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PhD student paddles 315 miles down Hudson River to show it’s cleaner than many think
By
Ramsey Khalifeh
and
Phil Corso
Published Aug 11, 2025
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Courtesy John Henkelman
By
Ramsey Khalifeh
and
Phil Corso
Published Aug 11, 2025
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The view under the George Washington Bridge was just one of many milestones for John Henkelman, a PhD student who has spent the past month canoeing the Hudson River from its headwaters in the Adirondacks to New York City.
On Sunday, he capped his 315-mile trip in Manhattan.
Henkelman, 38, who studies natural resource management at the University of New Hampshire, combined his background in chemical testing with a passion for paddling to investigate the Hudson’s health and challenge a common belief.
“Everybody that isn’t a paddler thinks that the water is the dirtiest thing in the world,” he said. “So far, all of my tests have been clean.”
Armed with tools to measure nitrates, phosphates, dissolved oxygen and carbon dioxide — “what I like to call river vital signs,” as he put it — Henkelman took samples at stops along the way. While he found slightly lower oxygen levels in Yonkers, which he said was “kind of expected” due to vegetation and muck on the riverbed, he described the Hudson as healthy overall.
Henkelman navigates the waters of the Hudson River during his monthlong paddle to New York City.
Courtesy John Henkelman
“That’s just something I wanted to highlight,” Henkelman said, noting some studies suggest the river is the cleanest it's been since the Civil War. “It’s the foresight of generations before us that recognized that clean water and clean air is important.”
The trip doubled as a fundraiser for American Rivers, a national nonprofit dedicated to protecting and restoring waterways. Henkelman has been posting his test results online and encouraging people to support the group’s mission, which he summed up as “healthy rivers equal healthy communities.”
He said he launched his journey at Henderson Lake in the Adirondacks, navigating a month of varied conditions from the whitewater of the Hudson River Gorge to the busy boat traffic in New York City's waters. At one point, a dam closure forced him to transport his canoe for 15 miles over a mountain, he said.
The idea for the journey came together quickly, just months before he pushed off. Henkelman, who previously worked for a decade in the pharmaceutical industry, said he had a rare block of time between jobs and decided to seize it.
“I could have done a river up in Maine, which is where I live, or New Hampshire, where I go to school,” he said. “But you can’t go wrong with paddling 315 miles and ending at the most American place you can ever think of — the Statue of Liberty.”
As he approached the city skyline, Henkelman admitted the moment might overwhelm him.
“If I see the Statue of Liberty while we’re talking, I’ll probably break down crying. I’m not really a crying type person,” he said.
Henkelman didn't actually make it to the statue. He said he pulled out of the river near 13th Street on Sunday after the fire department warned him of choppy waves in the water.
"I set eyes on Lady Liberty and will by cycling to my last water test point tomorrow," he said in a text message. "Not the ending I want, but safety comes first."
Tagged
Health and Science
environment
hudson river
new york city
new york state
Ramsey Khalifeh
Ramsey Khalifeh is a transportation reporter on the NYC Accountability desk covering the largest transit system in the country. He was previously a general assignment reporter at Gothamist and worked on the Boston Globe's metro and copy desk. Got a tip? Email [email protected]
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Phil Corso
Phil Corso is the evening news editor at WNYC/Gothamist. Got a tip? Email [email protected].
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Gothamist is funded by sponsors and member donations
Gothamist is funded by sponsors and member donations
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