Dam removal restores 39 km of Cuyahoga River, spurring rise in fish diversity
After the 2020 removal of the Brecksville Diversion Dam, researchers documented 15 new fish taxa in Ohio's lower Cuyahoga River, most of them native.
A research team headed by Matthew Ross Acre examined fish data collected from 1984 through 2024 to evaluate the ecological impact of removing the Brecksville Diversion Dam on Ohio's Cuyahoga River. The demolition instantly reconnected 39 kilometres of river linked to Lake Erie, more than doubling the habitat available below the upstream Gorge Plant Dam. Subsequent monitoring recorded 15 fish taxa not previously detected downstream, including 12 native species expanding into new spawning grounds and three non-native species.
Comparisons of sites upstream, within, and downstream of the Gorge Plant Dam revealed minimal change upstream, indicating the remaining barrier still restricts migration. Statistical models identified the dam’s position and the rate of removal across the basin as the strongest drivers of fish assemblage shifts, with local conditions such as flow speed and turbidity also influencing species spread. While the study highlights the rapid recovery of native fish, it also warns that restored river corridors can facilitate invasive species, a concern for upcoming projects like the planned removal of the Gorge Plant Dam.
Why it matters
The study shows how dam removal can quickly boost native biodiversity but also raises concerns about invasive species spread.
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