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#[[Green roofs]], [[absorbent landscapes]] and [[permeable paving]] often receive very little flow from other surfaces, so that the I/P ratio is close to 1.
#[[Green roofs]], [[absorbent landscapes]] and [[permeable paving]] often receive very little flow from other surfaces, so that the I/P ratio is close to 1.
#[[Infiltration trenches]], [[Infiltration chambers| chambers]] and [[bioretention cells]] have a maximum recommended I/P ratio of 20.
#[[Infiltration trenches]], [[Infiltration chambers| chambers]] and [[bioretention cells]] have a maximum recommended I/P ratio of 20.
===Determine the effective infiltration coefficient==
<math>q'=\frac{q}{SCF}</math>
The following equations assume that infiltration occurs primarily through the base of the facility.
The following equations assume that infiltration occurs primarily through the base of the facility.
*''D'' = Duration of design storm in hrs
*''D'' = Duration of design storm in hrs
*''i'' = Intensity of design storm in mm/hr
*''i'' = Intensity of design storm in mm/hr
*''q''' = Infiltration rate of underlying soil in mm/hr
*''q''' = Infiltration coefficient in mm/hr (accounting for SCF)
*''SF'' = Safety factor
*''SF'' = Safety factor
*''V<sub>R</sub>'' = Void ratio (porosity), as measured (or default to 0.35 for all aggregates)*
*''V<sub>R</sub>'' = Void ratio (porosity), as measured (or default to 0.35 for all aggregates)*