Willamette River Dam Improvements

Carrying out the Reasonable and Prudent Alternative (RPA) from the 2008 Willamette Project Biological Opinion requires a suite of actions determined necessary to protect Endangered Species Act (ESA)-listed Upper Willamette River spring-run Chinook salmon and Upper Willamette River winter-run Steelhead.

Key actions which apply for all of the Willamette Project dams covered under NOAA Fisheries’ 2008 Biological Opinion include:

• Meeting ramp rates and flow targets for the Willamette River mainstem and tributaries.
• Conducting interim operations to improve conditions for fish passage, spawning, incubation, and rearing, until permanent solutions can be developed and completed.
• Research, monitoring, and evaluation efforts to inform decision-making for downstream fish passage, temperature control, and to analyze the effectiveness of actions which have already been undertaken.
• Provide downstream passage for outmigrating juveniles (at the dams described below).

Below is additional information about the Willamette Project dams and RPA actions for each.

Detroit and Big Cliff Dams on the North Santiam River

Detroit Dam is located at river mile 49 on the North Santiam River, about 45 miles southeast of Salem, Oregon. Detroit Dam has two hydropower generating units capable of producing 50 megawatts each.

Big Cliff Dam is also on the North Santiam River three miles downstream of Detroit Dam and re-regulates water released from Detroit.

RPA actions for Detroit and Big Cliff Dams include:

• Minto adult collection facility rebuild was completed and began operating in 2013 - Read about Minto's updated fish collection facility.
• Detroit temperature control to be completed (date to be determined).
• Detroit downstream fish passage to be completed (date to be determined).

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Green Peter and Foster Dams on the Middle Santiam River

Green Peter Dam is located at river mile 5.5 on the Middle Santiam River, 11 miles northeast of Sweet Home, Oregon. Green Peter Dam has two hydropower generating units capable of producing a total of 80 megawatts.

Foster Dam is located at river mile 38.5 on the South Santiam River, at the confluence of the South Santiam and Middle Santiam rivers, four miles northeast of Sweet Home, Oregon. Foster Dam is located about 7 miles downstream of Green Peter Dam, and is used to regulate water releases from Green Peter Dam and flows in the South Santiam River. Foster Dam has two generators capable of producing 10 megawatts each.

RPA actions for Foster Dam include:

• Foster adult collection facility rebuild was complete and it has been operating since 2014, with ongoing testing to resolve temperature issues.
• Operation of a spillway weir to pass downstream fish during spring outmigration, currently in testing with modifications anticipated in 2020.

Cougar Dam on the South Fork of the McKenzie River

Cougar Dam is located at river mile 4.4 on the South Fork McKenzie River, about 42 miles east of Eugene, Oregon. Cougar Dam has two hydropower generating units capable of producing 25 megawatts in total.

RPA actions for Cougar Dam include:

• Operate the Cougar adult collection facility to trap and haul adult Chinook salmon and bull trout to spawning habitat above the dam (construction completed in 2010)
• Operate the Cougar temperature control tower to provide water temperatures downstream that will attract spawners, and will improve growth and survival of Chinook salmon eggs, juveniles and adults (construction completed in 2004)
• Design, construct, and operate Cougar downstream fish passage (date to be determined). Research continues to support identification of the most efficient and cost-effective method for downstream fish passage.

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Lookout Point and Dexter Dams on the Middle Fork of the Willamette River

Lookout Point Dam is at river mile 21.3 on the Middle Fork of the Willamette River, about 22 miles southeast of Eugene, Oregon. Lookout Point Dam has three hydropower generating units capable of producing 50 megawatts each. Dexter Dam is located three miles downstream and is used to regulate power-generating water releases from Lookout Point Dam. Dexter Dam has one generator capable of producing 15 megawatts.

RPA actions for Lookout Point and Dexter Dams include:

• Dexter adult collection facility rebuild.
• Lookout Point downstream fish passage.

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Fall Creek Dam on Fall Creek, a tributary of the Middle Fork of the Willamette River

Fall Creek Dam is located at river mile 7.2 on Fall Creek, a tributary of the Willamette River, about 20 miles southeast of Eugene, Oregon. In coordination with Lookout Point and Hills Creek Dams, the three dams work together for the purposes of flood risk management, water quality improvement, irrigation, and fish and wildlife habitat and recreation.

RPA actions for Fall Creek Dam include:

• Draw-down and operate Fall Creek Dam at an elevation of 714 feet or below to improve passage and survival of juvenile Upper Willamette River Chinook salmon. Research is being conducted to evaluate the effectiveness of this action. Learn more about how habitat above Fall Creek Dam supports spring-run Chinook salmon.
• Fall Creek adult collection facility rebuild completed and operating in 2018.

More Information

• Learn More information about these and other Willamette Valley Projects
• Learn more about the Willamette River Biological Opinion
• Learn more about Dams on the West Coast