FEWS-RISK: A STEP TOWARDS RISK-

Transcription

1 FEWS-RISK: A STEP TOWARDS RISK- BASED FLOOD FORECASTING D. Bachmann D. Eilander, A. de Leeuw, K. de Bruijn, F. Diermanse, A. Weerts, J. Beckers, P. Gijsbers, M. Ponziani (Deltares, NL) L. Boelee, C. Hazlewood, E. Brown (HR Wallingford, UK) FEWS-User Days 2015, Deltares Delft

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3 h Common practice in operational flood forecast System river Forecasted process chain Meteorology (catchments) Water level time series Precipitation, temperature, wind etc. t Hydrology (catchment) Discharge Hydrodynamic (river) Water level

4 h How to make a decision based on water levels? System river How will my flood defence line perform? Water level time series t Crisis manager What will be the impacts of flooding?

5 h Extension by workflow 1 System river and flood defence line Forecasted process chain In advance p f = 100% Failure probability time series Meteorology (catchments) Hydrology (catchment) t Hydrodynamic (river) Water level Reliability transformation Fragility curve Failure analysis (flood defence line)

6 The concept of Fragility curves (FRC) Summary of the performance or failure probability of a structure depending to the load (e.g. water level [m])

7 Determination of Fragility curves (FRC) INPUT: Geometry, zonation, sub soil, soil parameter etc.

8 h Support for decision makers by workflow 1 System river and flood defence line Where is my weak section given the hydraulic load? p f = 100% t Failure probability time series Where and when inspection should increased or emergency measures should be taken? Crisis manager Where and when a breach is probable?

9 What happens if a breach occurs? System river, flood defense line, hinterland How fast, how much and where the water will flow? How relevant is the protection task of this section? Crisis manager When and which emergency measures should be triggered?

10 National Information system Floodmapping Predicted hazard: Waterdepth after dike failure for pre-calculated scenarios

11 What happens if a breach occurs? System river, flood defense line, hinterland How fast, how much and where the water will flow? How relevant is the protection task of this section? Crisis manager When and which emergency measures should be triggered?

12 Extension by workflow 2 System river, flood defence line, protected area Forecasted process chain Hydrology (catchment) Hydrodynamic (river) Water level Police Breaching (flood defence line) Hospitall School Flood spreading, hydraulic values Discharge Hydrodynamic (protected area) Transformer Impacts to people, critical infrastructure etc. Impacts (protected area)

13 Support for decision makers by workflow 2 System river, flood defence line, protected area How fast, how much and where the water will flow? Police How relevant is the protection task of this section? Hospitall Transformer School Flood spreading, hydraulic values Impacts to people, critical infrastructure etc. Crisis manager When and which emergency measures should be triggered?

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15 The Rotterdam area and dike rings Delft Western part of the Netherlands at the delta of Rhine and Maas rivers to the North Sea Highly populated area (ca. 1.3 million people) High flood protection standards

16 Reliability analysis 15 dike sections (14 in Ijsselmonde and 1 in Pernis) Pre-calculated fragility curves available

17 Examples fragility curves Available fragility curves: km14_1, km47, Pernis Manipulated fragility curves: km14_1, km47 (demonstration purpose); 50 % weaker as determined

18 Hydrodynamic model: Discretization Tool: Subgrid software (part of 3di-package) 500 km² model domain with ca quad tree elements (computational elements) Quad tree resolution: 100x100 m (min)/400x400 m (max) Subgrid resolution: 25x25 m (Lidar-data)

19 Hydrodynamic model: Boundary condition 3 Dirichelet-boundary (water level time series 50 h model-time) Assumptions (demonstration purpose): Based on flood event November 2007 (could be also forecasted data); Maeslant-Barrier is not closing 25% increase of water levels

20 Impact analysis Qualitative impact analysis Focus on persons (CBS-data) and critical infrastructure (OSM-data)

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22 Customization workflow 1

23 Hydrodynamic analysis without breaching Computational time: ca. 45 min (Intel Core i5-3230m CPU 2.60 GHz)

24 Reliability transformation Water level time series at dike sections Failure probability time series with thresholds

25 Spatial distribution of dike performance

26 Support for decision makers by workflow 1 Where is my weak section given the hydraulic load? Where and when inspection should increased or emergency measures should be taken? Where and when a breach is probable?

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28 Customization workflow 2

29 Breach development Water level time series at dike sections Starting breach development by defined failure probability (here 50 %)

30 Flood spreading breach km14_1 and km47

31 Qualitative Impact analysis: What happens when?

32 Qualitative Impact analysis and evacuation

33 Support for decision makers by workflow 2 How fast, how much and where the water will flow? How relevant is the protection task of this section? Crisis manager When and which emergency measures should be triggered?

34 Summary Extend current operational flood forecast systems with approaches of strategic flood risk analysis Probability of failure Impact analysis Provide transformed and compact model-base forecasted information to support decision makers Weak spots in the flood defense line (Workflow 1) Impacts of flooding (Workflow 2) Supports the development and adaptation of emergency measures in real-time

35 Outlook: Ongoing projects Deltares ID-Lab project: Coupling of global forecasting models as boundary conditions to local models Deltares ID-Lab project: Combining real-time sensor data from a dike (DAM-Live) with fragility curves TO2 project Crisis management (program Safe Society): Integration of ensemble forecast and quantitative impact analysis

36 Outlook: Coupling to global models Global forecasts Forecasted process chain Global Forecast storm surge / discharge Police Hydrodynamic (river/coastal &overland) Hospitall School Flood spreading, hydraulic values local water levels Inundated area Transformer Impacts to people, critical infrastructure etc. Impacts Local impact forecast

37 Outlook: Combining with sensor data Precalculated fragility curve Real time dike data, e.g. seepage line

38 Outlook: Including ensemble forecast Ensemble forecast for water level- time series Precalculated fragility curve Ensemble forecast for breach widthtime series Ensemble forecast for failure probability- time series

39 Outlook: Including quantitative impact analysis Ensemble forecast for flooding

40 More information at the next FEWS-user days 2016!

41 FEWS-RISK: A STEP TOWARDS RISK- BASED FLOOD FORECASTING D. Bachmann D. Eilander, A. de Leeuw, K. de Bruijn, F. Diermanse, A. Weerts, J. Beckers, P. Gijsbers (Deltares, NL) L. Boelee, C. Hazlewood, E. Brown (HR Wallingford, UK) FEWS-User Days 2015, Deltares Delft