A European flood risk model and its

use for analyzing climate change

adaptation strategies

Andreas Burzel, Friederike Holz, Hessel Winsemius,

Karin de Bruijn and Laurens Bouwer

IAHR World Congress, The Hague

Why do we need a European Flood Risk Model?

• Evaluation of current flood risk at a European level

• EU28 + 11 EEA member states

• Impact of new climate change scenarios (RCPs), and new

socioeconomic scenarios (SSPs)

• Estimating costs and benefits of adaptation measures, including

links to local scale adaptation

• structural flood protection measures (dikes, adapted buildings)

• Part of the FP7 BASE project (“Bottom-Up Climate Adaptation

Strategies Towards a Sustainable Europe”)

• Application of the new Flood Impact Assessment Tool

(Delft-FIAT)

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Methodology: Hazard modeling

Inundation depth

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Flood hazard modelling

Flood hazard

Hydrology: PCRGLOBWB DynRout

Inundation: GLOFRIS (1x1 km)

Flood extents for RP 1, ... 1000 yrs

RCP4.5 and 8.5 climate projections

Definition of flood risk in this study:

Flood risk = f (hazard, exposure, vulnerability)

Methodology: Exposure assessment

Flood hazard modelling

Provided by BASE project

(PCR-GLOBWB)

Potential maximum monetary damage

Exposed assets

CORINE land cover 2006

(product of EEA, 44 land use

classes, covering most of EU)

5 most relevant impact categories:

Residential, commercial, industrial,

infrastructure, agriculture

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Exposure assessment

Methodology: Exposure assessment

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CLC classes (shapefiles)

(http://sia.eionet.europa.eu)

Grid files showing

%-share per grid

cell for each of the

5 impact

categories

5

Overlay of the 5 impact categories

Methodology: Vulnerability assessment

Exposure assessment

Vulnerability assessment

Potential maximum monetary damage

Using EU-average

relative depth-damage

functions (Huizinga, 2007)

Exposed assets

CORINE land cover 2006

(product of EEA, 44 land use

classes, covering most of EU)

5 most relevant impact categories:

Residential, commercial, industrial,

infrastructure, agriculture

Maximum damage values

Maximum damage values per

impact category (Euro/sqm) from

Huizinga, 2007

Scaled by GDP per capita to

regional level

Residential 824

Commercial 682

Industrial 587

Infrastructure 26

Agriculture 0.85

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Flood hazard modelling

Provided by BASE project

(PCR-GLOBWB)

Methodology: Flood risk assessment

Exposure assessment

Vulnerability assessment

Potential maximum monetary damage

Using EU-average

relative depth-damage

functions (Huizinga, 2007)

Exposed assets

CORINE land cover 2006

(product of EEA, 44 land use

classes, covering most of EU)

5 most relevant impact categories:

Residential, commercial, industrial,

infrastructure, agriculture

Maximum damage values

Maximum damage values per

impact category (Euro/sqm) from

Huizinga, 2007

Scaled by GDP per capita to

regional level

Residential 824

Commercial 682

Industrial 587

Infrastructure 26

Agriculture 0.85

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Flood hazard modelling

Provided by BASE project

(PCR-GLOBWB)

Flood risk

Risk expressed as

expected annual damage (EAD)

Damage-probability curve

Damage calculated for

9 return periods

Building a damage-probability

curve to obtain flood risk

Flood protection standards

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Source: Messner et al. 2007

Source: Modification of figure by Jongman et al., 2014

Damage-probability curve

8

Kilometers

Results – Change of flood risk – climate change

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Climate change scenario RCP 4.5

(Mean of 5 climate models, NUTS2

level, 2010-2049)

Climate change scenario RCP 8.5

(Mean of 5 climate models, NUTS2

level, 2010-2049)

