Using simplified bathymetry and SAR imagery in the validation of a hydraulic model for the Tagus River floodplain

• Published in: Journal of coastal research Vol. 75; no. sp1; pp. 13 - 17
• Main Authors: Araújo, Maria Amélia V.C., Pestana, Rita, Matias, Magda, Roque, Dora, Trigo-Teixeira, António, Heleno, Sandra
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Coastal Education and Research Foundation 01.03.2016; Coastal Education and Research Foundation, Inc; Allen Press Inc
• Subjects: Accuracy; Algorithms; Bathymetry; commission and omission errors; Dams; Datasets; Drying; Flood predictions; Floodplains; Floods; Freshwater; High flow; Historic floods; Hydraulics; Hydrology models; Hydrometric stations; Main courses; Mathematical models; Methodology; Methods; Modeling; Radar imagery; Riverbanks; RIVERS; SAR imagery; Satellite imaging; simplified bathymetry; Simulations; Topography; Tuflow; Water levels; Tagus River; Portugal; ANE, Portugal
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/SI75-003.1

Araújo, M.A.V.C.; Pestana, R.; Matias, M.; Roque, D.; Trigo-Teixeira, A., and Heleno, S., 2016. Using simplified bathymetry and SAR imagery in the validation of a hydraulic model for the Tagus River floodplain. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 13 - 17. Coconut Creek (Florida), ISSN 0749-0208. This work presents several approaches in the validation of the hydrodynamic model Tuflow on the simulation of flood extents and water levels, based on satellite SAR imagery. A methodology that uses a simplified bathymetry in the river main course is employed, which proves to be reliable and accurate for high-flow events. This was made possible as the digital terrain model was acquired in a dry period, accounting for large dry areas in the river bed, avoiding in this way the need of expensive river bathymetry surveys. Also, two methods are applied to the SAR imagery to extract the flood boundaries: visual interpretation followed by manual delimitation and an object-based algorithm approach. The hydraulic model is tested on a reach of the Tagus River, Portugal, where the largest flood inundation areas occur, using a historical flood event to verify its robustness and reliability. The accuracy of model prediction is done through comparisons of water levels at a hydrometric station and the determination of commission and omission errors of flood extent, between the reference SAR image and the predicted inundation. It was concluded that the methodology followed in this work is well suited for the hydraulic model validation.