Stormwater Source Control Design Guidelines 2005 - Waterbucket

Stormwater Source Control Design Guidelines 2005Green RoofGreen RoofDescriptionA green roof is a conventional roof with a veneer ofdrainage and growing media that supports livingvegetation.Green roofs with a relatively shallow growing mediumthickness are generally called ‘Extensive Green Roofs’.These are often designed for stormwater, insulationand climate amelioration functions, and usually haveno public access. Vegetation is selected for its ability towithstand harsh conditions and its ability to maintainitself over the long-term.‘Intensive Green Roofs’ are usually designed withpublic access and use in mind, and have deepergrowing medium depths to support larger plants andtrees. Intensive green roofs also have stormwaterbenefits, but are heavier and more expensive todevelop, and therefore less affordable for the large flatroof expanses that are common inindustrial/commercial developments.This section is focused on the stormwater aspects ofExtensive Green Roofs.Photo Credit: Goya NganExtensive green roof – Halle Zoo, GermanyPhoto Credit: Lanarc ConsultantsApplicationsSuitable for many rooftop situations – industrialand warehousing, commercial buildings,municipal office complexes, hospitals, schools,institutional/administrative buildings and offices,residential developments and garages.Suitable for flat roofs and, with proper design,roofs of 20º slope or more (Peck & Kuhn, 2001).These may be inverted or traditional roofingsystems. Shingle and tile roofs are not suitable forgreening (ForschungsgesellschaftLandschaftsentwicklung Landschaftsbau e.V (FLL),2002).Extensive green roof – AmsterdamGreater Vancouver Sewerage & Drainage District63