The Assabet River Watershed

Rowing our boat against the current, between
wide meadows, we turn aside into the Assabeth.
A more lovely stream than this, for a mile above its
junction with the Concord, has never flowed on earth.
--Nathaniel Hawthorne

Assabet Watershed Facts

SuAsCo Watershed: The Assabet is one of three rivers in the greater Sudbury, Assabet and Concord River watershed (SuAsCo). The Assabet flows into the Concord River in Concord, MA, which flows into the Merrimack River in Lowell, MA and into the ocean at Plum Island.

Towns in the Watershed: 19 towns and one city; including 9 towns along the mainstem (Westborough, Northborough, Berlin, Marlborough, Hudson, Stow, Maynard, Acton, Concord).

Political Boundaries: The Assabet watershed is divided by the 3rd and 5th Congressional districts and spans a part of Worcester and Middlesex counties.

River Length: About 31 miles (dropping 320 feet) from the headwaters in Westborough to Concord where it merges with the Sudbury River at Egg Rock to form the Concord River.

Wild and Scenic Status: In 1999, last 4 miles were designated as Wild and Scenic by the federal government recognizing the recreation, ecology, scenery, and historic/cultural resources of the river.

Watershed Area: 177 square miles.

Watershed Population: Over 170,000.

Water Quality: Goal: Class B; fishable and swimmable.

Major Tributaries: Cold Harbor Brook, Hop Brook, North Brook, Fort Meadow Brook, Danforth Brook, Elizabeth Brook, Nashoba Brook, Taylor Brook, Spencer Brook.

Water Withdrawals: 7 of the Assabet’s main towns (Westborough, Northborough, Marlborough, Hudson, Maynard, Acton, Concord) get all or part of their public water supply from groundwater and surface sources in the Assabet Watershed.

Water Discharges: 4 municipal wastewater treatment plants: Westborough, Marlborough, Hudson, Maynard (all with total phosphorus summertime discharge limits of 0.1 mg/L beginning 2010/2011), and Concord MCI.

Dams: 7 old mill dams (Aluminum City Dam, Allen Street Dam, Hudson Dam, Gleasondale Dam, Ben Smith Dam, Powdermill Dam, Damonmill Dam) and 2 flood control dams (Nichols Dam and Tyler Dam).

Recreation: Canoeing, kayaking, fishing, hiking, bird watching.

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