Foresight Flood and Coastal Defence Project

1. 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

2. 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

3. 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 national-level policy making.

4. Methodology

5. The watershed and coastal flooding system

6. The urban flooding system

7. Foresight Futures 2020 + UKCIP2002 climate change scenarios Medium-low emissions Medium-high emissions High emissions and Low emissions Low emissions

8. Drivers Processes that change the state of the system Change in risk System state variables System analysis Sources rainfall sea level storm surges wave heights etc. Pathways urban surfaces fields, drains channels flood storage flood defences floodplains Receptors communities homes industries Infrastructure resources ecosystems Risk Probability x consequences (economic, risk to life, social, natural environment etc) Change in risk Responses Interventions that change the state of the system • .

9. Qualitative Analysis: Flood Risk Drivers

10. Drivers of Flooding and Coastal Erosion Risk “… phenomena that change the state of the flooding system…”

11. Baseline ranking of river and coastal drivers • Socio-economic drivers • Climate change • Coastal drivers • Environmental Regulation • Big scenario differences

12. Drivers of intra-urban flood risks • Plus…… • Stakeholder behaviour • Urban planning policy

13. Ranking of intra-urban scale drivers • Social impacts • Asset deterioration • Precipitation • Environmental management and regulation • Buildings and contents

14. Quantitative Analysis (Baseline Case)

15. Modeling: National quantitative risk analysis: Risk Assessment for Strategic Planning Data used: 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

16. Calculating Flood Risk

17. Dominant Floodplain Class (2002)

18. Flood Risk in 2050 and 2080 for ‘World Markets’

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

20. Future Coastal Erosion Risks

21. 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

22. Coastal Erosion – Annual Expected Damages Average annual coastal erosion damage estimates for the 2080s (£millions) derived from ‘Future Coast 2000’ Annual losses due to coastal erosion may increase by 3 to 9 times

23. Serious Impacts on Coastal Environments • 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 Some valuable coastal habitats appear threatened under all futures, especially coastal wetlands and marshes.

24. 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%.

25. ResponsesOptions for managing future flood and coastal erosion riskssustainably

26. Potential Responses 80 individual responses Organised into 25 response groups • And5response themes • Reducing urban runoff • Reducing rural runoff • Managing flood events • Managing flood losses • Engineering and large scale re-alignment or abandonment

27. Definition, Function and Efficacy Governance Sustainability Qualitative Analysis of Responses • Potential for implementation • under each • Foresight • future scenario

28. Responses with the most potential for risk reductions • Structural: Rethink Coastal & River Defences • Non-structural: Manage down flood & erosion consequences

29. 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

30. 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.