Hydraulic Performance of Lined Permeable Pavement Systems in the Built Environment

The hydraulic performance of permeable pavement (PP) systems has been well demonstrated when based on full or partial on-site infiltration, while there is only limited research on lined PP systems built to provide detention and volume reduction by evaporation only. In this study, we tested the performance of commercially available PP components when constructed as lined PP systems with un-throttled discharge to explore basic hydraulic function in a real-life-setting. Four types of PP surface products and three types of sub-base aggregates were tested in six unique combinations, built as side-by-side parking lots into an existing parking area, each stall having a size of 25 m2 and 0.5 m of depth with individual lining. Based on 12 months of monitoring precipitation and discharge from each stall, total volume reduction ranged from 3% to 37%. Analysis of up to 22 single events, representing return periods of up to two years, revealed marked detention capacities, expressed as median volume reduction of 40%, spanning 27–69% and median lag time of 1:38 h, spanning 0:39–3:16 h, across all stalls. The considerable range in hydraulic properties can be ascribed to both surface and sub-base properties

Stormwater management:Methods for measuring near-surface infiltration capacity in clayey till

Glacial till forms a major proportion of the surface deposits in Northern Europe, and in Denmark more than 40% of the land surface is covered by clayey till. At the same time the majority of densely populated areas are situated on this fertile sediment type. In urban areas, one of the major tools in adaptation to climate change are sustainable drainage systems (SuDS). Their function is to manage the increasing amounts of stormwater on site, often by direct infiltration into the sediment. Accordingly, a realistic estimate of nearsurface hydraulic properties is required when dimensioning SuDS for infiltration