BMP Monitoring Sites - Urban Drainage and Flood Control District
BMP Monitoring Sites - Urban Drainage and Flood Control District
BMP Monitoring Sites - Urban Drainage and Flood Control District
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UDFCD <strong>BMP</strong> MONITORING SITES<br />
Porous Asphalt Pavement<br />
D<br />
L max = 1. 5∗ So<br />
◊ Lmax = maximum distance between cut-off<br />
membrane normal to the flow (ft)<br />
◊ So = slope of the base course (ft/ft)<br />
◊ D = depth of gravel base course (ft)<br />
Subdrain System<br />
When the porous asphalt pavement is located on NRCS<br />
Type D soils, when the Type B or C soil sub-base is to be<br />
compacted for structural reasons, or when an<br />
impermeable membrane liner is needed, install a<br />
subdrain system using perforated HDPE pipe.<br />
Locate each perforated pipe just upstream of the lateralflow<br />
cut-off barrier. Do not exceed 20-foot spacing. Use a<br />
control orifice sized to drain the pore volume of empty<br />
each cell in 6 hours or more.<br />
Design Area Ratio The design area ratio shall not exceed 2.0 (ratio =<br />
And Effective contributing impervious area/porous pavement area). The<br />
Imperviousness interim recommendations for the effective<br />
imperviousness are given in the Manual.
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