The draft Environmental Impact Statement (DEIS) for the Isabella Lake Dam Safety Modification Project is now available for public review at http://www.spk.usace.army.mil.
This dam safety modification project involves the remediation of seismic, seepage, and hydrologic dam safety concerns at the Isabella Lake Main and Auxiliary Dams.
Preparation of the draft EIS has been a cooperative effort between the Corps' Sacramento District, and the U.S. Forest Service, Sequoia National Forest.
The team reached agreement on a tentative plan for risk reduction at the project, including major modifications to both dams and the spillway and a crest raise as high as 16 feet on both dams.
The draft focused on the environmental effects of a variety of remediation alternatives. To implement such a large, complex remediation project, alternatives include altering the dams and spillway, constructing new facilities, and conducting numerous support actions over a multi-year construction period. This draft EIS helps to ensure that implementation of this project can be achieved with the fewest possible effects.
The draft EIS also provides the opportunity for public and agency information, involvement, and comment. During the 45-day public review period, the Corps will host three public hearings to discuss the status of the remediation project, present the results of the draft EIS, and encourage public questions and comments on the project.
Copies of the draft EIS are now available by request; electronically, online at the US Army Corps Sacramento District's website http://www.spk.usace.army.mil; and for viewing at the following locations: Beale Memorial Library, 701 Truxtun Avenue, Bakersfield; Southwest Branch Library, 8301 Ming Avenue, Bakersfield; Ridgecrest Branch Library, 131 East Las Flores Avenue, Ridgecrest; Kern River Valley Library, 7054 Lake Isabella Blvd., Lake Isabella; U.S. Forest Service, Sequoia National Forest, Forest Supervisor's Office, 1839 South Newcomb Street, Porterville; U.S. Forest Service, Sequoia National Forest, Kern River Ranger District, Kernville Office, 105 Whitney Road, Kernville; U.S. Forest Service, Sequoia National Forest, Kern River Ranger District, Lake Isabella Office, 4875 Ponderosa Drive, Lake Isabella.
The public review period for this draft EIS will extend from March 23 to May 7. All comments received on this draft document will be considered and incorporated into the final EIS, as appropriate.
Specific responses to the comments will be included in a Comments and Responses appendix in the final EIS. Please send any comments to: U.S. Army Corps of Engineers, Sacramento District, Attn: Mr. Tyler Stalker, Public Affairs Specialist, 1325 J Street, Sacramento, California 95814.
If you have any questions, or would like a copy of the draft EIS, Tyler Stalker may be reached at (916) 557-5102 or by e-mail at: email@example.com.
The team has updated the draft Environmental Impact Statement (EIS) based on district quality control, ATR, and risk management AFB comments. As a result of these actions, the draft EIS will be released in the federal register on March 23. Public meetings will follow on April 17-19 and further coordination and information will be disseminated shortly.
Rock corings along the proposed Borel tunnel alignments are complete and this data will be used to identify ground support needed during construction.
Agency Technical Review (ATR) – The second phase (of three) of the modification report will undergo ATR in late April upon updating the documents and after incorporating additional information as identified during the risk management AFB. The alternative formulation process and updated alternative plans will be included in this phase of the report.
Borel Canal Tunnel Investigations – Both tunnel alignments (Auxiliary Dam right abutment and the Main Dam outlet works) continue to be developed through continued hydraulic studies and structural analyses for incorporation into the modification report. This data will serve to support a recommended plan moving forward.
Civil Design – Civil engineering drawings are being revised to reflect the alternative that resulted from the risk management AFB; to reduce uncertainty in the cost estimates; and to support the documentation in the DSM report.
Dam Safety Modification (DSM) Report – The team is working on completing the next phase of the DSM Report which includes the alternative risk management plans, cost estimates, and construction schedules and is scheduled for submittal for ATR review by April 20.
• Economics – Continued adjustments to the life loss and economic damage estimates are required for complete comparison of alternative plans and will be documented in the draft DSM report.
• Environmental Impact Statement (EIS) – Public meetings are moved to April 17-19 in Kernville, Lake Isabella, and Bakersfield due to the March 23 release of the EIS. More information will be provided in this report as well as advertised in the local media.
• Programmatic Agreement (PA) – The letters to transmit the programmatic agreement to SHPO, the Forest Service, and the Tübatulabel Tribe were recently signed in the District.
• Geophysical Surveys – The USGS will complete its report within the next two weeks. Information is being used to assess the Borel tunnel alignments and the emergency spillway excavation.
• Hydraulic Structures – The team must consider and carry forward a 16-foot high dam crest raise in combination with a new spillway structure. This alternative is designed to accommodate the very large flood events and allows a controlled release of water out of the reservoir, without causing additional downstream consequences. This was incorporated into the draft EIS and will become part of the DSM report.
• Structural Evaluation – Structural evaluation of the Borel tunnel alignments and control towers is ongoing; this information will be used to substantiate cost estimates and feasibility. The analysis will also be used as a bases to jumpstart the next phase of the project.
•Current Lake Status – The current, as of Feb. 29, pool volume is 168,400 acre-ft, at an elevation of 2560.2 feet (restricted elevation is 2585.5 feet IPD).
• Funding – The total budget for the Isabella Lake Dam Safety Project for FY 2012 is $4,900,000. Total funding currently available to the project is $3,018,000. The remaining funds will be distributed at the end of March and June. The funding is being used to fund the PDT’s efforts on the project, to support contracted efforts, and to complete various project reviews in preparation for a final DSM Report.