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D3) Incorporating past performance

Start: 09/2017
End: 09/2021
Status: Active

Contact details

Mark van der Krogt

Delft University of Technology

Expected outcome

Improved methods for estimating dike failure probability, incorporating past performance, and the benefits hereof.

Top: Examples of slope instability in the landward side with and without flooding due to dike breach (source: and Landesbetrieb für Hochwasserschutz und Wasserwirtschaft Sachsen-Anhalt). Bottom: Construction of a dike (photo by Pascal Ogink, Combinatie dijkverbetering HOP).

Motivation and practical challenge

As of 2017, flood safety in the Netherlands is expressed in terms of the probability of occurrence of typical failure modes. Dikes are assessed for safety by (semi-)probabilistic analyses methods. However, these failure probability estimates are dominated (among other factors) by the knowledge about the ground, which is often limited and uncertain. This is particularly the case for slope instability failures at the landward side, which may or may not lead to flooding due to dike breach (top photos).

Measuring, monitoring and adding information about the past performance of dikes can reduce uncertainty and thus lead to better failure probability estimates. Some of this performance information is available when measuring the soil properties or monitoring existing dikes. Even more information is gathered during dike reinforcement projects (bottom photo), for example, pore water pressure monitoring and measurement of settlement during the dike construction. However, not all information are used to assess the safety of dikes, or to improve estimates of the expected lifetime.

Research challenge

This research aims to develop updating methods to efficiently combining different sources of performance information into safety assessments. I focus on dikes with high reliability requirements as this is often the case of flood defences in the Netherlands which are designed with low probability of failure due to the high potential flood damage.

Innovative components

I explore several ways to improve failure probability estimates by incorporating different types of past performance information:

  • Identification of how error sources combine into the total uncertainty in the spatial average of soil properties measured using cone penetration tests (CPTs on figure 1).
  • Investigating the Value of Information for proof loading (figure 2) and pore pressure monitoring (figure 3), using a decision tree (joint component with related project A1).
  • Exploration of how loads during the construction stage (figure 4) such as the weight of the soil that is used to reinforce dikes can be used to improve reliability estimates for a dike in flood conditions. 
  • Exploration of how we can further reduce uncertainty by combining observations during the construction (figure 4) about height settlement, pore water pressure monitoring, and no instability presence.
  • Development of event trees to estimate the probability of flooding based on several (figure 5) successive conditional instabilities.

Figures 1 to 5 with the type of performance information considered into this project.

Figure 5) adapted from Calle, E.O.F., Dijk doorbraak processen (2002), translated here to English.

Relevant for whom and where?

Researchers interested in probabilistic analysis and organizations wanting more targeted and cost-effective flood protection.

The components of this research are developed for a range of typical dike sections for the Dutch riverine area, and for a case study of a full-scale test embankment in Eemdijk.

Progress and practical application

First findings show, for example, that it is possible to reduce the uncertainty in soil properties such as the undrained shear strength by minimizing the distance between boreholes and soil investigation tests (CPTs) as well as reducing the bias in the measurements. The event tree analysis of slopes instabilities for typical dike sections in the Netherlands shows that considering the probability of instability equal to the probability of flooding is a very conservative estimate, especially at relatively low water levels. Moreover, by considering typical dike sections and a full-scale test location on Eemdijk, the updated failure probability with construction loads can be several orders of magnitude lower than the failure probability without construction loads information. Finally, uncertainty reduction measures such as proof loading and pore water pressure monitoring applied to typical dike sections in the Netherlands have a positive Value of Information, thus are often worth investing. For a detailed description of each finding, please click on related outputs below.

Status for day-to-day practice

Measuring, monitoring and adding information about the performance of dikes for example during the construction of dikes are valuable uncertainty reduction methods for better failure probability estimates.

Next steps

The developed methods offer a guide for their broad implementation in dike reinforcement projects and the management of dikes to more targeted and cost-effective flood protection.

Last modified: 21/06/2020

Contributing researchers

Mark van der Krogt

Delft University of Technology

Supervisory team

Dr. Timo Schweckendiek

Delft University of Technology Matthijs Kok

Delft University of Technology

Contributing partners

Proof loading and monitoring to optimize flood defence asset management

We calculate the expected value of extra information obtained from proof loading and monitoring. The additional information improves failure probability estimates for slope stability.

Mark van der Krogt

Delft University of Technology

Wouter Jan Klerk

Delft University of Technology

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  • Van der Krogt, M.G., Schweckendiek, T. & Kok, M. Improving Dike Reliability Estimates by Incorporating Construction Survival. (in preparation)
  • Van der Krogt, M.G., Klerk, W.J., Kanning, W. & Schweckendiek, T. Value of Information of Combinations of Proof Loading and Pore Pressure Monitoring for Flood Defences. (in preparation)