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Supplemental EA #7, Water Control Manual Deviation 
To All Interested Parties Letter - Sept. 19, 2017
Draft SEA - Sept. 19, 2017
Final SEA - Oct. 31, 2017

Supplemental EA, SR 155 at French Gulch Rec Area
Final SEA/FONSI - Sept. 18, 2017
Draft SEA - July 10, 2017

401 Application Public Notice - Oct. 24, 2016

Final SEA #5/FONSI Dams & Spillway Design Refinements - Oct. 6, 2016

Contact Information

For more information on the
Isabella Dam Safety Modification Project,
please contact us at the following:



Mailing Address:
U.S. Army Corps of Engineers,
Sacramento District
Isabella Dam Safety Modification Project
1325 J Street, Room 1513
Sacramento, CA 95814

Isabella Lake Dam Safety Modification Project

Isabella Reservoir is located forty miles northeast of Bakersfield, Kern County, California, and consists of an earthfill main dam and auxiliary dam across Kern River and Hot Springs Valley, respectively. The dam was authorized under the Flood Control Act of 1944 and construction was completed in 1953. The reservoir provides flood-risk management, irrigation and recreational benefits. With more than 300,000 people living and working below the dams, primarily in the town of Lake Isabella and the city of Bakersfield, the U.S. Army Corps of Engineers began a dam safety modification study in 2006 to address seismic, hydrologic (potential over-topping during an extreme flood event) and seepage issues at the dams.

An operating restriction is currently in place, limiting the lake’s normal storage capacity and reducing the risk of the seepage and seismic concerns while a permanent solution is investigated. USACE has implemented increased surveillance and monitoring; stockpiling of emergency materials; warning sirens in the town of Lake Isabella; installation of additional instrumentation for monitoring; and continued public outreach with Kern County and the local public.

Following the signing of the Record of Decision in December 2012, the Corps entered the Pre-Construction Engineering and Design phase of the project, and from 2013 to 2016, focused on design improvements to the existing dams and the relocation of U.S. Forest Service buildings located in the excavation footprint. Construction of the USFS warehouse/administrative buildings in Kernville and the USFS fire station in Lake Isabella were completed in 2017. 

In September 2017, the Corps awarded a $204 million contract to Flatiron/Dragados/Sukut Joint Venture of Benicia, California, to construct the Phase II dams and spillways modifications. The project is expected to be complete in 2022.

Frequently Asked Questions

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The approved plan includes:

  • Raising the main and auxiliary dams up to 16 feet higher to minimize the risk of over-topping.
  • Adding a filter and drain on the downstream slope of the main dam to increase stability.
  • Improving stability of the existing spillway.
  • Creating an additional 300-foot-wide emergency spillway.

In addition,the Borel outlet works will no longer be realigned as proposed in the 2012 DSMR. Instead, “just compensation” will be paid to Southern California Edison and they will likely decommission the Borel Canal, subject to approval by the Federal Energy Regulatory Commission. Safety remains our #1 priority – we have to reduce the risk from a potential failure for the people living below these dams. We feel this is the best way to do that.

First off, it’s important to understand that the disposition of the Borel Canal is a separate action from acquiring the easement. Supplemental Environmental Assessment #4 addresses only the easement acquisition and only the section of the Borel Canal immediately upstream, through and immediately downstream of our ongoing dam safety modification project. All other portions of the canal, upstream and downstream, are not on Corps property or our project area and, therefore, we have no authority to determine what is done with those portions of the canal.

If agreement is reached with Southern California Edison and the Corps proceeds with the Borel easement acquisition without constructing a replacement tunnel as detailed in SEA #4, it would permanently cut off water supply to the Borel Hydroelectric Project. SCE would then be responsible for determining any actions (including potential decommissioning) related to the canal and power station. SCE could also negotiate for another agency to take the lead in the decommissioning process.

Regardless of who takes that lead, other agencies would then partner together to ensure a smooth and appropriate process. For example, the California Public Utility Commission would be responsible for approving any change in power plant status to ensure local ratepayers and private landowners are not unfairly affected.

