LIMA — A low-head dam removal on the Ottawa River just west of Dutch Hollow Road began Thursday to improve water quality in the area and allow fish to head upstream.
Initiated by the Ottawa River Coalition in response to a 2010 EPA water quality study, the dam’s removal is estimated to allow the river’s fish to better use their river habitat and propagate instead of running into the man-made barrier.
Currently, the four miles of river upstream of the dam are largely devoid of fish.
The coalition got the dam removal project off the ground back in 2018 after holding a number of public meetings to hear from local neighbors. At the time, neighboring property owners adjacent to the dam, including Dominion Energy, had no objection to ripping out the concrete structure.
As for the river’s flow, the dam’s removal is expected to have limited impacts to the amount of water moving through the area, according to studies completed by federal and state agencies. The biggest change is expected to be a thinning in the river roughly one third of a mile up stream as the river readjusts its flow.
Initially, the Allentown dam was built in 1933 to support a stream flow gauging station operated by the U.S. Geological Survey, but that purpose was nixed in 1984. Other low-head dams constructed on the Ottawa River in the same time period — eight in total — had been constructed to deepen the river where dry stream-beds once stood.
As for the Allentown dam’s purpose today, the 88-foot-long concrete dam does little but trap sediment, including three feet of rock, stone, gravel and sand that has since raised the stream bed.
Once the $13,500 project is completed by the Ottawa River Coalition’s contractor Degen Excavating, coalition volunteers will still have to relocate freshwater mussels in the area. Without doing so, some of the mussels could become stranded in deeper water, and volunteers are using Thursday and Friday to move them to more accommodating areas of the river before any changes in the river destroys their viability.
According to the Ottawa River Coalition, the Ottawa River is home to 54 different species of fish that are sometimes separated by the river’s low-head dams, and the coalition is actively working through ways to open up the river, through dam modification or removal, to allow a more natural flow of native species.
Reach Josh Ellerbrock at 567-242-0398.