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 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 Lobster Smack in 1902: the defences were described at the time as being “practically invulnerable” ??? 2100 defences

The future view for London?

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

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

At Risk The Current Defences 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 Thames Barrier Climate change will increase the risk Future Scenarios Control structures/walls Flood water storage 337kms of Defences Adapting behaviour & expectation Flood event management FORESIGHT FUTURES World Markets National Enterprise Global Sustainability Local Stewardship Possible Responses

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

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

2 Establish decision- making criteria 3 Assess risk 4 Identify options 5 Appraise 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 decision- making criteria 3 Assess risk 4 Identify options 5 Appraise 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. Steps 2 to 5 iteration

Define appropriate risk analysis framework Define appropriate cost benefit calculation framework Estimate costs of interventions Consequential losses Short uncertainty analysis 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 of flood fatalities Analysis and reporting Short social / environmental analysis High level economic appraisal

Databases MDSF Customised GIS & Database Data:  Background maps  Existing flood maps  DEM  Property data  Land use  Environmental  Coastline  Etc Local Data:  Local reports  Etc Outputs (electronicplans?) General Features:  Import & store data  Case/scenario management  Metadata  Generate views Coastal Erosion:  Import erosion contours Flood Mapping:  Import water levels  Generate (or import)flood depth grids Economic Analysis:  Flood damages  Erosion damages Social Impacts:  People affected  Social flood vulnerability Policy Evaluation:  Compare baseline with scenarios Uncertainty Estimation:  Acknowledgeand estimate uncertainty Case Definition:  Climate  Land use  Policy Further analysis, iteration, consultation and review leading to: CFMP / SMP Strategy Plan MDSF- System Overview External‘tools’ to provide: (1) flood depths (optionally extents) (2) erosion contours 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

Spare slides…..

Decision Testing Framework Agency’s day to day decisions informed with Increasing Confidence Socio – Economic Scenarios Intervention Models & Tools Conceptual Model + Support Tools Environment Framework Engineering / Asset Studies Estuary Processes Refinement Conceptual High Level Options G High Level Options G Strategy Envelope G Social Framework Climate Change Scenarios S t a k e h o l d e r D i a l o g u e t h r o u g h o u t d e v e l o p m e n t o f P l a n Estuary FRM Plan G