Clearing the Waters: A Record Year for Water Chestnut Removal and River Stewardship

October 10, 2025

OARS River Log | By Sarah Kwan, OARS’ Director of Advancement | Published Oct 10, 2025

The numbers are in—and they tell a story of incredible progress and community power.

In 2025, OARS 3 Rivers hosted seven water chestnut pulls across the Sudbury, Assabet, and Concord rivers, more than doubling the number of organized events from previous years. Together with local partners and volunteers, we removed 1,690 baskets of water chestnut—an estimated 10.7 million seeds—from our rivers and tributaries.

A thick mat of invasive water chestnut covers the Sudbury River during the Southbridge Boat House Community Pull on July 16, 2025. A canoe sits ready with a basket full of freshly removed plants—part of a growing community effort to restore open water and river health. (Photo by Jane Gruba-Chevalier, Executive Director, Concord Land Conservation Trust)

That’s a huge leap from 1,417 baskets in 2024 and 962 baskets in 2023, and the impact is equally impressive: over 10 million seeds prevented from taking root, slowing next year’s regrowth before it starts.

Stronger Together: Expanding Partnerships & Community Reach

This year marked an exciting expansion of collaboration. OARS partnered for the first time with the Concord Land Conservation Trust through our watershed’s Weed Warriors program, and we also worked closely with the Town of Acton to host two highly successful community pulls.

These partnerships brought even more hands, canoes, and enthusiasm to the fight against this highly invasive aquatic plant—demonstrating the power of collective action for cleaner, healthier rivers.

Water chestnut (Trapa natans) is notorious for forming thick mats that block sunlight, choke oxygen levels, and crowd out native species. By working together to pull these floating invaders by hand, volunteers are doing more than clearing water—they’re restoring balance, improving habitat, and protecting biodiversity across the SuAsCo watershed.

A Watershed-Wide Effort

Our 2025 pulls spanned all three rivers, with community events in Acton, Bedford, Billerica, Carlisle, Concord, and Framingham, and countless independent efforts logged through OARS’ Water Chestnut Reporting App.

Each basket pulled represents countless hours of volunteer dedication—and every community that joined in helped make our rivers cleaner, healthier, and more resilient.

Community volunteers work together at the Ice House Landing Water Chestnut Pull in Acton on August 16, 2025—paddling canoes filled with baskets of invasive plants while others unload along the shore. The event, organized in partnership with the Town of Acton, showcases the power of teamwork in restoring healthy, open waterways.

From Invasive Mats to Flowing Rivers

Removing 10 million seeds may sound abstract, but its meaning is tangible. It means more open water for paddlers, less stress on native fish and aquatic plants, and a healthier ecosystem for everyone—human and wild—who depends on these rivers.

It also means fewer nutrients trapped in dense plant mats, contributing to better water quality and a stronger defense against future algal blooms and eutrophication.

Looking Ahead

OARS’ water chestnut management program continues to grow, fueled by community enthusiasm and strong partnerships with local organizations and municipalities. In 2026, we’ll build on this momentum with even more volunteer pulls, partner collaborations, and an upcoming workshop focused on aquatic invasives—so that anyone can learn how to identify and report these problem plants.

Want to get involved? Join the Weed Warriors, keep an eye out for our 2026 water chestnut pull schedule, or report sightings through our Water Chestnut App.

Together, we’re reclaiming our 3 rivers—basket by basket.

River Log

~30%

of the SuAsCo rivers watershed is wetlands, crucial for wildlife habitat and water quality

~30%

of water samples in the SuAsCo rivers watershed contain PFAS, leading to increased monitoring and remediation by local authorities and environmental groups

~70%

of dams in the SuAsCo watershed are over a century old, requiring extensive upkeep and presenting obstacles to river restoration and fish passage

>40%

of the land within the watershed is publicly accessible, offering recreational opportunities such as hiking, boating, and birdwatching to the community

~15%

of the land in the SuAsCo rivers watershed is covered by impervious surfaces such as roads, rooftops, and parking lots. This contributes to stormwater runoff and water pollution issues

>40%

of the land within the Sudbury, Assabet, and Concord rivers watershed is publicly accessible, providing endless opportunities for paddling, hiking, and wildlife exploration.