Typically designed to handle the smaller, most frequent storm events, LID practices in Ontario are usually sized according to the 90th percentile event. The rainfall depth of the 90th percentile event varies geographically. Use the map on the right to determine the typical 90th percentile event based on the site location. Controlling this amount of runoff may provide stormwater engineers with control of over 90 % of the mean annual pollutant load <ref>Pitt, R. 1999. Small Storm Hydrology and Why it is Important for the Design of Stormwater Control Practices. In: Advances in Modeling the Management of Stormwater Impacts, Volume 7. Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press. 1999</ref>. | Typically designed to handle the smaller, most frequent storm events, LID practices in Ontario are usually sized according to the 90th percentile event. The rainfall depth of the 90th percentile event varies geographically. Use the map on the right to determine the typical 90th percentile event based on the site location. Controlling this amount of runoff may provide stormwater engineers with control of over 90 % of the mean annual pollutant load <ref>Pitt, R. 1999. Small Storm Hydrology and Why it is Important for the Design of Stormwater Control Practices. In: Advances in Modeling the Management of Stormwater Impacts, Volume 7. Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press. 1999</ref>. |