Green roofs can stop dirty runoffs at the source.
Even the biggest architecture firms in Malaysia love utilizing green roofs. When you compare the usual nonplanted roof with a green one, the storm water effects are obvious. The nonplanted one is a big surface area that the water falls onto, then rolls off of fast. In urban area, this quick runoff is an issue, since it increases the flood downstream. In case of heavy storms, green roofs help slow down the water.
Green roofs intercept water.
It is possible for planted roofs to intercept rain water, depending on the amount of rainfall. They can absorb water, and then release it as it transpires. By intercepting rainwater in this matter, it mimics the natural condition of the plants releasing and absorbing water, which helps prevent flooding. Shallow green roofs can completely intercept water when the rainfall is than one inch at a time!
Green roofs can slow down runoff.
Apart from intercepting much smaller storms, green roofs can also buffer and filter water during intense, long rainfall periods. During these moments, water travels longer through the plant, as well as other green roof media layers.
Green roofs can lessen the storm water runoff load on other systems.
In residential landscapes, roof stops can account for 40% or more of the area footprint. Putting a green roof on your home means that you can intercept a big amount of storm water runoff even before it gets to the other areas on the site. Moreover, it lessens the load on the other sustainable systems you might be using, such as permeable paving and rain gardens.