It's another major step in a planning process that has been ongoing since 2006.
The U.S. Army Corps of Engineers this week released the final environmental impact statement on its plan to strengthen and expand Isabella Dam -- with significant changes included since the draft EIS was released months ago.
The 60-year-old dam, located on the Kern River about 40 miles upstream from Bakersfield, is leaking, sits on an active earthquake fault and tops the federal government's list of dams urgently in need of repair.
"The release of the final EIS is a very significant milestone," said David Serafini, the technical lead engineer for the Isabella Dam project.
"It means it's out of the study phase and into the development phase."
The publication of the 600-page document follows years of study, community scoping meetings in Kernville and Bakersfield, lengthy comment periods and refinements made to the plan in response to those comments.
In the report, the corps analyzes a wide variety of issues such as seepage, seismic risks associated with an ancient earthquake fault that runs beneath the auxiliary dam, and the need to raise the height of the two dams by 16 feet to contain water from what corps officials have referred to as a possible but exceedingly rare "Noah's flood" event.
The corps also lays out plans to minimize impacts from construction.
"We actually received 435 comments from the public and agencies addressing a wide variety of issues," said Mitch Stewart, the project's environmental lead.
But by far, most comments reflected concerns by residents and businesses in the Kern River Valley about the need to temporarily lower the lake level to facilitate construction, and the impact it will have on recreation, tourism and the local economy, Stewart said.
Lake water quality and air quality in the region were also common concerns.
But refinements made to the plan now include components that directly reduce those impacts. For example:
* Changes to the construction schedule and duration, which will reduce the time needed to lower the lake level and concentrate the work in non-peak tourism months.
* Engineers have figured out a way to use materials excavated during the construction of a much larger spillway for buttresses designed to stabilize the dam. The change negates the need to move hundreds of truckloads of rock and soil from the Southlake area.
* Planners will substitute electrical power on the work site for previously planned diesel generators and other equipment. This includes replacing up to four diesel generators running 24-7 to provide electrical power needed to run a dewatering pump system. The use of electricity where possible is expected to greatly reduce emissions and noise.
Changes will also include the relocation of Borel Canal to the west of its current location.
And highways 155 and 178 must be moved to accommodate the raising of the dam's crest. However, the realignment of Highway 155 has been modified to be closer to the existing roadway and will include a widening of the existing bridge rather than the construction of a new bridge.
The document is now available for public review. A 30-day comment period begins Friday and continues to Nov. 26.
You can review the document at the Beale Memorial and Southwest library branches in Bakersfield, and at U.S. Forest Service offices in Lake Isabella and Kernville. You can also review it online at http://tinyurl.com/9lvwcwc.
The corps will hold three public meetings to discuss the final report and solicit comments. The National Environmental Quality Act, which governs and requires public interaction, does not require the corps to respond to comments this late in the process, only to document them.
Meeting details are as follows;
Kernville -- 6 p.m. to 9 p.m. Nov. 13, Odd Fellows Hall, 50 Tobias St.
Lake Isabella -- 6 p.m. to 9 p.m. Nov. 14, Kern River Valley Senior Center, 6405 Lake Isabella Blvd.
Bakersfield - 6 p.m. to 9 p.m. Nov. 15, Rabobank Convention Center, Potato Room, 1001 Truxtun Ave.