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ESPACE: Decision Testing Framework Thames Pilot Study Tim Reeder & Bill Donovan, Environment Agency Jon Wicks, Halcrow Structure of talk • • • Challenges of flood risk management in the Thames Estuary UKCIP decision making framework Application of the framework to the Thames Estuary 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 • • 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” 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 The future view for London? Interim Defences during the construction of the Thames Barrier > 1928 Flood & subsequent 1930 Flood Act > Late C19 update to Flood Act > 1879 Flood Act > 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 FORESIGHT FUTURES • World Markets • 1.25million people • £80bn Property • International Habitats & Species • Port of London generates £2.7bn/yr. • National Enterprise - 400 Schools, 16 Hospitals - 30 Mainline Railway Stns - 68 Underground & DLR Stns - 8 Power Stations • Global Sustainability • Local Stewardship 337kms of Defences Thames Barrier • At Risk Possible Responses • The Current Defences • Control structures/walls • Adapting behaviour & expectation • Climate change will increase the risk • Flood water storage • Future Scenarios • Flood event management Thames Estuary 2100 Project • To achieve the project objectives we have based our programme of studies around the UKCIP Decision-Making Framework… • www.ukcip.org.uk Helps deliver policies and projects that are robust in the face of an uncertain future climate Eight-stage decision-making framework 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 Application to Thames Estuary • Currently in steps 2 to 5 Steps 2 to 5 iteration • 2 Establish decisionmaking criteria 3 Assess risk • 5 Appraise options 4 Identify options • 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. Steps 2 to 5 iteration • 2 Establish decisionmaking criteria 3 Assess risk 5 Appraise options 4 Identify options • 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. 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 MDSF Economic direct flood damages analysis Broadscale ISISTUFLOW simulation to generate flood depth grids MDSF Social impact analysis Repeat for each scenario Export MDSF results Estimate costs of interventions Consequential losses Short social / environmental analysis Analysis and reporting Short uncertainty analysis Estimate of flood fatalities MDSF - System Overview MDSF Customised GIS & Database Databases Data: Background maps Existing flood maps DEM Property data Land use Environmental Coastline Etc Local Data: Local reports Etc General Features: Import & store data Case/scenario management Metadata Generate views Case Definition: Climate Land use Policy Flood Mapping: Import water levels Generate (or import) flood depth grids Coastal Erosion: Import erosion contours External ‘tools’ to provide: (1) flood depths (optionally extents) (2) erosion contours Outputs (electronic plan s?) Economic Analysis: Flood damages Erosion damages Social Impacts: People affected Social flood vulnerability Further analysis, iteration, consultation and review leading to: Policy Evaluation: Compare baseline with scenarios CFMP / SMP Strategy Plan Uncertainty Estimation: Acknowledge and estimate uncertainty Repeat for all ‘cases’ ISIS-TUFLOW broad scale flood model • • Could show 10m tuflow – greenwich? Shows use of same tools at greater detail 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 • • • Currently working on further iterations • High level economic appraisal (strategic options) • Early conceptual options • High level options Stakeholder engagement • Send results to FloodRanger • More text here FloodRanger & FloodRanger Pro 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 Thank you