Detroit Dam sits on the North Santiam River, East of Salem, Oregon. Detroit Dam is one of the 13 dams in the Willamette Valley System and one of the 8 hydropower dams within the system.

The U.S. Army Corps of Engineers (USACE) is preparing a report to Congress as outlined in section 8220 of the Water Resources Development Act of 2022.

USACE operates and maintains 13 multipurpose dams and reservoirs across Oregon's Willamette River basin. Congress authorized these dams for multiple purposes: flood risk management, hydropower, water supply, irrigation, water quality, recreation, fish and wildlife management, and navigation. Each dam serves the purposes set for it by Congress in authorizing legislation.

As a group, the 13 dams are operated as a system – the Willamette Valley System - to ensure that all purposes are served. Among its many important functions, the System is managed for flooding, minimum river flows, and water quality from Oakridge to Portland, Oregon.

Eight of the 13 dams are authorized by Congress to produce hydropower and include hydropower facilities. Section 8220 directs the Secretary of the Army to carry out a study, now being conducted by the Portland District, to determine the “federal interest” in continuing hydropower production in the Willamette Valley System. A “federal interest” determination looks at costs and benefits and environmental acceptability, along with other factors.

Specifically, the law says that the study should assess:

• whether and how discontinuing hydropower production at one or more of the eight dams would affect how those dams, other dams in the system, and the system as a whole would be operated for their other authorized purposes;
• 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.

The report to Congress will be submitted by June 2024.