Living With Peak Discharge Uncertainty: The Self-learning Dike


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Kok de, J.L. and Hoekstra, A.Y. (2008) Living With Peak Discharge Uncertainty: The Self-learning Dike. In: iEMSs 4th Biennial Meeting, International Congress on Environmental Modelling and Software Integrating Sciences and Information Technology for Environmental Assessment and Decision Making, July 7-10, 2008, Barcelona, Spain.

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Abstract:Although river dikes still play a key role for flood protection in the Netherlands
there is a growing interest for other measures to deal with larger peak discharges, such as
lowering or widening the floodplains. Regardless of the strategy chosen the assessment of
its effect on the flood risk depends on the peak discharge statistics. A problem here is that
the statistical analysis of peak discharges relies on probability distributions based on the
limited time series of extreme discharges. The extrapolation of these distributions are
subject to considerable uncertainty, because there is a measuring record of only about 100
years and the natural variability can be expected to change as a result of climate change.
This raises the question whether a more direct response to the effects of climate change is
possible. The natural variability of the peak discharge changes, the changes in this
variability due to e.g. climate change and the new statistical distribution can only be
established after the actual change has happened. Even with regular updates of the
statistical distributions it is inherent that the actions taken to reduce the flood risk are not
anticipatory but delayed. As an alternative, this paper presents an adaptive or so-called selflearning
approach to deal with the uncertainty in the peak discharge statistics. The
difference with the probabilistic design of flood defense works, which depends on the
analysis and prediction of uncertain peak discharges, is that the dike is adapted in direct
response to peak water levels exceeding the dike height minus a certain safety margin. The
results indicate that, on average, adaptive flood management based on observed peak water
levels is at least as safe as a probabilistic approach, which necessarily relies on uncertain
discharge statistics. Other advantages of the adaptive strategy are also obvious: the rule of
response is simple and easy to communicate to the public, and peak water levels are less
difficult to measure. In general the example demonstrates that flood management can be
based on a direct response to the effects of climate change, without tedious statistical
analysis of peak discharge records.
Item Type:Conference or Workshop Item
Copyright:© 2008 International Environmental Modelling and Software Society
Faculty:
Engineering Technology (CTW)
Research Group:
Link to this item:http://purl.utwente.nl/publications/61135
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