Title: Modelling elevations, inundation extent and hazard risk for extreme flood events
Abstract: Climate change is expected to result in more frequent occurrences of extreme flood
events, such as flash flooding and large scale river flooding. Therefore, there is a
need for accurate flood risk assessment schemes in areas prone to extreme flooding.
This research study investigates what flood risk assessment tools and procedures
should be used for flood risk assessment in areas where the emergence of extreme
flood events is possible. The first objective was to determine what type of flood
inundation models should be used for predicting the flood elevations, velocities and
inundation extent for extreme flood events. Therefore, there different flood
inundation model structures were used to model a well-documented extreme flood
event. The obtained results suggest that it is necessary to incorporate shock-capturing
algorithms in the solution procedure when modelling extreme flood events, since
these algorithms prevent the formation of spurious oscillations and provide a more
realistic simulation of the flood levels. The second objective was to investigate the
appropriateness of the “simplification strategy” (i.e. improving simulation results by
increasing roughness parameter) when used as a flood risk assessment modelling tool
for areas susceptible to extreme flooding. The obtained results suggest that applying
such strategies can lead to significantly erroneous predictions of the peak water
levels and the inundation extent, and thus to inadequate flood protection design. The
third and final objective was to determine what type of flood hazard assessment
methods should be used for assessing the flood hazard to people caused by extreme
flooding. Therefore, two different flood hazard assessment criteria were modelled for
three extreme flood events. The predicted results suggest that in areas prone to
extreme flooding, the flood hazard indices should be predicted with physics-based
formulae, as these methods consider all of the physical forces acting on a human
body in floodwaters, take into account the rapid changes in the flow regime, which
often occur for extreme events, and enable a rapid assessment of the degree of flood
hazard to be made in a short time period.
Publication Year: 2017
Publication Date: 2017-01-01
Language: en
Type: dissertation
Access and Citation
Cited By Count: 2
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