Delta Alliance - Comparative assessment of the vulnerability and resilience of 10 deltas Tom Bucx (Deltares) 8 June 2011 EEA Expert meeting Methods and tools for assessing coastal vulnerability to climate change

Comparative assessment of the vulnerability and resilience 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

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

DPSIR + Spatial layers approach

Framework for assessment Impacts | Responses

Towards indicators of change Delta descriptions

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

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

 Presure on space – population density ~500 inhabitants/km 2 ; 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 Delta description – qualitative and quantitative info Example: pressures on occupation layer in Rhine-Meuse delta:

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

Scorecard and related indicators

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

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

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

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

Website - downloads   Background information  Documents to download: Synthesis report Working document (with full delta descriptions)

Thank you Questions?

Project team