Understanding the hydrological performance of a permeable pavement

Abstract

Permeable pavements play an essential role in urban drainage systems, making them the subject of great interest to both researchers and practitioners. However, previous studies have demonstrated a significant degree of uncertainty regarding both the hydrological performance and the maintenance requirements of this type of pavement. Within this context, a one metre square surface area of permeable pavement and a laboratory rainfall simulator were constructed to investigate the influence of rainfall intensity on the hydrologic response of permeable pavements. The hydrological performance of permeable pavement was tested under clean laboratory conditions and under the influence of sedimentation. The design of the permeable pavement test rig complied with the SuDS manual guidance and British Standards (BS 7533-13:2009). Simulated rainfall event results demonstrate that the hydrologic performance of the pavement varied according to the rainfall intensity and duration. More than 40% of the total rainfall from all rain events was temporarily detained within the structure. The total volume of discharge from the permeable pavement ranged from 8% to 60% of the inflow, illustrating the storage capacity of the pavement. The results of the simulation showed that the outflow reduction due to the application of sediment was 6.4% within the first ten years. The reduction in outflow volume was a result of the increasing water content within the pavement structure over time. The impact of sediment addition on the pavement surface was evident in the third year of the simulation. The concentration of suspended solids in the outflow showed a slight variation following the addition of the sediment, but remained low. Further analysis showed the outflow duration increased over time and no temporary ponding occurred on the surface during the ten-year simulation.