Lessons from the Thames Estuary 2100 Project – T. Reeder and N. Ranger

1. Rowan Argent Lessons from the Thames Estuary 2100 Project – T. Reeder and N. Ranger

2. The River Thames

3. London 1.25 million people 400 Schools 16 Hospitals

4. London

5. London • World’s 2nd largest moveable flood defence • Built 1982 • Spans 520 meters • Protects 125 km² of central London

6. TE2100 • Established by the Environment Agency of the UK • Aim: “developing a strategic flood risk management plan for London and the Thames estuary through to the end of the century” • Key driver was climate change

7. Uncertainty “ The uncertainty over long-term mitigation policy creates challenges for adaptation planning” “particularly problematic for planning large-scale, long-lived and costly adaptation projects” “if forecasts are incorrect today, the project can become maladapted to climate”

8. Flexibility To counteract uncertainty, it is necessary to… • Incorporate flexibility By… • Accounting for a range of possible climates Or… • Using measures that can be adjusted Flexibility needs to outweigh Cost!

9. Aim of Report “outlines one approach to tackle this uncertainty that aims to ensure that adaptation decisions made today are resilient to a fast changing and uncertain climate” • This approach is the “route-map” approach, • Which is a context/policy first approach

10. Framework

11. Framework Comparison

12. Framework Benefits of context first: • Less resource and data intense • Less addition of uncertainty • Encourage thought on interactions with other risks and priorities

13. I. Structuring the Problem • Understand current vulnerability of the system. • Evaluating the current level of flood risk and the standards of protection around the Estuary • Map future sensitivities to climate change and other risks. • Modelling initially suggested a maximum increase in water level of 2.7m in 2100. An upper bound of 4.2m was used to represent a catastrophic sea level rise scenario. • Assess known (or estimated) key thresholds in between now and this upper-bound figure in terms of vulnerability to impacts. • Such as the limit of the present system of walls and embankments or the limit to adaptation, at 5m it would become difficult to continue to protect London in its current form, potentially requiring some retreat.

14. I. Structuring the Problem • Identify feasible adaptation response options (at high level) to cope with these thresholds. • Multiple options for the TE2100 • Check key interactions with other issues, such as development pressures, at macro level. • key potential trade-offs involved impacts on ecosystems and pressures from urban development plans. • Assemble high level route maps of response options that will tackle the thresholds. • no regrets measures such as emergency response which will work through the whole range of change.

15. Appraise Solutions • Compare costs, benefits and other relative criteria of each route under the most likely rate of change in extreme water level. • In TE2100 a multi criteria approach was taken to assess the cost and benefits of differing routes. • Recommend the preferred route under the most likely rate of change, along with key variables which should be monitored. • The final recommended plan for TE2100 recommends two options to be decided on by 2050.

16. Implementation • Implement and then monitor so you can bring things forward or put them back or change route • different rate of sea level rise could significantly delay or accelerate the program or high rates of erosion to the defences in the outer estuary could accelerate the need for upgraded defences.

17. Route Map • Avoids irreversible decisions and encourages more flexible approach • Designed as a number of “packages” • Each tested for different scenarios

18. Route Map

19. Decision Points • Times when decisions must be made • i.e Threshold point • Can be changed • Final decision can include more knowledge

20. Decision Points

21. Disadvantages • Additional costs • No-regrets first, buys time • Needs initial detailed knowledge e.g. Thresholds and long term records • Needs constant monitoring and review

22. Conclusions • Has potential to be used in both developed and developing countries • Can be shorter term as well as long term • Relatively quick to produce and reduces model dependence • As long as developed and monitored correctly has potential to be a very effective system

23. Key Points • Cost vs. Flexibility • Monitoring • Other Interactions • Good to see a case study

24. References • Reeder, Tim, and Nicola Ranger. "How do you adapt in an uncertain world?: lessons from the Thames Estuary 2100 project." (2011). • Environment Agency, (2012),TE2100 • http://www.bbc.co.uk/london/content/image_galleries/thames_barrier_gallery.shtml?12 • http://www.chiddingstone.kent.sch.uk/homework/riverthames/kids/index.html • http://cruises.about.com/od/seabournsojourn/ig/Seabourn-Sojourn-Outdoors/Seabourn-Sojourn-in-London.html • http://www.environment-agency.gov.uk/homeandleisure/floods/38353.aspx • http://famouswonders.com/house-of-parliament/ • http://www.globalculturetravel.com/daily-culture/london-underground • http://www.londonforidiots.com/Tower_of_London.html • http://en.wikipedia.org/wiki/File:Thames_Barrier_-_simple_operation_diagram.png