Data Synthesis and Design Considerations for Stormwater Thermal Mitigation Measures

Several practices have been implemented across Ontario to help mitigate the thermal impact of ponds on receiving waters.  In this project, commissioned by the City of Brampton, we examine the effectiveness of different measures installed in southern Ontario that are either being used, or have the potential to be used as a means of reducing thermal pollution from stormwater ponds.  Monitored practices reviewed and analyzed in this project include: 

  • 18 stormwater pond subsurface draw outlets 
  • 1 stormwater pond night-time release outlet
  • 18 cooling trenches
  • 14 low impact development practices (e.g. bioretention, infiltration trench, green roof) 
  • 1 subsurface pond 
  • 1 floating island 
  • 1 vegetated channel (a long one!) 

Based on the data review and synthesis, the report provides insights into how the different measures work, expected performance ranges, and factors that should be considered in the design and maintenance of the practices

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