Integrated design of flood defence systems

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Integrated design of

flood defence systems

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About the presenter:

Name: Mark Voorendt

Employer: TU Delft, Department of Hydraulic Engineering Function: Researcher and Lecturer Hydraulic Structures Contact details:

office: CiTG 3.76

tel.: 015 - 27 83340

E-mail: M.Z.Voorendt@tudelft.nl

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Integrated design

of flood defence systems

C O N T E N T S

• Integrated design method of Roozenbrug & Eekels • Flood risk control

- flood protection - spatial planning

- disaster management - insurance

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Integrated design

of flood defence systems

C O N T E N T S

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Why integrated design?

Different (design) cultures: ideology ↔_technocracy

design ↔_engineering

fascination ↔_{functions, requirements}

'Architects design things that look beautiful (or at least interesting), but do not work.'

'Engineers design things that work, but look awkward.'

By cooperating, things could be

designed that are both beautiful and useful.

Moreover:

professionals ↔_stakeholders

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Integrated design

of building projects, urban development, civil engineering works, ...

Integrated design method of Roozenburg and Eekels (1995, 2010), two professors at Industrial Design Faculty of Delft University of

Technology:

Start with problem description (= discrepancy between present and desired situation) and defining the goal of the design (= functions that have to be fulfilled).

Make a list of requirements and generate alternative solutions

Compare these alternatives systematically, make them feasible and make a choice

Repeat these steps at subsystem level (cyclic design, working from general to detailed level)

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The design cycle

Starts with abstract formulation of a function, ends up with concrete shapes

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Analysis

Problem analysis →_{goal of the design (solve a problem)}

Analysis of the surrounding area; boundary conditions; system borders

Prevailing laws and regulations Risk analysis

Involved stakeholders Requirements

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Example: New water front for Medemblik

2nd year BSc-design project 2009 group B02

Problem

Because of the foreseen raise of the water level of the IJsselmeer with 1.5 m, the flood risk in

Medemblik will exceed the standard (so it will be too unsafe)

Objective

Ensure flood protection of

Medemblik in the new situation and make it an attractive place for living, working, leisure and investment.

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The step from function to spatial dimension:

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Translate the circle graph into a bubble diagramme and a relational diagramme

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Sieve analysis

(Find a suitable location to realise the 2D-concept plan;

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Potential surface analysis

(orthogonal arrangement) (organic arrangement)

(combined arrangement)

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Synthesis

How to realise the solution?

(Analysis is more about what to realise) Creative phase

Transition from abstract formulation of a goal to concrete shapes

Generation of ideas for solutions:

→_{development of different alternatives with different visions}

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Development of different alternatives with help of: • brainstorm sessions (generating 'wild ideas')

• attribute listing (try changing attributes or properties) • morphological method (systematic inventory of

possibilities)

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Simulation

Alternatives should meet all requirements and thus reach the goal of the project.

Check if the alternatives will actually 'work': • space

• time • finance • technology

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Evaluation

Systematic comparison of the alternatives on basis of criteria

→_{multi criteria evaluation (MCE)}

1. Find relevant criteria (≠_{requirements and}≠_costs!)

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Evaluation

3. Determine the weighing factor per criterion

4. Determine the scores per alternative

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Evaluation

5. Determine the costs per alternative

6. Calculate the value/cost ratios per alternative

7. Compare the value/cost ratios and find the highest ratio. This is considered the best alternative.

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For the favourite alternative,

the design cycle will be repeated for the subsystems

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Integrated design

of flood defence systems

C O N T E N T S

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Flood risk control

Flood risk = probability of flooding x consequences of a flood

Risk control aims at risk reduction, which can be accomplished by: • reducing the probability of flooding (= preventive measures)

− flood defences

• reducing the consequences (economic losses, fatalities): − sustainable spatial planning

− disaster management

• insurance (actually does not reduce the damage, but only compensates losses)

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Flood risk control

Dutch policy:

Multi-layered safety (Meerlaagsveiligheid)

Flood risk reduction in three layers: 1. Prevention

2. Spatial planning

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Layer 1: Prevention

A flood defence is a hydraulic structure, being part of a complete system, that resists against temporary covering by water of land normally not covered by water

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Layer 1: Prevention

"anything that can be used to divert, restrict, stop or otherwise manage the natural flow of water" - USACE

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Layer 1: Prevention

a dike ring, including the organisation of

operation and maintenance, and stipulation of safety levels

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Layer 1: prevention: flood defences

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Schematized cross-sections could give wrong impressions about spatial impact!

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Layer 1: prevention: flood defences Room for the River project

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Herwijnen, 2012

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Layer 1: prevention: urban integration

Sliedrecht, 2012 Where is the flood defence?

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Kampen, 2011 Where is the flood defence?

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Kampen, 2011 Where is the flood defence?

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Layer 2: spatial planning: urban integration

Hamburg, 2012 This is not a flood defence!

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Hamburg, 2012

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Hamburg Hamburg

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Layer 2: spatial planning: floating houses

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Layer 2: spatial planning: houses on piles

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Layer 2: spatial planning: houses on mounds

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Layer 3: disaster management: precaution, creating awareness

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Layer 3: disaster management: evacuation, shelters

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Multi-layered flood safety

Results of recent research

• "A flood defence system heavily based on dike rings does not lend itself to implement the multi-layered approach." (Hoss, 2011)

• Measures to reduce the probability of flooding (first layer) and non-expensive measures of risk

management (third layer) can be cost-effective. Physical measures in spatial planning (second layer) are less or not at all cost-effective (Kolen, 2011, 2013)

Conclusion: prevention of floods still is the best method

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Multi-layered flood safety

Measures in the second layer, however, can be justified if other values than flood protection become prevalent

(Kolen 2011).

Drawbacks:

• Only process requirements for 2nd and 3rd layer • Each layer has a different responsible authority • Different response of people to flood risk

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Integrated design

of flood defence systems

C O N T E N T S

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Integration of functions / structures

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Shared use:

a structure is (temporarily) used by another function

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Optimisation:

shape of flood defence is modified to save space

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Overlay:

one structure is built on or in the other

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Integration:

both spatial elements are making use of the same structure

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Rotterdam, 2012

Integration:

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