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Notice

B.F. Sisk Dam Corrective Action Project, Merced County, CA

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

Bureau of Reclamation, Interior.

ACTION:

Notice of intent to prepare an environmental impact statement/environmental impact report (EIS/EIR) and notice of public scoping meeting.

SUMMARY:

The Bureau of Reclamation (Reclamation), as the lead federal agency, and the State of California Department of Water Resources (DWR), as the lead state agency, are preparing a joint EIS/EIR, pursuant to the National Environmental Policy Act (NEPA) and the California Environmental Quality Act (CEQA), respectively, for the B.F. Sisk Dam Corrective Action Project (proposed action). The purpose of the proposed action is to improve public safety by modifying B.F. Sisk Dam to mitigate potential safety concerns identified in the ongoing Corrective Action Study (CAS). Engineering and economic studies are currently being conducted by Reclamation and DWR to determine corrective action alternatives (modifications) that would address potential safety concerns related to structure stability under extreme seismic loading conditions. A scoping meeting will be held to obtain input on alternatives, concerns, and issues to be addressed in the EIS/EIR. Written comments may also be sent, emailed, or faxed.

DATES:

A public scoping meeting will be held on Wednesday, September 23, 2009, from 3 p.m. to 7 p.m. at the San Luis Recreation Area, Gustine, CA.

ADDRESSES:

The scoping meeting will be held in the conference room at the California Department of Parks and Recreation Four Rivers Sector Office, 31426 Gonzaga Road, Gustine, CA 95322.

Written comments on the scope of the EIS/EIR should be sent by close of business on Tuesday, October 6, 2009 to: Ms. Patti Clinton, Bureau of Reclamation, South-Central California Start Printed Page 46453Area Office, 1243 N Street, Fresno, CA 93721, or via e-mail to pclinton@usbr.gov, or by fax to 559-487-5397.

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FOR FURTHER INFORMATION CONTACT:

Ms. Patti Clinton, Bureau of Reclamation, South-Central California Area Office at the above address or e-mail address, or by phone at 559-487-5127.

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SUPPLEMENTARY INFORMATION:

B.F. Sisk Dam is a 300-foot-high compacted earthfill embankment located on the west side of California's Central Valley approximately 12 miles west of Los Banos, California. The dam is more than 31/2 miles long and impounds San Luis Reservoir, which has a total capacity of over 2 million acre-feet. The dam was built between 1963 and 1967 to provide supplemental irrigation water storage for the Federal Central Valley Project and municipal and industrial water for the California State Water Project. Water is lifted into the reservoir for storage by the Gianelli Pumping-Generating Plant from the California Aqueduct and from the Delta-Mendota Canal via O'Neill Forebay. B.F. Sisk Dam (also known as San Luis Dam) is owned by Reclamation and operated by DWR. Of the total reservoir storage capacity, 55 percent is allotted to State uses and 45 percent is allotted to the Federal uses.

The dam and reservoir are located in an area of high potential for severe earthquake loading from identified active faults, primarily the Ortigalita Fault that crosses the reservoir. In the early 1980s, Reclamation conducted an extensive investigation of the seismic safety of B.F. Sisk Dam. The investigation included drilling holes to sample the soils and test their density in place, laboratory testing of the samples, and geophysical tests. Using the methods available at the time, the amount of deformation that would occur under severe shaking was predicted to be small, and the conclusion was that the dam had no safety deficiencies.

By 2005, the state of the art in seismic analysis of dams had changed significantly, and additional dam safety investigations were performed. These included a reevaluation of the Ortigalita Fault, development of a new understanding of the behavior of the soil materials (including embankment fill) under earthquake loading, and development of new computer-based analysis methods for predicting the behavior of the dam under various loadings. With the updated methods and earthquake loadings, the dam crest was predicted to settle, during the most severe earthquakes, resulting in the height of the dam crest being at the maximum water level in the reservoir.

While the current state of the art of analysis still involves uncertainties and does not permit precise calculation of the amount of settlement that would occur, it is possible (although not likely) that the embankment deformation would exceed the available freeboard, resulting in the reservoir overtopping the embankment and eroding a breach of the dam. Even without overtopping, it is possible that water flowing through cracks in the dam embankment could erode a breach as well.

Reclamation is taking the lead on the CAS. DWR is an active participant and has participated in the Risk Analysis, has reviewed technical documents, and is participating in other CAS activities.

Scoping

Scoping is an open process that assists agencies in determining the scope of the EIS and in identifying potentially significant issues related to the proposed action. Scoping also provides an opportunity to identify alternatives to the proposed action and possible mitigation measures. All interested persons, organizations, and agencies wishing to provide comments, suggestions, or relevant information on the proposed action may do so by sending input by regular mail to Reclamation at the above address; attending and providing comments at the public scoping meeting, or by sending e-mail to the above e-mail address.

Special Assistance for Public Scoping Meeting

If special assistance is required at the public hearings, please contact Ms. Lynnette Wirth at 916-978-5102, or via e-mail at lwirth@usbr.gov. Please notify Ms. Wirth as far in advance as possible to enable Reclamation to secure the needed services. If a request cannot be honored, the requestor will be notified. A telephone device for the hearing impaired (TDD) is available at 916-978-5608.

Public Disclosure

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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Dated: July 2, 2009.

Anastasia T. Leigh,

Acting Regional Environmental Officer, Mid-Pacific Region.

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[FR Doc. E9-21723 Filed 9-8-09; 8:45 am]

BILLING CODE 4310-MN-P