Learn How We’re Making the Most of Rainwater
In 2017, we embarked on a mission to install Canada’s first smart blue roof system that is compliant with the Canadian Standards Association’s new rainwater harvesting systems standard (CSA B805-18) at our head office in Mississauga. Construction is now almost complete and we’re ready for the rain!
How Does it Work?
Smart blue roof technology allows us to safely store 40,000 litres of rainwater on top of the roof for reuse by:
- Providing non-potable water for applications such as toilet flushing.
- Providing cooling benefits during warmer weather.
The smart blue roof also slowly releases rainwater back into the municipal stormwater system, reducing the risk of flooding, stream erosion and other ecological impacts.
Standard flat-roofed buildings are commonly used on industrial, commercial and institutional (ICI) buildings. They have passive roof drains, which allow water to quickly flow from roof surfaces down into storm sewers. A smart blue roof is different. Control valves open and close to strategically hold water on the roof surface or allow it to drain to head office’s basement rainwater harvesting tank.
This technology is smart because it uses control logic to decide how captured rainwater is best used:
- Hold rainwater until it evaporates from the rooftop.
- Send rainwater to a harvesting tank where the water can be reused.
- Slowly release rainwater into the municipal stormwater system.
Smart Blue Roof Technology as an Effective Stormwater Management Strategy
Smart blue roofs are an effective solution for stormwater management. ICI neighbourhoods often generate significant amounts of runoff during storm events. Holding rainwater on flat-roofed buildings for reuse can significantly reduce the peak flow rate of runoff that is caused by ICI lands during storm events, helping to reduce erosion and flooding.
Rainwater Reuse and Evaporative Cooling
Rainwater that is captured by our smart blue roof will be treated to non-potable standards by CSA-compliant treatment systems. After treatment, captured rainwater can be used in our toilets, reducing the need for potable water supplied by the City of Mississauga. By cutting back on city water, CVC’s utility bill will decrease and less water is pumped from Lake Ontario.
We’ll also see energy savings through the process of evaporative cooling. When water evaporates from the roof, it cools the building, reducing energy use and greenhouse gas emissions.
Potential for Wider Adoption
Being the first of its kind, this pilot project is anticipated to break new ground for the wider adoption of active stormwater controls. We are expecting construction to conclude later this year. We’ll be sharing our lessons learned through the Sustainable Technologies Evaluation Program.
This pilot project was made possible by funding from Intact Insurance and the Federation of Canadian Municipalities.
Learn how CVC’s smart blue roof is helping to build resilient communities by capturing rainwater.
Do you have questions about our blue roof system? Connect with us on LinkedIn, Twitter and Facebook.
By James Cowan, Coordinator, Integrated Water Management
Here at Whole Village Farm/Ecovillage we have a 15,000 sq. ft. flat roof and are re-covering it after the original membrane failed due to the high UV rays. I read your article but couldn’t find what membrane you are using for your new roof. Would you let us know, please?
Hi Brenda, for our Smart Blue Roof, we are using a white PMMA (polymethyl methacrylate) membrane. PMMA membranes are liquid-applied (rolled on like paint) so there are no seams on the roof surface. White roof surfaces generally reflect more sunlight. This PMMA membrane replaced a white TPO (thermoplastic polyolefin) membrane that covered the Smart Blue Roof area prior to construction beginning.
Works like a cistern in bygone days.
If this is a success then perhaps it should used for all the warehouses recently installed in Caledon. It is of utmost importance that we be able to harvest rainfall rather than have it as a destruction time force.