Asphalt sustainable urban drainage system

摘要

The drainage system, for use with car parks and other similar impermeable surfaces, comprises a grid of vertical cored holes provided in the impermeable surface 2, which are provided with caps 1 and which allow water to flow directly to a porous sub-base 6. The caps are preferably installed so as to be flush with the surface. A sealant 3 may be provided around the bevelled edge of the cap to form a seal with the cored edge of the hole. The cored hole may be provided lined with a small diameter pipe 4 and provided with gravel 5 at the base of the hole.