Crews are removing more than 850,000 cubic yards of contaminated sediment from the Cuyahoga River in Cuyahoga Falls, Ohio, as part of a major cleanup around the Gorge Dam.
asserted
Crews → remove → Dam
The material contains pollutants including heavy metals, oil, grease and industrial chemicals that have remained trapped in the river for decades.
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that → contain → decades
Instead of being left in the river or simply moved elsewhere, the dredged material is being transported two miles downstream, where it is processed, strengthened and placed in a specially prepared area.
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it → leave → area
The work is expected to continue through 2027, according to the
US Environmental Protection Agency.
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work → expect → Agency
Why more than 850,000 cubic yards of contaminated sediment is being removed
The sediment has built up in the pool behind the Cuyahoga Gorge Dam, where pollutants from the river's long industrial history have remained trapped.
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pollutants → remove → history
According to the US EPA’s Cuyahoga Gorge Dam cleanup project, an estimated 865,200 cubic yards of contaminated sediment will be remediated as part of the project.
uncertain
yards → accord → project
The material contains polycyclic aromatic hydrocarbons, polychlorinated biphenyls, oil and grease, as well as heavy metals such as cadmium and lead.
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material → contain → cadmium
Removing it is intended to reduce the risk of exposure for people, fish and other wildlife.
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Removing → remove → people
The scale of the work is substantial, but it is also part of a long effort to restore a river that has already undergone major changes.
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that → restore → changes
The Cuyahoga River has a long history of industrial pollution
For much of the 20th century, the Cuyahoga River was heavily affected by industrial waste.
UniquePlacestoSave reports that factories and oil refineries discharged solid and chemical waste into the river, including material containing toxic heavy metals.
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factories → have → metals
The river caught fire repeatedly, with fires recorded as far back as 1868.
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fires → catch → 1868
The 1969 fire drew particular national attention after an oil slick caught fire, helping turn Cuyahoga into a powerful symbol of severe water pollution, according to UniquePlacestoSave.
uncertain
slick → draw → UniquePlacestoSave
The situation began to change after stronger pollution controls were introduced.
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controls → begin → ?
The organisation notes that the Clean Water Act of 1972 gave the federal government greater authority to limit pollution and regulate discharges.
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Act → note → discharges
Over time, industries reduced the dumping of chemical waste and cities improved their sewage systems.
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cities → reduce → systems
How the dredged material is being stabilised downstream
The sediment is not simply being dug out and dumped at another location.
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sediment → dredge → location
The EPA says it is transported through a pipeline to a specially constructed processing and placement area about two miles downstream from the dam pool.
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it → say → pool
At the processing site, the dredged sediment is mixed with Portland cement to make it stronger and more stable.
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it → dredge → cement
The resulting material is known as stabilised dredged material.
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material → result → material
It is then placed in designated cells, where it is graded and allowed to cure.
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it → place → cells
The EPA's project updates show that crews regularly test the material as it cures to make sure it reaches the required strength.
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it → show → strength
The process is designed to hold the contaminated sediment securely in place rather than leaving loose material exposed.
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process → design → material
An excavator directs the flow of stabilised dredged material (SDM) as it is being pumped and placed within the Sediment Placement Area.
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it → direct → Area
Image Credit: US EPA
What happens to the sediment once it reaches the placement area
The placement area has been designed to receive the processed material in layers.
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area → happen → layers
EPA project information shows that the stabilised sediment is pumped or transported into placement cells, where excavators spread and grade it.
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excavators → show → it
Crews also monitor the strength and moisture of the material during the process.
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Crews → monitor → process
Some of the dredged material is separated into different components, including sand and debris, before the remaining sediment is processed.
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sediment → dredge → sand
The EPA says soil from a nearby borrow area will eventually be used as a top layer over the stabilised sediment mounds.
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soil → say → mounds
The finished areas will then be seeded with native plants to help them fit into the surrounding landscape.
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them → seed → landscape
In the foreground, the SHERP UTV mixes dredged material in the sediment surge basin.
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UTV → mix → basin
In the background, excavators are grading and placing stabilised dredged material.
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excavators → grade → material
Image Credit: US EPA
Gorge Dam remains central to the river's recovery
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Dam → remain → recovery
The sediment cleanup is closely linked to the future removal of the Gorge Dam.
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cleanup → link → Dam
The EPA says the dam itself will be removed through a separate project after the sediment remediation is completed.
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remediation → say → project
The dam has stood in the river since 1911.
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dam → stand → 1911
Once it is removed, a significant section of the Cuyahoga will be able to return to a free-flowing condition for the first time in more than a century, according to the EPA.
uncertain
section → remove → EPA
UniquePlacestoSave describes the Gorge Dam as one of the final major obstacles to the river's wider recovery.
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UniquePlacestoSave → describe → recovery
5 other dams along the Cuyahoga have already been removed over the past two decades, leaving the Gorge Dam as the last major obstruction between Lake Erie and the river's upper reaches.
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dams → remove → Erie
Importance of cleanup for wildlife and local communities
The EPA says removing the contaminated sediment will reduce the risk posed by pollutants to people, fish and other wildlife.
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removing → say → people
It also expects the project to help restore fishing and recreational opportunities along the river.
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project → expect → river
…and 7 more, not listed.
The Aporia
