EWEB pauses power generation at Trail Bridge Powerhouse to support seasonal fish migration
The Eugene Water & Electric Board (EWEB) will pause electricity generation at the Trail Bridge Powerhouse for four months to support young fish as they travel downstream.
From July 2 to Oct. 31, EWEB will change operations at Trail Bridge Powerhouse to make it easier for fish migrating downstream to safely move from upstream of Trail Bridge Dam to the rest of the McKenzie River downstream. Specifically, EWEB will shut off the powerhouse and instead spill water through the spillway.
The Trail Bridge Powerhouse is part of the Carmen-Smith Hydroelectric Project on the upper McKenzie River. Trail Bridge Dam — which contains the powerhouse — is the farthest upstream that fish can travel on their own.
Though Trail Bridge generates some power, most of the power generation at the Carmen-Smith project comes from the Carmen Powerhouse, which is a separate facility slightly further upriver. The Carmen Powerhouse can generate 110 megawatts, compared to less than 10 megawatts at the Trail Bridge Powerhouse.
Conducting such “full spill” operations at Trail Bridge is a requirement of the license that EWEB’s regulator, the Federal Energy Regulatory Commission (FERC), has granted to EWEB to operate the dam. It also reflects EWEB’s partnership with regulatory agencies to balance different aspects of environmental responsibility, which is a core value for EWEB. In essence, actions to benefit fish also have a direct impact on EWEB’s ability to generate carbon-free hydropower.
“The goal is to give young fish an easier pathway to connect to the rest of the McKenzie,” said EWEB’s Chief Electric Operations Officer Lisa Krentz. “At the same time, carbon-free hydropower is what will enable our community to meet our climate goals. We need to balance those tradeoffs.”
Upstream of Trail Bridge Dam, just a handful of miles of habitat for fish spawning and rearing exist because of natural barriers, specifically Tamolitch Falls, which is impassable to fish.
EWEB is currently working with fisheries regulators to design a “trap and haul” facility below Trail Bridge Dam to move adult salmon and bull trout, providing access to spawning areas above the dam. The new, permanent trap and haul will replace the existing temporary upstream fish passage measures.
After the permanent trap and haul facility is operational, EWEB will cease nearly all power generation at the Trail Bridge Powerhouse, in accordance with the terms of the FERC license.
EWEB is also planning to invest $24 million into a permanent facility to assist downstream fish passage at Trail Bridge.
Along with changing hydropower operations to reduce fisheries impacts, EWEB has invested $45 million in projects connected to reducing fisheries impacts as part of relicensing the Carmen Smith Hydroelectric Project, with a projected additional $135 million for upcoming fisheries-related projects to construct by 2032.
