Collective Stormwater Infrastructure Project

A corporate leader in water stewardship for the Highland Creek watershed

Calstone Inc., a manufacturer of steel-based furniture products located in Scarborough, has extended its commitment to sustainability by installing innovative Low Impact Development stormwater management infrastructure on their property.

After receiving $5,000 from City of Toronto’s Hometown Heroes Earth Day award to install a rainwater harvesting tank and plant a garden, Calstone approached Partners in Project Green’s Water Stewardship Committee. Using funds from an
Ontario Ministry of Environment and Climate Change Showcasing Water Innovation grant and Partners in Project Green’s Water Stewardship capital grant, the stormwater management retrofit project was scaled up by an investment from Calstone, to reach a the final project value of $97,920.

Before construction commenced, geotechnical reports were consulted to estimate the water table depth below the property and tests were performed to determine the asphalt pavement thickness and permeability of the underlying subsoil (3.3 mm/h). Additionally, Calstone’s expansion, improvement and maintenance plans were developed and reviewed by Grounds Covered, XCG Consultants Ltd. and the Sustainable Technologies Evaluation Program (STEP),. An important lesson learned was that, although there are inherent challenges in collaborating with so many partners, the ability to provide maximum added value to a project increases when all parties remain fully engaged.

The system includes two rainwater harvesting tanks, of which one overflows into three infiltration ponds. Two of the ponds provide temporary water storage and infiltration functions while the third functions as an attractive permanent water feature. Employees and visitors are able to walk along the edge of these ponds on a permeable walkway, which leads to an infiltration trench at the back end of the building.

These stormwater management systems will set Calstone apart from other medium-sized manufacturers in the area for having a distinct, enhanced green space for employees and showing dedication to exemplary water stewardship within the Highland Creek watershed. Since stormwater infrastructure servicing this area is aging, this showcase of Low Impact Development best management practices demonstrates to the community ways that the cost of retrofitting municipal infrastructure could be avoided.

Once fully operational, the stormwater management system will be able to capture 100% of the rainwater from Calstone’s 3,900 square metre roof, which will be used to enhance employee green space, irrigate landscaped areas and for on-site stormwater infiltration. Annually, this will divert approximately 1.8 million litres of rainwater from being directly discharged to the municipal storm sewer and, thereby help to restore a more natural water cycle to Highland Creek.

The monitoring and testing of these stormwater management systems as well as the official planting of native, drought-resistant trees, plants and shrubs will be completed in 2015. The understanding gained from analyzing the treatment and cost effectiveness of such systems can be used to inform decisions about future private-property retrofits across southern Ontario.

Calstone Inc.’s project was a stop on WaterTAP’s 2014 domestic media tour as it aligns with Partners in Project Green’s objective to showcase lot-level stormwater management techniques to lower the burden on aging municipal infrastructure. The long- term goal is to increase the number of these projects in the GTA by taking a collaborative approach to their execution.

Article Credit: Partners in Project Green.