ESPACE: Decision Testing Framework Thames Pilot Study

1. ESPACE: Decision Testing Framework Thames Pilot Study Tim Reeder & Bill Donovan, Environment Agency Jon Wicks, Halcrow

2. Structure of talk • Challenges of flood risk management in the Thames Estuary • UKCIP decision making framework • Application of the framework to the Thames Estuary

3. The Thames Estuary • 1.25 million people £80bn property at risk • Ageing defence infrastructure • Increased development pressure • 160,000 new homes – most in protected floodplain • Impacts of climate change include • Southend max level (say +1m 2050, +2m 2100) • Fluvial flows, +20%? to 2050

4. ??? 2100 defences The same building in 2002: the defences, raised following the 1953 flood and raised further in the 1980s are now level with the roof eaves 200 years of Rising Sea Levels at Canvey Island The Lobster Smack in 1902: the defences were described at the time as being “practically invulnerable”

5. The future view for London?

6. Interim Defences during the construction of the Thames Barrier > 1928 Flood & subsequent 1930 Flood Act> Late C19 update to Flood Act > 1879 Flood Act>

7. Thames Estuary 2100 Project • Aim: • Develop a flood risk management plan for London and the Thames Estuary for next 100 years • Addressing: • Management of estuary from a risk perspective and a ‘whole society’ approach

8. FORESIGHT FUTURES • World Markets • National Enterprise • Global Sustainability • Local Stewardship • 1.25million people - 400 Schools, 16 Hospitals • £80bn Property - 30 Mainline Railway Stns • International Habitats & Species - 68 Underground & DLR Stns • Port of London generates £2.7bn/yr. - 8 Power Stations 337kms of Defences Thames Barrier Possible Responses • At Risk • Control structures/walls • Adapting behaviour & expectation • The Current Defences • Climate change will increase the risk • Flood water storage • Flood event management • Future Scenarios

9. Thames Estuary 2100 Project • To achieve the project objectives we have based our programme of studies around the UKCIP Decision-Making Framework…

10. Helps deliver policies and projects that are robust in the face of an uncertain future climate www.ukcip.org.uk

11. Eight-stage decision-making framework

12. The decision-making framework: • Directs you to undertake rapid risk characterisation and screening exercises before deciding to spend more time/money on more detailed risk assessment • Helps you refine the problem and objectives and modify your options before making a decision • Guides you to review a decision

13. Application to Thames Estuary • Currently in steps 2 to 5

14. 2 Establish decision-making criteria 3 Assess risk 5 Appraise options 4 Identify options Steps 2 to 5 iteration • Expect 3 iterations: • High level economic appraisal (strategic options) • Early conceptual options • High level options • Leading to Thames Estuary Flood Risk Management Plan • Further work to implementation.

15. 2 Establish decision-making criteria 3 Assess risk 5 Appraise options 4 Identify options Steps 2 to 5 iteration • Detail increases with each iteration, as: • Better data become available • Decision-making criteria become better established • Increased stakeholder involvement • But basic decision-making framework (and many underlying tools) remain the same.

16. High level economic appraisal Define appropriate cost benefit calculation framework Define appropriate risk analysis framework MDSF analysis: test strategic options under climate change scenarios (2000, 2050, 2100) => AAD Broadscale ISIS-TUFLOW simulation to generate flood depth grids MDSF Economic direct flood damages analysis MDSF Social impact analysis Repeat for each scenario Export MDSF results Estimate costs of interventions Consequential losses Short social / environmental analysis Short uncertainty analysis Estimate of flood fatalities Analysis and reporting

18. MDSF - System Overview MDSF Customised GIS & Database Databases Data: General Features: · Background maps · Import & store data · Existing flood maps · Case/scenario management · DEM · Metadata · Property data · Generate views · Land use · Environmental · Coastline Case Definition: · Etc · Climate · Land use Local Data: · Policy · Loc al reports · External ‘ t ools ’ Etc to provide : Flood Mapping: · Import water levels (1) flood · Generate (or import) flood depths depth grids ( optionally extents ) Coastal Erosion : (2) erosion · Import erosion contours contours Outputs (electronic plan s ? ) Economic Analysis: · Flood damages · Erosion damages Social Impacts: · People affected · Social flood vulnerability Repeat for all ‘cases ’ Further analysis, iteration, consultation and review Policy Evaluation: leading to: · Compare baseline with scenarios CFMP / SMP Uncertainty Estimation: Strategy Plan · Acknowledge and estimate uncertainty

19. ISIS-TUFLOW broad scale flood model

20. Could show 10m tuflow – greenwich? • Shows use of same tools at greater detail

21. Findings • 4 strategic options tested: • 1 - Do nothing (walk away & leave barriers open) • 2 - Maintenance only – declining standards • 3 - Do ‘something’ A giving 1:1000 protection • 4 - Do ‘something’ B giving 1:5000 protection • Analysis shows high benefit/cost ratios for 2, 3 & 4 • But not sufficient ‘detail’ to: • Select best strategic option • Understand benefits of spatially varying standard • And no information on actual interventions

22. Currently working on further iterations • High level economic appraisal (strategic options)  • Early conceptual options • High level options

23. Stakeholder engagement • Send results to FloodRanger • More text here

24. FloodRanger & FloodRanger Pro

27. Conclusions – to be written • UKCIP - Good framework –generic • Need tools to assess risk • MDSF – • FloodRanger - • Range of details, both spatial and data • But can use same basic framework and tools • Plug for uncertainty analysis to drive where to go into more detail

28. Thank you