Abstract
Spatial variability and limited measurements often result in low reliability estimates of geotechnical failure modes of dikes (i.e., earthen flood defences). Required dike reinforcements are usually not executed within a few years after inception, which enables efforts to improve reliability estimates by reducing uncertainty. Often decision makers are unclear on whether uncertainty reduction is worth investing, and which (combination of) methods yields the highest Value of Information (VoI). This paper presents a framework to assess the VoI of two uncertainty reduction methods (proof loading and pore pressure monitoring) for a case study of a typical river dike with an insufficiently stable inner slope, using a decision tree. In all cases, a positive VoI was found for at least one strategy consisting of a proof load test, monitoring or both. The optimal strategy of proof loading and monitoring has a VoI of 4.0 M€, being a reduction in total cost of 25% compared to a conventional dike reinforcement. It was also found that sometimes proof loading enhances the VoI of pore pressure monitoring, which demonstrates the benefits of jointly considering different methods in a single decision tree. The decision framework yields insight in total cost and VoI of risk reduction strategies, which enables decision makers to determine where proof loading and/or pore pressure monitoring are efficient, leading to more efficient flood defence asset management.
Highlights
Dikes are important structures to mitigate flood risks in deltas around the world
Both monitoring and proof loading reduce total cost, with the optimal strategy being a combination of proof loading and monitoring (VoI 1⁄4 4.0 Me)
For the optimal strategy the reduction in total cost is 25% compared to a conventional reinforcement, strategies with only proof loading or monitoring have a lower and positive Value of Information (VoI)
Summary
Dikes (i.e., earthen flood defences) are important structures to mitigate flood risks in deltas around the world. Benefits of flood defences are mainly reduction of risk, as expressed by various risk indicators, such as loss-of-life and economic damage (Jonkman et al, 2003) Based on such requirements for acceptable risk, optimal reliability targets can be derived based on the relation between investment cost and risk reduction (Vrijling, 2001), which are taken as a starting point for decision analysis. One major issue that often arises is that the reliability estimates for geotechnical failure modes such as inner slope instability and backward erosion piping are dominated by large uncertainty in load (effects) and soil properties These are typically knowledge uncertainties that are the result of spatial variability, measurement uncertainty, and a limited amount of measurements This is called the Value of Information (Raiffa & Schlaifer, 1961)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
