Yakima River Basin Water Storage Feasibility Study

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In May 2003 the Bureau of Reclamation initiated the Yakima River Basin Water Storage Feasibility Study (Storage Study) to examine the feasibility and acceptability of storage augmentation in the Yakima River basin. The additional water storage is to benefit threatened and endangered species, irrigated agriculture, and municipal water supply.

The study was authorized by Congress in 2003. In accordance with the authorization, the initial emphasis of the study evaluated the feasibility of the Black Rock Dam alternative. Then evaluation of other storage alternatives will occur as well as an environmental impact evaluation of all alternatives. The environmental evaluation will be an environmental impact statement and will be a joint document that combines a planning report and an environmental impact statement that complies with both National Environmental Policy Act (NEPA) and State Environmental Policy Act (SEPA) requirements. Map PDF 688 kb >>

The State of Washington, represented by the Department of Ecology, is the co-lead and cost share partner in the Storage Study. In addition to the Bureau of Reclamation’s authorization and focus on storage augmentation, Ecology will evaluate a broad range of potential actions encompassing both structural and non-structural options both within the Yakima River basin and at locations outside the basin that may improve water availability for fish, irrigation, and municipal demands.

The Storage Study is generally confined to resources within that area of the Yakima River basin currently served by the Reclamation’s Yakima Project water storage and distribution features. However, since the feasibility of importing Columbia River water for delivery to the Yakima Project water users is a major component of the Storage Study, the effects of such an action on Columbia River water and on other resources will also be evaluated.

There have been many analyses performed in the Yakima Basin related to water storage and water resource management. The Storage Study analyses uses these past reports to meet the objectives set forth by Congress. Additional analyses and reports have been prepared for the Storage Study process.

Purpose and Need

The purpose of the Storage Study is to evaluate plans that would create additional water storage for the Yakima River basin and assess each plan’s potential to supply the water needed for fish and the aquatic resources that support them, basinwide irrigation, and future municipal demands.

The need for the study is based on the existing finite water supply and limited storage capability of the Yakima River basin. This finite supply and limited storage capability does not meet the water supply demands in all years and results in significant adverse impacts to the Yakima River basin’s economy, which is agriculture-based, and to the basin’s aquatic resources—specifically those resources supporting anadromous fish. Reclamation and Ecology seek to identify means of increasing water supplies available for purposes of improving anadromous fish habitat and meeting irrigation and municipal needs.


Improve anadromous fish habitat by restoring the flow regimes of the Yakima and Naches Rivers to more closely resemble the natural (unregulated) hydrograph. Through a collaborative process with Yakima basin entities, Reclamation has developed nonbinding target flows to assist in measuring goal achievement.

Improve the water supply for proratable (junior) irrigation rights by providing a not less than 70-percent irrigation water supply during dry years at diversions subject to proration. This 70% goal equates to 896,000 acre-feet of proratable entitlements.

Meet future municipal water supply needs by maintaining a full municipal water supply for existing users and providing additional surface water supply of 82,000 acre-feet for population growth to the year 2050.


Section 214 of the Act of February 20, 2003 (Public Law 108-7 PDF 1.3 mb), states:

The Secretary of the Interior, acting through the Bureau of Reclamation, shall conduct a feasibility study of options for additional water storage in the Yakima River Basin, Washington, with emphasis on the feasibility of storage of Columbia River water in the potential Black Rock Reservoir and the benefit of additional storage to endangered and threatened fish, irrigated agriculture, and municipal water supply. There are authorized to be appropriated such sums as may be necessary to carry out this Act.

Authority for the State of Washington is contained in the 2003-2005 Capitol Budget (Section 316 (1)(a) of Substitute Senate Bill 5401 as enacted June 26, 2003, Water Supply Facilities Program (04-4-006):

The appropriations in this section are subject to the following conditions and limitations:

(1)(a) $1,000,000 of the state building construction account appropriation and $3,000,000 of the state and local improvements revolving account appropriation are provided solely for expenditure under a contract between the department of ecology and the United States bureau of reclamation for the development of plans, engineering, and financing reports and other preconstruction activities associated with the development of water storage projects in the Yakima river basin, consistent with the Yakima river basin water enhancement project, P.L. 103-434. The initial water storage feasibility study shall be for the Black Rock reservoir project. The department shall seek Federal funds to augment the funding provided by this appropriation.

Contact Us

Wendy Christensen
(509) 573-8050

Bureau of Reclamation
Pacific Northwest Region
Columbia-Cascades Area Office
1917 Marsh Road
Yakima, WA 98901-2058
(509) 575-5848 x370

Last Updated: 9/25/18