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Contact Information

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

Phone:
916-557-5100

Email:
isabella@usace.army.mil

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

Construction

Construction is tentatively scheduled to begin in 2017. We are still in the Pre-Construction Engineering and Design phase.

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 (USACE) began a dam safety modification study (DSMS) in 2006 to address seismic, hydrologic (potential overtopping 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, to reduce 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.

In 2013, following the signing of the Record of Decision in December 2012, the Corps entered the Pre-Construction Engineering and Design phase of the project. A number of procedural tasks must still be completed in preparation of physical construction, which is scheduled to begin in 2017.

Frequently Asked Questions

Project Plan & Construction
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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.

Not under the current dam safety modification study. Increasing of the storage capacity would require separate authorization and would require a different study.

We understand the concern regarding the duration of construction and are doing everything possible to shorten completion dates. Currently, we are finalizing our costs and schedule for design and construction, and will have a more accurate reflection once that is complete. There are always unknowns associated with construction, but we are committed to minimizing any impacts that may arise. We will continue to refine the schedule to ensure efficiency in construction.

There are no guarantees in regards to funding. However with the continued support of the community and the “high risk” ranking of the dam, we will continue to express the need for timely funding to keep the project on schedule.

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 900-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.

A downstream replacement dam at the auxiliary dam site was evaluated, but not selected based on increased cost, larger demand for materials, a longer construction schedule and increased air quality concerns based on the additional earthwork. This project won’t come cheap, but our duty is to modernize the dams by getting the most value for every taxpayer dollar, and that’s what we believe our identified plan does.
Integration of renewable energy is now required for all federally funded projects. Our initial proposal for wind turbines was a way to highlight the latest technology, however, based on public comment, we are now also considering solar panels.

Since the initial proposal, we have learned that the building energy sustainability requirement is only 10% of the building’s power needs vs. the 30% originally considered. As a result, the proposal to install six vertical-axis wind turbines (VAWTs) has been reduced to just two turbines, or to solar panels only that would cover an area of 30 by 40 feet. Either of these reduced options would sufficiently meet the 10% sustainability requirement.

The Corps will evaluate both options and make a decision for renewable energy type based on criteria of energy efficiency, cost, and public input for visual preference.

The Auxiliary Dam Recreation Area cannot properly accommodate flush toilets due to inadequate drainage fields there. The vault toilet replacements are preferred due to reduced maintenance costs and lower water use. New vault toilets are also engineered to better reduce odor. Cost benefit assessments are not conducted within the NEPA process, but will be evaluated in the decision process.

Some examples of the proposed vault toilets can be viewed here

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.

The Record of Decision allows for the official start of the next phase of the project and was signed at the Corps’ headquarters in Washington, D.C., by James Dalton, Chief of Engineering and Construction in December 2012. The ROD is a document that states what the decision is; identifies the alternatives considered, including the environmentally preferred alternative; and discusses mitigation plans, including any enforcement and monitoring commitments. Read more about the ROD here.
The estimated project cost is $400-$650 million.
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.

In 2013, we entered the Pre-Construction Engineering and Design phase of our project. We still have a number of procedural tasks to complete in preparation for physical construction of the authorized plan. The highway relocations would have begun in 2014, however, that is no longer required for implementation of the authorized plan. The major components of construction will begin in 2017.

The workforce will vary depending on the phase of construction; however, the rough estimate of 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.
The Freedom of Information Act (FOIA) process is the best way to obtain documents that are not released for public review at a minimal cost (if any).
Impacts
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The Auxiliary Dam Recreation Area is planned to primarily be a temporary staging area that would be returned for recreation use after the project is complete. It will also serve as a secondary on-site borrow source for filter sand on the main and auxiliary dams should the excavation of the emergency spillway not be able to provide sufficient quantities.

Other camping areas around the lake are not scheduled to be affected by the project, and the U.S. Forest Service would continue as the managing agency for these areas.


We recognize and appreciate the value of the public lands here, so a draft recreation report was released in February 2014 to further explore and identify options for mitigation to offset adverse effects on recreation. Public participation will be solicited to address concerns over the negative impacts of the project. View the draft recreation report here.

Investigations have shown that obtaining borrow materials from the lake bottom are not cost effective for filter and drain materials and would introduce other environmental concerns, such as water quality effects associated with lake lowering, and increased fugitive dust concerns.
We are working with the U.S. Forest Service and local community groups to further minimize the impacts to local events on the lake, campgrounds, boat launches, etc. The majority of the time the lake would remain under its current operation with the pool restriction, and recreation will still be permitted on the lake during construction.

We are committed to working with the community, and one of the concerns we are hearing is about reducing the amount of time the lake elevation would be reduced. As a result, under the authorized plan, the lowered pool elevation for construction has been limited to a single four-to-six month window between October 2020 and March 2021.


