It's been a long and winding project. But now the end is finally in sight at Isabella Dam.
"We can see a light at the end of the tunnel," said Anthony Burdock, project manager for the Isabella Dam Safety Modification Project, a gargantuan effort by the U.S. Army Corps of Engineers intended to redesign and repair the aging earthen dam.
The multiyear project will ultimately change the face of the dam, probably the most important hunk of government infrastructure in Kern County.
The dam — now nearly seven decades old — is located on the Kern River about 40 miles upstream from Bakersfield. Water seeping below the dam was discovered close to a decade ago. It sits on an active, though long-quiet, earthquake fault, and was determined later to be vulnerable to a rare, 100-year flood.
It topped the federal government's list of dams urgently in need of repair.
According to Burdock, who along with Public Affairs Specialist Jeremy Croft, talked with reporters during a visit Thursday to The Californian, the project is scheduled to be completed in 2022, but visible construction and repair work will be done much sooner, in July 2021.
One of the most visible aspects of the project happening now is the construction of a much larger emergency spillway. Workers will remove 2.8 million cubic yards of material to make room for the spillway, Burdock said.
That's nearly as much material as it took to build the Great Pyramid of Giza in Egypt, added Croft.
The modifications to Isabella include raising the profile of the main and auxiliary dams 16 feet, adding buttresses and other safety features, and excavating to build the huge spillway.
The chance that the new spillway will ever be needed is "very small," Burdock said. It would only be needed if a massive amount of snowmelt came roaring down the river, overfilling and overwhelming the lake. But should that unlikely event happen, the emergency spillway is designed to prevent the flood from overtopping the dam and causing its collapse.
The chance of such a flood happening has been calculated as one chance in 9,000, Burdock said.
Meanwhile, blasting continues to help loosen material, which is eventually broken down into small, uniform rocks that will be reused in the construction process.
Asked if the blasting is a significant disruption for area residents, Burdock said it's not.
"We're happy to report the blasting is very unimpressive," he said.
"You'd definitely hear it if you were outside," he said.
The water level in the lake will continue to be restricted, approximately one-third less than the lake's normal capacity, until the safety features are completed. Corps of Engineers officials have said they expect the reservoir's capacity will return to normal once the project is finished.
There is no further need to lower lake levels for the duration of the project.
That means Kern Valley residents could see a full lake in the spring of 2022, depending on the snowpack.
Following two strong earthquakes in the Ridgecrest area, one on July 4 and a second, stronger temblor the following day, Army Corps engineers immediately began inspections to look for damage. They found none.
"It immediately ruined their Fourth of July plans," Burdock said of the multiple Army Corps employees who descended on the dam.
"There was absolutely no damage," he said. "We had a lot of people on the dam very quickly.
"There were no changes. No cracking. No earthworks movement," he said. "The dam is OK."