1. Fault tree analysis for urban flooding.
- Author
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ten Veldhuis, J. A. E., Clemens, F. H. L. R., and van Gelder, P. H. A. J. M.
- Subjects
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FLOODS , *PROBABILITY theory , *STORMS , *RAINFALL , *WATERSHEDS , *HYDRODYNAMICS , *HYDROLOGICAL research - Abstract
Traditional methods to evaluate flood risk generally focus on heavy storm events as the principal cause of flooding. Conversely, fault tree analysis is a technique that aims at modelling all potential causes of flooding. It quantifies both overall flood probability and relative contributions of individual causes of flooding. This paper presents a fault model for urban flooding and an application to the case of Haarlem, a city of 147,000 inhabitants. Data from a complaint register, rainfall gauges and hydrodynamic model calculations are used to quantify probabilities of basic events in the fault tree. This results in a flood probability of 0.78/week for Haarlem. It is shown that gully pot blockages contribute to 79% of flood incidents, whereas storm events contribute only 5%. This implies that for this case more efficient gully pot cleaning is a more effective strategy to reduce flood probability than enlarging drainage system capacity. Whether this is also the most cost-effective strategy can only be decided after risk assessment has been complemented with a quantification of consequences of both types of events. To do this will be the next step in this study. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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