Editing Permeable paving (section)

=== Runoff volumes ===
Permeable pavements are designed to replace Effective Impervious Areas (EIAs), but can be used, in some cases, to manage [[stormwater]] from other impervious surfaces on site.<ref>{{Citation |last=Fassman |first=Elizabeth |year=2010 |title=Urban Runoff Mitigation by a Permeable Pavement System over Impermeable Soils |journal=Journal of Hydrologic Engineering |volume=15 |issue=6 |pages=475–485 |publisher=American Society of Civil Engineers |doi=10.1061/(ASCE)HE.1943-5584.0000238 |url=https://ascelibrary.org/doi/full/10.1061/%28ASCE%29HE.1943-5584.0000238 |access-date=2020-12-08|hdl=10983/24857 |hdl-access=free }}</ref> Use of this technique must be part of an overall on site management system for stormwater, and is not a replacement for other techniques.

During large storm events, the water table below the porous pavement can rise to a higher level, preventing the precipitation from being absorbed into the ground. Some additional water is stored in the open graded or crushed drain rock base, and remains until the subgrade can absorb the water. For clay-based soils, or other low to 'non'-draining soils, it is important to increase the depth of the crushed drain rock base to allow additional capacity for the water as it waits to be infiltrated.