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By Margeaux Sippell THE BOSTON GLOBE  MARCH 29, 2018

KEITH BEDFORD/GLOBE STAFF/FILE 2017 Volunteers cleaned garbage and debris from the Charles River in Cambridge.

Renata von Tscharner is retiring after 18 years as president of the Charles River Conservancy, which she founded in 2000 with the goal of cleaning up the river and its banks to make the Charles swimmable. The Globe recently spoke with von Tscharner, who was trained as an architect and urban designer in Switzerland, about her tenure and the challenges the conservancy faces moving forward.

This interview has been edited and condensed.

Q: What were some of your proudest moments leading the Charles River Conservancy?

A: The opening of the skate park [in East Cambridge] in fall 2016 was extraordinary because land that was contaminated, that was not used by anybody, suddenly was a place where athletes could gather and practice their sport. It created a space that helped people do something healthy and active in the city.

Another thing I’m very proud of — 14 years ago, together with [the performance group] Revels, we started something called River-Sing. It’s a celebration of the autumnal equinox, where thousands of people gather in late September at the Weeks Bridge to sing songs, and then a boat comes down the river . . . it’s an absolutely magical celebration [that] brings out the beauty of the river.

Q: What were the most challenging parts of your job?

A: There are always a lot of challenges when you work with different agencies. We work both with the Department of Conservation and Recreation and also with the Mass DOT on bridges. Whenever you work with different agencies to coordinate all those efforts, it’s a challenge.

Q: Do you swim in the Charles yourself?

A: I certainly do — on those official “City Splash” days. I’m also a windsurfer, so sometimes I fall in. It’s a wonderful experience to swim in the Charles and look up at the greenery and up at the State House. We’ve picked a location for a swim park [downriver from the Museum of Science] where there’s no conflict with boats and there’s parkland next to it. It’s a wonderful place to swim.

Q: What kind of challenges does the new executive director, Laura Jasinski, face?

A: We have a new capital project that we’re working on, and that is to create a swim park — we will raise the money to build it, just as we did with the skatepark. The water is swimmable most of the time, but there is no approved location for swimming, so the conservancy has been offering what we call “City Splashes” one day a year. So far 1,200 people have participated and many are on the waitlist. So that will be a major effort, where people can swim not just one day a year, but for the [whole] season.

Q: Do you have any plans for retirement?

A: I have a granddaughter in Paris, so I guess I will see her a bit more often! I deeply care about [Boston], about the river, so my main goal is to make sure that the organization is ready for the new leader. I will remain on the advisory board — I will not be in the office after my retirement gala on June 2, but I will definitely be available if Laura can use my help.

Q: What do you see as the future of the Charles?

A: I think that the Charles already is an enormous asset, but it could be so much more than it is today. This is a very densely settled city, so to have this publicly owned land in the middle is an extraordinary chance. The potential of the river is not fully used yet, so that’s what the conservancy will be working on — to make the river and parkland on both sides more accessible and attractive, to have places where people can sit in restaurants along the river. There are many improvements, and we’ve only just started.

Margeaux Sippell can be reached at Follow her on Twitter @MargeauxSippell.

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By Amy Saltzman
Cambridge Chronicle 

Renata von Tscharner, founder and president of the Charles River Conservancy, bikes along the river in Lechmere Canal Park on Feb 5. [Wicked Local Staff Photo/Ann Ringwood]

She’s been called one of the most remarkable women in Boston — and a pain in the ass — but if there’s one thing Renata von Tscharner is known for: she gets things done.

As the founder of the Charles River Conservancy — a position she plans to retire from in June– von Tscharner has made it her mission to improve the water quality of the Charles River and to beautify its surrounding parklands, from Boston Harbor to the Watertown Dam.

She’s done just that and then some over the last 18 years since the start of her nonprofit in 2000. And in the process she has raised more than $14 million; wrangled over 28,000 volunteers; built a $5 million skatepark; made swimming in the Charles River attainable; helped start Revels RiverSing, the annual autumnal equinox celebration; and filmed over 100 CCTV shows, to name a few of her accomplishments.

But the Charles River Conservancy had a very humble beginning.

