Laboratory testing and modelling of the hydrological performance of a resin gravel permeable pavement

Permeable pavements (PPs) allow increasing the resilience of the built environment to water-related risks, although their hydrological contribution is often assumed rather than demonstrated. A PP was tested in the laboratory by monitoring the outflow from a standardized test bed under various rainfall inputs. The results are fitted with the mathematical formulation of the step response of the first- and second-order dynamic systems, and the proposed formulation is validated in different test conditions showing a Pearson coefficient larger than 0.990. Performance indices were calculated, showing significant peak reduction (detention) between 8% and 30%, and retention between 9% and 22%. Quantitative trends were derived to extrapolate the behaviour of the PP to morphological/climatological conditions that were not tested and to support more informed design/installation of this PP. The role of this solution at the catchment scale can be assessed by integrating specific simulation modules based on the proposed formulation into hydrological models.