Wellesley Dam repairs complete

Repairs to the embankment at the Grand River Conservation Authority (GRCA)’s Wellesley Dam are complete. The discharge gate has been returned to service, and the pond is currently filling. An engineering assessment of the concrete spillway structure has been completed. The initial results of the assessment indicate that although the structure is in fair condition overall and does not currently present any risk to dam safety or public safety, there are areas in poor condition that will require remediation in the near future. GRCA staff will continue regular inspections of the structure, including the concrete spillway. The length of time to fill the head pond will depend on weather conditions and inflows. GRCA staff have completed a wildlife scan of the area and have not identified any nesting animals or wildlife that would be negatively impacted by the filling of the head pond.

Background

The Grand River watershed experienced a mixed precipitation event from April 2 to April 3, 2025, including snow, freezing rain, thunderstorms and significant amounts of overall precipitation. Water levels in some river systems were already elevated at the time, due to previous rainfall and snow melt in late March 2025.

The extremely high water levels resulted in damage to the GRCA’s Wellesley and Baden dams, both of which are former mill dams that do not serve a flood control or flow augmentation function as part of the GRCA’s water control infrastructure. In both cases, water either overtopped the dams’ embankments or seeped through the embankments. The high water levels also resulted in the loss of operation of gate discharge equipment at Wellesley Dam. GRCA staff were present at both locations during the weather event and were able to immediately identify the separate occurrences as dam safety incidents, which would impact the stability and safety of these structures. Emergency repairs were initiated, and both sites were stabilized within hours of the dam safety incidents being identified.

Future Studies

For Wellesley Dam, the GRCA will be initiating a future study to complete a comprehensive conditions assessment of the structure and identify recommendations for future work. For Baden Dam, an additional study may be required.

In both cases, the studies would consider the long-term future of these structures that is cost-effective and mitigates risk to the public, the dam structure and the environment. Possible alternatives may include repair, modification or decommissioning of the dams. Any studies related to the long-term future of these structures will incorporate consultation with interest holders, including the municipalities, local community and First Nations.

For more information about the Wellesley Dam repair project, please refer the GRCA’s May 16, 2025 news release.

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Media Contacts:

Serena Catania, GRCA Supervisor of Communications and Marketing
Phone (519) 621-2763 x2240  |  Email scatania@grandriver.ca

Lisa Stocco, GRCA Director of Strategic Communications and Environmental Education
Phone 519-621-2763 x2316  |  Email lstocco@grandriver.ca