One reason for its low cost effectiveness is that green roof does not treat.
Vegetation volume fraction green roof.
Manuscript title a modeling study of the interflow in the green roof.
The cost effectiveness of green roof expressed as percentage of peak runoff reduction per thousand dollars and volume of peak runoff reduction per thousand dollars i e 0 02 10 3 us and 0 02 l 10 3 us s is the least among the three lid practices.
Control name lid type layer parameter value gr your initial green roof surface berm height 3 vegetation volume fraction 0 2 surface roughness 0 1 surface slope 1 0 soil thickness 6 porosity 0 5 field capacity 0 2 wilting point 0 1 conductivity 0 5 conductivity slope 10 suction head 3 5 drainage mat thickness 1 void fraction 0 5 roughness 0.
Green roofs also referred to as vegetated roofs eco roofs and roof gardens consist of a layer of vegetation that covers an otherwise conventional flat or moderately pitched roof.
Modelling results demonstrated that the conversion of 30 of roof area to green roof 10 of green areas to rain gardens and 35 of paved areas to permeable pavement could increase the baseline volume capture ratio from 59 9 to 82 2 indicating that sponge city goals can be met within the case study area with realistic levels of lid.
Both of the roofs have considered with extensive green roofs having a 150 mm depth of surface layer for root growth shown in fig.
The gradient of the surface slope.
1 as gr1 and gr2.
Vegetation volume fraction the fraction of the volume within the surface storage depth filled with vegetation.
Porosity the volume of pore space relative to total volume of soil as a fraction.
But only 3 to 6 inches 75 to 150 mm for green roofs.
24 control name lid type layer parameter value gr your initial green roof surface berm height 3 vegetation volume fraction 0 2 surface roughness 0 1 surface slope 1 0 soil thickness 6 porosity 0 5 field capacity 0 2 wilting point 0 1 conductivity 0 5 conductivity slope 10 suction head 3 5 drainage mat thickness 1 void fraction 0 5 roughness 0.
Fraction of the area above the surface that is filled with vegetation.
Besides this value is calculated by the area and depth of the grs in this study.
A green roof is composed of multiple layers which may include a waterproofing roof protection layer moisture interception layer drainage layer leak detection.
2 the volume of the rainwater tanks is better larger than 0 045 m 3 for per unit area m 2 of grs.
This is the volume occupied by stems and leaves not their surface area coverage.
An extensive green roof is most suitable for implementation at the individual level or small scale which provides the best cost benefit ratio with the least maintenance as compared to the intensive green roof.
