Changes

*''D'' = Duration of the design storm event event (hr)

*''D'' = Duration of the design storm event event (hr)

*''i'' = Intensity of the design storm event (m/hr)

*''i'' = Intensity of the design storm event (m/hr)

*''R'' = the ratio of impervious contributing drainage area to permeable pavement area; ''A_i''/''A_p''}}

*''R'' = the ratio of impervious contributing drainage area to permeable pavement area; ''A_i''/''A_p''

*''A_i = Impervious contributing drainage area (m²)

*''A_i = Impervious contributing drainage area (m²)

*''A_p = Permeable pavement area (m²)

*''A_p = Permeable pavement area (m²)

*''f''' = [[Design infiltration rate]] of underlying native soil (m/hr)

*''f''' = [[Design infiltration rate]] of underlying native soil (m/hr)

*''C'' = Runoff coefficient of impervious contributing drainage area (e.g., 0.9 for asphalt)  

*''C'' = Runoff coefficient of impervious contributing drainage area (e.g., 0.9 for asphalt)  

*''n'' = Porosity of the stone bed aggregate material (typically 0.4 for 50 mm dia. [[reservoir aggregate|clear stone]])  

*''n'' = Porosity of the stone bed aggregate material (typically 0.4 for 50 mm dia. [[reservoir aggregate|clear stone]])}}

It is important to note that R should not exceed 2 to limit hydraulic loading and help avoid premature clogging.  Also important to note is that the contributing drainage area should not contain pervious areas that are sources of sediment that can lead to premature clogging.  

It is important to note that R should not exceed 2 to limit hydraulic loading and help avoid premature clogging.  Also important to note is that the contributing drainage area should not contain pervious areas that are sources of sediment that can lead to premature clogging.