Goal & focus of research to multifunctional flood defences

Before multifunctional flood defences can be implemented, a number of questions must be answered, questions regarding design, safety assessment, and management strategies. The ambition of the proposed program is to address these research questions to dissolve the constraints restricting the discussion and development of multifunctional flood defences.

The focus of the programme is to gain a deeper understanding of multifunctional flood defences to provide a foundation for the design, assessment and management of such defences. 
The design and assessment of multifunctional defences is investigated with the ambition to substantially increase safety over current defence designs, such that the yearly failure probability is less than 106.

Research is carried out related to governance of multifunctional flood defences in an atmosphere of multiple users, multiple sets of administrative rules and multiple legal frameworks. The flexibility and robustness of the defences are investigated in an integral way, considering both economic and engineering perspectives.

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Tiel proposal (Grontmij)

The objectives of the research programme

  • To gain insight into the behaviour of the multifunctional flood defences during extreme storms, e.g. extreme water levels and waves.

  • To develop and design new principles of risk assessment methods for multifunctional flood defences, in both urban (delta urbanism and architecture)and rural areas (landscape and ecology);

  • To integrate technology for multifunctional and flexible flood defences in the development of urban and rural landscapes;

  • To develop new governance and asset management principles for multifunctional flood defences in the design phase and in the management phase;

  • To integrate new physical and safety knowledge into the design of multifunctional flood defences;

  • To include (deep) uncertainty (e.g. due to climate change or socio-economic developments) in the design approach for multifunctional flood defences, and develop new design principles for flexibility and robustness.

Predominant scientific
​challenges​

  • Reliability and risk evaluation of multi-functional defences.
This requires new methodologies since the risk to a multi-functional defence is not simply the sum of the risk to the individual functions. Currently, extra functions are neglected in the assessment of the failure probability. For example, it is unknown how a road on top of a dike influences the failure mechanisms;
  • Knowledge of behaviour of (e.g. concrete) objects in soil bodies has not yet been well investigated.
We will apply modern numerical modelling tools in combination with experimental work (e.g. laboratory experiments to validate these models) in order to assess the structural behaviour;
  • Governance strategies, financial forecasting and real estate predictions under uncertain future conditions.
The appeal of multi-functional flood defences in the long term: flood defence managers tend to prefer mono-functional flood defences because the reliability of multifunctional dikes has not been investigated, and because the time scale of changes of the other functions can differ from the function of flood protection. The financial and governance principles of multi-functional flood defences; without adequate financing and governance, their reliability will decrease;
  • Integration of multi-functional flood defences into urban and rural river landscapes.
The flood defence is now often seen as an unwanted obstacle, and the challenge is to find ways to integrate protection into urban and river landscapes;
  • The flexibility and ability to adapt of multi-functional flood defences to accommodate for large uncertainty in future safety standards (due to changing hydrological conditions by climate change or socio-economic evolution);
  • The integration of the challenges above into an integral design of multifunctional flood defences

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De Boompjes Parkdijk Rotterdam

Case studies are important in this research programme

The users will provide these case studies and the advantages are twofold: the new knowledge can immediately be tested, and the users receive new knowledge in a very efficient way. In the program, we distinguish two research lines: disciplinary extension research themes and multi-disciplinary integration challenges.

Extension research themes aim to extend disciplinary theories and to develop new theories and knowledge, while trans-disciplinary integration challenges (interdisciplinary research) extends knowledge to adjacent research fields.

In total we distinguish five work-packages:

1. Disciplinary extension challenges
          1.1. Multifunctional flood risk assessment
          1.2. Urban and Rural multi-functional flood 
                  defences design
          1.3. Governance and finance

2. Multidisciplinary integration challenges
          2.1. Integrated design
          2.2. Adaptivity and robustness

Disciplinary extension challenges address the development of the following disciplines: (urban and landscape) design, flood risk assessment (including for example erosion mechanisms of flood defences with buildings), governance (multi-sectoral), and financial forecasting of real estate development.
Trans-disciplinary integration challenges address the flexibility and adaptivity issue and integrated design.

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