By Colby McCoy
Construction on the Lake Isabella auxiliary dam is on track to reach a flood-elevation level of 2,570 feet by November 2020, just in time for the beginning of flood season, the U.S. Army Corps of Engineers (USACE) said.
Work on the auxiliary dam is part of a larger $600 million Dam Safety Modification Project in Kern County, where both Lake Isabella dams are to be raised by 16 feet in order to prevent over-topping.
Filters are being added to each dam to increase their stability over the coming years. In addition, improvements will be made to an existing spillway, and a brand-new emergency spillway is planned for construction.
David Serafini, USACE lead engineer for the project, described the difficulty of the project.
“Modifications to the main and auxiliary dams require work to be performed during specific work windows because of reservoir operations during flood seasons to account for rainfall and snowmelt changes in lake levels,” he told ENR California.
Although the effects of the COVID-19 pandemic and rampant wildfires have greatly impacted the state of California, the Corps of Engineers said that even with the additional safety protocols in place to protect workers, progress on the project has largely remained unhindered.
As of today, State Route 155 continues to operate under single-lane traffic through December 2020.
State troopers have been deployed to the area to ensure the safety of both workers and pedestrians.
The project is likely to be finalized by 2022, the Corps of Engineers told ENR.
The Isabella Lake Dam is 40 miles northeast of Bakersfield and was originally built in 1953. The main dam is centered at the confluence of the north and south forks of the Kern River, and the auxiliary dam is located approximately a mile to the east.
In total, the Lake Isabella reservoir boasts a storage capacity of 568,075 acre-feet and is a primary source of water for the residents of Kern County.
As of today, the current pool capacity for the lake sits at 100,630 acre-feet, or 39% of restricted pool levels.
By the project’s end, work crews will have excavated 3.5 million cubic yards of earth and used 67,000 cubic yards of concrete, pointing to the enormous size of the project.