GREEN ROOFS
Description:
A green roof is a stormwater management practice that incorporates layers of vegetation, growing medium, filter fabric, drainage panels, gravel, insulation, and geotextile to reduce runoff from an impervious roof surface. This practice is generally recommended for flat roofs but can be installed on steeper roofs with extra fasteners. There are three main types of green roof systems- extensive, semi-intensive or intensive. The types of green roofs are primarily defined by the depth of growing medium, which determines the amount of runoff the roof can hold.
Water that is retained in the plant substrate will evaporate or evapotranspire back into the atmosphere instead of running off the roof. Nutrients and other pollutants can also be consumed by the plants.
Benefits:
The main function of a green roof is to reduce stormwater runoff in urban areas where space is limited for installing water quality improvement practices. However, it has been shown that green roofs also mitigate the urban heat island effect, improve air quality, provide aesthetically-pleasing functional green space in ultra-urban areas, provide habitat for birds and beneficial insects, and increase the life expectancy of the roof.