Rivieroverstromingsmodellering via combinatie van 1D hydraulische modellen en 2D GIS informatie = River flooding analysis using quasi-2D hydraulic modelling and geospatial data
Timbe Castro, L.M. (2007). Rivieroverstromingsmodellering via combinatie van 1D hydraulische modellen en 2D GIS informatie = River flooding analysis using quasi-2D hydraulic modelling and geospatial data. PhD Thesis. Katholieke Universiteit Leuven (KUL): Leuven. ISBN 978-90-5682-848-6. XVI, 276 pp.
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| Beschikbaar in | Auteur |
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Documenttype: Doctoraat/Thesis/Eindwerk
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| Trefwoorden |
Flooding
Floodplains
Information systems > GIS
Mapping
Methodology
Modelling
Models > Scale models > Hydraulic models
Satellite imagery
Simulation
België, Dender R. [Marine Regions]; België, Denderbekken [Marine Regions]
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| Abstract |
River flood and floodplain modelling by means of a one-dimensional (1D) full hydrodynamic model in a quasi 2D setting allows optimal balance to be obtained between model accuracy and computational time. Two-dimensional floods can be modelled when the 1D system is combined with two-dimensional spatial information on floodplain topography using geographical information system (GIS). In the quasi 2D setting, the floodplains are described in the hydraulic model as a network of fictitious river branches and spills with the main rivers (quasi 2D approach). The GIS is used for both pre- and post-processing tasks.In the Ph.D. study, most efficient quasi 2D modelling procedures have been developed and evaluated for the river Dender in Belgium. The evaluation includes analysis of the influence of the resolution of the digital elevation model (DEM), the topographical resolution in the hydraulic model, the accuracy of combining the DEM with the cross-sectional field survey data, etc. The implementations have been made in the MIKE11 and MIKE21 / MIKE FLOOD software of DHI Water & Environment. Both quasi 2D and full 2D implementations have been compared. The flood mapping is done both for historical events and synthetic events for various return periods. Based on the flood maps for historical events, validations are carried out for the final model results (historical flood maps from water authorities and from satellite imagery) and the total uncertainty calculated. This total uncertainty is for an upstream stretch of the river Dender split up in its different contributing uncertainty sources. Based on sensitivity runs and error propagations, the contribution is investigated of errors and uncertainties in the rainfall-runoff estimates, the river bed roughness, the hydraulic structure regulation, the dike and floodplain schematizations, etc. This uncertainty analysis provides information as to where available modelling resources should be focused on to improve the prediction power of flood simulation models. |
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