The Federal Energy Regulatory Commission, which permits hydropower production at Borel, would require that actions related to decommissioning be taken in a timely manner and that the canal not be left to create a safety hazard.

Finally, the US Forest Service and Bureau of Land Management, who own much of the land underneath the canal, would provide input into the final state of the canal.

As you can see, between USACE, FERC, CPUC, USFS, and BLM, there are several federal and state agencies working together with SCE and the public to put together the best environmental and economic plan for the fate of the Borel Canal, and regardless of the final
decision, the public will have a chance to review the proposed action and provide comment.

We want to answer your questions! If you’re curious about the process or have specific questions for us, please email us

Given the multiple purposes of this dam facility and the long-term benefits it provides, we require thorough analysis of any modification to assure public safety and benefits are not compromised by modification to the dam.

Dam analysis and designs are complex technical efforts. Risk assessments must be performed to understand the extent of a problem and to evaluate options to fix the dams. In this case the dam has multiple deficiencies that require correction which increases the time required to understand and to start the fixes.

We also take great effort to comply with the National Environmental Protection Act and the Endangered Species Act which does require significant time to assure that all requirements are met.

Kern County and the U.S. Forest Service are working together to determine specific agreements, timing, and location of the permanent visitor center. Once those determinations are made, the Corps will move forward with construction at the agreed upon location.

We are still in the Pre-Construction Engineering and Design phase. Once complete, construction would begin. Our current schedule shows construction beginning in 2017.

It could range from 4 years to 8 years depending on final recommendations, designs and availability of funds. We have a current construction schedule lasting from 2017 to 2022.

The workforce on this project will vary depending on the phase of construction; however, we estimate a typical work crew would likely be between 100-150 workers. We will hire a prime contractor on a national level to complete the work, and the contractor will be responsible for hiring any work force to complete the job.

If you are an individual, we recommend contacting companies who have been awarded contracts for possible job opportunities. Please see “award” contracts below.

If you are a contractor, you need to start by registering in the System for Award Management (SAM) database. Click here to start: SAM

To bid on current contracts, see “solicitation” contracts below.

Contract Opportunities

No contract opportunities at this time. Please visit the Isabella Archive page for past contracts.

Recreation and Water Levels

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The Isabella reservoir offers fishing, boating, water sports, camping, and picnicking. Close proximity to Los Angeles and Bakersfield makes this lake a popular yearround vacation spot for southern Californians. The lake is one of the state’s most popular windsurfing areas; reliable afternoon winds, from 35-50 miles an hour, create ideal conditions for intermediate to advanced windsurfers. Enjoy shoreline camping and day use activities at Auxiliary Dam, Old Isabella Road, or South Fork Recreation Area with the purchase of a Southern Sierra Pass or other Interagency Pass. South Fork Wildlife Area, one of the most extensive riparian woodlands remaining in California, provides fishing, hunting, canoeing, and hiking opportunities; no developed recreation facilities are located here. When operating on the lake, every boat, personal watercraft, and sailboard must display a permit from Kern County. These permits may be obtained at any lake marina or at various locations throughout the Kern River Valley. Be sure to check for required safety equipment.

More information on Annual, Senior, Access, Volunteer, and the Southern Sierra Passes including Fee-Free Days in 2017 can be viewed here:

Information is also available for Campfire Permits, River Permits, and Wilderness Permits at the same website. For more information, please contact the U.S. Forest Service at (760) 376-3781.

Weather information, including current temperature, wind speed, rainfall and humidity, as well as live weather webcams around Lake Isabella can be viewed here: 
From farmer's markets to firework displays, Lake Isabella is full of community events. For more information on events, visit: 
Current pool levels, inflow and outflow levels for Lake Isabella can be viewed here: You can view the elevation levels here: 
Information on developed campgrounds at Lake Isabella, managed by the U.S. Forest Service, can be viewed here: 
Water safety tips from the Kern County sheriff's office can be viewed here.