CVC Commissions Canada’s First ICC-Compliant Smart Blue Roof

In late June, Credit Valley Conservation (CVC) celebrated the official completion and commission of its smart blue roof. The rainwater storage and reuse system is the first in Canada compliant with International Code Council standards for rainwater harvesting. The early adoption of this water technology occurs as intensifying rain storms are raising the frequency and risk of flooding.

On Tuesday, 16 July the blue roof fully captured 72 mm (2.8 in) of rainfall or approx. 25,000 litres of water. This volume was in addition to 48 mm (1.9 in) of rainfall or 16,500 litres the system captured as remnants of Hurricane Beryl passed over Ontario, Canada on Wednesday, 10 July.

Innovative storage & reuse of stormwater

Standard flat-roof buildings immediately drain rain into the city’s stormwater system. However, the smart blue roof technology is designed to store 40,000 liters of rainwater on the roof for a variety of purposes.

The system optimizes use of drinking water supplied by the City of Mississauga. It increases non-potable water efficiency. Grey water is treated to non-potable standards using CSA-compliant treatment systems and then used to flush toilets. Reuse reduces the demand for water pumped from Lake Ontario.

CVC’s Mississauga headquarters show that industrial, commercial, and institutional (ICI) roofs among other impervious surfaces can significantly reduce the risk of flooding, erosion and other environmental impacts. During storms these buildings and areas can send large volumes of runoff into water networks without the capacity for them. Control over water flow into the city’s stormwater system reduces the risks and negative impacts.

In warmer weather, evaporative cooling from the roof cools the building. Reducing energy use and greenhouse gas emissions also creates cost savings.

Smart water choices

The system uses valves to strategically manage water, either storing water on the roof or channeling it to a tank in the basement.

Furthermore, this system uses control logic to determine the best use of captured rainwater. Based on present water levels on the roof or in the tank as well as weather forecasts, the system will suggest the most efficient course of stormwater management:

• Hold rainwater until it evaporates from the roof
• Send rainwater to a cistern for reuse
• Slowly release rainwater into the municipal stormwater system

A vision for the future

This first of its kind project is expected to catalyze wider adoption of active stormwater controls, logic and reuse. CVC began this ambitious project in 2017. Its goal was to install Canada’s first smart blue roof system compliant with the Canadian Standards Association’s new standard for rainwater harvesting systems (CSA B805-18). It received grant funding from Intact Insurance and the Federation of Canadian Municipalities.

Learn more CVC’s smart blue roof and the organization’s Sustainable Technologies Evaluation Program.

Raising the Profile of Roofs

Other KISTERS customers who have implemented smart roofs include Mississippi Watershed Management Organization (MWMO) in Minneapolis, USA and Bruntwood Works of Manchester, UK.

MWMO headquarters feature a stormwater park and learning center, where a native garden sits next to a green roof. The flat membrane roof absorbs and filters rain and snow, mitigating urban heat island effects and cooling the watershed district offices. Rainwater captured from the roof is stored in a 4,500 gallon cistern in the front yard and reused for irrigating the gardens and trees. Unstored rainwater passes through backyard water filtration experiments, slowing the flow of water entering the city’s drainage network and improving water quality.

In response to the UK Green Building Council’s Innovation Challenge, Bruntwood Works transformed an existing building to become more climate resilient and enhance biodiversity with as little disruption to occupants. The smart blue-green roof stores rainwater in a green roof substrate (akin to micro stormwater tanks) by Polypipe Civils & Green Urbanisation and reuses it to irrigate and sustain a rooftop flower garden that sustains pollinators. Control valves and logic help reduce the stormwater runoff entering United Utilities’ sewer network, lowing flood risk.