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Minidoka Dam Spillway Replacement; Minidoka County, ID

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Bureau of Reclamation, Interior.


Notice of intent to prepare an Environmental Impact Statement.


Pursuant to section 102(2)(C) of the National Environmental Policy Act (NEPA) of 1969, as amended, the Bureau of Reclamation (Reclamation) intends to prepare an Environmental Impact Statement (EIS) on the proposed Minidoka Dam Spillway Replacement. Alternatives currently being considered are No Action as required under NEPA, total replacement of the spillway and headgate structures, or replacement of just the spillway.

Reclamation is requesting early public comment and agency input to help identify significant issues or other alternatives to be addressed in the EIS. Information obtained during the scoping period will help in developing information to be included in the EIS. A draft EIS is expected to be provided to the public for review by winter, 2009 followed by opportunities to provide written and oral comments. The final EIS is scheduled for completion in winter, 2010. A Record of Decision, describing which alternative is selected for implementation, and the rationale for its selection, would then be issued following a 30-day waiting period.


Scoping meetings will be held on the following dates and times:

  • Idaho Falls, ID: December 3, 2008: Open House Meeting 6 pm to 9 pm.
  • Burley, ID: December 4, 2008: Open House Meeting 6 pm to 9 pm.

Written comments will be accepted through December 19, 2008 for inclusion in the scoping summary document. Please direct requests for sign language interpretation for the hearing impaired or other auxiliary aids, to Ms. Allyn Meuleman by November 24, 2008, at the telephone or fax numbers listed under the FOR FURTHER INFORMATION section of this notice.


Comments and requests to be added to the mailing list may be submitted to Bureau of Reclamation, Snake River Area Office, Attention: Allyn Meuleman, Activity Manager, 230 Collins Road, Boise, ID 83702-4520. Comments may also be submitted electronically to

The scoping meetings will be held at the following locations which are physically accessible to people with disabilities.

  • Red Lion Hotel, 475 River Park Way, Idaho Falls, ID 83402
  • Burley Best Western Inn, 800 North Overland Avenue, Burley, ID 83318
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Contact Allyn Meuleman, (208) 383-2258, fax: (208) 383-2237 for additional information. Information on this project can also be found at:​pn/​programs/​eis/​minidokadam/​index.html.

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The purpose of the proposed spillway replacement action is to prevent a structural failure of the Minidoka Dam spillway and associated structures.

Minidoka Dam impounds Lake Walcott and is a feature of Reclamation's Minidoka Project. They are located on the main stem Snake River about 18 miles northeast from the city of Burley, ID within the Minidoka Wildlife Refuge. After over 103 years of continued use, the over 2000 feet long concrete spillway at the Minidoka Dam has reached the end of its functional lifespan. The concrete that forms the spillway crest and the piers of the pier-and-stoplog structure shows extensive visible deterioration at numerous locations. In addition, the potential for ice damage to the stoplog piers requires that reservoir water levels be dropped each winter. The headgate structures at the North Side Canal and South Side Canal also show serious concrete deterioration similar to that seen along the spillway. The current conditions of the Minidoka Dam spillway and headgate structures present increasingly difficult reliability and maintenance problems. If structural problems are not corrected there is potential of partial or complete failure of the spillway and headgates. If these failures occur, Reclamation may not be able to meet contractual obligations for water delivery, power generation and Reclamation's commitments to deliver flow augmentation water under the Nez Perce Settlement Agreement and the Endangered Species Act.

A related action which may be considered is a structural raise (to be determined) of Minidoka Dam to accommodate a 5-foot raise in the Reservoir Water Surface (RWS) elevation. The Idaho Water Resource Board (IWRB) is funding a special study that explores the feasibility and costs associated with this action. The purpose of the dam raise is to increase the storage capacity of Lake Walcott by approximately 50,000 acre-feet as one element of efforts to address water supply concerns in the Eastern Snake River Plain Aquifer area. The IWRB anticipates the additional supplies of stored water could be used to help address surface and groundwater demands by implementing improvement measures being considered by the State. If the IWRB decides to pursue this action, a supplemental EIS will be developed to evaluate impacts.

Public Involvement

Reclamation will conduct public scoping meetings to solicit input on the alternatives developed to address replacement of the Minidoka Dam Spillway and associated structures and the impacts associated with those alternatives. Reclamation will summarize comments received during the scoping meetings and written comments received during the scoping period, identified under DATES, into a scoping summary document which will be made available to those who have provided comments. It will also be available to others upon request and will be posted on the Web site listed under FOR FURTHER INFORMATION.

If you wish to comment, you may provide your comments as indicated under the ADDRESSES section. Before including your name, address, phone number, e-mail address, or other personal identifying information in your comment, you should be aware that your entire comment (including your personal identifying information) may be made publicly available at any time. While you can ask us in your comment to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.

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J. William McDonald,

Regional Director, Pacific Northwest Region.

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[FR Doc. E8-26990 Filed 11-12-08; 8:45 am]