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Mormon Island Auxiliary Dam (MIAD) Modification Project, Sacramento and El Dorado Counties, CA

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Information about this document as published in the Federal Register.

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Bureau of Reclamation, Interior.


Notice of availability of the Final Supplemental Environmental Impact Statement/Environmental Impact Report (EIS/EIR).


Pursuant to the National Environmental Policy Act and the California Environmental Quality Act (CEQA), the Bureau of Reclamation (Reclamation), the lead Federal agency and the Sacramento Area Flood Control Agency (SAFCA), the CEQA lead agency, have prepared a Final Supplemental EIS/EIR for the MIAD Modification Project. The Final Supplemental EIS/EIR contains responses to comments received on the Draft Supplemental EIS/EIR.

A Notice of Availability of the Draft Supplemental EIS/EIR was published in the Federal Register on Friday, November 27, 2009 (74 FR 62346). The public review period on the Draft Supplemental EIS/EIR ended on January 18, 2010.

The MIAD Modification Project is a feature of the larger Folsom Dam Safety/Flood Damage Reduction (DS/FDR) Project currently underway by Reclamation, the U.S. Army Corps of Engineers (Corps), and the Corps' non-Federal sponsors, the Central Valley Flood Protection Board and SAFCA, to address hydrologic, static, and seismic issues at Folsom Dam and Reservoir. The analysis in the Folsom DS/FDR EIS/EIR considered several methods to modify MIAD to achieve Reclamation's risk standards for dam safety. Subsequent investigations have shown that the preferred alternative's design approaches and construction techniques need to be changed to achieve Reclamation's existing risk standards for dam safety. Specifically, the utilization of jet grouting to stabilize the foundation of MIAD will not meet Reclamation's dam safety standards. The MIAD Supplemental EIS/EIR analyzes additional techniques to stabilize the MIAD foundation to meet the existing risk standards for dam safety.

Additionally, the supplement addresses potential environmental effects associated with completing mitigation for the Folsom DS/FDR Project at the Mississippi Bar site. The two mitigation alternatives include the improvement of up to 80 acres of seasonal wetland and riparian habitat and the no action alternative. The environmental effects of the mitigation were not addressed in the previous environmental document as the location for mitigation had not been determined.


SAFCA will complete a CEQA Findings on the Final Supplemental EIS/EIR within 30 days of the document's release. No Federal decision will be made until 30 days after the release of the Final Supplemental EIS/EIR. After this 30-day waiting period, Reclamation will complete a Record of Decision (ROD) for the MIAD modifications. A second ROD is anticipated for the habitat mitigation actions at Mississippi Bar. The RODs and CEQA Findings will identify the recommended action to be implemented, including any measures found necessary to avoid, reduce, or mitigate any significant adverse project effects.


Send requests for a compact disk or a bound copy of the Final Supplemental EIS/EIR to Mr. Matthew See, Bureau of Reclamation, 7794 Folsom Dam Road, Folsom, CA 95630 (e-mail:; telephone: 916-989-7198). The MIAD Final Supplemental EIS/EIR will also be available at:​mp/​nepa/​nepa_​projdetails.cfm?​Project_​ID=​3472.

See the SUPPLEMENTARY INFORMATION section for locations where copies of the Final Supplemental EIS/EIR are available for public review.

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Mr. Matthew See at 916-989-7198, TDD 916-989-7285, e-mail

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The Folsom Facility consists of 12 structures (dams and dikes), that impound the American River forming Folsom Reservoir. As part of their responsibilities, Reclamation and the Corps have determined that the Folsom Facility requires structural improvements to increase overall public safety above existing conditions including addressing dam safety and security issues. Both Reclamation and the Corps share in the responsibility of ensuring that the Folsom Facility is maintained and operated under their respective agency dam safety regulations and guidelines, as defined by Congress. The improvements will enhance the facility's ability to reduce flood damages posed by hydrologic (flood), seismic (earthquake), and static (seepage) events. These events have a low probability of occurrence in a given year; however, due to the large population downstream of Folsom Dam, modifying the facilities is prudent and necessary to improve public safety above current baseline conditions and meet current safety standards.Start Printed Page 24966

Reclamation has identified the need for expedited action to reduce hydrologic, static, and seismic risks under its Safety of Dams (SOD) Program and security issues under its Security Program. These identified risks are among the highest risks for all dams in Reclamation's inventory, and the Folsom Facility is among Reclamation's highest priorities within its SOD Program. Both Reclamation and the Corps have conducted engineering studies to identify potential corrective measures for the Folsom Facility to alleviate seismic, static, and hydrologic dam safety issues and flood management concerns. These two Federal agencies have combined their efforts resulting in (1) a Joint Federal Project for addressing Reclamation's dam safety hydrologic risk and the Corps' flood damage reduction objectives and (2) other stand-alone flood damage reduction and dam safety actions to be completed by the respective agencies in a coordinated manner. The MIAD Modification Project Final Supplemental EIS/EIR discusses the project background, purpose and need, project description, and proposed action. Responses to all comments received from interested organizations and individuals on the Draft Supplemental EIS/EIR during the public review period and at the public meetings are addressed in the Final Supplemental EIS/EIR.

The Final Supplemental EIS/EIR addresses the impacts of project construction on aquatic resources, terrestrial vegetation and wildlife, hydrology, water quality, flood control, groundwater, water supply, socioeconomics, cultural resources, soils, minerals, geological resources, visual resources, transportation and circulation, land use, planning and zoning, recreation resources, public services and utilities, air quality, public health and safety, growth inducement, noise, environmental justice, and Indian trust assets. There is the potential for significant impacts to air quality, recreation resources, and visual resources.

The MIAD Modification Project proposed action considered by the lead agencies is the alternative that includes:

  • Cellular open excavation as the preferred method to excavate and replace the downstream MIAD foundation to reduce seismic (earthquake) risks associated with the downstream foundation.
  • Placement of an overlay on the downstream side of MIAD to address seismic (earthquake) risks associated with the upstream foundation and installation of filters and drains to reduce static (seepage and piping) risks.
  • Creation of up to 80 acres of riparian habitat mitigation and 5 acres of seasonal wetland mitigation at Mississippi Bar.

Copies of the MIAD Modification Project Final Supplemental EIS/EIR are available for public review at the following locations:

  • Bureau of Reclamation, Denver Office Library, Building 67, Room 167, Denver Federal Center, 6th and Kipling, Denver, CO 80225.
  • Bureau of Reclamation, Mid-Pacific Regional Office Library, 2800 Cottage Way, W-1825, Sacramento, CA 95825-1989.
  • El Dorado County Library, 345 Fair Lane, Placerville, CA 95667-5699.
  • Folsom Public Library, 411 Stafford Street, Folsom, CA 95630.
  • Natural Resources Library, U.S. Department of the Interior, 1849 C Street, NW., Main Interior Building, Washington, DC 20240-0001.
  • Roseville Public Library, 311 Vernon Street, Roseville, CA 95678.
  • Sacramento Central Library, 828 I Street, Sacramento, CA 95814-2589.

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: March 19, 2010.

Pablo R. Arroyave,

Deputy Regional Director, Mid-Pacific Region.

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[FR Doc. 2010-10716 Filed 5-5-10; 8:45 am]