The mean performance value recorded at the outlet for Bioretention practices' ability to remove Total [[Phosphorus]] (TP) was calculated based on 301 separate recordings between 2005-2007, 2011-2019 and 2021 amongst the sixsites previously mentioned.
The mean performance value recorded at the outlet for Bioretention practices' ability to remove Total Suspended Sediments (TSS) was was calculated based on 301 separate recordings between 2005-2007, 2011-2019 and 2021 amongst the six sites previously mentioned.
As can be seen in the corresponding boxplot the mean performance removal efficiency of the bioretention practices monitored are well below the suggested guideline of 30 mg/L (Canadian Water Quality Guideline (CWQG), </ref>).
The median value of the 355 samples taken was '''0.87 mg/L''' whereas the mean was '''0.123 mg/L''', with an 86% guideline exceedance. Given the age of most of these practices, more inspection, maintenance and necessary rehabilitation will be needed to ensure they are able to meet the federal government's guideline requirement for stormwater quality.