SWMM - LID Controls - Green Roof

Green Roofs - are another variation of a bio-retention cell that has a layer of soil over a special drainage blanket material that transports excess rain percolated from the roof.

Schematically:

• SWMM
  • Draining Material
    • Voice Index - The ratio between the void volume and the total volume in the draining layer
    • Thickness - Thickness of the drainage layer
    • Roughness - Manning coefficient of the draining material
  • Soil
    • Field Capacity - Volume of pore water in relation to total volume after soil drains completely
    • Hydraulic Conductivity - Hydraulic Conductivity for fully saturated soil
    • Conductivity Slope - Slope of the curve of log (Conductivity) versus soil moisture content (dimensionless)
    • Thickness - Thickness of the soil layer
    • Wilting Point - Volume of pore water in relation to total volume for a very dry soil, where only bound water remains
    • Porosity - The volume of pore space in relation to the total soil volume
    • Suction Potential - The average value of soil capillary suction along the wetting front
  • Surface
    • Vegetable Coverage
    • Slope - Surface slope
    • Side Slope - Slope of the side walls of a cross section of a ditch
    • Storage Depth - Storage Depth
    • Surface Roughness - Roughness