This is the first in a series exploring initiatives around Boston, the country, and the world that have succeeded or hold great promise, from government to business to culture.
Next month, a few hundred people plan to plunge into the Charles River for a rare sanctioned frolic. The annual event will be a reminder of how far the waterway’s cleanup has come since the days when diving in necessitated an immediate shower — or medical attention.
That same week, some 3,400 miles away, Paris will celebrate a far grander urban vision: To fanfare, the city will unveil a trio of public swimming areas in a once-polluted canal that promise a summer-long respite from the heat.
Floating docks will surround the swimming areas. There will be beach chairs and lifeguards. Officials expect to attract 1,000 people daily.
The feat — accomplished fairly easily and quickly — raises the question: If Paris can pull off urban swimming in a natural waterway that’s open all summer long, why can’t we?
Local advocates hope the Paris project — and similar swim areas built in Copenhagen’s harbor — will serve as a model and inspire more support for their proposal to build a permanent swimming area on the Charles, which now meets federal standards for swimming most of the year.
“There is a tradition in Europe to swim in urban rivers,” said Renata von Tscharner, founder and president of the Charles River Conservancy, the nonprofit behind the plan to create a swim park near North Point Park and the Museum of Science.
“It’s very much a part of the culture,” said von Tscharner, who grew up swimming in urban rivers in Switzerland. “They just go out to the rivers with a towel around their neck and go for a swim and go back to work or on their way.”
But in the United States, she said, many people — including Boston — are not so laissez-faire and believe urban waterways are not clean enough to swim in. “We have more of a psychological obstacle to overcome,” von Tscharner said.
This summer, von Tscharner plans to visit Paris — and another official from the conservancy plans to visit Copenhagen — to swim in, and learn from, the swimming areas in those cities.
In Paris, residents have never seemed overly concerned about water quality, said Jean-François Martins, deputy mayor in charge of sport and tourism. In fact, Martins said, officials in previous years have had issues keeping locals from diving in when they weren’t supposed to. Martins himself did it when he was younger.
“To be honest, there are some people who haven’t waited for us,” Martins said by phone, chuckling. “They would, maybe after two or three drinks, jump into the water themselves.’’
Still, he said, government leaders didn’t want to take chances and took steps to ensure the water was safe in the area that will soon open for swimming — in the Bassin de la Villette, in the 19th Arrondissement. (The waterway connects with other canals that eventually flow into the Seine River.)
The canal’s water has been shown to meet French regulatory standards for swimming. Regular testing will be conducted upstream from the swim areas, and swimming will be suspended if test results show hazardous bacteria levels, which can flare up occasionally in rivers, as they do at beaches and in other waterways.
As with the Charles, work to clean up the la Villette channel began as an environmental project; the idea of ever swimming there was more of a dream than anything else.
“We worked hard, step by step, to identify each source of pollution, each source of input in this river, and we tried to fix it one by one to make this river clean,” Martins said.
In recent years, as water quality improved in the Parisian canal, swimming became a possibility and was eventually tested in the form of one-off events, similar to those held in the Charles in recent years.
Paris spent nearly $1.7 million to build a large network of floating docks that form three designated areas where people can swim in the water that flows through the canal.
Martins said the temporary structures, which also feature submerged floors at varying depths so children can swim in some areas, will be set up each summer, a process that takes only a couple of weeks.
As part of a long-term plan, Paris hopes to open another waterway, Lac Daumesnil, to swimming by 2019. And as part of its bid to host the 2024 Olympics, the city hopes to clean up the Seine enough so that it, too, can be a place to dive into.
Swimming in the Seine has been off limits to the public for about a century. Cleanup efforts over the years have improved its condition, but it does not yet meet regulatory standards to allow swimming.
Last summer, it attracted more than 126,000 visitors, said Jacob Christian Schroeder, who manages the spot.
“We get a lot of positive feedback every year,” he said via e-mail. “It is a pride of Copenhagen.”
The city has since opened two more harbor swim areas and even allows brave souls to take a dip during the winter.
Water quality is monitored constantly. Heavy rains sometimes cause runoff that contaminates swimming areas, but they typically close just two to three days a year.
SJ Port, the conservancy’s development and communications director, said a swimming area in the Charles would be monitored and would be closed temporarily if measurements showed high bacteria levels.
The river’s water quality has improved dramatically since it inspired the Standells’ song “Dirty Water” in 1966. In 2015, the most recent year for which data are available, it met federal standards for swimming about 70 percent of the time, up from just 19 percent in 1995.
Conservancy officials say the ratio of swimmable days is even higher during the summer.
There are, of course, key differences between what Paris and Copenhagen have done and the proposal for Boston.
Perhaps most notable: The two European projects were led by city governments, giving them clear sources of funding and streamlining regulatory approvals.
The Boston group expects it will still need to raise several million dollars for the project. And it expects to need approvals from various governmental bodies, including state and federal agencies and the cities of Boston and Cambridge.
And, even with water-quality issues addressed, there are unique physical challenges to overcome. For example, the conservancy is still studying designs to ensure swimmers don’t kick up sediments at the bottom of the Charles, which may contain hazards, including contaminants and debris.
In most of those places, as with the Charles, the proposals seem a ways away from being reality.
For now, conservancy officials plan to continue studying and lobbying for their idea.
Port said there’s no better way to recruit supporters than to have them plunge into the Charles themselves.
“You have an incredible view from that water,” she said. “You feel like you’re in a postcard.”Matt Rocheleau can be reached at email@example.com. Follow him on Twitter @mrochele.