Evaluation of Underground Stormwater Infiltration Systems

In this ongoing project, the performance of four different configurations of infiltration chambers/ trenches are being examined to evaluate their effectiveness relative to original design goals, and to provide insight on the site conditions under which infiltration chambers and trenches can be cost effective options for on-site water balance control.

Three of the systems being monitored in Caledon and Richmond Hill receive roof drainage only, while the forth in Brampton treats both roof drainage and parking lot runoff. The latter system is designed primarily for detention rather than infiltration of runoff because of the clay dominated soils in this area.  Together with other STEP evaluations of infiltration technologies (e.g. permeable pavements, bioretention areas, etc.), this study will help address a significant gap in knowledge about the efficacy of these technologies on sites with low permeability, fine grained soils.

Photo credit: GeoStorm Inc.