Evaluating the efficiency of permeable pavement: Grass-filled pavers in the Netherlands

Permeable pavements are implemented at more than thousand locations enabling rainfall infiltration and evapotranspiration of stormwater in The Netherlands. However, the efficiency has not been extensively tested. Therefore, research is conducted using a full-scale infiltration test (FSIT) method to measure the infiltration rate at 33 locations with grass-filled pavements across six Dutch cities. The infiltration rates show a high variation: 50 to 1400 mm/h with a median value of 344 mm/h. This is in line with previously reported infiltration rates of permeable and pervious pavers. All measured infiltration rates on permeable pavements are higher than conventional ‘grey’ pavement with infiltration capacities in the range of 3-10 mm/h measured with FSIT. The infiltration rate decreases when the full-scale test is repeated due to higher saturation with a factor between 0.5 and 0.8 (average 0.68 for all tests). The infiltration rate reduces over time after construction but seems stabilise at a higher than conventional pavement. The soil surface and vegetation are important factors that influence the infiltration rate. Based on these findings, stormwater managers can design, plan for green infrastructure with more confidence to ensure performance over their intended life span and mitigate the effects of (extreme) rainfall and droughts.