Detroit Dam & Lake Downstream Passage Project

The U.S. Army Corps of Engineers is conducting an environmental review to aid in developing a project that will provide downstream juvenile fish passage for Upper Willamette River Chinook and temperature control at Detroit Dam. The Detroit Dam and Lake spans the Linn County–Marion County border in the Oregon Cascades on the North Santiam River near the city of Detroit. 


Detroit Dam, southeast of Salem, Ore., on the North Santiam River, provides a variety of functions including flood risk management and power production. However, it also blocks fish passage and the U.S. Army Corps of Engineers is in the process of building temperature control and fish passage at this site.

The Corps operates and maintains 13 multipurpose dams and reservoirs (including Detroit Dam and Lake) in the Willamette River Basin in Oregon, collectively referred to as the Willamette Project

The listing of several species under the Endangered Species Act (ESA) requires the Corps to perform an assessment of the Willamette Project and its operations’ impact on listed species. Based on this assessment, the National Marine Fisheries Service (NOAA Fisheries) released a Biological Opinion (BiOp) in 2008 which identified the required actions to avoid jeopardizing the existence of ESA listed fish in the Willamette basin. These include downstream fish passage at Detroit Dam and the minimization of water quality effects, temperature in particular, associated with operations of Detroit and Big Cliff dams, by making structure modifications or major operational changes. 

If feasible and more efficient to achieve both purposes through one construction project, the BiOp allows for this.

Upcoming Public Meetings

There are no scheduled upcoming public meetings at this time. Check back for future meeting dates. 

NEPA - The Environmental Policy Act Process, Scoping Phase and Your Role

The National Environmental Policy Act of 1969 (NEPA) is one of the nation’s oldest environmental laws that encourages federal agencies to make environmentally responsible decisions. NEPA requires all federal agencies to consider and disclose the environmental effects of their proposed actions in an EIS. The Citizen's Guide to NEPA explains this law and how to effectively submit your input.

Per NEPA, an EIS assessing impacts of the proposed project on the human environment will be provided to the public for review and comment. The public will be notified when opportunities for comment arise. Collecting the right level of information at the right time is important to developing a project plan, requiring early and frequent engagement of all affected federal, state and local agencies, Native American Tribes and interested groups and individuals. “Scoping” is an early step in the process when the public is invited to provide substantive information and identify issues and potentially significant effects to be considered in the project’s EIS.

Public scoping comments help the Corps:

  • Define the breadth of environmental resources and affects to evaluate.

  • Identify alternatives to be considered.

  • Determine new sources of data or information.

  • Identify and eliminate from detailed study issues that are not significant or that have been covered by prior environmental review.


In addition to Scoping, there will be other opportunities to comment (public meetings, website, letters, e-mails, etc.) and meet with the project team. Once we have a draft EIS, the public will be provided an opportunity to review and supply comments. The Corps will consider these comments when finalizing the EIS. The public will then be provided an opportunity to review the final EIS.

Examples of areas for evaluation in the EIS include:

Air Quality
Cultural Resources
Floodplain Management
Economic Impacts
Environmental Justice
Endangered Species Act
Land Use
Migratory Birds
Sediment Transport,
Deposition, Composition
Social Considerations
Tribal Interests
Water Quality










Environmental Impact Statement Process Overview


Collect information, ideas and concerns from public, tribes, agencies and others to consider while planning for downstream juvenile fish passage and temperature control at Detroit Dam.

Notice for public input.

This input informs the analysis of potential effects, the suite of alternatives that meet the project's purpose and need, and the criteria for evaluation and comparison of alternatives. View the summary and analysis of recent scoping here: Scoping Report.

Develop & Evaluate Alternatives

Develop criteria for evaluating alternatives. 

Develop a range of alternatives that meet the plan's purpose, using public input and technical information

Verify alternatives are technically feasible, consistent with the Corps' authorities and priorities, and are consistent with applicable laws.

Draft EIS & Develop Preferred Plan

Identify alternatives to be assessed in detail and compare direct, indirect, and cumulative environmental effects of the alternatives and select the preferred plan.

Notice of availability for public review & comment.

The Draft EIS and preferred plan are available for agency, tribal, and public review and comment.

Final EIS & Plan

Prepare and publish the final integrated EIS, which will include responses to substantive comments.

Notice of availability for public review.

Record of Decision

Decision by Corps' Northwestern Division Commander completes the Corps' NEPA process.