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Willamette Basin Review - Reservoir Study

The thirteen federal reservoirs in the middle and upper Willamette Basin were authorized for
construction beginning in the late 1930s. The combined conservation storage capacity is over 1.6 million acre-feet. The projects 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 will place new demands on the reservoirs and could affect project operations. The Willamette Basin Review (Reservoir Study) will determine to what extent the reservoirs may help to meet future water demands in the valley and if changes in project authorizations are necessary to meet those needs.



The Reservoir Study is a cooperative cost-shared study with the U.S. Army Corps of Engineers. Funding for the Study has been provided by the federal government, the State of Oregon and more than 60 cities, special districts, organizations and commercial and industrial firms. The Study will determine if operational changes or modifications in the allocation of stored water would better serve present and future resource needs in the basin.

The major challenge of the Reservoir Study will be to identify ways to balance competing demands and help meet future water needs in the valley while retaining those aspects of current operations that people value today and in the future. Work on the Study has been delayed to allow consultation with federal fish management agencies regarding the impacts of reservoir operations on fish, wildlife and plant species listed as threatened or endangered under the Endangered Species Act (ESA). The 2000 interim report (see below) provides a discussion of the work that has been completed under the Study and options for future work. 

Willamette Stakeholder Meetings
Monday, July 22, 2013 Draft Agenda ​Meeting Materials (coming soon)

Staff Reports & Other Items
Commission Staff Reports:
·         Aug. 8, 2013 Staff Report (coming soon)
·         Feb. 8, 2013 Staff Report
·         Jan. 26, 2012 Staff Report
·         Nov. 18, 2010 Staff Report
·         Jun. 9, 2009 Staff Report
·         Feb. 25, 2009 Staff Report
Other Resources:
·         WRC Resolution on Willamette Storage  (Mar. 2012)  
·         Small Scale Water Supply Allocation Report  (Jan. 2011)
  In 2008, municipal water providers in the southern portion of the Willamette Basin
  conducted a study, exploring the issues associated with obtaining stored water to meet
  municipal and industrial water supply and flow augmentation needs.
Historical Documents:
·         Status Report on Reservoir Study Tasks (Dec. 2001)
·         Willamette Interim Report  (Jan. 2000)
·         Willamette Brochure  (Apr. 1998)


Related Online Resources
Adopted in August 2012 by the Water Resources Commission, the Strategy provides a set of actions to help the state better understand and meet its instream and out-of-stream needs, taking into account water quantity, water quality, and ecosystem needs.  Recommended Action 10.B is directly aimed at improving access to storage, including stored water in the Willamette Basin reservoirs.

Willamette 2008 Biological Opinion
On July 11, 2008, the federal government issued a final Biological Opinion for ESA-listed fish in the Willamette Basin.

U.S. Army Corps of Engineers Willamette Valley Project
This site provides background information on the 13 dams and reservoirs owned and operated by the U.S. Army Corps of Engineers.