A logo etched on an envelope

When von Tscharner first moved to Cambridge from Switzerland in 1979, she said her first instinct was to jump into the Charles River. But that wasn’t something people did, she was told, unless they fell in or were dared. The river, which hadn’t been open to recreational swimming since the 1950s, was too contaminated with E. coli and blue green algae.

So, she decided to do something about it, becoming a water tester to help improve the quality. And therein lies von Tscharner’s character.

“She is one of the more remarkable people I know — very creative, very caring, a big heart, but also very determined to succeed with great knowledge about city planning and public space,” said Cambridge Councilor Dennis Carlone, a city planner who has worked with von Tscharner for decades. “I consider her, truly, one of the few very special people in Cambridge and Greater Boston. Even though I’ve known her over 30 years, I’m always impressed by her success, again largely through determination and being a very outgoing, friendly person, but bright as all can be.”

von Tscharner originally moved from her home in Bern, Switzerland, where she was an assistant city planner, because she fell in love with an American. They married and had three children together. When she decided to start the Charles River Conservancy in 2000, she used her daughter’s bedroom as an office and a logo her husband, Peter Munkenbeck, etched on an envelope.

Then she wrote a letter to 100 friends, colleagues and officials, describing her idea and organizing a symposium. Several of those 100 sent money, and she was able to hire an intern. Then the nonprofit really blossomed.

Around that same time, in 2000, the state’s parks agency, then known as Metropolitan District Commission, had finalized its master plan for the banks of the Charles and they estimated it would cost several hundred million dollars to implement.

“What could a brand new nonprofit do to help the state implement that plan,” von Tscharner said. “We started recruiting landscape volunteers who would form a powerful corps of people who would physically improve the banks and who cared and could become advocates. Thus the Conservancy Volunteers were launched with now well over 28,000 participants.”

Making the river swimmable

In addition to cleaning up the banks of the river, von Tscharner still had her sights set on making the river swimmable. After years of work and years of testing and years of advocacy, the first public swim event in the Charles River in over 50 years was held on July 13, 2013. In 2007, the Conservancy and Charles River Swimming Club organized the first one-mile swim race in the Charles River, which is now an annual tradition.

Recreational swimming had been prohibited in the Charles since the 1950s, when a growing awareness of the health risks posed by pollution in the river caused the beaches and bathhouses lining the river to close.

Now, the Conservancy wants to open up a seasonal swim spot at North Point Park, eventually expanding that concept in other areas along the river. In her native country of Switzerland, von Tscharner said swimming in rivers is a part of the “urban culture,” a concept she wants to bring to Cambridge. Despite misconceptions that people may be disinterested in swimming in the “dirty” water of the Charles, von Tscharner said it’s been made clear residents are eager to make the river a swimming destination.

According to a 2016 feasibility study, the water quality of the Charles River went from a “D” grade in 1995 to an “A-” in 2013. In 2011, the Charles River won the Thiess International Riverprize for being one of the cleanest urban rivers in the United States.

While they may never get to 100 percent swimmable days in the Charles, von Tscharner said residents should be able to enjoy the investment in clean water on the days that are.

“Renata is a visionary and a determined advocate. That combination resulted in improvements to the banks of the Charles, a yearly swim in the Charles, and the incredible skatepark on land that would otherwise have been junk,” said Alice Wolf, a former mayor of Cambridge and state representative who worked on legislation with von Tscharner to work toward making the river swimmable.


A gala celebrating von Tscharner’s work and retirement will be held June 2 at Harvard University’s Annenberg Hall. Over 350 people are expected to attend, including elected officials, volunteers, donors, family and friends.

A committee to find a new CRC executive director has already made its selection, according to von Tscharner. A formal announcement of her successor will be made prior to her retirement.

As she sets her sights on her retirement day, von Tscharner reflects on her time at CRC, calling the skatepark one of her biggest accomplishments.

“I am so glad I did not know about the challenges of working with so many different agencies and the toxic soil we would encounter and would have to remediate,” she said, looking back on the difficult first steps of the skatepark. “But 12 park commissioners later, a million dollars in legal fees (all donated by Wilmer Hale), 400 skaters participating in workshops, and more than $5 million in design and construction, we opened with 2,000 people at the event.”

