Wetland Wednesdays target invasive water chestnuts in Van Cortlandt Park

Posted Friday, July 31, 2026 10:04 am

Holding a freshly pulled water chestnut, Noel Hefele pointed to groups of leaf clusters, known as rosettes. A small flower on every rosette produces as many as two dozen seeds that can remain viable for more than a decade. “It self-pollinates, which is part of why it can explode so intensely,” Hefele said. "We end up having a pretty intimidating game of numbers that we're engaged in here."

GARY JEAN-JUSTE photos

Participants used a floating rake to pull water chestnuts toward shore. Some volunteers experimented with new collection methods this year, including mesh onion bags, allowing crews to gather larger quantities of invasive plants before transporting them away from the water.

Urban Eco-Teen interns unload wheelbarrows overflowing with water chestnuts after returning from the pond. The paid seven-week internship prepares rising high school juniors and seniors for college and careers in environmental stewardship through hands-on restoration work, scientific field studies and leadership opportunities.

Volunteer Kennedy Hill, right, and fellow participants carried orange mesh bags filled with water chestnuts from the pond. Hill traveled from Chelsea for her first volunteer event after learning community service hours could help qualify her for an upcoming trail-running race. “I love it,” she said. “It’s just nice to experience something kind of new and be a little bit more in nature.”

Urban Eco-Teen interns Aryel Pinero, right, and Jordan Smallwood-Jackson helped remove invasive water chestnuts, with Smallwood-Jackson saying the internship changed how he sees the park. “You wouldn’t think that it would be invasive or damaging until you actually learn about what they are,” he said. “Once you identify the plant, you see it everywhere.”

Participants paddled canoes through Hester and Piero’s Mill Pond, reaching patches of invasive water chestnuts that cannot be accessed from shore. The additional boats allowed crews to spread out across the pond and collect plants from areas where volunteers working on foot cannot safely reach.

Van Cortlandt Park Alliance staff transferred cartloads of freshly harvested water chestnut into a utility vehicle after a morning of restoration work. Once loaded, the invasive plants were driven to a designated disposal area away from the pond, where they can decompose without reentering the connected waterway.

by Michelle Mullen

Editor's note 7/31/26: A previous version of this article incorrectly stated Wetland Wednesday ran for most of the year. It runs from late May to early August. The previous version also stated New Yorks City Department of Parks and Recreation staff took part in Wetland Wednesdays, however only Van Cortlandt Park Alliance staff were involved.

For most of the summer, Van Cortlandt Park Alliance volunteers, staff and teenage interns join together week after week to wade through Hester and Piero’s Mill Pond, formerly Van Cortlandt Lake. It’s part of the alliance’s Wetland Wednesdays program, which centers on removing an invasive plant from the waterway during the summer season.

Water chestnuts form dense mats across the water’s surface that block sunlight from reaching native plants, said Christina Taylor, deputy director of the Van Cortlandt Park Alliance. When the invasive greenery dies in late summer, she added, oxygen levels in the lake can drop dramatically, sometimes killing off fish.

The work is timed to remove water chestnuts before they produce seeds, which can remain viable up to 12 years, said Taylor.

“If we weren’t doing this, basically the entire pond would be covered with it,” said Taylor.

The problem is a relatively recent one, she said, explaining water chestnuts have only been an issue in the area for the past 10 to 15 years.

Taylor said the plant’s spread most likely traces back to Tibbetts Brook upstream in Yonkers, which flows downstream through the connected waterway. The removal effort is also tied to a larger plan to eventually “daylight” Tibbetts Brook, or unearth a buried portion of the brook and connect it to the Harlem River. This makes it important to keep the invasive plant from getting further established before the project moves forward.

Helping lead the work are 17 students in the alliance’s paid “Urban Eco-Teens” internship, a seven-week summer program that introduces high school students to ecological restoration and careers in natural resource management.

“It’s basically our job to try and to reverse some of the damage that the invasives have done.” said 17-year-old Aryel Pinero, who is participating in the program for a second summer.

Volunteer coordinator Noel Hefele said the Wetland Wednesdays initiative has steadily expanded since he first joined as a volunteer in 2020, growing from two boats to four while attracting a loyal group of returning volunteers.

“It’s been very much learning in real time how we engage with the plant,” Hefele said. “Each successive year, our efficiency and scope has gotten better.”

Keywords

Van Cortlandt Park Alliance, Wetland Wednesdays, Hester and Piero's Mill Pond, Van Cortlandt Lake, water chestnuts, invasive species, Tibbetts Brook, ecological restoration, Urban Eco-Teens, Bronx parks, wetland restoration, environmental conservation, volunteer program, Riverdale, New York City Parks