Abstract. Laboratory experiments are a viable approach to improve process-understanding and generate data for the validation of computational models. However, laboratory scale models of urban flooding are often distorted, i.e. different scale factors are used in the horizontal and vertical directions. This may result in artefacts when transposing the laboratory observations to the prototype scale. The magnitude of such artefacts was not studied in the past for the specific case of urban flooding. Here, we present a preliminary assessment of these artefacts based on the reanalysis of two recent experimental datasets related to flooding of a group of buildings and of an entire urban district, respectively. The results reveal that, in the tested configurations, the influence of model distortion on the upscaled values of water depths and discharges are both of the order of 10 %. This is comparable to other sources of uncertainties, such as on hydrological data.
Supplementary material to "Laboratory modelling of urban flooding: strengths and challenges of distorted scale models"
