What intensity and duration of storms can be managed?

It depends on the amount of water that drains onto the PICP, the depth (and storage capacity), the base, the infiltration rate of the soil under an open-graded base and the presence of drain pipes within an open-graded base. PICPs are intended to manage water quantities and pollutants from smaller, more frequent storms such as those with a return period of 10 years or less. These storms tend to be shorter in duration and often have the highest concentrations of pollutants. PICPs are not intended to control flooding from larger, infrequent rainstorms.