At the November 2015 groundbreaking, von Tscharner recalls with a smile when Congressman Mike Capuano spoke, calling her a “real pain in the ass” but in the “best possible way” since she gets things done.

In a followup interview, Capuano said he believes he called her a “pleasant, persistent pain in the neck.” But, either way, he feels “Renata is a perfect example of how an effective activist should work.”

All in all, the skatepark groundbreaking was a “very happy day for the skaters, the Conservancy, my son and for me,” she said.

When asked what she hopes to do in retirement, von Tscharner said she plans to remain an advocate for the parklands and the river.

“I’m not going to Florida to play golf. I care about the river and the organization, so I want to make sure we have a good transition,” she said.

To learn more about CRC, visit or call 617-608-1410.

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Cambridge Community Television | Seth Myer

The Charles River Conservancy offers residents the opportunity to swim in the Charles at the fifth annual CitySplash event. The event took place at the Fiedler Dock along the Esplanade on July 18, 2017.

City Splash was filmed by Sam Bruce and edited by Zach Ben-Amots.


By Feargus O’Sullivan, CityLab

Parisians pack the three pools in the city’s once-fetid Bassin de la Villette. Charles Platiau/Reuters

We’ve all heard promises from cities to make their once-fetid urban waterways swimmable—probably too many. Boston has been pledging to extend the Charles River’s swimmable days for years now, while Berlin’s beautiful plans to turn an arm of the River Spree into a naturally filtered bathing pool remain just that—plans. Baltimore’s proposal to render the oft-garbage-y Inner Harbor swimmable via floating islands of pollution-sucking vegetation and a googly-eyed trash-eating boat are edging ever closer to a 2020 deadline, with limited progress so far, while London’s likeable scheme for a Thames Bath remains the preserve of local enthusiasts rather than actual decision-makers. (Meanwhile, when an environmental activist went for a dip in New York City’s Gowanus Canal in 2015, he had to essentially wear a spacesuit to protect himself from the bacteria-laced toxic soup.)Among all these maybes, could-bes, and never-attempts, one city stands out for actually making things happen: Paris. For years, the French capital has been promising to open up its urban waterways for safe, clean public swimming. This month, it’s done exactly that.

On Monday, Paris’s Mayor Anne Hidalgo opened-up new open-air swimming enclosure in the Bassin de la Villette, a basin constructed for barges that links the Canal de l’Ourcq with the Canal Saint-Martinin the city’s inner northeast. In temperatures of over 90 degrees Fahrenheit, Parisians lined up to splash about the three new pools fed directly from the canal’s waters, separated from the watercourse’s general flow only by filter meshes to keep leaves and other objects out.Up to three hundred people at any time can use the lifeguard-protected pools, although the pools only have locker space for 80. Located in a part of Paris already popular as a place to stroll in fine weather, the new bathing spot is likely to prove a major hit in an already hotter-than-average summer. Early reports suggest that the water is indeed delightful, though a small residuum of green algae does make a post-bathe shower a good idea.

How did Paris pull this off? The city’s been working on cleaning up the waters here for decades. Paris’s canals here were once unsurprisingly filthy, running as they do through a former industrial area once packed with cargo barges and polluted by sewage. Since the 1980s, however, regulations managing industrial run-off have tightened substantially, while Paris has invested heavily in wastewater treatment and in preventing sewage from being discharged into the canal during periods of high water. Two years ago, following a concerted clean-up, bacteria levels dropped below safe levels, and rogue bathers have been jumping in the water here for a while. Meanwhile, the Canal Saint Martin, which runs downstream from the basin down to the Seine, was entirely drained and cleaned in 2016, a process that sent a powerful visual message to Parisians that the area’s historic filth was being swept away.


By Craig LeMoult, WGBH News

Last week, the EPA released a report downgrading the water quality of the Charles River from a B+ to a B. But that didn’t stop hundreds of people from jumping in the river and going for a swim Tuesday. Nobody seemed to hesitate as they enthusiastically leapt into the Charles.

As Sally Graham of Dorchester waited her turn to take the plunge, she said this was something of a bucket list item.

“When I first moved here, it was almost like Lake Erie,” she said. “You could almost set it on fire. And the fact that there’s been a huge investment in the infrastructure to clean it up, I think is very exciting.” She also said she had no concerns about it. “I don’t swallow. I wear goggles. I wear earplugs. So most of the places where I could develop infections are covered.”

