The District Municipality of Muskoka owns the Muskoka Road 169 bridge over the Bala north channel and the proposed project to build a hydro-electric generating station could damage this bridge, both during the proposed construction and the proposed operation. For example:
- During the proposed construction, the proponent would need to build an upstream cofferdam to keep the water from their proposed intake excavation. They have proposed two two types of cofferdams, the only one that would conform to the MNRF’s required cofferdam lowering plan would require boring 1′-diameter holes, 5′-deep directly adjacent to the support piers for both the MNRF’s Bala north dam and the District’s highway bridge.
We don’t know if the District has been informed of these risks to their bridge, and that is why this entire process is wrong. Such impacts should have been disclosed by the proponent as part of their environmental assessment, so all stakeholders would be informed of negative impacts and their mitigation.
- During the proposed operation, the support piers for the District’s highway bridge would be subjected to water speeds and directions for which it may not have been designed.
For example, while the maximum flow through the Bala north dam is 218 m3/s, so clearly the bridge could withstand this flow. However, the maximum flow through the proposed generating station would be 96 m3/s and these flows could occur simultaneously, for example if the Bala south channel had to be closed for maintenance work. In addition, the direction of flow would change due to the location of the intake. The highway bridge support piers may not have been designed for this.
On December 3, 2016 we therefore sent this letter to the MNRF asking if these impacts had been considered. We have not received any response.