Flood Risk as %-change to baseline

-50

-50 - -25

-25 - -5

-5 - 0

0 - 5

5 - 10

10 - 25

25 - 50

> 50

Neighbouringcountries

Results – Change of flood risk – GDP growth

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GDP growth scenario SSP2

(NUTS0 level, 2010-2049)

GDP growth scenario SSP5

(NUTS0 level, 2010-2049)

Flood risk as %-change to

0

0 - 25

25 - 50

50 - 75

75 - 100

100 - 125

> 125

Neighbouringcountries

Results – Flood risk as % of GDP

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NUTS 0 NUTS 2

Flood risk as % ofGDP

0 - 0.05

0.05 - 0.1

0.1 - 0.25

> 0.25

Neighbouringcountries

Adaptation strategies

• Flood prevention:

• Improve protection level to at least 1/100 years

• Adapted building:

• Flood proofing to 1,5 metres (upper end estimate) for areas

with flood RP 10-50 yrs (residential, commercial, industrial)

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Damage functions adapted from Huizinga (2007)

EU: 127 billion Euros (2011) per year

Uniform protection standards 1/1 Flood Risk (expected annual damage)

Baseline scenario (1960-1999)

Results – Different protection standards

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EU: 15.6 billion Euros (2011) per year EAD [million Euro per year]

0 - 5

5 - 10

10 - 25

25 - 50

50 - 100

100 - 150

> 150

Neighbouringcountries

Regional protection standards

basin level, minimum 1/10 Flood Risk (expected annual damage)

Baseline scenario (1960-1999)

EU: 8.3 billion Euros (2011) per year

Minimum protection standards 1/100 Flood Risk (expected annual damage)

Baseline scenario (1960-1999)

Areas relevant for adapted building

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Current risk without adaptation

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Current risk with adaptation

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Effect of adaptation measures

• Risk prevention to RP 1/100:

• Expected annual damages baseline: 15.6 bn

• Expected annual damages adjusted prevention: 8.3 bn

(reduction of 47%)

• Risk reduction dry-proof:

• Expected annual damages baseline: 15.6 bn

• Expected annual damages adapted buildings: 9.8 bn

(reduction of 37%)

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Conclusions

• Impacts from socioeconomic change larger than climate change

(time slice (2010-2049))

• Substantial effects (benefits) from adaptation measures

• Improving prevention

• Adapted building

• Next steps:

• Establish a do-nothing scenario

• Run adaptation measures for future time slices

• Assess costs of adaptation measures

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References

BASE (2015). Research project website, see www.base-adaptation.eu

Delft-FIAT Wiki (2015): https://publicwiki.deltares.nl/display/DFIAT/Delft-FIAT+Home

Holz, F. (2014). “A European-scale approach to flood risk assessment. A land use based appraisal

of present and future flood risk as support for climate change adaptation and disaster risk

reduction” Masterthesis, Deltares / Christian-Albrechts-Universität zu Kiel, Delft and Kiel.

Huizinga, H. J. (2007). “Flood damage functions for EU member states.” Technical report. Technical

report, HKV Consultants. Implemented in the framework of the contract 382441-F1SC awarded

by the European Commission-Joint Research Centre.

Jongman, B., Hochrainer-Stigler, S., Feyen, L., Aerts, J. C. J. H., Mechler, R., Botzen, W. J. W.,

Bouwer, L. M., Pflug, G., Rojas, R., and Ward, P. J. (2014). “Increasing stress on disaster-risk

finance due to large floods.” Nature Climate Change, advance online publication.

Messner, F., Penning-Rowsell, E., Green, C., Meyer, V., Tunstall, S., and Van der Veen, A.

(2007). “Evaluating flood damages: Guidance and recommendations on principles and

methods.” Report Number: T09-06-01, Revision Number: 2_2_P44.

Winsemius, H. C., Van Beek, L. P. H., Jongman, B., Ward, P. J., and Bouwman, A. (2013). “A

framework for global river flood risk assessments.” Natural Hazards and Earth System

Sciences, 17(5), 1871–1892 HESS.

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