Repairs to the Wareham spillway

What is the Wareham spillway?

The Wareham dam and spillway make up part of the Mayo Generating Station and were commissioned in 1952. Just upstream of Wareham dam, water enters an underground pipe that goes to the Mayo A and Mayo B generators to make electricity. When there is too much water to use, it flows down the spillway and back into the Mayo River.

What's happening?

We conduct regular dam safety inspections. After one of these inspections, we noticed there was damage to the concrete on the base of the spillway. We made temporary repairs to the structure in 2021 and 2022, but recent inspections have found that additional, permanent repairs are urgently needed.

We completed temporary repairs to reduce the risks of additional damage to the spillway in the spring of 2024. 

What's the plan going forward?

The temporary repairs we completed have allowed us to use the spillway while we work on a permanent solution. We have started work on the permanent solution and hope to have it in place by 2026. As part of this work, we are considering fish-friendly options.

We have also developed a monitoring plan to detect any additional damage to the spillway. We will continue to work with the First Nation of Na-Cho Nyäk Dun and the Village of Mayo throughout the process and as we seek additional authorizations from our regulators.