The East Branch Clarion River Lake Dam Safety Project in Elk County is earmarked to receive $56.3 million under President Donald Trump’s proposed budget.
The U.S. Army Corps of Engineers, Pittsburgh District, is hosting an open house and tour from 10 a.m. to 1 p.m. Saturday of the East Branch Dam Safety Initiative to include the seepage, cutoff-wall construction site.
“The goal of the open house and dam safety project tour is to give the public an update on the construction progress; to introduce them to the project and lake staff; and to show integral features of work such as grouting, cutoff wall construction, and instrumentation and monitoring devices for dam safety including piezometers and weirs,” U.S. Army Corps of Engineers said in a prepared statement.
The wall will consist of a minimum 18-inch-wide continuous vertical concrete cutoff wall approximately 2,300 feet long with an approximate maximum depth of 250 feet through the existing embankment dam into bedrock. Completion of the cutoff wall and follow on verification of the repair will allow the Corps to operate the dam at full capacity and restore the reservoir to its regular water levels.
The additional work is expected to extend the dam safety project for an additional seven months. The most recent estimated completion date of the seepage cutoff wall construction is early 2020. The Army Corps and the contractor are working to identify and implement efficiencies in sequencing of the work that will reduce the construction schedule.
In 2008, the Pittsburgh District initiated a dam safety investigation into seepage-related concerns at East Branch Clarion River Lake. To reduce the risk to the public, Pittsburgh District implemented several interim risk reduction measures, including increased monitoring, continuous on-site staffing, updated emergency action plans and lowered water levels in the reservoir to relieve pressure on the dam. These and other short-term actions have allowed the district to minimize dam safety risk while still fulfilling the authorized purpose of the dam until permanent risk reduction measures are constructed.
A Dam Safety Modification Study was completed and approved in October 2010. In August 2014, the Pittsburgh District awarded the $132.5-million East Branch Dam Cutoff Wall Rehabilitation Project to Layne Christensen Company of Ruther Glen, Virginia. The company’s Bencor Division, of Frisco, Texas –– which is performing the dam safety work –– was subsequently acquired by The Keller Group LLC. The work consists of constructing a full-depth seepage cutoff wall within the existing earthen embankment dam.
“Following the completion of the cutoff wall, the Army Corps will conduct an evaluation of the repair to ensure that it meets the agency’s dam safety standards,” officials said. “Upon verification of the work, the district will implement a water management plan that incrementally raises lake levels while monitoring the performance of the repair. The district’s main objective is to ensure public safety while returning operation of the dam and management of the reservoir to its regular water management plan.”
