Credit Valley Conservation (CVC) is one of 36 conservation authorities in Ontario that delivers programs and services to protect, enhance and manage the natural environment on a watershed-basis. Since 2009, CVC’s Greening Corporate Grounds (GCG) program has been helping businesses and institutions manage stormwater on their properties with sustainable landscaping and low impact development (LID) solutions.
CVC undertook two parking lot retrofits at its Mississauga head office in 2009 and 2012. The projects show how LID practices can help typical commercial properties manage stormwater.
CVC in Action
CVC’s parking lot retrofit was one of the key features in an office expansion project that included building a LEED certified addition to the original office building. It involved installing permeable pavement and grass swales. These features help manage stormwater sustainably and reduce run-off into municipal storm sewers. Features like these help businesses in Mississauga qualify for Mississauga’s Stormwater Credit .
Permeable pavement is an alternative to conventional asphalt that uses interlocking pavers to allow rainfall to drain directly into the ground. In winter, they prevent meltwater from pooling, reducing slippery surface conditions and minimizing the need for road salt. Road salt affects water quality and is toxic for freshwater wildlife.
CVC’s permeable paver lot covers 3,800 m2. Grass swales border the asphalt roadway leading to the parking lot. The swales collect and direct run-off back into the ground. The swales also improve water quality by filtering particles and sediment. Periodic vacuuming is required to remove trapped debris and to maintain infiltration capacity. Vacuuming frequency is determined by intensity of use and presence of external debris. CVC vacuumed both its lots in 2017 and 2019 in order to ensure long-term performance.
Stepping Stones of Success
One of the project’s objectives was to monitor performance and analyze results. During the initial assessment period, CVC’s parking lot retrofit reduced run-off volumes from rain events by 63 per cent and removed 81 per cent of total suspended solids. This translates into reduced pressure on municipal infrastructure and reduced sediment pollution of our lakes and rivers.
Talking the Walk
CVC’s parking lot retrofit shows how LID and green infrastructure projects bring value to commercial properties and benefit the environment. It delivers evidenced-based results that can stand behind our recommendations to Greening Corporate Grounds members. For more information on how a parking lot retrofit could benefit your property, connect with us at [email protected]