Foresight Flood and Coastal Defence Project Government Office

Foresight Flood and Coastal Defence Project Government Office for Science Department for Innovation, Universities and Skills Overview by: Colin Thorne University of Nottingham colin. thorne@nottingham. ac. uk on behalf of the Foresight Team

Overview • Project aims • Methodology • River, Coastal and Intra-urban Drivers • Predicting Future Risks (baseline case) • Responses: Structural and nonstructural measures • Costs and Affordability of Responses • Final Messages and Further Information

June 2007

July 2007

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 flooding system

Foresight Futures 2020

Foresight Futures 2020 + UKCIP 2002 climate change scenarios Medium-high emissions High emissions and Low emissions Medium-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

Flood Risk Drivers: Deep Description and Qualitative Analysis

Future Flood Risks: Drivers of River and Coastal Flooding

Drivers of Flood and Coastal Erosion Risk “… any phenomenon that changes the state of the flooding system…”

Baseline ranking of river and coastal drivers • Socio-economic drivers • Coastal drivers • Precipitation • Big scenario differences

Major uncertainties: • Sea level rise • Coastal morphology • Surges • Precipitation • Stakeholder behaviour • Public Attitudes+Expectations

Future Flood Risks – Drivers of intraurban flooding • The catchment and coastal risk analysis treated urban areas as receptor units containing people, property and infrastructure. • Another set of sources and flood pathways at local scales operates within urban areas due to extremely intense rainfall and/or congested drainage (sewer) flooding - termed ‘intra-urban flooding’.

Drivers in urban areas Plus: • Stakeholder behaviour • Urban planning policy

Ranking of intra-urban scale drivers • Social impacts • Asset deterioration • Intense Precipitation • Environmental management and regulation

Quantitative Analysis of Future Flood and Coastal Erosion Risks (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 future flood risk

Dominant Floodplain Class (2002)

Flood Risk Predictions for 2050 and 2080

Expected annual damages: £ millions (currently ~ £ 1 billion)

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 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 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 responses

Deep Response Descriptions • • • Definition, Function and Efficacy Governance Sustainability • • • Costs Interactions Case example Emerging issues Uncertainty • Potential for implementation under each of the four Foresight future scenarios

Responses with the most potential for risk reductions • Structural: Important, but need to rethink Coastal Defences • Non-structural: We can manage down flood & erosion losses

How much will it cost – are responses affordable? • The cost of implementing engineering- based structural approach alone to achieve the indicative standard of defence in the 2080 s is ~ £ 52 billion • The cost of using structural defences as part of an integrated portfolio of structural and non-structural responses is ~ £ 22 billion

Delivering the message • • First level – Briefing notes for elected officials Second level – Technical reports, papers and book Third level – Working documents and project record Fourth level – Video game for practitioners and students

Flood Ranger Video Game

Final 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 Flood Risk Management. • But we must act now in developing new policies to allow non-structural measures to be effective in time.

Closing Statement Have confidence: UK Foresight proves it is possible to develop a long-term vision for IFRM. Politicians will listen and act provided that your messages are clear and are properly supported by the best science and engineering analyses available.

Further Information Flood Foresight: www. foresight. gov. uk • Follow links for flood and coastal defence UK Research Consortium on Flood Risk Management: www. floodrisk. org. uk

Over to the Break-out Groups! Colin Thorne University of Nottingham colin. thorne@nottingham. ac. uk