Relics of the Canal Age: Six-Mile Dam and Lock No. 5

Relics of the Canal Age: Six-Mile Dam and Lock No. 5. . The State of Ohio constructed the Six-Mile Dam approximately 2.4 miles downstream of Warsaw in the late 1830s as part of the Walhonding Canal. Contractors built the dam as a rock- filled, timber-crib structure with a plank facing. It measured 304 feet long and stood 4.5 feet above the river at low water. The dam provided a slackwater pool that allowed canal boats to cross the Walhonding River from Lock No. 4 on the south side of the river to Lock No. 5 on the north side. Lock No. 5 was a lift lock, allowing boats back into the canal. Remnants of Lock No. 5 can be viewed on the nearby island once a year by arrangement with ODNR., In 1908, the state built a new concrete dam here, closing off boat traffic above the dam. The new dam converted the canal to a water supply source for the mills at Roscoe Village. Engineers designed the new dam with three feeder gates where the new dam closed off the canal prism. These gates could control the amount of water flow through raising and lowering metal plates covering openings in the dam wall., One gate operating mechanism is preserved here. The canal below Six-Mile Dam was supplied with water until 1978, when ODNR permanently closed the feeder gates and the channel gradually filled with silt., The state removed the deteriorating Six-Mile Dam in 2020 with funds from the Ohio EPA Division of Environmental and Financial Assistance Water Resource Restoration Sponsor Program to address a safety hazard and restore aquatic habitat in the Walhonding River. Habitat quality in the river has improved, connecting previously isolated endangered mussel populations and allowing native fish species to return upstream to habitats where they had not been seen in over a century. Image courtesy of The Ohio State University Stream and River Ecology Laboratory.