For traditional roofs nearly all precipitation turns into runoff. Green roofs retain a fraction of precipitation, reducing storm-water runoff and associated impacts. Multiple studies indicate that green roofs can reduce 50% or more of the annual storm-water runoff. The soil and plants on a green roof can reduce storm-water runoff volume and peak runoff flows. They can also delay the time to peak runoff flows by retaining and partially decreasing the volume of water during a rainstorm event (Bliss, Neufeld, & Ries, 2009).
According to their research in Pittsburgh, PA from August 2006 to January 2007, (Bliss et al., 2009) the green roof outperformed the control roof in several key areas: total storm-water runoff volumes were reduced; the runoff flow rate was consistently lower; and peak flow rates were delayed. The results also show that the green roof affected the …show more content…
Research from Southern Illinois University Edwardsville (SIUE), located near St. Louis performed a ground level field study that had 28 built-in-place (BIPs) green roof models, four modular units, and four roof decks with standard black membrane were arranged in a completely randomized design (CRD). The storm-water runoff quantity and quality were monitored for nearly three years (September 2005 - June 2008). Their results indicate that green roof systems significantly reduced storm-water runoff and that system design, growth media depth, and presence of plants impacted storm-water retention (Morgan, Celik, & Retzlaff, 2013). When analyzing the 5 cm. controls versus the 5 cm. BIP green roofs, the green roof had nearly threefold the amount of retained water. The amount of storm-water retained also increased in the 10-20 cm. BIP green roofs as well. The 15 cm. BIP model retained the most runoff even when compared to the 20 cm. BIP model oddly
According to their research in Pittsburgh, PA from August 2006 to January 2007, (Bliss et al., 2009) the green roof outperformed the control roof in several key areas: total storm-water runoff volumes were reduced; the runoff flow rate was consistently lower; and peak flow rates were delayed. The results also show that the green roof affected the …show more content…
Research from Southern Illinois University Edwardsville (SIUE), located near St. Louis performed a ground level field study that had 28 built-in-place (BIPs) green roof models, four modular units, and four roof decks with standard black membrane were arranged in a completely randomized design (CRD). The storm-water runoff quantity and quality were monitored for nearly three years (September 2005 - June 2008). Their results indicate that green roof systems significantly reduced storm-water runoff and that system design, growth media depth, and presence of plants impacted storm-water retention (Morgan, Celik, & Retzlaff, 2013). When analyzing the 5 cm. controls versus the 5 cm. BIP green roofs, the green roof had nearly threefold the amount of retained water. The amount of storm-water retained also increased in the 10-20 cm. BIP green roofs as well. The 15 cm. BIP model retained the most runoff even when compared to the 20 cm. BIP model oddly