Use of permeable, reservoir pavement constructions for stormwater treatment and storage for re-use

Permeable surfaces for roads and footpaths have been used as a means of disposal of stormwater in developed urban areas. Such surfaces provide an alternative to impermeable concrete or tarmacadam surfaces which would otherwise produce rapid stormwater runoff, leading to possible flooding and degeneration of receiving water quality through the uncontrolled discharge of polluted urban waters. A further advantage may be obtained from such constructions by undersealing them so as to retain stormwater for re-use for non-potable uses. The potential for general introduction of this type of storage and re-use system in residential areas is discussed and possible alternative designs for the drainage infrastructure proposed. To have widespread impact such a strategy must deliver cost savings as well as reduce the impact on the water environment of anticipated water usage demands. The source of such cost savings and the general environmental benefits of such systems will be presented. The materials used in such a sealed construction and the beneficial changes to the stored water quality are outlined. Recent work has also shown that where the pavement is used for car parking any oils dropped on the surface and washed into the structure by the stormwater may also be degraded. Details will be given of a site in the UK where the above construction is to be used to provide stormwater storage for re-use in flushing toilets at a Youth Hostel.