Make the McKenzie Connection!
Make the McKenzie Connection!
Trail Bridge hydro shuts down for fish passage through October
Work on improvements to Trail Bridge Reservoir is scheduled to wrap up in early November, including excavation for the left bank anchor. Officials say the replacement boom will be much more robust than the existing on, with proved effective in containing a contaminants from a nearby milk truck accident in May of this year. Total costs, including the boom and related construction, are estimated at about $2.9 million.
The Eugene Water & Electric Board (EWEB) has temporarily halted power generation at its Trail Bridge Powerhouse on the upper McKenzie River to help young fish safely migrate downstream during their annual journey.
From July 2 through Oct. 31, water that would normally pass through the Trail Bridge Powerhouse turbines is now being released over the dam's spillway. The seasonal change is intended to give juvenile salmon and other fish with a safer route from regions upstream of Trail Bridge Dam into the lower McKenzie River.
The Trail Bridge Powerhouse is part of the utility's Carmen-Smith Hydroelectric complex near the headwaters of the McKenzie River. When producing electricity, it generates less than 10 megawatts-only a small portion of the project's overall output. Most of the project's power comes from the nearby Carmen Powerhouse, which can generate up to 110 megawatts.
The seasonal "full spill" operation is required under EWEB's federal operating license issued by the Federal Energy Regulatory Commission (FERC). The requirement was reached during the relicensing process to reduce the hydroelectric project's impacts on native fish populations.
"The goal is to give young fish an easier pathway to connect to the rest of the McKenzie," according to Lisa Krentz, EWEB's chief electric operations officer. "At the same time, carbon-free hydropower is what will enable our community to meet our climate goals. We need to balance those tradeoffs."
The Trail Bridge Dam is at the uppermost point fish can naturally reach the McKenzie River. Beyond the dam, only a few miles of spawning and rearing habitat are available before Tamolitch Falls, a natural barrier that blocks further upstream passage.
EWEB is currently working with state and federal fisheries agencies to construct a permanent "trap-and-haul" facility below Trail Bridge Dam. It's designed to allow adult salmon and threatened bull trout to be captured and transported upstream, replacing the temporary fish passage system currently in use.
Once the permanent upstream passage facility becomes operational, EWEB plans to discontinue nearly all electricity generation at the Trail Bridge Powerhouse, as required under the terms of its FERC license.
The utility is also planning to invest approximately $24 million in a permanent downstream fish passage facility at Trail Bridge to further improve fish migration.
The fish passage projects are part of a broader environmental mitigation effort tied to the relicensing of the Carmen-Smith Hydroelectric Project. EWEB says it has already invested about $45 million in fisheries-related improvements and expects to spend an additional $135 million on fish habitat and passage projects by 2032.
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