3 Rivers

Protected & Clean

Flowing Free

For all to Enjoy

Wild & Scenic

WATERSHED ORGANIZATION
FOR THE SUDBURY ASSABET & CONCORD RIVERS

Our Vision

A watershed with resilient streams and rivers that provide healthy wildlife habitat, water supplies, beauty, education, and recreational opportunities for all. OARS is the voice of the rivers, and is an effective, innovative, and inclusive science-based non-profit organization.

The Rivers

The quiet beauty of the Sudbury, Assabet, and Concord (SuAsCo) rivers in eastern Massachusetts provides an antidote to our modern lives. They form the 399-square mile SuAsCo watershed. The rivers flow north through mill towns and farms, small cities and suburbs, to pass through the Merrimack River in the City of Lowell. Sections were federally designated as Wild and Scenic Rivers in 1999 for their outstanding recreation, ecology, scenic, and historic resources and place in American literature.

Learn More

Recognizing Indigenous Stewardship

We would like to honor all the ancestral stewards of this land including the Massachusett, Nipmuc, and Pawtucket Nations. We endeavor to be responsible stewards of their traditional and contemporary territories. We recognize their invaluable efforts by continuing the conservation legacy they started as caretakers of our watershed.

 

The name Assabet is likely from a Nipmuc word for the area’s marshes. The confluence of the Assabet and Sudbury rivers is named Musketaquid, where the waters flow through the grasses.

Diversity and Belonging

OARS is committed to the ongoing work of promoting diversity, equity, inclusion, and belonging within our organization so that all may enjoy and benefit from these rivers.

Enjoy and help our rivers!

River Maps

Recreational guides for Sudbury, Assabet, and Concord rivers are available as a series of single-river maps and as an interactive online map.

RIVER MAPS

Events!

Upcoming events. Explore our opportunities and get involved!

SEE WHAT’S HAPPENING

Dam Removal

Our watershed has over 160 dams. Many are old mill dams in disrepair and result in aquatic weed growth, flooding, warmer water, and degraded wildlife habitat. Learn more about our efforts to let our rivers run clean and free.

DAM REMOVAL

River Science

Read our latest findings on water pollution and work to build climate resilience.

UNDERSTANDING OUR RIVERS’ HEALTH

Report & Pull Water Chestnut

Help us manage invasive water chestnut by using our reporting app to share where you have seen or pulled water chestnuts.

HELP COMBAT INVASIVES

RIVER REPORT CARD

How healthy are your Sudbury, Assabet, and Concord rivers?

READ OUR REPORT CARD
6

OARS Events Spotlight

Upcoming Events

Events Calendar

The Rivers of Concord Show

March 27 - June 20, 2025

Join us for the our newest community art show, The Rivers of Concord, curated by ArtScape at the Bradford Mill and offered in partnership with OARS3Rivers. Light refreshments will be …

Learn More

PARTNER ORGANIZATION—Run of the Charles

April 27 - April 27, 2025

Registration is now open for the Run of the Charles, Boston’s premier paddling race, returning on Sunday, April 27. Paddlers across New England, regardless of skill level, are encouraged to register now for …

Learn More

Concord River Race

May 04 - May 04, 2025

  CONCORD RIVER RACE Proudly part of the NECKRA Point Series   When: Sunday, May 4th, 2025 | 11:00 AM–1:00 PM Where: Bedford Boat Ramp | 285–305 Carlisle Road, Bedford, MA …

Learn More

River RATs Canoeing Trip—Billerica May

May 14 - May 14, 2025

WHEN WHERE Wednesday, May 14, 5:00–7:00 PM Billerica Parks & Rec Boat Launch & Yard 248 Boston Road, Billerica, MA 01821   Join us for a memorable paddle along the …

Learn More

River RATs Kayaking Trip—Maynard May

May 22 - May 22, 2025

WHEN WHERE Thursday, May 22, 5:30–7:30 PM Ice House Landing Assabet River Rail Trail, Maynard, MA 01754   Join us and paddle the scenic Assabet River! If you’re interested in …

Learn More

River RATs Canoeing Trip—Framingham May

May 29 - May 29, 2025

WHEN WHERE Thursday, May 29, 5:30–7:30 PM Kellogg Park Kellogg Street, Framingham, MA 01710   Join us for a memorable paddle along the historic and scenic Sudbury River! These FREE …

Learn More

River RATs Canoeing Trip—Billerica June

June 11 - June 11, 2025

WHEN WHERE Wednesday, June 11, 5:00–7:00 PM Billerica Parks & Rec Boat Launch & Yard 248 Boston Road, Billerica, MA 01821   Join us for a memorable paddle along the …

Learn More

Community Water Chestnut Pull—Simpson Park, Framingham

June 14 - June 14, 2025

Help Remove Invasive Water Chestnut! Join us in protecting our waterways by removing invasive water chestnut!   WHEN: Saturday, July 12, 9:00 AM to noon WHERE: Simpson Park—Framingham, MA (exact …

Learn More

River RATs Kayaking Trip—Maynard June

June 19 - June 19, 2025

WHEN WHERE Thursday, June 19, 5:30–7:30 PM Ice House Landing Assabet River Rail Trail, Maynard, MA 01754   Join us and paddle the scenic Assabet River! If you’re interested in …

Learn More

River RATs Canoeing Trip—Framingham June

June 26 - June 26, 2025

WHEN WHERE Thursday, June 26, 5:30–7:30 PM Kellogg Park Kellogg Street, Framingham, MA 01710   Join us for a memorable paddle along the historic and scenic Sudbury River! These FREE …