It was a nice summer day to jump in the Charles. Photo credit: Craig LeMoult/WGBH News

As he came out of the water, Josh Posner seemed exhilarated. “The water is great,” he said. “Nice and fresh. Great temperature.” He pointed out, Boston’s a city with a river just right there.

“We see it everyday,” he said. “Who wouldn’t want to dive in?”

That’s what the Charles River Conservancy believes. SJ Port is with the group, and says although this is just a one-day-a-year event, they’re hoping in the future it will be more regular.

“We are proposing a designated spot off of the public dock in North Point Park,” Port said. “And the reason we’re doing it there and not in the Esplanade where we’ve held our City Splash events is that this is a prime boating area down here, and we’d like to keep the boaters as our friends.”

The question people might have, of course: Is it safe to swim in the Charles? Port says yes.

“It is safe to swim in the Charles, as long as the water quality is tested beforehand,” she said.

Port wasn’t discouraged by last week’s report that downgraded the Charles from a B+ for water quality to a B. The EPA report was based on monthly water sample tests.

“Some of those samples this year were taken during or after rain events. Rain events, we know, cause a rise in E. coli and other bacteria in the river because you’ve got all the stuff washing off the roads and off the parks into the river,” she said. “And it also includes winter months, when most of us aren’t interested in swimming.”

Swimmers relax the the mild but refreshing water. Photo Credit: Craig LeMoult/WGBH News

The Conservancy hired Max Rome, an environmental engineering graduate student at Northeastern to test the water quality every day this summer. Rome pointed out that Boston has forgotten that back in 1940, people used to swim in the river off Magazine Beach in Cambridge on hot summer days.

“What happened since then was that as we started caring more and more about sanitation, perversely we built more and more wastewater treatment plants and sewer systems that ended up dumping into the river,” he said.

In recent years, though, since the cleanup of Boston Harbor began, we stopped that kind of dumping and the water quality has improved.

“And then the next place after that is, where are there places where our storm water system is connected to our sanitary sewer system?” Rome said. “That’s kind of the trickier problem. Places where those systems are connected, when it rains really hard, some sewage can end up getting washed out into the Charles River. And basically, Cambridge, Boston have done a really good job. As you go father up the river, there’s a lot more work that needs to be done.”

So, it’s actually cleaner in the more urban area.

For many, jumping in the Charles has been a dream for a long time. Photo Credit: Craig LeMoult/WGBH News

Another concern these days is outbreaks of a blue-green algae known as cyanobacteria, which is pretty toxic. But Rome says that tends to show up later in the summer, when the water gets warmer.

“We test every single day, we’re kind of looking under the microscope to see who’s swimming around in there. And there’s not much to speak of yet.”

It was a sunny one, and pretty hot. Port gave one more guarantee this was a good idea: “This is safe for your health, it is good for your health,” she said.

And that was enough to encourage anyone, including a radio reporter, to jump in the Charles.


By Philip Marcelo (AP)

People dive into the Charles River during the “City Splash” event, Tuesday, July 18, 2017, in Boston. For the fifth year in a row, intrepid swimmers get a rare chance to beat the summer heat with a dip in the once notoriously filthy Charles River, where conservationists are working to build a permanent swim park.

BOSTON (AP) — They dove in, splashed around and blissfully floated in the murky river water.

Intrepid swimmers got a once-a-year chance to beat the summer heat with a dip in the once-notorious dirty water of Boston’s Charles River on Tuesday.

The annual “City Splash” is one of the few days the state permits public swimming on the city’s stretch of the 80-mile river, which gained notoriety in the Standells’ 1960s hit “Dirty Water.”

The event, now in its fifth year, spotlights the nonprofit Charles River Conservancy’s efforts to build a permanent feature on the river that would allow visitors to enjoy the water without coming in contact with any leftover contaminants. They call it a “swim park,” which would include floating docks for swimmers to safely jump into the river without touching the hazardous bottom. The water quality would be regularly tested.

Nearly 300 people signed up to take the plunge.

