Comparison of the hydraulic behaviour and the quality of highway runoff water according to the type of pavement

This paper presents the results of an experimental investigation aimed at determining the impact of the type of pavement, whether conventional or porous, on the hydraulic behaviour and on the quality of runoff water. Data obtained from a French highway bath before and after the replacement of a conventional asphalt by a porous asphalt are compared. Statistical tests have been used to evaluate the significance of the differences detected. Firstly, the differences in hydrological behaviour between the two types of pavement is highlighted (retardant effect on the evacuation of water into the outlet, peak flow attenuation, mitigation of splashing by the pervious pavement). Secondly, the impact on water quality is investigated. The retention of particulate pollution by the porous pavement, which acts as a filter, is clearly demonstrated. This study also shows the probable impact of the type of pavement an the pollutant content in a dissolved form. (C) 2000 Elsevier Science Ltd. All rights reserved.