The Bolivar Dam Rehabilitation Project, which was completed in October 2017, nearly 18 months ahead of schedule and $18 million under budget has, now been given the Corps' highest possible safety rating.
The Bolivar Dam project delivery team conducted a Post-Implementation Evaluation (PIE) and presented their findings to the Dam Senior Oversight Group (DSOG). "The Bolivar Dam Project is an example of the Corps' commitment to the pursuit of excellence in the execution of its flood risk management program," said August Martin, Chief, Engineering and Construction Division, Huntington District.
The PIE reviewed the series of risk-reduction measures, which included construction of a partial-length seepage barrier wall, the augmentation of the existing downstream seepage blanket, a two zone, double-line grout curtain across the left abutment, new gates and operating equipment, and the continued efficient maintenance of existing downstream relief wells. These measures were implemented to substantially reduce seepage beneath the dam during high water events, ensure the project's ability to control the release of water as intended and allow for continued monitoring of the dam during high water events.
The DSOG reviewed the project delivery team's findings and made the recommendation to reclassify Bolivar a Dam Safety Action Classification (DSAC) 5 - Normal (Safe), the first dam in Huntington District to receive this classification.
"Achieving a DSAC 5 rating is a major accomplishment," said Jeffery Maynard, Lead Engineer. "With all of the hurdles that had to be overcome, I think Bolivar set the standard for how local USACE districts, national dam safety centers, and our construction contractors can all work together as a team to achieve success and accomplish the mission," he said. I am proud and humbled to have been a part of that amazing team who worked countless hours to reach this monumental rating. As an engineer and civil servant, it is a very satisfying feeling knowing that you played a significant role in reducing the risk to the public and their property. I couldn't have asked to have led a better team of professionals, working together, to achieve this DSAC 5 rating," said Maynard.
Prior to repairs, Bolivar Dam was a DSAC 2 due to the potential for backward erosion piping of the foundation's upper and lower outwash and erosion of the embankment into and along the rock at the left abutment. DSAC 2 means that dam failure could have begun during normal operations or as the consequence of a significant rain event. The likelihood of failure from one of these occurrences, prior to remediation, was too high to assure public safety; or, the combination of life or economic consequences with probability of failure was very high.
The Major Rehabilitation Project at Bolivar consisted of a series of risk-reduction measures, including an impervious seepage barrier, seepage blanket augmentation, service gate replacement and instrumentation contracts. Measures were implemented to substantially reduce seepage beneath the dam during high water events, ensure the project is able to control the release of water as intended, and to allow for continued monitoring of the dam during high water events.
The construction of Bolivar Dam was originally completed in September 1938. It is considered a "dry dam", meaning that it does not retain a normal upstream pool unless required for flood risk management during rain events. It is one dam in a system of 14 dams designed to provide flood control and water conservation in the Muskingum Watershed in Ohio. The dam is a rolled earth-fill dam with an impervious clay core founded on glacial outwash material. The maximum height of the dam is 87 feet, with a crest length of 6,300 feet and a crest elevation of 985.5 feet. The project has an uncontrolled saddle type spillway at the left abutment with a crest length of 540 feet and a crest elevation of 962.0 feet. The project has an intake structure containing six sluice gates measuring 7 feet by 15 feet which discharge through two horseshoe shaped tunnels measuring16 feet by 16 feet. The drainage area upstream of the dam is 504 square miles.