Green Roof Stormwater Runoff

Green roof runoff does contain concentrations of some nutrients and other parameters but values are in line with other planted systems.

Green roof stormwater runoff.

In urban areas like. Green roofs have a layer of plant material that absorbs water like a sponge. Stormwater runoff that comes from downspouts rushes onto roads picking up copper from brake pads fuel and chemicals. Green roofs aim to help eliminate excess stormwater.

Their major drawback is the initial cost. They capture water when it rains slowly releasing it through evaporation and plant use. Due to the volume reduction actual nutrient loadings from. Green roofs can significantly reduce the amount of rain water that would otherwise run off an impervious roof surface.

A typical extensive green roof of 3 5 inches depth will reduce the volume of runoff by about 55 in central pennsylvania and attenuate the peak runoff rates to the level of the pre development land use.