As a kid, Mike Johnson was warned not to go into the Cuyahoga River.

It’s impossible to ignore the river in Cuyahoga Falls, a city of about 50,000 just north of Akron. The city takes its name from the waterway, which runs through the area, and the waterfalls that dot its southern boundary. By the 1840s, several decades after Cuyahoga Falls’ founding, the river was a source of power and revenue as the city’s manufacturing prowess grew.

But by the time Johnson was growing up in the 1970s, people had a very different view of the river. “It was not a place you wanted to go,” he says. “I remember a lot of visual pollution. I remember people telling stories of serious illnesses associated with being in the water.”

Johnson is now the chief of conservation for Summit Metro Parks, a park system in Summit County, Ohio. He oversees a group tasked with protecting the area’s natural and cultural resources – including the Cuyahoga River, which runs through much of the park system – while still making them available for public use.

Today, through the work of conservationists like himself, the Cuyahoga is a completely different river – a fact Johnson was reminded of in April when an otter was spotted along the water in downtown Cuyahoga Falls. It led to several local news stories about river otters and a very popular Facebook video of the slippery critter.

River otters are native to Ohio, but they were eradicated by the early 1900s due to industrialization. In 1986, the Ohio Division of Wildlife began re-introducing the otter along several major rivers, and in 2002 they were delisted as a state endangered species.

Katie Dennison, a biologist with the division, says otters are “pretty common” in the upper Cuyahoga River, but less so in the lower part, which runs through Akron and Cleveland. “From what I could find in our records, we had one sighting in the lower Cuyahoga River watershed – not in the river itself – in the year 2000,” she says. “The earliest confirmed sighting I could find in the river itself was 2009.”

In the past year, Dennison has heard more about sightings in the Cuyahoga, which she says is a good sign that the work being done along the river to improve wetland areas and floodplains is having an impact. “All of that is going to positively impact the river otters themselves to some extent, but also the food that river otters rely on,” she explains. “As those fish and crustaceans come back to the area, then river otters are going to have something to feed on, so they’re going to come back too. The wetlands provide important habitat for river otters, so as those are restored or created in the area, that’s going to [create] habitat for river otters.”

Johnson wasn’t surprised to learn of the otter sighting. After all, otters have been spotted along the river before, albeit not this close to an urban environment. Still, he was very happy about the news.

“It is just one more piece of a puzzle that we’ve been putting together since the 1950s, trying to restore [the] water quality of our area piece by piece,” Johnson says.

In 1969, people outside of Northeast Ohio became aware of the Cuyahoga River when it infamously caught fire. What people might not know is it wasn’t the first time the river caught fire – nor was it the worst. Between 1868 and 1969, the river caught fire 13 times. A fire in 1912 led to five deaths. Another in 1952 caused more than $1.3 million in damages. And although the fire in 1969–caused by an oil slick ignited by sparks from a passing train–didn’t cause as much damage, it eventually became a media sensation.

At the time, Carl Stokes was Cleveland’s mayor, and he made pollution a focal point. Stokes rallied voters to approve a $100 million bond issue to clean up the city’s waterways. He also brought reporters to the site of the 1969 fire. But it wasn’t until Time published an article about the river in August 1969 that people outside of Cleveland began to take note. “Chocolate-brown, oily, bubbling with subsurface gases, it oozes rather than flows,” the article described the Cuyahoga. The media attention worked. In December 1970, President Nixon established the Environmental Protection Agency, and in 1972 the Clean Water Act became law. In Cleveland, the newly formed Northeast Ohio Regional Sewer District, as well as the Ohio EPA, made cleaning up the river a priority and took aim at major polluters in the area, leading to a grand jury investigation of 12 companies accused of polluting the water.

While the overall health of the river has improved throughout the years, decades of industrial pollution in Cleveland mean there’s still work to be done, specifically in the Lower Cuyahoga, which runs into Lake Erie.

Much of the current work being done to improve the river falls under the Cuyahoga River Area of Concern Committee, which is part of the larger Great Lakes Areas of Concern. Under the 1987 Great Lakes Water Quality Agreement, an area of concern is defined as a geographic area “where significant impairment of beneficial uses has occurred as a result of human activities at the local level.”

The Great Lakes’ beneficial use impairments address problems with wildlife, pollution, drinking water, habitat loss and more. Restoration targets are created by state and local groups. As the targets are met, impairments are removed from the area of concern. The Cuyahoga Area of Concern began with 10 impairments. Four of them, addressing public access, undesirable algae, fish consumption and aesthetics, have been removed. The committee was able to remove those four after developing new parks and public access points, implementing nutrient reduction efforts to reduce algae, aligning fish consumption advisories with Lake Erie and curbing occurrences of materials like sludge deposits and oil sheens.

Once all the impairments are removed, an area of concern is delisted. The Cuyahoga River is expected to be delisted between 2027 and 2030.

Jennifer Grieser, chairwoman of the Cuyahoga’s committee, says when it comes to addressing the river’s remaining six impairments, some are tackled simultaneously while others are handled on an individual basis.

“Currently, there are three that we packaged together. Those are the ones related to fish populations, macro invertebrate populations and fish habitat,” says Grieser, who is also the director of natural resources for Cleveland Metroparks. “When it’s beneficial for fish habitat, it’s beneficial to fish populations and macro invertebrate populations. So you improve the habitat, presumably, you improve those populations as well.” They aim to fully address those three interlinked impairments by 2025.

In terms of completing the other three impairments, she says it often comes down to when opportunities arise. For the impairment “Restrictions on Navigational Dredging Activities,” for example, the state decided to first pursue removing the impairment on the smaller Black River Area of Concern, located west of Cleveland. Now that the impairment has been removed from the Black River, the state can apply the lessons it learned from the process to its larger areas of concern that are dealing with degradation impairments.

The restoration the Cuyahoga has undergone in the 53 years since it caught fire is breathtaking in scope, advocates say. The number of organizations, government agencies and community activists working to create healthier waterways is impressive. The public are a large part of the story as well. Both Johnson and Grieser mentioned the growing popularity of the river as a top recreation spot for locals.

“Never before, at least in my lifetime, have so many people wanted access to the water,” says Johnson. “People want to get into the Cuyahoga River. They want to swim in it. They want to go fishing in it. They want to kayak it. And for the first time in decades, it’s possible to do all of those things.”