Abstract
Modelling urban floods at the scale of the conurbation remains a challenging task owing to the size ratio between the hydraulic features and the modelling domain. Upscaling makes such modelling possible. Macroscopic models allow CPU and model pre-processing times to be divided by 102 to 103 compared to classical models. Macroscopic inundation fields may be interpolated for finer scale simulations. Four types of macroscopic urban flood models are currently available from the literature: the single porosity model, the integral porosity approach, the conveyance reduction factor model and the multiple porosity model. Analysing the four formulations indicates that they can be expected to exhibit significantly different behaviour in a variety of hydraulic configurations. So far, they have been applied to different types of urban layouts or only compared to numerical simulations. Identifying the best formulations call for a systematic experimental benchmarking involving steady state and transient regimes.