“It felt refreshing and wonderful,” said Ira Hart, a Newton, Massachusetts, resident as he hopped out of the river, goggles in hand. “They used to talk about how it was toxic sludge and you’d glow if you came out of the Charles. Well I’m not glowing, at least not yet.”

Boston is among the cities hoping to follow the model of Copenhagen, Denmark, which opened the first of its floating harbor baths in the early 2000s. Paris opened public swimming areas in a once-polluted canal this week, and similar efforts are in the planning stages in New York, London, Berlin, Melbourne and elsewhere.

In Boston, the Charles River Conservancy still needs to raise a few million dollars and garner approvals from state, federal and city agencies.

But S.J. Port, the group’s spokeswoman, said the biggest hurdle already has been overcome: The Charles is now among the cleanest urban rivers in the country.

The U.S. Environmental Protection Agency announced this month the river earned a “B” grade for water quality last year, meaning it met the standards for boating 86 percent of the time and 55 percent of the time for swimming. That’s a marked improvement from the “D” the Charles was given in 1995, when cleanup started in earnest, but down from 2015’s “B+” grade.

Here’s a sampling of where other efforts to reclaim urban rivers for swimming stand:



The city partnered with a local civic group to entice residents to take a dip in the Willamette River this summer.

They opened the first official public beach with lifeguards on the river earlier this month. They’ve also launched a public awareness campaign and scheduled a range of water-centered events.

Among them was last weekend’s Big Float inner tube river parade that drew about 2,500 revelers.



A group of architects, designers and engineers have proposed a series of pools in the middle of the iconic River Thames, where river water would be constantly filtered.

Chris Romer-Lee, a lead organizer of the Thames Baths project, said the group aims to submit plans to local authorities by early 2018.

The group launched an online crowd-funding campaign last year that raised about $182,000 to refine their design but are working to secure almost $19.6 million in outside investment for the project itself.



Four local artists and architects launched the idea for +Pool , a floating, filtered pool in the shape of a plus sign in 2010.

Since then, they’ve successfully tested a filtration system that removes bacteria without using chemicals, said Kara Meyer, deputy director for the nonprofit effort.

She said organizers also have raised nearly $2 million to continue developing the project, are exploring potential sites on the East and Hudson rivers and are preparing to seek necessary city approvals.



The nonprofit Yarra Swim Co. unveiled its concept for a floating pool on the city’s Yarra River at Australia’s Venice Biennale Exhibition last year.

Michael O’Neill, the effort’s co-founder, said the company will be reaching out to community groups and government agencies starting next month to get their feedback on what the Yarra Pools project should offer and to promote its broader vision for use of the river.



The long-gestating Flussbad project calls for cleaning up a canal off the German capital’s Spree River for public bathing.

Barbara Schindler, a spokeswoman for the effort, said the idea has been around since the 1990s, but has reached notable milestones in recent years.

She said the organization completed a water quality study in 2015 and has received $4.6 million in government funding to hopefully turn the concept into reality.



Hundreds signed up for a chance to swim in the “dirty water.” WBZ-TV‘s Jim Smith reports.


By Jackie DeFusco, WBUR News

Nearly 300 people cooled off on Tuesday by jumping into the Charles River near the Esplanade in Boston.

It’s the fifth year that the Charles River Conservancy held “City Splash” — a day of state-sanctioned swimming in the river. The conservancy has been working to create a permanent floating dock on the river near North Point Park. The group still needs to raise money and receive approvals from federal, state and city agencies before it could make the plan a reality.

But one of the biggest hurdles — cleaning up the notoriously dirty river — has been overcome, conservancy spokesperson S.J. Port says.

In 1995, the Environmental Protection Agency said the Charles was safe enough for swimming just 19 percent of the time. In federal tests last year, it was found to be safe 55 percent of the time.

We caught up with some of the people who jumped in on Tuesday. (Hear what they had to say by clicking the red player button atop this post.)

Some jump, some make a slower entry into the Charles River at City Splash. (Robin Lubbock/WBUR)

A life guard watches over swimmers in the Charles River at City Splash. (Robin Lubbock/WBUR)

Swimmers jump into the Charles for City Splash. (Kathleen Dubos for WBUR)

Lucie McCormick takes a break from her run for a swim in the Charles. (Robin Lubbock/WBUR)

A lonely pair of shoes and a sun visor on the dock await their owner, at City Splash. (Robin Lubbock/WBUR)


For those who have grown up in the Boston area, deciding to go for a swim in the Charles River would historically elicit a brow-furrowing response of confusion.

