Feasibility of the Polders
When can the Dutch polderconcept become economically unviable?
M. Prevaes (TU Delft - Civil Engineering & Geosciences)
M. Kok – Mentor (TU Delft - Hydraulic Structures and Flood Risk)
Bas Jonkman – Graduation committee member (TU Delft - Hydraulic Structures and Flood Risk)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Adequate flood protection is important to many countries, but especially so to the Netherlands. With a large share of its population centers located below sea level, in so-called polders, the need for flood protection systems quickly becomes apparent. This need is even more pressing with the rise of sea levels and the increase in river discharge variability due to the onset of climate change. To future proof themselves, the Netherlands needs to maintain and strengthen their flood defences. Especially precar- ious is the situation for polders, which are low-laying areas protected by one or more dikes. From a technical perspective, the feasibility of the polder system has been proven to withstand the expected water level rise as result of climate change for at least 2 to 3 meters sea level rise, shown by Kok et al. (2008). However, research into the economic perspective on the feasibility of the polder concept has been less extensive.
To more accurately determine the economic viability of the Dutch polder concept, additions to the research of Eijgenraam are proposed that fill in the current knowledge gaps. The result of this research is a mathematical framework for the optimization of dike reinforcements in two dimensions, the lifetime of the structure and the crest height increase of the dike. The framework consist of a discounted Cost-Benefit Analysis with a financial constraint and a constraint on the maximum allowable time before reinforcement is needed. This framework contains stochastic elements in it’s parameters and a stochastic model for the discount rate. The derived framework was subsequently used to analyse two case studies based on regions in the Netherlands. The two case studies were based on the dikering of IJsselmonde (dikering 17) and the dikering of Walcheren (dikering 29). The results were determined for the two climate scenario’s posed by the IPCC and KNMI by means of a Monte Carlo simulation.
This research has opened up the possibility to compare alternatives over different time periods and re- inforcement measures with different constraints and stochastic parameters, adding to the work done by Eijgenraam. As such, a more risk-informed discussion on the general viability of the polderconcept can be had, ultimately resulting in a more informed decision on the future of the polders in the Netherlands.