Corps recommends draining Cougar's Lake
Salmon would pass through the bottom of the dam
March 2, 2023 | View PDF
Salmon and steelhead will be better treated according to changes the U.S. Army Corps of Engineers is recommending for the 500 trillion gallons of water stored in 13 dams and reservoirs it manages in the Willamette Basin. Flood control will remain a priority but endangered fish will move up a list of considerations that includes drinking water, irrigation, and recreation opportunities.
The agency's recently released 2,200-page draft Programmatic Environmental Impact Statement (PEIS) includes plans for producing less hydropower, retaining more water behind the Blue River Dam, and scaling back some operations at fish hatcheries that were built to mitigate the impact of dams on native fish.
Public comment on the seven alternatives in the plan ended on February 23rd. Following reviews and responses to the agency's preferred alternative, a final decision should be announced by late summer 2024.
Cougar Dam - and the lake formed behind it - would be the site of the most changes under Alternative 5 (the one favored by the Corps). In the spring, the reservoir would undergo a "deep drawdown" to ensure fish have easier access to upstream spawning areas, rather than capturing and trucking salmon as they are today. In the fall, Cougar Reservoir would again be drained to let migrating juveniles a clear route to swim downstream on their way to the ocean.
The document includes ways of reducing the competition for spawning and rearing areas between wild and hatchery fish. Also in the plus column are contributions "to future economic prosperity by creating jobs during construction and social well-being by continuing to reduce flood risks for the community."
"The system of dams and reservoirs protecting the Willamette Basin has served us well for decades. Changes to the system for the benefit of endangered species will help rebalance those benefits," according to Erik Petersen, the Corps' Willamette Valley operations project manager. "It's incredibly complex, and I'm glad that we've had more time to build public understanding and gain substantive feedback from as many stakeholders as possible. That feedback is critical to shaping our decision-making process."
The measures included in the Preferred Alternative would be implemented over a 30-year period. Last updated in 1980, the prior EIS went through years of lawsuits and court orders before it was put into practice.
While the drawdown of Cougar Reservoir was rated as the best option for fish migration, it will have "major adverse effects to reservoir recreation at this location," the EIS says. The Corps defines that season as extending from April 15th through September 15th.
During the drawdown at Cougar, reservoirs behind the region's other dams would release water to keep flows nearer to normal levels in the Willamette River. That could cause the pool behind Blue River Dam and other sites to be filled sooner and last longer, benefitting the boat-based recreation season.
Questioning some of the details in the Corps' plans was the McKenzie River Guides Association. One concern was the proposal to lower water levels by another 120 feet. That, the guides said, would drop the lake to less than the 1,450 feet level that had been "established by the USACE as the minimum pool level to prevent high turbidity levels and high rates of sediment transport downstream of Cougar Dam. That fear was bolstered by prior downstream muddying of the McKenzie Rivet that occurred in 2002-2004 during the construction of the Cougar Dam water temperature control tower.
The guides group was also concerned about the overall impacts on the region's long-established recreational economy.
The Oregon Chapter of the Backcountry Hunters and Anglers echoed some of those concerns.
"The PEIS timelines for completion of the projects and the beginning of fish passage seem to be quite long considering the urgency of the issues (20 or more years, in some cases)," according to Stephen Maher, the group's president. He went on to note that, "If current trends continue, the fish that these projects are intended to help may well be gone. Furthermore, funding for the projects will be linked to the timelines. In other words, longer timelines will likely lead to delayed funding."
IMpacts won't be limited to the McKenzie River region, the Corps notes. "This is a qualitative assessment considering the full-time jobs created/lost by the changes in water levels resulting from the measures under each alternative, making conditions more/less conducive to water-based recreation and the regional (sub-basin) output," the report says. It goes on to say that "the regional output is equal to the sum of employee compensation, plus proprietor income, plus other property type income, and plus indirect business taxes. This analysis was predicated on the potential effects of localized jobs associated with dollars gained or lost as a function of water level fluctuation at a particular project's county. The higher the impact the greater the projected number of jobs lost and reduction in regional output."
The Corps' analysis doesn't reflect the transfer of recreational activity from one area to another but states that "a medium impact means there would be greater than one job lost in any basin and a reduction in regional output less than $150,000 in multiple basins."