The thirteen federal reservoirs in the middle and upper Willamette Basin were authorized for construction beginning in the late 1930s. The combined storage capacity is more than 1.6 million acre-feet. The reservoirs provide important benefits of flood control, generation of electricity, and water storage.
Recreational use at many of the reservoirs is significant and releases provide instream benefits for fish, wildlife, navigation, and water quality. Only a small percentage of the total storage is currently under contract for irrigation.
Population growth, increasing development, agriculture, and listings under the Endangered Species Act have placed new demands on the reservoirs, affecting project operations and furthering the need to examine how stored water should be managed in the future to meet both instream and out-of-stream needs.
The Willamette Basin Review (Reallocation) Study was initiated in 2015 as a cooperative feasibility study with the U.S. Army Corps of Engineers. Funding for the Study was provided by the federal government and the State of Oregon. The Study's goal was to determine if operational changes or modifications in the allocation of stored water would better serve present and future resource needs in the basin. The Study was completed in December 2019 and approved by Congress in 2020. To access the study and recommended plan, click here.