Stormwater Source Control Design Guidelines 2005 - Waterbucket

Pervious Paving Stormwater Source Control Design Guidelines 2005Photo Credit: Lanarc ConsultantsPervious unit paving with aggregate jointsat bike rack.Construction Practices shall meet Master MunicipalConstruction Document 2000 requirements, and:1. Isolate the permeable paving site from sedimentationduring construction, either by use of effective erosionand sediment control measures upstream, or bydelaying the excavation of 300mm of material over thefinal subgrade of the pavement until after all sedimentproducingconstruction in the drainage area has beencompleted (Maryland Dept. Environmental ResourceProgram, 2001).2. The subgrade should be compacted to 95% standardproctor for walk/bike areas, and 95% modified proctorfor vehicular areas. Remove and replace soft areas(Smith, 2001).3. Prevent natural or fill soils from intermixing with thereservoir base, sub-base, or bedding courses and filtercloths. All contaminated stone aggregate and clothmust be removed and replaced (Smith, 2001).4. Reservoir drain rock sub base and base courses shallbe installed in 100 to 150mm lifts and compacted withat least 4 passes with a minimum 9 T steel drum roller(Smith, 2001).5. When all base courses are compacted the surfaceshould be topped with filter cloth and a layer ofbedding aggregate, and the surface graded carefullyto final slopes, as the bedding aggregate will compactdown much less than sand. Unit pavers shall beplaced tightly butt jointed according to manufacturersspecifications. Blocks should be vibrated with avibrating plated compactor. Following a first pass, alight dressing of 3mm single size clean stone should beapplied to the surface and brushed in, approximately 2kg/m2. Blocks should again be vibrated and anydebris brushed off (Formpave, 2003).6. For maintenance, the surface should be brushed atleast twice a year with a mechanical suction brush(vacuum sweeper) – in the spring and in autumn afterleaf fall (Formpave, 2003).58Greater Vancouver Sewerage & Drainage District