Underwater breaker challenge on the Cuyahoga

Remediation of the Cuyahoga River in Ohio, USA, to return it to its pre-industrial condition required the removal of two dams across its flow. RiverReach Construction, a specialist in environmental stream and wetland restoration, was brought in to remove the structures. The first to go was the Sheraton Mill dam, a 12 m (40 ft) long and 3 m (10ft) high structure, however access to this dam was only possible from upstream so RiverReach had to adopt an unusual approach.

A 4.8 tonne Komatsu PC45MR zero tail swing excavator equipped with an Atlas Copco SB 552 breaker was floated into place on a modular barge and moored above the dam and the breaker was then used to open ‘windows’ in the dam structure to allow the water level behind the dam to fall. An Atlas Copco XAS 185 compressor supplied a flow of air to prevent the water from entering the percussion mechanism of the breaker during the work.

Once the level had fallen sufficiently, a 39 tonne Komatsu PC360 equipped with an Atlas Copco HB 3100 breaker, again supplied with air by the compressor, was used to remove the rest of the dam structure. It took just one day to complete the work. The PC360 with the HB 3100 then moved on to remove the second dam, the Lefever Dam, a 27.4 m (90 ft) long and almost 4 m (13 ft) high structure. This time access was possible from the downstream riverbank, allowing the PC360/HB 3100 combination to quickly remove the structure.

Once demolition was complete, RiverReach cleaned up accumulated debris and remnants of the concrete and rebar. Concrete support walls were then built to support the old powerhouses to protect these historic structures from variations in river flow and the debris that comes down the river during high water events.