Testing a simple 2D hydraulic model in an urban flood experiment

Hydraulic modelling of flood events involving urban areas constitutes a difficult challenge due to the complexity of topography and flow dynamics that characterize such an environment. Despite the increasing availability of detailed, high-resolution topographic data, the assessment of model performance is still hampered by the scarcity of observed data describing the development of flood events. In the present paper, a simple two-dimensional (2D) diffusive model is tested by reproducing a number of experiments carried out using an urban district physical model. The availability of measured water level data allows us to evaluate the model performance in detail and to investigate its limitations in reproducing complex flow dynamics. In addition, simplified approaches to represent urban areas within the model grid are considered and tested, and their influence on model results is assessed. The tested approaches include a simplified porosity-based approach and the increase of roughness for urban grid cells. Overall results show that the proposed diffusive model is able to reproduce main flow processes, although some localized flow dynamics were poorly simulated. Simplified methods for representing the urban district provided similar results to detailed grid representations, suggesting that they could be proficiently used in combination with reduced complexity models. Copyright © 2012 John Wiley & Sons, Ltd.

[1]  Stuart N. Lane,et al.  Urban fluvial flood modelling using a two‐dimensional diffusion‐wave treatment, part 2: development of a sub‐grid‐scale treatment , 2006 .

[2]  Michael Smith,et al.  Comment on ‘Analysis and modeling of flooding in urban drainage systems’ , 2006 .

[3]  P. Bates,et al.  Comparing the performance of a 2‐D finite element and a 2‐D finite volume model of floodplain inundation using airborne SAR imagery , 2007 .

[4]  T. Chang,et al.  Inundation simulation for urban drainage basin with storm sewer system , 2000 .

[5]  Luis Cea,et al.  Unstructured finite volume discretization of two‐dimensional depth‐averaged shallow water equations with porosity , 2009 .

[6]  P. Bates,et al.  Utility of different data types for calibrating flood inundation models within a GLUE framework , 2005 .

[7]  Gareth Pender,et al.  Sub-grid scale parameterisation of 2D hydrodynamic models of inundation in the urban area , 2007 .

[8]  Jean A. Cunge,et al.  Of data and models , 2003 .

[9]  André Paquier,et al.  Modelling flash flood propagation in urban areas using a two-dimensional numerical model , 2009 .

[10]  K. Beven,et al.  Uncertainty in the calibration of effective roughness parameters in HEC-RAS using inundation and downstream level observations , 2005 .

[11]  P. Bates,et al.  Evaluating the effect of scale in flood inundation modelling in urban environments , 2008 .

[12]  Sandra Soares Frazao,et al.  Computation of the ‘isolated building test case’ and the ‘model city experiment’ benchmarks , 2003 .

[13]  Pietro Prestininzi,et al.  Suitability of the diffusive model for dam break simulation: Application to a CADAM experiment , 2008 .

[14]  C. Sampson,et al.  Benchmarking urban flood models of varying complexity and scale using high resolution terrestrial LiDAR data , 2011 .

[15]  Julien Lhomme,et al.  Two-dimensional shallow-water model with porosity for urban flood modelling , 2008 .

[16]  B. Sanders,et al.  Integral formulation of shallow-water equations with anisotropic porosity for urban flood modeling , 2008 .

[17]  Matthew D. Wilson,et al.  Simple spatially-distributed models for predicting flood inundation: A review , 2007 .

[18]  P. Bates,et al.  A simple inertial formulation of the shallow water equations for efficient two-dimensional flood inundation modelling. , 2010 .

[19]  Paul D. Bates,et al.  Flood-plain mapping: a critical discussion of deterministic and probabilistic approaches , 2010 .

[20]  P. Bates,et al.  Near real time satellite imagery to support and verify timely flood modelling , 2009 .

[21]  Keith Beven,et al.  Estimation of flood inundation probabilities as conditioned on event inundation maps , 2003 .

[22]  James Brasington,et al.  Reduced complexity strategies for modelling urban floodplain inundation , 2007 .

[23]  C. Aricò,et al.  MAST-2D diffusive model for flood prediction on domains with triangular Delaunay unstructured meshes , 2011 .

[24]  Francisco Alcrudo,et al.  Flash flood flow experiment in a simplified urban district , 2007 .

[25]  Yves Zech,et al.  The Impact European Research Project on Flood Propagation in Urban Areas: Experimental and Numerical Modelling of the Influence of Buildings on the Flow , 2007 .

[26]  B. Sanders,et al.  Unstructured mesh generation and landcover-based resistance for hydrodynamic modeling of urban flooding , 2008 .

[27]  S. Lane,et al.  Urban fluvial flood modelling using a two‐dimensional diffusion‐wave treatment, part 1: mesh resolution effects , 2006 .

[28]  V. Guinot,et al.  Flux and source term discretization in two‐dimensional shallow water models with porosity on unstructured grids , 2006 .

[29]  Francesco Dottori,et al.  Developments of a flood inundation model based on the cellular automata approach: Testing different methods to improve model performance , 2011 .

[30]  P. Bates,et al.  Distributed whole city water level measurements from the Carlisle 2005 urban flood event and comparison with hydraulic model simulations , 2009 .

[31]  A. Paquier,et al.  Modeling floods in a dense urban area using 2D shallow water equations , 2006 .

[32]  Stuart N. Lane,et al.  Interactions between subgrid‐scale resolution, feature representation and grid‐scale resolution in flood inundation modelling , 2011 .

[33]  B. Sanders,et al.  Two-dimensional, high-resolution modeling of urban dam-break flooding: A case study of Baldwin Hills, California , 2009 .