Effect of the choice of different methods on the permeable pavement hydraulic characterization and hydrological classification

The permeable pavement is a compensatory drainage technique for urban waters that aims to control runoff and to ensure ideal hydrological conditions. This work had as main objectives to evaluate the infiltration capacity of a permeable pavement (PP) at real scale, through analytical and numerical modeling. It relies on water infiltration experiments and related modeling for the hydrodynamic characterization of the coating layer (saturated hydraulic conductivity, K_s, and sorptivity, S). A large panel of analytical and numerical models was considered, and several estimates were obtained. Then, the criteria for the evaluation of the maintenance requirement of the permeable pavements were computed for all the K_s-estimates considering the NCRS standards (assessment of permeability levels). The results indicated nice fits and accurate estimates for both the saturated hydraulic conductivity and the sorptivity. However, the K_s-estimates depended on the considered model and led to contrasting results in terms of classification. For 8 of the 9 models, the value of the K_s-estimate leads to the classification of “Group A” of the NCRS soil classification, meaning a very permeable material. In contrasts, the last method (numerical inverse modeling) classified the permeable pavement as “Group D”, i.e., soils with low permeability. Those results show the importance of the selection of characterization methods regarding the assessment of the hydrological classification of permeable pavements.