• Toronto and Region Conservation Authority (TRCA) will begin maintenance work along Stouffville’s Flood Control Channel on Feb. 18.
  • TRCA owns the Channel lands and manages the system from just north of Main Street to Burkholder Street.
  • Work includes tree trimming and debris and vegetation removal to ensure the waterway remains unobstructed.
  • The Channel, built in 1980, works alongside the Stouffville Dam to divert flood water away from the Downtown area.
  • TRCA is also exploring options to naturalize the Channel, with implementation expected in 2027.
  • Upgrades to the Stouffville Dam, needed to align with current safety guidelines, are in the design stage.
  • The upcoming Channel maintenance project is expected to take four weeks.

 

Stouffville’s Flood Control Channel, built in 1980, works with the Stouffville Dam and reservoir on Millard Street to manage excess water from the Duffins Creek watershed. These systems help protect Stouffville’s Downtown and properties along the area’s floodplain.

That water then flows south along Stouffville Creek, eventually winding through York and Durham regions before reaching Lake Ontario via the Duffins Creek in Ajax.

According to TRCA, crews will cut and remove trees that have grown within or fallen into the Channel. Any damaged or unhealthy trees in the area will also be removed if deemed unlikely to survive.

“The removal of trees and vegetation is essential for reducing flood risk in the downtown Whitchurch-Stouffville area,” a TRCA notice states. “This is because trees and vegetation can reduce the flood flow capacity of the river.”

The Channel was constructed using gabion baskets—wired containers filled with rocks—that provide structural integrity and protect against erosion during high flow periods. It was dredged in 2012 to restore capacity, and maintenance is conducted on an as-needed basis.

According to Craig Mitchell, TRCA’s Senior Manager of Flood Infrastructure and Hydrometrics, the last servicing took place in 2022. Crews will use chainsaws to remove shrubs and saplings that have regrown within the system.

TRCA is also assessing options for full replacement of the gabion baskets, which can corrode over time and lose effectiveness against erosion. A feasibility study examined whether a natural channel lining with stones and vegetation could be used instead.

“The study found that naturalizing the Channel is possible with small amounts of channel widening to maintain the 100-year flood conveyance,” Mitchell said in comments to Bullet Point News. “We will be moving on to the next phase of implementation, which will be coming up with a final design.”

“We will be working closely with the Town of Whitchurch-Stouffville and York Region to arrange funding for construction,” Mitchell added. “TRCA is targeting a final design in 2026 with construction starting in 2027.”

The Stouffville Dam, built in 1969, is also regularly inspected to ensure it remains functional and safe. This is particularly important as the dam provides flood protection, but any failure increases flood risk. TRCA has identified necessary dam upgrades and is now working to advance their implementation.

“The dam requires some upgrades to the earthen embankment and emergency spillway to meet current dam safety guidelines,” Mitchell said. “The dam is safe under normal conditions, however, there is a small risk during extreme, but rare, flood events.”

Design work has begun, and TRCA is seeking construction funding. “Until funding is secured, it is difficult to put a timeline to implementation,” Mitchell noted.

Flooding in the area can occur at any time. Rising water levels and sudden flows can create ice jams in winter, while spring melts can bring increased flow throughout the watershed. In summer and fall, heavy storms can overwhelm small creeks and rivers, causing them to overflow their banks.

Urban flooding can also increase threats to floodplain properties when stormwater management systems and sewers reach capacity during major rain events. While conservation authorities like TRCA manage riverine flooding, stormwater infrastructure is the responsibility of municipal governments.

In the event of a dam emergency, evacuation notices are sent via Canada’s Alert Ready system, broadcasting alerts on television, radio, and mobile phones. TRCA also recommends subscribing to its flood messaging system for those living near creeks and rivers that can pose flood risk.

Whitchurch-Stouffville Fire and Emergency Services may also announce necessary evacuations.

“When it comes to flood preparedness, everyone—homeowners, landlords, renters, and condo owners—has a role to play,” TRCA states. “If you receive notice to evacuate, do so immediately.”

Comprehensive flood preparedness information is available on TRCA’s website.