~ £1billion)
Future Coastal Erosion Risks
•
•
•
•
Future Coastal Erosion
is likely to be more
severe along the coasts
of:
Holderness
Thames, Severn and
Humber Estuaries
Lincolnshire and the
Wash
Suffolk and Essex
Coastal Erosion – Annual Expected Damages
Average annual coastal erosion damage estimates for the
2080s (£millions) derived from ‘Future Coast 2000’
Today
North-East
Anglian
Southern
South West
North West
Total
2.6
1.2
6.4
3.2
1.0
14.4
Global
Local
National
Sustainability Stewardship Enterprise
6
7
10
4
5
9
17
18
36
15
16
27
4
4
6
46
51
87
World
Markets
13
13
53
38
8
126
Annual losses due to coastal erosion may
increase by 3 to 9 times
Serious Impacts on Coastal
Environments
Some valuable coastal habitats
appear threatened under all
futures, especially coastal
wetlands and marshes.
• Floodplain and
coastal systems
change due to
changes in floods
and their
management.
• The four scenarios
suggest divergent
environmental futures
• Coastal squeeze is a
major threat to
habitats &
ecosystems
Baseline Conclusions:
unless we act:•
Future flooding and coastal
erosion are very serious
threats to the UK.
•
They represent a major
challenge to government and
civil society.
•
Combining the World Markets
and Low emissions scenarios
reduces future expected
annual economic damages by
only ~25%.
Responses
Options for managing future flood and
coastal erosion risks
sustainably
Potential Responses
80 individual
responses
And 5
response themes
• Reducing
urban runoff
• Reducing rural runoff
• Managing flood events
• Managing flood losses
• Engineering and large scale
re-alignment or abandonment
Organised into 25
response groups
Qualitative Analysis of Responses
• Definition, Function and Efficacy
• Governance
• Sustainability
•
Potential for
implementation
under each
Foresight
future scenario
Envir onm e n ta l Q ua lity
++
Co s t Effe c tive ne s s
So c ia l J u s tic e
-Flood r is k
— neutral
Ro bus tn e s s
Pr e c a u tion
Responses with
the most potential
for risk reductions
Responses Groups ranked by potential risk reduction in the 2080s
Rank
1
2
3
4
•
•
Structural: Rethink
Coastal & River
Defences
Non-structural:
Manage down flood &
erosion consequences
5
6
7
8
9
10
11
12
Legend
13
Colour Interpretation
code
Major reduction in flood risk ( S < 0.7)
Marked reduction in flood risk (0.7 < S < 0.9)
Minor reduction in flood risk (0.9 < S < 1.0)
Ineffective ( S = 1)
Likely to Increase flood risk ( S > 1.0)
14
15
16
17
18
World
Markets
River
Defences
Coastal
Defences
Flood Proofing
Buildings
Reduce Coastal
Energy
Morphological
Coastal Protection
Realign Coastal
Defences
Real-time Event
Management
River
Conveyance
Individual Damage
Avoidance
Pre-event
Measures
Engineered Flood
Storage
Land Use Planning
and Management
Manage Urban
Runoff
Flood Water
Transfer
Catchment-Wide
Storage
Rural
Conveyance
Rural
Infiltration
National
Enterprise
River
Defences
Coastal
Defences
Reduce Coastal
Energy
Realign Coastal
Defences
Morphological
Coastal Protection
Coastal Defence
Abandonment
Flood Proofing
Buildings
River
Conveyance
Catchment-Wide
Storage
Land Use Planning
and Management
Engineered Flood
Storage
Real-time Event
Management
Pre-event
Measures
Rural
Conveyance
Rural
Infiltration
Individual Damage
Avoidance
Manage Urban
Runoff
Flood Water
Transfer
Local
Stewardship
Land Use Planning
and Management
Flood Proofing
Buildings
Individual Damage
Avoidance
River
Defences
Catchment-Wide
Storage
Pre-event
Measures
Real-time Event
Management
Engineered Flood
Storage
Rural
Conveyance
River
Conveyance
Rural
Infiltration
Manage Urban
Runoff
Flood Water
Transfer
Coastal
Defences
Realign Coastal
Defences
Morphological
Coastal Protection
Reduce Coastal
Energy
Coastal Defence
Abandonment
Global
Sustainability
Land Use Planning
and Management
Catchment-Wide
Storage
River
Defences
Coastal
Defences
Flood Proofing
Buildings
Rural
Conveyance
Realign Coastal
Defences
Reduce Coastal
Energy
Morphological
Coastal Protection
Engineered Flood
Storage
Real-time Event
Management
Pre-event
Measures
Individual Damage
Avoidance
River
Conveyance
Rural
Infiltration
Manage Urban
Runoff
Flood Water
Transfer
How much will it cost – are responses affordable?
• The cost of using structural defences alone to achieve the indicative
standard of defence in 2080s as part of an integrated portfolio of
structural and non-structural responses is ~ £22 billion
• The cost of implementing engineering- based structural approach alone
to achieve the same standard of defence is ~ £52 billion
Take Home Messages
• Future flood and coastal erosion risks are likely to
increase due to climate, economic, social and planning
drivers if we go on as we are.
• We can make it easier or harder for ourselves by our
actions on global emissions and governance.
• There are feasible and sustainable responses that can
hold risk at present day levels affordably - if
implemented through Integrated FRM.
• But we must act now in developing new policies to allow
non-structural measures to be effective in time.