Comparative assessment of the vulnerability and resilience of 10 deltas

1. Delta Alliance - Comparative assessment of the vulnerability and resilience of 10 deltasTom Bucx (Deltares) tom.bucx@deltares.nl 8 June 2011 EEA Expert meeting Methods and tools for assessing coastal vulnerability to climate change

2. Comparative assessment of the vulnerability andresilience of 10 deltas • Provide a first step towards a comprehensive overview of the current and future state of deltas • Provide a ‘Delta assessment framework’: integrating scientific, social and management knowledge and addressing future data collection on key-indicators • Support decision-making process on adaptive strategies and measures towards resilient and sustainable deltas

3. Deltas studied Rhine-Meuse Danube Ganges- Brahmaputra- Meghna Yangtze California Bay-Delta Mississippi Nile Mekong Ciliwung Incomati

4. DPSIR + Spatial layers approach

5. Framework for assessment Impacts | Responses

6. Towards indicators of change Delta descriptions

7. Delta description - format • Drivers of change • Pressures / potential problems • Land and water use (occupation layer) • Infrastructure (network layer) • Natural resources (base layer) • Governance (institutional and organisation aspects) • Adaptive measures • Technical methods and tools • Needs for knowledge exchange and research gaps • Lessons learned Score card

8. Delta description – qualitative and quantitative info • Example: Drivers of change in Rhine-Meuse delta: • Climate change – higher peak river discharges (winter) • long drought periods (summer) • sea-level rise ≤ 0.65 to 1.3 m in 2100 • Subsidence – Tectonic subsidence ~10 cm/century • ≤10 mm/year surface-lowering due to peat • compaction and oxidation

9. Delta description – qualitative and quantitative info Example: pressures on occupation layer in Rhine-Meuse delta: • Presure on space – population density ~500 inhabitants/km2; high pressure on space • Vulnerability to flooding – high safety levels: 1/1250 (river dikes) to 1/10,000 years (coastal defense); sea-level rise and growing investments will increase flood risk • Freshwater shortage – rising sea levels will increase salt water seepage and will cause local freshwater shortages

10. Delta description – quantative main indicators Example: main indicators (draft) for Rhine-Meuse Delta:

11. Scorecard and related indicators

12. Scorecard – ‘weighting method’ Assessment of the current and future state of the delta

13. Comparative overview of delta score cards resilience/sustainability: ++ (very good), + (good), 0 (medium), - (low), -- (very low)

14. Comparative overview of delta score cards - Conclusions • For most of the deltas current resilience and sustainability is not satisfactory • Reasons differ per delta but some general mechanisms: • An imbalance between demands and supply with regard to land and water use; • An inadequate or ageing infrastructure in the delta; • Disruption of the natural delta processes; • Inadequate governance to address problems and implement solutions. • For a number of deltas the challenge is defining a comprehensive • (multi-sectoral) delta plan • The combined DPSIR-layer approach has proven to be useful

15. What’s next? • Develop set of key (quantitative) indicators • Optimize scoring and ranking method • Work out scenarios in more detail • Include more deltas (Rhone, Po, Thames, …) • Work out concrete collaborative research ideas/proposals across deltas

16. Website - downloads • www.delta-alliance.org • Background information • Documents to download: • Synthesis report • Working document (with full delta descriptions)

17. Thank you Questions?

18. Project team