Barrie, Ont. innovative stormwater safe, a Lego block-like construction
Another in a series of proactive initiatives to protect the health of Lake Simcoe, the fourth largest lake entirely in Ontario and a major tourist destination, is nearing completion in Barrie, Ontario.
Designed by Aquafor Beech Limited, the City of Barrie Conservation Authority and Lake Simcoe Region joint venture is a $1.6 million storm management pond renovation Irwin in the Kidd’s Creek watershed in the northwest corner of the city.
Construction began in the fall of 2021. The general contractor is Groupe Greenspace and the equipment supplier is Terrafix.
Once the upgraded pond is fully brought back online, it will significantly reduce the amount of stormwater entering the creek, which empties into Lake Simcoe, while reducing phosphorus loading to the lake by 58%.
These environmental goals will be achieved through the first-ever installation of the Triton Stormwater Vault System in a stormwater management pond in Canada.
Although this system and others like it have been placed under parks, parking lots and other sites, “this is the first time it has been used under a municipal stormwater management pond in Canada,” says Jeff Henry, Technical Project Manager for the City of Barrie.
Buried just 0.5 meters below the pond bottom and lined with light stone that will provide additional storage and infiltration of runoff water, the segmented vault system is made up of 450 modules that look like a series of large blocks Lego. Inserted by hand by the contractor, they’ve been locked together with a top cap that allows them to become a single unit, he says.
The modules are essentially holding tanks that allow rainwater to naturally infiltrate into the ground. After entering the pond, stormwater will be diverted to a two-unit oil/grit separator, which will remove oil, debris and other suspended solids, and then routed to the vault system.
In times of extremely heavy downpours, an outlet channel will direct water into a storm sewer that extends to Kidd Creek.
But the purpose and intention of the meter-high arch system is to reduce this harmful impact. The pond’s storage capacity will have been increased from its current capacity of 5,640 cubic meters to just over 8,000 cubic meters, he says.
Irwin Pond is a dry pond, Henry explains, explaining that during extended periods without rain, it is dry and only fills with water when it rains, then slowly drains back into the watershed.
“That (the dry condition) made it easier to build. But it was a difficult site and there was no place to store the materials,” says Henry, referring to the location of the pond next to Sunnidale Road and right next to a residential area. .
Although work was limited to the original footprint of the pond, approximately 2,050 cubic meters of topsoil and soil had to be removed. After the vault system was installed, approximately 320 cubic materials of this material were reused to cover it.
As the site is quite small, Greenspace used a limited number of machines, including diggers and mini-diggers. However, construction did not generate dust or impact traffic on Sunnidale Road and neighboring property owners understood the need for the project, he says.
A critical part of the construction was the construction of a berm between the active excavation and the existing low-flow channel to protect the work area from storm water inflows. It was in line with the construction sequence and in accordance with the project’s erosion and sediment control plan.
Later this spring, the berm will be removed and the site restored with landscaping for an expected project completion date in early June, he says.
A 2001 drainage master plan first identified the need for the project and this need was later confirmed in a second plan in 2018. Design work began the same year.
The City of Barrie is leading the project, while the Lake Simcoe Region Conservation Authority has provided technical advice, as well as funding through its Phosphorus Offsetting Funding and water balance,” says Henry.
Irwin Pond is technically known as Sunnidale SWMF KD03 because it is the third pond that drains into the Kidd’s Creek watershed. The city is considering installing the Triton system in one of those other ponds, as well as incorporating similar systems in other ponds around Barrie, he says.
The project is a “great example” of the partnerships that have been forged between municipalities and the conservation authority, says its chief executive, Rob Baldwin.
“We know our watershed will experience above-average annual temperature increases and we expect to see more frequent and intense rainfall and the possibility of more widespread flooding,” Baldwin says, stressing the need for projects like as the renovation of Irwin Pond.
A number of other projects are also in the works for 2022, he says.
“We are currently developing a plan to improve stormwater management in the East Holland River sub-watershed. When completed, it can formulate the basis for a watershed-scale approach to stormwater management.
Several other restoration projects are planned for this year, including two in Barrie, one of which is the renovation of another stormwater pond to help improve the health of Sophia Creek, Baldwin says.