“‘Ew you’re disgusting — you’re crazy!’” Tamara Lawrence of Roxbury said, imagining telling her friends about such a scenario.

But Tuesday afternoon, the prospect of swimming in the Charles seemed neither disgusting nor crazy, as dozens of swimmers gathered at Fiedler Dock near the Esplanade to take their turn doing what, most days, is not an option: plunge into the Charles for a swim.

“It’s heavenly!” one woman popped above the surface to shout, splashing around with about 40 other swimmers.

Hosted by the Charles River Conservancy, City Splash is an annual chance to spend the afternoon in the Charles. Swimmers reserved a spot between 2:30 and 6:30 p.m. for $10, which granted them a 25-minute foray into the water.

Boston, MA -- 7/18/2017 - Swimmers jump off of the dock together during sanctioned swimming in the Charles hosted by the Charles River Conservancy. (Jessica Rinaldi/Globe Staff) Topic: 19charlesswimpic Reporter:

Swimmers jumped off of a dock during sanctioned swimming in the Charles River. / JESSICA RINALDI/GLOBE STAFF

“It’s really quite a magical story, because most urban rivers have really struggled and gotten worse, and we haven’t paid any attention to keeping them clean,” said Paul Parravano, an Arlington resident who had just climbed out of the river, using his midday work break at MIT for a swim.

“It’s not clean every day, but it’s such a dramatic turnaround from what it was 20 years ago, when we started talking about doing this,” Parravano said.

As of last week, the river has been given a “B” by the Environmental Protection Agency. Though swimming in the Charles isn’t usually permitted, SJ Port, director of development and communications with the conservancy, said the river was tested and the event received a special permit from the Department of Conservation and Recreation, also working with the Massachusetts Water Resources Authority and the Department of Public Health.

“Unless you really engage with your water, and your parks, you don’t appreciate how much they bring to the community,” Port said.

Barbara Evans of Lakeville climbed out of the water Tuesday after a sanctioned swimming event in the Charles.

Barbara Evans of Lakeville climbed out of the water Tuesday after a sanctioned swimming event in the Charles. / JESSICA RINALDI/GLOBE STAFF

Throughout the five years of City Splash, Port has noticed that all sorts of swimmers come out to the event. Some have come every year, swim caps and goggles in tow. For others, finding the event was an accident as they stumbled upon it during their run along the river.

“The 2:30 slots — those are the diehards,” Port said, referring to the visitors who were the first ones sunscreened and lined up along the dock, ready for the river.

Port said most people leave the event wishing this was something they could do more often.

And perhaps that day isn’t too far off. City Splash gives locals a taste for what could come in the future with the Swim Park Project, an initiative put forth by the conservancy to build a permanent swimming facility in the Charles River at North Point Park. According to a recent study by Stantec, an engineering services company, this sort of complex is feasible with “further study and due diligence,” according to a statement.

“It’s not something that most Bostonians grew up with — we grew up making fun of [the Charles] and how dirty it was,” Parravano said. “There’s something really great about fresh water. It’s just a great feeling to be able to jump in water that, on a hot day, makes you feel clean and refreshed and invigorated.”

“Everybody ought to have that opportunity,” he said.

One woman floated in the river.

One woman floated in the river. / JESSICA RINALDI/GLOBE STAFF 

Lifeguards kept a foot on the dock ladder to make sure it remained secure.

Lifeguards kept a foot on the dock ladder to make sure it remained secure. / JESSICA RINALDI/GLOBE STAFF

Kiana Cole can be reached at Follow her on Twitter @kianamcole.


The push mirrors efforts to revive ailing rivers in other US cities, from the Charles River in Boston to the concrete-lined Los Angeles River, where efforts have been underway in recent years to reverse decades of environmental damage.

The Christian Science Monitor

By Gillian Flaccus (AP)

Portland is well-known as a tree-hugging, outdoorsy city, but the river that powers through its downtown has never been part of that green reputation.

