Stormwater Source Control Design Guidelines 2005 - Waterbucket

Pervious Paving Stormwater Source Control Design Guidelines 2005LimitationsA greater design and construction control effort is requiredwhen compared with impermeable pavements (Smith,2001).Minimum depth from base of drain rock reservoir to watertable or solid bedrock 610 mm (Smith, 2001).The pavement should be downslope from buildingfoundations, and the foundations should have pipeddrainage at the footing (Smith, 2001).At least 30m should be maintained between permeablepavements and water supply wells (Smith, 2001).Total catchment area draining onto the permeablepavement is not greater than 2 ha (Smith, 2001).To avoid surface plugging, it is critical to protect this BMPfrom sedimentation both during and after construction. Inaddition, identify pollutant sources, particularly inindustrial/commercial hotspots, that require pre-treatmentor source control upstream of this BMP (Maryland Dept.Environmental Resource Programs, 2001).For designs which rely on full exfiltration from the reservoirinto underlying soils, the infiltration rate of underlying soilshould be 12.5 mm/hr. minimum (Smith, 2001), or asdetermined by detailed geotechnical engineering.Types of permeable interlocking concrete pavements thathave wide joints (some manufacturers) should not be usedfor disabled persons parking stalls or pedestrian ramps atstreet crossings (Smith, 2001).Photo Credit: Lanarc Consultants Ltd.Permeable unit paving streetside parking in theNetherlands.54Greater Vancouver Sewerage & Drainage District