How vegetation reduce stormwater runoff on green roofs

available from ctbuh journal article

1. Research shows, extensive green roofs reduces storm water runoff up to 60-100%, depending on
-green roof design
-substrate depth
-slope angle
-vegetation species used

*differences of intensive and extensive green roof depends on the substrate depth
a) extensive green roof - shallower substrate depth (150mm and below)
b) intensive green roof - more commonly used due to i) building weight restrictions and ii) costs

Fern is the most effective one (in rainwater run off control).

1. fern

2. herb

3. sedum

4. grass

Increase in vegetation structure density & leaf character
Kaempferia galanga-wide waxy leaf surface enables it to hold water in the center of surface creating the lotus effect.
Sedum mexicanum - thin leaves leaving no opportunity to hold stormwater runoff upon interception


Vegetation biomass size
Increase of vegetation size - better stormwater runoff reduction
1. Support by Nagase and Dunnett (2012)
2. Nephrolepis biserrata has larger biomass, best stormwater reduction rate.

Types of vegetation