Author(s): Anuar Md. Ali; Giuliano Di Baldassarre; Dimitri P. Solomatine
Linked Author(s):
Keywords: Cross sections; Bridge; Hydraulic modelling; Models performance; Flood hazard
Abstract: In the field of flood risk management, flood inundation mapping is often done with the help of one-dimensional (1D) hydraulic models. These models require a number of cross sections across the river as topographical input data. However, the effects of inclusion/exclusion of the cross sections, and/or hydraulic structures such as bridges on the results of the hydraulic models, and therefore on flood inundation mapping, are still largely unexplored and poorly understood. We assess these effects on a case study: the Johor River, in Malaysia. In particular, numerical analysis is carried out using two models with different geometrical configurations: the first model is based on a large number of river cross sections and including the detailed geometry of a bridge; and the second model – on the same cross sections, but without the presence of the bridge. The numerical results of the two simplified hydraulic models are compared in terms of: (i) water surface elevations and inundated area; (ii) sensitivity of the hydraulic model to changes in the cross section spacing; and (iii) flood hazard classification. Results indicate that while the models are producing similar results in terms of 1D hydraulic models performance, significant differences arise in terms of simulated water level, flood inundation extent and flood hazard mapping.
Year: 2013