By Kathe Malouf
Special to the Sun
The long-awaited Isabella Dam Safety Modification Project got underway last week with the ceremonial tossing of dirt by representatives from the U.S. Army Corps of Engineers, U.S. Forest Service, Congressional and local Supervisorial districts.
The groundbreaking ceremony held April 3 marked the beginning of phase two of the massive project that will fix safety deficiencies at both the main and auxiliary dams that were identified by the Army Corps of Engineers 12 years ago.
Congressman Kevin McCarthy, called the groundbreaking of the Isabella Dam Safety Modification a major event, one that has been a priority for him since he first came into office.
“You wonder if you will ever get to this day,” McCarthy said as he addressed the gathering of Kern Valley residents and representatives from the Corps, U.S. Forest Service, construction workers and political representatives. “Today is a great day. This is not the end, but the beginning of phase two and I look forward to the ribbon cutting ceremony and the raising of the water.”
McCarthy thanked the Corps for their continued progress and commitment to the project.
“On a personal level, this has been an unbelievable accomplishment,” McCarthy said.
The Isabella Dam Safety Modification Project (DSMP) has been in the works since 2005, when the Corps determined that Isabella posed unacceptable risk to life and public safety. They began a safety study to address seismic concerns, potential overtopping and seepage issues at both dams. Following years of environmental studies and public meetings, the Corps published a Final EIS in 2012 which outlined the proposed remediation of the dams and moved on to the preparation phase of the project.
Phase one included design work and the relocation of the Forest Service administration compound, located on top of Isabella reservoir. A new Ranger Station and administrative complex was constructed in Kernville and a new fire station and interim visitor’s center was built in Lake Isabella. Both were completed in October of 2017.
In September of last year, the Corps awarded a $204 million contract to Flatiron/Dragados/Sukut Joint Venture to construct the modifications to the dams. The groundbreaking ceremony marked the beginning of phase 2 of the project that is scheduled to be completed in 2022.
Last week’s ceremony took place near the buildings that once housed both the Corps and Forest Service. That site is where the first work will begin in late May or early June, when crews will demolish and remove the buildings, then dig down about 120 feet and remove the material in preparation of the new 300-foot-wide emergency spillway. In addition to a new emergency spillway, the DSMP will raise both main and auxiliary dams by 16 feet.
Throughout the morning, speakers discussed the benefits of the project and the importance of the partnerships that have been developed between the Corps, the Forest Service and Kern River Valley community members.
McCarthy summarized the benefits. “No. 1 is to protect the community and everyone below the dam; No. 2, it will allow more water to be stored; and No. 3 is it will improve recreation.”
McCarthy thanked the community for their involvement and input on the project. He also asked for continued community support. “As we proceed, the water will have to go down for safety reasons.” With an impressive view of Isabella Lake in the background, McCarthy assured the audience that the view will only get better upon the completion of the project.
Brigadier General Peter Helmlinger, Commander of the USACE South Pacific Division said that the life-safety modification project at Isabella is the largest civil project currently underway within the Southern Pacific Division, with a total overall cost of $600 million.
Ann Carlson, Acting Forest Supervisor with the Sequoia National Forest, noted that the Forest Service is intricately connected to the Kern River Valley community, saying that the Sequoia National Forest benefited through their partnership with the Corps, pointing out the recent opening of the new Ranger Station in Kernville and the new fire station and interim visitor’s center in Lake Isabella.
First District Supervisor Mick Gleason focused on the partnership between the Corps and community, specifically thanking the members of the Isabella Dam Task Force for their commitment to the project. “The Army Corps has done a great job, and now we need to stay focused on the year 2022 when we will be out of the restricted pool.”
Steve Francis, representing Flatiron/Dragados/Sukut Joint Ventures said the day marked an historic event, when they are able to raise a lake. He noted that the safety modification project will require a million man hours, adding that their goal is to get the project done and get the lake filled up as quickly as possible, with minimal impact to the public and community and with no injuries.
The construction project will bring some disruptions and inconveniences to motorists traveling on Highway 155 between Wofford Heights and Lake Isabella. Once the demolition and construction gets underway, Hwy. 155 will be temporarily rerouted, resulting in traffic delays and one-way escorts.
According to Julie Martinez, Corps’ resident engineer, detours will start sometime in June, with two-way traffic. In August, traffic will be reduced to one-way with escorts for a period of two to three months. Initially, the design included the realignment of Hwy. 155 and Hwy. 178; however in 2015, the plan was refined eliminating the need to realign the highway, resulting in time and cost savings.
Colonel David Ray, Commander with the Corps’ Sacramento District, noted that they are still in negotiations with Southern California Edison for the acquisition of the Borel Canal easement.
While the lake won’t be drained during construction, it will be lowered to a level of about 72,200 acre feet for a period of 4 to 6 months during either the upcoming winter or the winter of 2019-2020. Currently, Isabella sits at 198,700 acre feet, or 35 percent of capacity.
The lake has been operating with a restricted pool of 361,250 acre feet since 2006. That restriction that will be removed once the project is completed in 2022.