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[[File:90th percentile.png|thumb|Recommended regional 90th percentile volume targets for Ontario]]
[[File:90th percentile.png|thumb|Recommended regional 90th percentile volume targets for Ontario]]
Runoff Volume Control Target (RVC<sub>T</sub>)
Typically designed to handle the smaller, most frequent storm events, LID practices in Ontario are usually sized according to the 90th percentile event. In many areas this translates into events that are < 30 mm in depth. Note that 25 mm is considered to be a suitable representation of the ‘first flush’ volume, and that controlling this amount of runoff may provide stormwater engineers with control 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>.
===Runoff Volume Control Target (RVC<sub>T</sub>)===
{{textbox|1="The means to achieve the RVC<sub>T</sub> includes:<br>
{{textbox|1="The means to achieve the RVC<sub>T</sub> includes:<br>
'''Retention''' - where the captured volume shall be ultimately [[infiltration|infiltrated]], [[Evapotraspiration|evapotranspired]] or [[Rainwater harvesting|re-used]] and the specified volume will not later be discharged to sewer networks (with the exception of internal water re-use activities) or surface waters and does not therefore become runoff, and
'''Retention''' - where the captured volume shall be ultimately [[infiltration|infiltrated]], [[Evapotraspiration|evapotranspired]] or [[Rainwater harvesting|re-used]] and the specified volume will not later be discharged to sewer networks (with the exception of internal water re-use activities) or surface waters and does not therefore become runoff, and