Corps could end hydro production

The U.S. Army Corps of Engineers Portland District is assessing whether it should continue to produce hydroelectric power at its Willamette Valley project dams.

In total, nine of those 13 federally-owned dams are capable of producing upwards of 500 megawatts of power - enough to power about 300,000 homes, the Corps said. However, in August 2019 (an average water year) the energy output was in the 184.4 MW range.

“Right now, a team of experts is diving deep into data and studies about the dams to provide initial information for a report to Congress,” the Corps said in a news release. “The report will inform future actions on whether the Portland District should proceed to a full “disposition” study. That study would assess, in detail, whether to remove hydropower at one or more dams and the effects that action would have on the system of dams.”

The Water Resources Development Act of 2022 calls for assessments of whether - and how - discontinuing hydro-power production at one or more of the eight dams would affect the system. How the costs of discontinuing hydropower would be apportioned, and what impacts there would be on dam safety and compliance with the Endangered Species Act. Deauthorizing power production has already been recommended at two of the dams - Cougar on the McKenzie River and Detroit on the North Santiam River.

Managing floods was a primary driver for constructing the dams between 1941 and 1989.

The Corps estimates flood control has prevented some $2 billion in damages, and in 2019 had prevented flooding in the Willamette Valley after a 7-day storm event. The Corps uses the reservoirs’ storage capacity to keep streams below flood stage, Bengtson said.

Besides flood control and hydro-power, officials cite water supply, irrigation, water quality, recreation, navigation, and fish and wildlife management as benefits derived from the dams.

The U.S. District Court of Oregon issued an interim injunction on September 1st, 2021, requiring the Corps to take actions to improve fish passage and water quality at several Willamette Valley Project dams for endangered salmon and steelhead.

In his ruling, Judge Marco Hernandez ordered deep draw-downs at Cougar Dam on the South Fork of the McKenzie River and at Fall Creek Dam on the Middle Fork Willamette to aid downstream migration of juvenile salmon and steelhead, along with a spring spill at Foster Dam on the South Santiam to aid juvenile downstream migration. Hernandez also directed the Corps to build temperature control outlets similar to the one at Cougar Reservoir at the Detroit and Big Cliff dams on the North Fork Santiam River.

The Corps’ Draft Environmental Impact Statement includes language calling for a reduction of spawning and rearing habitat competition caused by hatchery fish and the creation of nature-based structures that would help prevent bank erosion as well as increase ESA-listed fish passage survival at the Willamette system dams.

Currently, the Corps is working in coordination with the National Marine Fisheries Service, U.S. Fish and Wildlife Service, Bonneville Power Administration, and the U.S. Bureau of Reclamation to implement the measures, some dating back to the fall of 2021.

Of the nine dams that produce power, eight are operated by the Corps. The Federal Energy Regulatory Commission operates the other one.

Plans for later this year call for the Corps to host spublic “listening” sessions, for the public to provide perspectives and opinions on the future of hydropower across the Corps’ Willamette Valley system of dams. The dates of the sessions will be published on the Corps’ Portland District website.