Willamette River Basin Plan

An engaging overview of the largest infrastructure project in the history of the Pacific Northwest.

This scarce mid-century engineering map outlines the U.S. Army Corps of Engineers’ ambitious water resource infrastructure plan across the Willamette River Valley in western Oregon. Drawn in 1953 by draughtsman Eric Gustavus Michelson for the Portland Engineer District, the map illustrates the expansive network of dams constructed or planned south of the river’s confluence with the Columbia.

Oriented with South at the top, the map covers the entire drainage basin, framing the Willamette River and its primary tributaries, including the Coast and Middle Forks, the McKenzie, the Santiam, and the Yamhill Rivers. The image stretches from Portland in the north down through Salem, Albany, Corvallis, and Eugene to the surrounding Cascade and Coast Ranges. Existing, Authorized, and Recommended Dams are noted according to the shading of their outflow. Over a dozen different structures are identified, representing significant federal efforts towards regional flood control, energy generation, agricultural irrigation, recreational areas, and maritime navigation. Of particular note are the recently completed Detroit and Big Cliff Dams.

The stylized aerial perspective captures the Willamette Valley Project at an important midpoint in its development. The Corps had completed its comprehensive basin survey in 1937, and Congress authorized the initial seven-dam program in 1938, but World War II interrupted construction after work had begun on several projects. By 1953, postwar construction was proceeding rapidly: Detroit Dam was completed that year, while Big Cliff and several other major reservoirs were still under construction or in the planning stages. The full system ultimately grew to thirteen dams and reservoirs, with the final major project, Green Peter Dam, completed in 1969.