For decades, residents have been repulsed by the idea of swimming in the Willamette River because of weekly sewage overflows that created a bacterial stew.

Now, the recent completion of a $1.4 billion sewage pipe has flushed those worries – and the river once shunned by swimmers is enjoying a rapid renaissance.

The city has partnered with a civic group called the Human Access Project to entice residents into the Willamette this summer with a roster of public swimming events and a flood of announcements that the river, finally, is safe for human use. The campaign is aimed at reversing the impact of decades of public health warnings in an eco-savvy city with a hard-earned green reputation.

The push mirrors efforts to revive ailing rivers in other US cities, from the Charles River in Boston – where occasional city-sanctioned swimming started in 2013 – to the concrete-lined Los Angeles River, where efforts have been underway in recent years to reverse decades of environmental damage along an 11-mile (18-kilometer) stretch.

In Portland, the movement has clearly found its moment.

The river is the city’s largest public space, but less than 5 percent of the city’s footprint has access to the waterfront, said Willie Levenson, who heads the Human Access Project and is working closely with Portland to expand swimming options.

Beaches in other communities along the river attract crowds, but swimmers in downtown Portland have nowhere to dive in despite increasing demand. Since the completion of the sewage control project in 2011, swimmers have been congregating on a floating esplanade for bikers and runners and sneaking onto city docks reserved for fire boats.

“We cannot pretend that swimming isn’t happening in downtown Portland anymore. It’s a livability issue, and Portland cares about livability,” Mr. Levenson said. “It’s time for our community to stop making jokes about our river and start digging in and looking to make a difference.”

The Human Access Project has been working for several years to generate interest in the Willamette and has found a willing partner in new Mayor Ted Wheeler.

This week, a new beach with lifeguards and safety ropes opened on the city’s south waterfront, within walking distance of hipster-friendly cafes and shops.

An inner tube river parade planned by the Human Access Project for this weekend is expected to attract several thousand participants, and members of a river swim group cross the Willamette several times a week in fluorescent green swim caps bearing the name River Huggers.

Mr. Wheeler, himself a swimmer, laid out a multipoint plan for increasing access to the river earlier this year and plans to swim the river later this month with 500 residents in the inaugural “mayoral swim.” The city hopes to open two more beaches in coming years, install floating docks along the riverbank, and place public restrooms, picnic benches, umbrellas, and showers on site.

In a recent state-of-the-city address, Wheeler even spoke of one day eliminating Interstate 5 where it snakes along the Willamette’s east bank to improve river access.

“We have a chance to reshape the face of our city,” he said. “I also believe we have a chance to reshape our spirit.”

Portland’s relationship with the Willamette River hasn’t always been easy to navigate.

For decades, the river was considered a watery highway, and industrial pollution severely contaminated its waters. This winter, after a 16-year wait, federal environmental officials released a plan to clean a 10-mile (16-kilometer) stretch near its confluence with the Columbia River in a project that will take decades of work and billions of dollars.

But in the heart of Portland, the primary problem has been human excrement. Residents grew accustomed to seeing near-weekly warnings about water quality during the winter rainy season, where even one-tenth of an inch (2.5 millimeters) of rain could trigger overflows.

Now, the city issues just a handful of warnings in winter and none during the peak swimming months of July and August, said Diane Dulken, spokeswoman for Portland’s Bureau of Environmental Services. Testing at sites where people are already using the river show the water is safe, she added.

“We are really making a push to publicize our weekly testing because there is absolutely still a public perception out there, ‘I will not go in the river.'”

On a recent blazing afternoon, Portland resident Alex Johnson was ready to take the city at its word.

The 24-year-old swim teacher and lifeguard began diving into the Willamette with the River Huggers swim group this month.

On this day, he joined 30 others as they swam from the Hawthorne Bridge to the Morrison Bridge – through Portland’s bustling business district – and back in the 70-degree (21 Celsius) water. Teenagers lounged like harbor seals on a nearby dock and jet skis zipped by as the swimmers completed the more than half-mile (0.8-kilometer) journey.

“I’ve heard stories that it’s pretty polluted. It tastes a little funny, but it is river water,” Mr. Johnson said. “It’s a huge resource, and we don’t take advantage of it – and it feels great.”