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2014 Water

City of Mississauga, Ontario, and Credit Valley Conservation

Elm Drive Right-of-way Retrofit

Population:  Project duration:  Total project value:
715,000 2010–2011 $585,000


The City of Mississauga's Elm Drive right-of-way retrofit project is the first in Ontario to use low-impact development (LID) practices that capture and treat stormwater runoff through permeable pavement and bioretention planters.

To protect natural environments and promote a green culture, the city partnered with Credit Valley Conservation to channel stormwater through innovative roadway landscaping and reduce runoff into the storm sewer system. The high cost of land makes building end-of-pipe stormwater management systems in developed areas very expensive. This space-efficient approach uses the existing road allowance and an adjacent school property.

LID practices will reduce Mississauga's stormwater management costs. Additional savings will come through the city's new stormwater user rate, designed to encourage private owners of rooftops, parking lots, and driveways to follow LID practices as they build or renovate. The Elm Drive right-of-way retrofit demonstrates that municipalities can use LID techniques to meet environmental targets within existing stormwater infrastructure.


Environmental Economic Social
  • Only 1 of 89 recorded rainfalls less than 25mm has resulted in discharge to storm sewers, compared to 100% for conventional roads

  • 99% reduction in total suspended solid levels in storm sewer discharge

  • Supports lifecycle analysis by collecting and sharing data that identifies costs and benefits

  • Improves infrastructure resiliency to extreme weather events

  • Partnerships with internal and external collaborators

  • Case studies and fact sheets highlight barriers and solutions for other communities

  • Demonstrates Canada's leadership in water technology


  • Detailed design drawings were required to support the contractor during LID installation.

  • Landscape design plans had to define both functional and aesthetic expectations, including clear direction on sediment and erosion controls during and after construction.

  • Contractors and workers did not always understand the special requirements of innovative materials and technology.

Lessons learned

  • Learn from neighbours and through on-site observation how the site and adjacent areas are used. This should guide the design of the LID feature.

  • Good partners are essential. The collaboration between City of Mississauga, Credit Valley Conservation and the Peel District School Board was one of the project's great successes.

  • At the initial stages, consider what departmental and staff participation will be needed, and when. This can save money through resource sharing and synergies.

  • The innovative LID "treatment train" approach - situating green infrastructure in sequence — offers added reliability, flexibility and resilience that a single technology could not provide.

Page Updated: 27/04/2018