Author(s): Parna Parsapour-Moghaddam; Colin D. Rennie; Jonathan Slaney

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Abstract: This study aims at hydrodynamic modelling of Bow River, which passes through theCity of Calgary, Canada. Bow River has a mobile gravel bed. Erosion and deposition processeswere exacerbated by a catastrophic flood in 2013. Channel banks were eroded at variouslocations, and large gravel bars formed, which could lead to water level changes and accordinglymore flooding. This study investigates the performance of Delft3D-Flow and MIKE 21 FM tosimulate the hydrodynamics of the river during the 2013 flood. MIKE 21FM employsunstructured triangular mesh while Delft3D-Flow model uses curvilinear structured grids. Performance of each model was evaluated by the available historical water levels. The results ofthis study demonstrated that, with approximately the same averaged grid resolution, MIKE 21FM resulted in more accurate results with a higher computational cost compared to the Delft3D-Flow model. It was shown that Delft3D-Flow model may require higher grid cell resolution toresult in comparably same depth-averaged velocities throughout the study area. However, considering the balance between the computational cost and the accuracy of the results, bothmodels were capable to adequately replicate the hydrodynamics of the river during the 2013flood. Results of statistical KS and ANOVA test analysis showed that the model predictions weresensitive to the horizontal eddy viscosity and the Manning roughness. This confirms thenecessity of an appropriate calibration of the generated numerical models. The findings of thisstudy shed light on the Bow River flood modelling, which can guide flood management.

DOI: https://doi.org/10.1051/e3sconf/20184002004

Year: 2018