Removing an Ohio dam reopened 39 km of Cuyahoga River habitat

A concrete dam that blocked migrating fish on Ohio’s Cuyahoga River for more than a century no longer stands, and aquatic life is returning to the river. Long-term monitoring found 15 fish taxa that had not previously been detected in the lower Cuyahoga after the Brecksville Diversion Dam was removed in 2020.

The dam’s removal reopened 39 kilometres of connected, free-flowing river habitat with a direct link to Lake Erie. It also more than doubled the amount of open river available to migrating fish below the Gorge Plant Dam, another 18-metre structure farther upstream.

The findings come from a study published in Restoration Ecology by Matthew Ross Acre and researchers from several agencies. The team compared four decades of fish surveys collected between 1984 and 2024, examining communities downstream, within, and upstream of the area impounded by the Gorge Plant Dam.

Fish communities downstream of the former Brecksville site changed clearly over time, as native species arrived and established themselves. Upstream of the remaining Gorge Plant Dam, researchers saw little overall change. Most movement there involved resident fish shifting within the area rather than new migratory species arriving.

Of the 15 newly recorded taxa in the lower Cuyahoga, 12 were native. They used newly available seasonal spawning areas or expanded their range from Lake Erie. Three were nonnative species, adding a risk to the ecological changes brought by reconnecting the river. Water depth, flow speed, turbidity and forest cover also influenced how individual species spread.