Laboratory Study on the Hydraulic Performance of Bioretention for Stormwater Management in Cold Climates

• Author / Creator

  Li,Zhan

• Bioretention has shown effective stormwater peak flow and volume reduction in warm and temperate climates. However, the applicability of bioretention for successful stormwater management in cold and semi-arid regions such as Edmonton is still not well understood. Four large bioretention columns were designed for this study and set up in a temperature-controlled laboratory with the capacity of lowering temperature to – 20 °C. Designed storm events were applied and monitored for 1st summer operation, one winter exposure and 2nd summer operation. Synthetic stormwater was applied weekly in summer conditions to investigate the hydraulic performance of two different soil types, with and without an internal water storage layer. Column 1 and Column 3, with less porous soil media (50.8% sand, 29.4% silt, and 19.8% clay), were shown to effectively attenuate peak flow for 1:2 year events, with a mean peak flow reduction of 83% and 91% respectively in 1st summer, and 77% and 73% respectively in 2nd summer. Column 2 and Column 4, with more porous soil media (67.2% sand, 19.6% silt, and 13.2% clay), maintained high hydraulic conductivity (9.6 cm/hr and 9.1 cm/hr respectively) after 2nd summer operation. Under winter conditions, columns with more porous soil media retained more volume of water within the columns, took less time for soil thawing and water breakthrough, and ponding vanished faster over frozen soil than columns with less porous soil media. After columns underwent an extreme winter condition of columns frozen at 20 °C air temperature three times, their hydraulic performance was able to rebound quickly. All columns successfully managed 1:2 year events in terms of the infiltration rate, ponding depths and durations. Preliminary results also showed that both less and more porous soil media have the potential to accept and drain the less frequent, large volume events (1:5 and 1:10 year events).

• Subjects / Keywords

  • Hydraulic Performance
  • Cold Climate
  • Stormwater
  • Bioretention

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-9mx0-mj63

• License

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