foresight future floding ian meadowcroft, environment agency jimhall
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Foresight future floding Ian Meadowcroft, Environment Agency JimHall University of Bristol, Department of Civil Engineering Paul Sayers, HR Wallingford. Use best available science to provide a vision for flood and coastal defence, 2030 - 2100 Independent look Broad scope - PowerPoint PPT PresentationTRANSCRIPT
Foresight future flodingIan Meadowcroft, Environment Agency
JimHall
University of Bristol, Department of Civil Engineering
Paul Sayers, HR Wallingford
Aim of the project
• Use best available science to provide a vision
for flood and coastal defence, 2030 - 2100
• Independent look
• Broad scope
• Sustainability analysis - economic, social and
environmental consequences
Project stages
• Phase 1 - Conceptual model, drivers and
responses
• Phase 2 - Impacts (assuming no change in
current policy)
• Phase 3 - Responses
• Reporting / hand over
Overview of approach - The flooding system
Conceptual risk model
• Probability and consequences
• Source - Pathway - Receptor
• Recognise a wide range of drivers and responses
• Holistic risk model ‘glued’ the team together - over
60 experts involved in providing information and data
• Also enabled integrated analysis of river, coastal and
urban flooding
Overview of approach to risk
.
System descriptorsPathways
beaches, flood defences,
urban surfacesfields,
floodplains
Receptorspeoplehouses
industriesinfrastructure
ecosystems
Sourcesrainfall
sea levelmarine storms
etc.
Risk
economic, risk to life, social, natural environment etc
System analysis
Drivers (Phase 2)Processes that change the state of the
systemChange in risk
Responses (Phase 3)Interventions that modify the behaviour of
the system
Change in risk
Portfolios for catchment-scaleflood-risk management
Common menu of responses implemented under the four scenarios
Low regulation and limited emphasis on the
environment. Piecemeal engineering measures to reduce risk, centrally-
managed with limited local capabilities
National wealth does not keep pace with increasing
risk. Abandonment of fluvial and coastal floodplains. Reinstatement of natural
systems. Diversity of approaches across UK
regions
Free market provision of measures to reduce impacts of flooding and hedge risks. Major engineering measures to keep pace with increasing
risk.
Strategic regulation of development, management of runoff and reduction of
impacts. Strategic soft engineering of rivers and
coasts. Universal protection through public-
private schemes
Developing scenarios of future flood risk reduction policies
Summary of Expected Annual Damage from the baseline analysis of flood risk
Present dayWorld Markets 2080s
National Enterprise 2080s
Local Stewardship 2080s
Global Sustainability 2080s
Total flood risks (£ billions) 1.2 28.6 20.2 2.3 6.8
GDP (£ billions) 1,070 15,100 4,910 2,780 8,630
Growth in GDP relative to present day
1.0 14.1 4.6 2.6 8.1
EAD as a percentage of GDP 0.13% 0.19% 0.41% 0.08% 0.08%
Scenarios of engineering responses World markets National
enterpriseLocal stewardship
Global sustainability
Flood/coastal defences (embankments)
High standard hard defences to protect areas of high economic value
Reliance on hard defences to protect areas of high economic value
Retreat and abandonment. Defences to protect urban areas.
Towards soft defences. High tech monitoring and control of soft systems
Storage/detention (rural)
Major strategic storage systems and flood relief channels. High tech control.
Some storage schemes
Restoration of natural floodplain functions. Limited engineering control.
Major strategic storage systems and flood relief channels. High tech control.
River management
River management to maximise conveyance.
River management to maximise conveyance
Widespread restoration of natural river systems
Multi-use river management for conveyance and environment
Coastal management
Collapse of some schemes. New hard defences in high value areas. Measures to improve amenity, mainly privately-funded.
Piecemeal approaches to coastal management result in continued reduction in sediment supply to beaches.
Natural coastal processes reinstated.
Strategic coastal management, regionally and nationally coordinated Some improvement in sediment supply to beaches.
Managed retreat In areas of abandoned agricultural production
Parochial pressures limit opportunities for managed retreat
Regionally diverse. Some reinstatement of natural processes.
Strategic managed retreat in rural and some coastal areas
World markets
National enterprise
Local stewardship
Global sustainability
Managed retreat
In areas of abandoned agricultural production
Parochial pressures limit opportunities for managed retreat
Regionally diverse. Some reinstatement of natural processes.
Strategic managed retreat in rural and some coastal areas
World markets
National enterprise
Local stewardship
Global sustainability
Flood/coastal defences (embankments)
High standard hard defences to protect areas of high economic value
Reliance on hard defences to protect areas of high economic value
Retreat and abandonment. Defences to protect urban areas.
Towards soft defences. High tech monitoring and control of soft systems
Quantified analysis of theresponse portfolios
Realignment of Flood Defence Infrastructure + + ++
+++
Wales
Midlands
East Anglia
North-east
South-west
Thames
North-west
South-east
IFM as percentage of 10km x 10km grid cell<1%1 - 5%5 - 20%20 - 50%> 50% Drawing numberJob number
Date
Percentage of Indicative Flood Plainper 10km x 10km grid cell
Revision
Foresight - Future Flood Risks
June 2003 1.01
CDS 0438
0 50 10025Kilometres±
This map is reproduced from Ordnance Survey materialwith the permission of Ordnance Survey on behalf ofthe controller of Her Majesty's Stationary Office.(c) Crown Copyright. Unauthorised reproductioninfringes Crown Copyright and may lead to prosecutionor civil proceedings.Department of Trade and Industry. 100037208. 2003.
