Gehad Ujeyl - "Flood Resilience Strategies Behind the Dikes"

7/29/2019 Gehad Ujeyl - "Flood Resilience Strategies Behind the Dikes"

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FLOOD RESILIENCE STRATEGIES BEHIND THE DIKES

Erik Pasche, Gehad Ujeyl, Jrg Knieling, Mareike Schaerffer


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Flood resilience strategies behind the dikes

Motivation

Consequence of climate change: frequency and intensity of storm eventsand sea level will rise in coastal zones

Increasing risk of flooding for societies living in these areas

Cities along shorelines are in general areas of economic growth which will

further increase their vulnerability for flood events

These factors of steadily increasing flood risk urge for new strategies in

flood risk management


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Introduction Present Practice in Flood Management

North Sea

Hamburg

Hamburg

Frankfurt

Berlin

Cologne


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Flood risk due to storm surges in the city of Hamburg

The urban areas which are protected by flood defence structures

host more than 180.000 citizens

and more than 140.000 jobs.

The overall damage totals more than 10 bill.


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Present Practice in Flood Management

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Structural measures currently

under construction

Status Quo: February 2007

already realised

under construction

planning in progress

Polder areas

before planning phase

Wilhelmsburg


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Development Concept Leap over the Elbe

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Metropolis Hamburg Growing City

Urban development focuses on theElbe island Wilhelmsburg

Ongoing investments until 2013

International Construction

Exhibition


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Vulnerability


Why should we develop alternative strategies, when a ringdike

already exists?

Urban development

Construction activity /

Population growth

Accumulation of assets

Climate change

Dike-raising:- extension, heights?

-required space

-costs

Risk of failure

Higher extreme water levels


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Consequence of missing flood defense strategy behind the dikes


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Consequence of missing flood defense strategy behind the dikes


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Cascading Flood Compartments - CFC-strategy


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Impact of Climate Change

Grossmann, I., Woth, K., von Storch, H. (2006): Localization of

global climate change: Storm surge scenarios for Hamburg in

2030 and 2085, Die Kste, 71, 169-182


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Climate change scenarios, dike overtopping

4,3 mio m 15,1 mio m

2030 2085


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Resilience strategy of Cascading Flood Compartments (CFC)

4,3 mio m 15,1 mio m

2030 2085


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Adaptations of the existing built environment


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Classification of the building environment


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Efficiency analysis for residential buildings


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Societal Acceptance of Flood resilience strategies

Does the local populationappreciate water-oriented building

and living?

How pronounced is the willingness

to accept constraints in

construction and use?


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Risk perception on Hamburg`s Elbe Island

72,6 % agree, that the danger of

extreme storms increases because of

the climate change


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Risk Perception on Hamburg`s Elbe Island

Half of the interviewed resistents

regard their quarter to be at risk


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Risk Perception on Hamburg`s Elbe Island

Half of the interviewees believe that it is

probable they might be affected

personally by storm surge


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Acceptance of Flood Resilience Strategies

Willingness to adapt is low

Population would keep staying on the island


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Acceptance of flood resilience strategies

limits concerning the implementation ofalternative settlement concepts

constructional flooding defence measures

may consider the needs of the population to

a greater extent

to enhance the acceptance of water-

related buildings participatory planning is

relevant


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Conclusion

Resilience strategy of cascading floodcompartments (CFC) needs active

support of the resisdents and

communication processes

An implemenation of CFC reduces the

vulnerability for flooding behind the

dikes significantly

Nevertheless the need for integrativeresilience strategies behind the dike is

very high


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Thank you for your attention!

Hamburg University of Technology

Institute for River and Coastal Engineering

Gehad Ujeyl

[email protected]

Date post:	04-Apr-2018
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Gehad Ujeyl - "Flood Resilience Strategies Behind the Dikes"

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