US Army Corps of Engineers
Portland District Website Website


Update on spillway gate rehabilitation work at Detroit Dam

Published Nov. 21, 2019
Detroit Dam

Detroit Dam

The Corps has decided to manage Detroit Dam’s reservoir levels between 1425 and 1450 ft. from now through the middle of Jan. 2020 during construction on two of the dam’s spillway gates.

“While we previously announced that rehabilitating the spillway gates wouldn’t impact reservoir levels, a shift in our work schedule and the need to take an additional spillway gate out of service during the construction period led us to reevaluate the associated risk mitigation,” said Erik Petersen, Willamette Valley Project operations manager.

“Due to this change, we have decided to be more conservative in the management of the reservoir water during this construction window.”

Flood risk management is the primary mission of Detroit Dam.

Managing the reservoir between 1425 and 1450 ft. ensures adequate storage space for potential winter storm events. Reservoir levels are expected to increase after the middle of Jan. 2020. There are no anticipated impacts to reservoir refill or summer pool elevations.

The Mongold boat ramp will be inaccessible from now through the middle of Jan. 2020 because it requires a reservoir level over 1450 ft.

This first phase of spillway rehabilitation work is expected to be complete in Feb. 2020. The Corps has scheduled the rehabilitation of two gates per year over the next three years and expects all six spillway gates to be restored to full structural capability by Feb. 2022.

The Corps encourages the public to check the teacup diagrams which are located at: Hover over each dam to read the water elevation, inflows and outflows, and click to read more details about each reservoir. For more information, call 503-808-4510.

For questions about parks and recreation, call the Oregon State Parks manager at 503-480-9858.


Willamette Valley Project: The U.S. Army Corps of Engineers operates 13 dam and reservoir projects in the Willamette River drainage system. Each dam contributes to a water resource management system that provides flood damage reduction, power generation, irrigation, water quality improvement, fish and wildlife habitat and recreation on the Willamette River and many of its tributaries. Since their completion, the dams have cumulatively prevented over $25 billion in flood damages to the Willamette Valley. For more information, visit:

Lauren Bennett

Release no. 19-029