Effects of model schematisation, geometry and parameter values on urban flood modelling

Abstract

One-dimensional (1D) hydrodynamic models have been used as a standard industry practice for urban flood modelling work for many years. More recently, however, model formulations have included a 1D representation of the main channels and a 2D representation of the floodplains. Since the physical process of describing exchanges of flows with the floodplains can be represented in different ways, the predictive capability of different modelling approaches can also vary. The present paper explores effects of some of the issues that concern urban flood modelling work. Impacts from applying different model schematisation, geometry and parameter values were investigated. The study has mainly focussed on exploring how different Digital Terrain Model (DTM) resolution, presence of different features on DTM such as roads and building structures and different friction coefficients affect the simulation results. Practical implications of these issues are analysed and illustrated in a case study from St Maarten, N.A. The results from this study aim to provide users of numerical models with information that can be used in the analyses of flooding processes in urban areas.

Modeling Flood Disasters: Issues Concerning Data for 2D Numerical Models

“…In general terms, the work to date has shown that the results from 2D models with different DTM resolution can produce significant difference in flow depths [20] (Fig. 2).…”

“…With the developments in computational power, 1D-2D approaches are increasingly gaining more attention [20][21][22][23]. A possibility of how to combine data-driven and physically based models for the purpose of modelling urban drainage flows can be found in [24] and [25].The accuracy of 2D models that can be reliably used in modelling flood disaster scenarios depends on the quality of terrain data, bathymetry and drainage network layouts [26][27][28].…”

High Resolution Decision Maps for Urban Planning: A Combined Analysis of Urban Flooding and Thermal Stress Potential In Asia and Europe

“…The coupled 1D/2D models are invaluable for this purpose. However, there is a great body of literature which suggests that great care is needed in the data collection and processing as well as the need to use an appropriate numerical modelling technique [8][9][10][11][12][13][14][15][16]. The DEM resolution used in the Ayutthaya work was 20x20 m. The model and maps produced were used for communication with local stakeholders and selection of remedial and flood protection works [3].…”

Holistic approach to flood risk assessment in areas with cultural heritage: a practical application in Ayutthaya, Thailand

“…These models have progressed through one-dimensional models that represent flow in channels or subsurface sewers, to the state of the art, which is represented by coupled one-dimensional-two-dimensional hydraulic models. These models can simulate the behaviour of flow in sewers and channels, and on the surface around buildings (Henonin et al 2013;Vojinovic et al 2011). These models have significant data requirements; these include data on extreme rainfall, information on surface properties including permeability, roughness, and topography, and data on the layouts and geometry of channel networks including elevations, diameters, and the properties of any control structures.…”