Green Roof Stormwater Runoff

Green roofs can help to reduce both storm water volume rate of run off entering the drainage system.

Green roof stormwater runoff. In urban areas like. 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. Green roofs have a layer of plant material that absorbs water like a sponge. Green roof runoff does contain concentrations of some nutrients and other parameters but values are in line with other planted systems.

Their major drawback is the initial cost. Due to the volume reduction actual nutrient loadings from. Green roofs aim to help eliminate excess stormwater. Green roofs can significantly reduce the amount of rain water that would otherwise run off an impervious roof surface.

They capture water when it rains slowly releasing it through evaporation and plant use.