IFM as percentage of 10km x 10km grid cell<1%1 - 5%5 - 20%20 - 50%> 50% Drawing numberJob number
Date
Percentage of Indicative Flood Plainper 10km x 10km grid cell
Revision
Foresight - Future Flood Risks
June 2003 1.01
CDS 0438
0 50 10025Kilometres±
This map is reproduced from Ordnance Survey materialwith the permission of Ordnance Survey on behalf ofthe controller of Her Majesty's Stationary Office.(c) Crown Copyright. Unauthorised reproductioninfringes Crown Copyright and may lead to prosecutionor civil proceedings.Department of Trade and Industry. 100037208. 2003.
Distribution of the Indicative Flood Plain (2002)
Wales
Midlands
East Anglia
North-east
South-west
Thames
North-west
South-east
Dominant valley classcoastallowland (intermediate / shallow valley slopes)upland (steep valley slopesno defences
Drawing numberJob number
Date
Dominant Valley Class
Revision
Foresight - Future Flood Risks
June 2003 1.01
CDS 0438
0 40 8020Kilometres ±
This map is reproduced from Ordnance Survey materialwith the permission of Ordnance Survey on behalf ofthe controller of Her Majesty's Stationary Office.(c) Crown Copyright. Unauthorised reproductioninfringes Crown Copyright and may lead to prosecutionor civil proceedings.Department of Trade and Industry. 100037208. 2003.
Dominant valley classcoastallowland (intermediate / shallow valley slopes)upland (steep valley slopesno defences
Drawing numberJob number
Date
Dominant Valley Class
Revision
Foresight - Future Flood Risks
June 2003 1.01
CDS 0438
0 40 8020Kilometres ±
This map is reproduced from Ordnance Survey materialwith the permission of Ordnance Survey on behalf ofthe controller of Her Majesty's Stationary Office.(c) Crown Copyright. Unauthorised reproductioninfringes Crown Copyright and may lead to prosecutionor civil proceedings.Department of Trade and Industry. 100037208. 2003.
Dominant Valley Class (2002)
Results of quantified risk analysis
• Results are presented using six risk metrics
– Number of people living within the floodplain.
– Annual probability of flooding.
– Number of people at high risk of flooding.
– Expected Annual Damage (residential and commercial properties).
– Expected Annual Damage (agricultural).
– Social flood vulnerability.
No. of people within Indicative Flood Plain
Probability of inundation - 2080s
Emphasis on “defence” and reducing flood probability
Emphasis on “managing” probability and impacts
Probability of inundation - 2080s
No. of people living with a high probability of being flooded - 2080s
Expected Annual Damage (Property) - 2080s
2002
2080sWorld Markets
2080sGlobal Sustainability
2080sLocal Stewardship
2080sNational Enterprise
Present day (2002)
2080s Foresight Scenarios
Key
Change from present day (2002)Negligible (-£1k to £1k)Low increase (£1k to £100k)Medium increase (£100k to £10,000k)High increase (>£10,000k)Decrease (<-£1k)Outside IFP
N
Feb 2004
0 100 200 km
Expected Annual Economic DamageNegligible (< £25k)Low (£25k to 250k)Medium (£250k to £2,500k)High (>£2,500k)Outside IFP
Comparative Risk - Expected Annual Economic Damage(residential & commercial property)
Expected Annual Damage (Property) - 2080s
Analysis of implementation costs
Aim:• To provide an indication of the
relative costs of implementation under each scenario
Example - under GS scenario:• Using engineering only: Cost £52
billion• Using engineering and non-
engineering: Cost £22 billion
Results of investment cost analysis
Note:
– Only the costs of engineering measures have been estimated (excluding non-structural interventions)
– Exclude land purchase, compensation or significant environmental mitigation
– Typical costs based on the Environment Agency national cost database
Sensitivity analysis - High growth / low emissions scenario
Conclusions
• These are not the only flood risk management portfolios that would be consistent with the four future scenarios
• Major flood risk reduction is achievable under all scenarios
• Non-structural measures can make a major contribution to reducing the need for (and hence costs and impacts of) engineered flood defences.
• Achieving a low emissions future could reduce flood risk by 25% assuming a high growth economy is maintained - a significant contribution to reducing flood risk but not a panacea.
Big messages
• Continuing with existing messages is not an option
• Should we accept increasing risk, seek to maintain present risk, seek to reduce the risk?
• Risks need to be tackled across a broad front:
– Sustainable responses, particularly increased investment in defences, catchment-wide storage, land use planning and realigning coastal defences
– Reduce global emissions
– Need to develop science, skills and governance issues
• Action Plan published and the baton passed to Defra, EA and others.
Finally...
• The project combined a new paradigm for combining cutting-edge science and futures analysis to inform policy.
• Information at www.foresight.gov.uk
• Reports available from DTI Publications:
– Executive Summary
– Action Plan
– Volume 1 and 2 technical reports