This takes advantage of the natural low reservoir elevations during the fall and winter months when it is already being drawn down for flood control operation, minimizing impacts to recreation, water quality, fisheries, and socioeconomics, and further reduces the impacts over the entire construction period. A more detailed Recreation Report resulting from this process was released February 2014 and is available here

Under the preferred plan, the construction pool elevation has been limited to a single four-to-six month window between October 2020 and March 2021 in order to take advantage of the natural low reservoir elevations during the fall and winter months when it is being drawn down for flood control operation. This reduces the potential for dust impacts described in the draft environmental impact statement from lake lowering.

For the majority of the construction period, the lake will remain under its current operation with the pool restriction. Potential impacts from windblown dust can be effectively reduced to less than significant levels through the use of best management practices, which will be required. These practices are described in Section 3.3.3 of this final environmental impact statement and Section 3.5.4 of the draft EIS.

The storage and release of flood water in Isabella Lake is under the control of our Water Management Section, however, we have no influence over the operation of the reservoir outside of flood operations. During construction, the release of water will continue to be dependent on inflow, irrigation needs and downstream storage capacity.


We’re doing everything we can to minimize the impact to the public, with as little disruption as possible. We released a draft recreation report in February 2014 that further explores and identify options for mitigation to offset adverse effects on recreation including the needs for recreational flows in the lower Kern River. View the draft recreation report here


As a side note, rafting companies that operate above the reservoir would continue operations as normal and be unaffected by the dam safety modification project.

The South Fork Delta sand borrow area has been eliminated as a sand source for the authorized plan. Sand will now be manufactured at the dam site utilizing waste materials generated from the emergency spillway excavation. This refinement has eliminated the largest contributor to short-term construction-related traffic and circulation impacts along Highway 178 within the Kern River Valley. The majority of the truck traffic is planned to occur onsite for excavation, processing, and fill placement to reduce impacts.

Highway trucks will still be required to meet all standards; therefore there should be no impacts to roads except for the everyday wear and tear that they are designed for. 

We have eliminated the original relocations of Highways 155 and 178. There will be some construction around Highway 155, but we will work to minimize the time and impact to local residents.

During the ongoing engineering and design phase for Isabella Lake Dam upgrades, the Corps identified 12 properties downstream of the dam that will be impacted by construction.

Impacted property owners have already been officially contacted or notified by a Corps real estate specialist as part of the process. There may be additional property owners contacted in the future, but everyone affected by this initial phase of acquisition has been contacted at this time. Until officially contacted or notified by a Corps real estate specialist, property owners are encouraged not to change, plan or do anything in anticipation of being contacted.

 

During the ongoing engineering and design phase for Isabella Lake Dam upgrades, the Corps identified 12 properties downstream of the dam that will be impacted by construction.

Impacted property owners have already been officially contacted or notified by a Corps real estate specialist as part of the process. There may be additional property owners contacted in the future, but everyone affected by this initial phase of acquisition has been contacted at this time. Until officially contacted or notified by a Corps real estate specialist, property owners are encouraged not to change, plan or do anything in anticipation of being contacted.

The refinements that went into the authorized plan will reduce many of the anticipated construction-related impacts, but negative short-term impacts on property values may occur during construction.


Our assessment of potential project impacts to the local economy found both short- and long-term benefits associated with construction-related spending in the Kern River Valley and unrestricted reservoir operations upon completion of the project.

Long-term economic improvement resulting from recreation, higher lake levels, employment opportunities, and lower safety risk would likely result in improved property values. These project benefits may serve to provide the Kern River Valley with greater long-term economic stability, which is a major factor in determining regional property values.

The current low water level is due to lower than average rainfall and snowmelt. The Corps is only responsible for directing releases during the winter months (Nov. 1 - Feb. 1) to maintain storage space for the rainy season and anticipated snowmelt. Downstream water users control the outflow based on irrigation demand the rest of the year. The Corps plays no role in those decisions.


Contracts & Employment
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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.

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


Contract Opportunities

Opportunity Type Award Date Posted On
Geophysical surveying   Presolicitation     June 13, 2014 
Materials investigation Award Apr. 4, 2014    Apr. 15, 2014

                                                  

 

Isabella Lake

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.

For more information on Annual, Senior, Access, Volunteer, and the Southern Sierra Passes including Fee-Free Days in 2013 can be viewed here: http://1.usa.gov/14x1ukz.

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: http://bit.ly/17qAuui 
From farmer's markets to firework displays, Lake Isabella is full of community events. For more information on events, visit: http://www.lakeisabella.net/events/ 
Current pool levels, inflow and outflow levels for Lake Isabella can be viewed here: http://1.usa.gov/13DKwjw You can view the elevation levels here: http://1.usa.gov/1enHdTy 
Information on developed campgrounds at Lake Isabella, managed by the U.S. Forest Service, can be viewed here: http://1.usa.gov/12t0MKA 
Water safety tips from the Kern County sheriff's office can be viewed here.