I performed visual assessments, soil characteristic testing, and infiltration rate testing at 20+ mature bioretention systems across Ontario. The main results from the visual assessments were that inlets need to be cleared out at almost all sites. Soil testing showed that cells are still primarily sand, with very little sedimentation or buildup of clays. The infiltration rates at all sites remained high and above the minimum rate required of 25 mm/hr.
This work can begin to contribute to determining the lifetime expectancy and long term maintenance needs of bioretention systems.
This study will become a manuscript that is current under preparation. I have presented this at the UofT Engineering Research Conference (June 2020), the ASCE LID Virtual Conference (July 2020) and the TRIECA Virtual Webinar Series (September 2020).