Anderson Ranch Dam Water Supply Study

Anderson Ranch Dam

In 2006, Reclamation completed the Payette/Boise River Basins Water Supply Assessment Study (2006 study). The Idaho Water Resources Board (IWRB), Idaho Water Users Association (IWUA) and others supported legislation to provide Reclamation with feasibility study authority to continue this work. In 2009, Public Law 111-11 provided Reclamation with feasibility study authority in the Boise River and Payette River basins to further pursue the opportunities identified in the 2006 Study, one of which was raising Anderson Ranch Dam.

In 2015 and 2016 Reclamation met with potential stakeholders to discuss a potential raise of Anderson Ranch Dam and the feasibility study process, and to elicit interest in contributing to the required 50% non-Federal cost share. Reclamation did not receive sufficient commitments for the non-Federal cost share and did not proceed at that time.

In 2016, the U.S. Army Corps of Engineers (USACE) and the IWRB terminated their Boise General Investigation (GI) due to a low benefit-cost ratio. The GI had focused on flood control with potential water supply benefits, with raising Arrowrock Dam by 70 feet as the primary alternative.

Due to the termination of the Boise GI, interest in potential Reclamation projects increased. IWRB asked Reclamation and USACE to explore potential system-wide solutions for increased storage for water supply and potential flood risk reduction. Subsequently, Reclamation and IWRB signed executed an agreement on March 12, 2018 to conduct this feasibility study.

For more information on the status of the Boise River Basin Feasibility Study, please visit

Related Documents
11/2016 Boise System Feasibility Study Draft Expanded Scope of Work PDF 442 kb
05/2016 Anderson Ranch Dam Raise Informational Meeting Powerpoint PDF 8.10 mb
04/2016 Anderson Ranch Dam Raise Preliminary Hydrologic Evaluation Technical Memorandum PDF 823 kb
02/2009 Modeling Spatial Water Allocation & Hydrologic Externalities in the Boise Valley PDF 1.37 mb
11/2008 A Distributed Parameter Water Budget Data Base for the Lower Boise Valley PDF 6.86 mb
07/2006 Final Boise/Payette Water Storage Assessment Report PDF 9.95 mb
11/2005 Boise and Payette River Basins: Literature Report for Potential Water Storage Opportunities PDF 11.93 mb
02/2005 Hydrologic Analysis of the Refill Probabilities Associated with Increasing the Storage Capacities of Anderson Ranch and Arrowrock Reservoirs PDF 125 kb
04/2015 Anderson Ranch Dam Feasibility Study Proposal PDF 1004 kb


Chris Keith
Project Manager
(208) 378-5360

Bureau of Recamation
Regional Office
1150 N. Curtis Road
Boise, Idaho 83706

Last Updated: 10/10/23