Changes

[[File:Bioretnetion TSS.jpg|200px|thumb]]

[[File:Bioretnetion TSS.jpg|200px|thumb]]

The whisker plot figure to the right......performance results for [[Bioretention]] practices, located within TRCA's watershed originate from six primary sites:  

The box plot figures to the right show combined stormwater effluent quality results from STEP monitoring projects conducted over a 16-year time period (between 2005 and 2021) at sites within Greater Toronto Area (GTA) municipalities. Total Suspended Solid (TSS) effluent concentration results for [[Bioretention]] practices represent the combined results from 9 sites in the GTA and a total of 301 monitored storm events.  Monitored sites include the following:  

*Kortright Centre

*Kortright Centre, Vaughan, Ontario

*Earth Rangers

*Earth Rangers, Vaughan, Ontario

*Seneca College

*Seneca College, King City, Ontario

*Central Parkway (Mississauga)

*Wychwood Subdivision (Brampton)

*IMAX Corporation, head office

*Central Parkway, Mississauga, Ontario

 

*Wychwood Subdivision, Brampton, Ontario

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.

*IMAX Corporation Head Office, Mississauga, Ontario

 

*Aurora Community Centre, Aurora, Ontario<br>

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), or

(background (assumed at <5 mg/L)+ 25 mg/L for short term (<24 hour) exposure) (CCME, 2002<ref>Canadian Council of Ministers of the Environment (CCME). 2002. Canadian water quality guidelines for the protection of aquatic life: Total particulate matter. In: Canadian Environmental Quality Guidelines, Canadian Council of Ministers of the Environment, Winnipeg</ref>; (TRCA, 2021<ref>TRCA. 2021. Spatial Patterns (2016-2020) and Temporal Trends (1966-2020) in Stream Water Quality across TRCA’s Jurisdiction Prepared by Watershed Planning and Ecosystem Science. https://trcaca.s3.ca-central-1.amazonaws.com/app/uploads/2021/10/29113334/2016-2020-SWQ-Report-v11_FINAL_AODA-FA.pdf</ref>).

Median TSS concentration was found to be 9.5 mg/L and exceeded the Canadian Water Quality Guideline of 30 mg/L (CCME, 2002<ref>Canadian Council of Ministers of the Environment (CCME). 2002. Canadian water quality guidelines for the protection of aquatic life: Total particulate matter. In: Canadian Environmental Quality Guidelines, Canadian Council of Ministers of the Environment, Winnipeg</ref>; (TRCA, 2021<ref>TRCA. 2021. Spatial Patterns (2016-2020) and Temporal Trends (1966-2020) in Stream Water Quality across TRCA’s Jurisdiction Prepared by Watershed Planning and Ecosystem Science. https://trcaca.s3.ca-central-1.amazonaws.com/app/uploads/2021/10/29113334/2016-2020-SWQ-Report-v11_FINAL_AODA-FA.pdf</ref>) during only 15% of the 301 monitored storm events.

 

The median value of the 301 samples taken was '''9.50 mg/L''' whereas the mean was ''' 18.63 mg/L''', with a '''15%''' guideline exceedance.

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