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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.
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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 and the State of Oregon. 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.
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Draft Integrated Report Available for Public Comment

 Open House Announcement
An informational Open House was held on Monday, December 11, 2017 from 3:00 -7:00 pm at the Oregon Department of Fish and Wildlife's office in Salem (4034 Fairview Industrial Drive).  
For more information, refer to the press release.
Draft Report Available for Review
The U.S. Army Corps of Engineers has released a draft report for public comment regarding the reallocation of 
storage from the Willamette Valley project reservoirs.  Comments are due by Friday, January 5, 2018.
For more information, click here for the public notice or visit the Corps' website: 
The Draft Integrated Report and associated appendices can be downloaded here:
Download PDF Main Report & Executive Summary
Download PDF

Appendix A: Municipal & Industrial Demand and Supply Analyses

Download PDF

Appendix B: Agricultural Irrigation Demand Analyses

Download PDF ​Appendix C: Calculation of Water Volumes Required to Meet Willamette BiOp Minimum Flows
Download PDF Appendix D: Flow Dataset Used for ResSim Analyses
Download PDF

Appendix E: ResSim Analysis for 2008 Baseline Flow Dataset

Download PDF Appendix F: ResSim WVP Releases and Live Flow Diversions for Base Year 2020, No Action Alternative, and TSP Model Runs
Download PDF Appendix G: ResSim Analysis for Base Year 2020, No Action Alternative 2050, and Tentatively Selected Plan 2050
Download PDF

​Appendix H: BiOp Flow Objective Performance of the No Action Alternative and Tentatively Selected Plan.

​Download PDF

​Appendix I: Reservoir-Related Boating, Recreation Benefits Impact Analysis 
Download PDF ​Appendix J: Hydropower Impact Analysis
Download PDF ​Appendix K: Discussion of Climate Change Impact on future Regualtion
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Willamette Stakeholder Meetings

Stakeholder meetings are open to the public and typically held at the Oregon Water Resources Department (725 Summer St. NE). Please check the meeting agenda for locations and times of stakeholder meetings.

​July 22, 2013 ​Agenda Presentation Handouts Meeting Notes
​September 11, 2014 ​Agenda ​Draft PMP
​March 10, 2016 Agenda
​March 1, 2017 Agenda Presentation Handouts ​​Meeting Notes​


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WaterSMART Plan of Study

In 2013, the Oregon Water Resources Department worked with the U.S. Bureau of Reclamation to complete a Plan of Study.  The focus of this effort was to gather informational sources and identify potential data gaps related to water demands in the basin (instream and out-of-stream), with the primary goal of supporting the Willamette Basin Reservoir Study efforts. Following the plan of study process, project partners decided not to pursue a full basin study through Reclamation’s WaterSMART planning program. 

​September 30, 2013 Workshop ​Agenda ​Presentations ​Meeting Materials


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Staff Reports & Other Items

Commission Staff Reports:
Other Resources:
Historical Documents:
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Surplus Water Supply Report

The U.S. Army Corps of Engineers released a Draft Surplus Water Letter Report for the City of Creswell in December 2013, and accepted public comments through January 14, 2014. A copy of the Public Notice and Draft Report are listed below. On July 21, 2014, Brigadier General John S. Kem, Commander of the Corps’ Northwestern Division approved the Report.  See below for the draft and final document report.
December 18, 2013 Public Notice                   
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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.
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Contact Information

​Alyssa Mucken ​Laurie Nicholas
​Oregon Water Resources Department ​U.S. Army Corps of Engineers, Portland District
​503-986-0911 ​503-808-4707
​To receive announcements regarding the Study, contact Alyssa (alyssa.m.mucken@state.or.us) to join the electronic mailing list
​ ​
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