CHICAGO — Rowing crews in their sleek boats slice through the murky water of the Chicago River, as the sun sets on the defunct century-old coal plant rising above.

These rowing teams have practiced on the river for more than a decade and once felt like aquatic urban pioneers. But now an increasing number of paddlers and pleasure boats ply the river, as diners, joggers and bikers enjoy it from the banks.

The river’s water is cleaner than it has been in decades. New amenities, including four new boat houses, riverside restaurants and the Riverwalk, a pedestrian promenade downtown, line its banks. Revitalizing the river was a major priority of Mayor Rahm Emanuel (D), who left office May 20.

“We’re now closer to fulfilling Daniel Burnham’s dream of a two-waterfront city than ever before,” said Emanuel, referring to the legendary 19th-century urban planner. “I made the river a park for the city. . . . It’s become fully present in city life.”

But many see the river through a lens often invoked in Chicago: as a tale of two cities, where the majority-white, wealthier North Side has flourished, while the lower-income, largely black and Latino South Side languishes.

The spot in the river where the rowers launch could be seen as the dividing point between the two sides of the Chicago River system. Just upstream is a lush park with a Chinese pagoda, and beyond that, the skyscrapers of downtown. Downstream, the river becomes increasingly industrial and filled with detritus — bloated dead animals, floating condoms and tampons — reminders that this waterway is made up largely of treated or sometimes untreated wastewater.

City and private planners working on riverfront redevelopment have attempted to plan riparian projects citywide. But the bulk of riverfront amenities constructed and planned fall in wealthier, North Side neighborhoods, an indication of how hard it can be to create equity in a city long characterized by segregation and inequality.

What many call the Chicago River is actually a web of connected waterways, including natural streams and man-made canals constructed more than a century ago, when city leaders famously reversed the Chicago River. That engineering feat ensured the sewage then dumped in the river instead traveled toward the Mississippi River, rather than flowing into Lake Michigan, the city’s water supply.

Now water flows slowly into the Chicago River from the lake, while much of the river’s volume consists of treated sewage. Untreated, raw sewage spews into the river when heavy rains overwhelm the city’s wastewater system, which is less frequent today than in years past.

Multiple canoe and kayak rental outfitters operate from the river’s north branch, downtown and in Chinatown, just south of downtown. And enthusiasts are even planning a competitive swim in the river. In these areas, people worry not about pollution but rather the risk of collision between water taxis, tour boats, kayakers and pleasure boats.

In the dirtier water downstream, barges filled with limestone, sand or other heavy material dominate the river, and most residents keep their distance.

Growing up in the Mexican immigrant neighborhood of Little Village, southwest of downtown, Kim Wasserman and her friends never dreamed of hanging out near the river. “If you fell in the river, it was like the ‘blob is going to get you,’ ” she said, laughing.

Today she is executive director of the Little Village Environmental Justice Organization, and part of a river redevelopment task force that is continuing under the administration of Mayor Lori Lightfoot (D). Wasserman feels perpetually frustrated by planners’ proposals for a bike trail along the river in Little Village. She says the community has had little input and wants much bigger river-related overhauls: the cleanup of buried coal tar, contaminated sediment and other pollution, and a halt to plans for a huge warehousing center along the river.

To Wasserman, asking residents to imagine sipping wine by the river, boating on it or biking alongside it reveals civic leaders’ lack of familiarity with communities such as hers. She sees such plans as idyllic promises that are not informed by the community’s real needs or desires.

“You want us to recreate out here, then . . . let’s feel that aggregate hitting your face from the concrete company,” said Wasserman, who in 2013 won the international Goldman Environmental Prize. “Yeah people would like to recreate on the river, but when they see what they would be breathing in, maybe not.”

Olga Bautista has similar feelings. She grew up on the Southeast Side of the city, where steel mills once employed tens of thousands. The mills are gone, but much riverside industry remains, as does pollution.

Bautista and other residents won a campaign to ban the storage of petroleum coke — a toxic byproduct of oil refining — in towering piles beside the Calumet River, which is considered part of the Chicago River system. But they still worry about petroleum coke that falls from barges, emissions of the neurotoxin manganese from a nearby plant and other riverside contamination.

Both Little Village and the Calumet River corridor are designated industrial zones, and residents would like to see green industrial development such as solar farms and light manufacturing. They’d also love to have riverside cafes or parks, Bautista said, but that dream feels far off.

“We were socialized to think the neighborhood was built for industry and the river’s not for us,” said Bautista, who recently started work as an advocate for the Calumet River out of the Alliance for the Great Lakes. “The roads around the river are saturated with trucks, it’s not safe to walk or bike.”

Josh Mogerman, spokesman for the Natural Resources Defense Council, juxtaposes Little Village and the Southeast Side with Goose Island in the river’s north branch. The island was once a hive of industry known as “Little Hell” by the European immigrants who toiled in tanneries, soap factories and lumberyards there.

Today most industry has left that area, and a nearby riverfront parcel is slated as the site of Lincoln Yards, a 50-acre upscale residential and commercial project controversially greenlit for city subsidies at the tail end of Emanuel’s administration. Floating gardens and boardwalks are planned for the adjacent stretch of river. The 78, another sprawling high-end commercial and residential development, is slated for 62 riverfront acres downtown.

“Up here, we’re consolidating multimillion-dollar condos around the river; down there, we’re still consolidating polluters along the waterways,” said Mogerman, sitting outside a downtown Starbucks overlooking the water. “There are still some very clear equity problems the city hasn’t figured out how to address.”

Along with such thorny debates, the river also faces systemwide engineering and water-quality challenges, including invasive species and a sewer system strained by heavier rains brought on by climate change.

Debra Shore, a commissioner for the Metropolitan Water Reclamation District of Greater Chicago, wants a re-envisioning of the river system as bold as the river reversal was in its day. She pictures cutting-edge technology reusing wastewater and sewage byproducts while creating jobs and providing green space.

“You can’t have a big city without having places to unload chemicals or fuel or salt,” Shore said. “But we should be doing a thorough review and asking questions. What is a 21st-century wastewater utility and waterway?”

James Burns, head of a volunteer parks advisory council, is keenly aware of the divisions that rend the city, having moved from the North to the South Side. He works to convene meetings of people from the demographically different neighborhoods and hopes people can venture into new areas while strolling along the river, or forge new friendships while fishing or learning to paddle.

“We’re so close yet so isolated from each other,” Burns said. “We hope the river can be the thing that unites rather than divides us.”