Future of Wellesley, Baden dams in question after early April flooding

An emergency situation is underway at the Wellesley and Baden dams as the fallout continues from the snow, freezing rain, and heavy downpours of early April.

The walls of both structures were flooded over the course of April 2 and 3, leading to extreme pressures and damage to each of the dams. That intense build-up meant the Grand River Conservation Authority (GRCA) needed to send out emergency repair crews to both sites to contain the issues and prevent further damage.

“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,” the GRCA said in a statement.

Crews were able to quickly stabilize both sites upon arrival, opening the gates at the Wellesley Dam to relieve the pressure, but it wasn’t quick enough to prevent extensive damage.

“These high water levels resulted in damage to the discharge gate equipment and erosion of the east embankment,” the GRCA said. “Due to the loss of operation of the control gate, the decision was made to secure the gate in an open position until repairs to both the gate and the embankment could be made to protect dam safety and prevent overtopping.”

The Wellesley Dam remains completely emptied, with the GRCA saying it will need to relocate all the local wildlife that would be impacted by the low water levels.

Meanwhile, the conservation authority revealed that the Baden Dam already had pre-existing damage to its walls even before the recent flooding.

“Possible alternatives may include repair, modification, or decommissioning of the dams,” the statement said.

The GRCA said staff identified a hole with active seepage during routine monthly inspections of the Baden Dam. After the recent extreme weather, “it was observed that the seepage had increased significantly.”

Construction on the immediate repairs, separate from the temporary measures already put in place, will commence in early May.

“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.”

It said additional studies are being conducted for both the Wellesley Dam and the Baden Dam, looking to develop a comprehensive conditions assessment of the structures, along with aiding in developing a list of recommendations to be brought forward.