Learn More

Community Water Chestnut Pull—Ice House Pond, Acton

June 28 - June 28, 2025

Paddle with a Purpose—Help Remove Invasive Water Chestnut! Join us in protecting our waterways by removing invasive water chestnut!     WHEN: Saturday, June 28, 9:00 AM to noon WHERE: …

Learn More

River RATs Canoeing Trip—Billerica July

July 09 - July 09, 2025

WHEN WHERE Wednesday, July 9, 5:00–7:00 PM Billerica Parks & Rec Boat Launch & Yard 248 Boston Road, Billerica, MA 01821   Join us for a memorable paddle along the …

Learn More

PARTNER EVENT—Nature Play Festival at Discovery Museum

July 11 - July 11, 2025

    WHEN: Friday, July 11 | 11:00 AM–7:00 PM WHERE: Discovery Museum | 177 Main Street, Acton, MA 01720     Have fun, explore, and learn outdoors and inside …

Learn More

Community Water Chestnut Pull—North Billerica

July 12 - July 12, 2025

Paddle with a Purpose—Help Remove Invasive Water Chestnut! Join us in protecting our waterways by removing invasive water chestnut!   WHEN: Saturday, July 12, 9:00 AM to noon WHERE: North …

Learn More

River RATs Kayaking Trip—Maynard July

July 17 - July 17, 2025

WHEN WHERE Thursday, July 17, 5:30–7:30 PM Ice House Landing Assabet River Rail Trail, Maynard, MA 01754   Join us and paddle the scenic Assabet River! If you’re interested in …

Learn More

River RATs Canoeing Trip—Framingham July

July 31 - July 31, 2025

WHEN WHERE Thursday, July 31, 5:30–7:30 PM Kellogg Park Kellogg Street, Framingham, MA 01710   Join us for a memorable paddle along the historic and scenic Sudbury River! These FREE …

Learn More

River RATs Kayaking Trip—Maynard August

August 14 - August 14, 2025

WHEN WHERE Thursday, August 14, 5:30–7:30 PM Ice House Landing Assabet River Rail Trail, Maynard, MA 01754   Join us and paddle the scenic Assabet River! If you’re interested in …

Learn More

River RATs Canoeing Trip—Framingham August

August 28 - August 28, 2025

WHEN WHERE Thursday, August 28, 5:30–7:30 PM Kellogg Park Kellogg Street, Framingham, MA 01710   Join us for a memorable paddle along the historic and scenic Sudbury River! These FREE …

Learn More

39th SuAsCo Rivers Cleanup

September 01 - September 30, 2025

 SAVE THE DATE more information coming soon     SEPTEMBER IS A GREAT MONTH TO CLEAN UP OUR RIVERS!   Join us for the 39th annual cleanup, which brings together …

Learn More

River RATs Kayaking Trip—Maynard September

September 18 - September 18, 2025

WHEN WHERE Thursday, September 18, 5:30–7:30 PM Ice House Landing Assabet River Rail Trail, Maynard, MA 01754   Join us and paddle the scenic Assabet River! If you’re interested in …

Learn More

River RATs Canoeing Trip—Framingham September

September 25 - September 25, 2025

WHEN WHERE Thursday, September 25, 5:30–7:30 PM Kellogg Park Kellogg Street, Framingham, MA 01710   Join us and paddle the scenic Assabet River! If you’re interested in river recreation, environmental …

Learn More
Calendar Prev
Calendar Next

News & Alerts

River Log

Invasive aquatic species invade Acton Town Hall

November 02, 2024

by Kim Kastens | Nov 2, 2024 | The Acton Exchange On October 22, Town Hall was transformed into a plant identification biology lab, as thirty-five lovers of local ponds …

Learn More

Water Chestnut Pull

October 21, 2024

Oct 19, 2024 | ActonTV   OARS partnered with the Town of Acton for a successful community water chestnut pull at Ice House Landing on September 28, 2024, as part …

Learn More

PRESS RELEASE: The Sudbury Foundation Awards Over $1,322,000 in Grants

October 11, 2024

by Sonia Shah, Executive Director, The Sudbury Foundation | October 11, 2024   FOR IMMEDIATE RELEASE   October 10, 2024 (SUDBURY, Massachusetts)—The Sudbury Foundation  recently awarded over $1,322,000 in grant …

Learn More

Environmental nonprofit OARS worries over water quality at Marlborough’s Hager Pond dam

September 03, 2024

by Tom Benoit | Sept 3, 2024 | The MetroWest Daily News   MARLBOROUGH — An idyllic pond located on the Marlborough-Framingham line has all the makings of a classic …

Learn More

Potentially invasive turtle species found in Merrimack River

August 13, 2024

by Peter Currier | Aug 13, 2024 | The Lowell Sun and The Boston Herald   LOWELL—A potentially invasive species of turtle was found in Lowell last week near the …

Learn More

PRESS RELEASE: OARS Intern Discovers Invasive Turtle Species in Merrimack River

August 10, 2024

by Sarah Kwan, Director of Communications & Development, OARS | August 10, 2024   FOR IMMEDIATE RELEASE   Lowell, MA—A new invasive species has been identified in the Merrimack River, …

Learn More
News Prev
News Next

Fast Facts for 2024

>295

water samples were collected to monitor our river health and provide data for informed decision-making

~106K

water chestnut rosettes were hand-pulled by the OARS community

~1700

members of the community joined OARS (and growing)

AAG Prev
AAG Next

In memory of Marty Moran of Hudson

Board member, steadfast volunteer, and lover of rivers. We are deeply grateful for all you have done for OARS. Your legacy gift, along with the generous support of the Sudbury Foundation, made the creation of this website possible.