University of Twente Student Theses
Alluvial Fan Flood Hazard Assessment based on DTM Uncertainty
Hosein, Tarick (2010) Alluvial Fan Flood Hazard Assessment based on DTM Uncertainty.
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| Abstract: | Alluvial fan flooding is considered to be one of the most dangerous form of flooding. Its assessment is difficult because of unpredictable flow paths brought about by dynamic terrain changes, such as sediment disposition, that occur during an event. The aim of this study was to assess the influence of DTM uncertainty on flood patterns, particularly on concentrated impulse paths. In order to better understand the consequences of such a flood, the study included an investigation of storms as the event triggers, and debris infilling and blockage as processes. Terrain dynamics were studied in the form of spatially correlated and uncorrelated noise added to the DTM to understand the effect of DTM uncertainty. The results in storm designs reflected the difficulty associated with spatially varying weather systems within ungauged mountainous watersheds. Channel backfilling was found to require over 100000m3 of debris material before potentially placing the whole alluvial fan at risk of flooding. During such a flooding scenario, the study found that there are systematic and unsystematic runoff flow path responses. This was found to be dependent on the design of noise added to the DTM. The use of spatially correlated noise gave biased systematic flow paths in the flood model. However, the results of the uncorrelated noise reflects typical flow path expectations, during such flooding. The addition of noise to the DTM can give a useful insight of the consequences of flooding in general, however the model of noise added should reflect the processes that may cause uncertainty. |
| Item Type: | Essay (Master) |
| Faculty: | ITC: Faculty of Geo-information Science and Earth Observation |
| Programme: | Geoinformation Science and Earth Observation MSc (75014) |
| Link to this item: | https://purl.utwente.nl/essays/92517 |
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