Assabet River Facts

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The Assabet River has had many names over the centuries. The name “Assabet” comes through the filter of time from the (spoken) Algonquin word for “the place where materials for making fish nets comes from.” You will also see it referred to as the Assabeth, Asabet, Elizabeth, Elizabet, and a dozen other variations as different cultures put their imprint on the landscape.

"A Stream Stapled to the Landscape by Bridges"
Starting in Westborough, the river falls 320 feet through the towns of Northborough, Marlborough, Berlin, Hudson, Stow, Maynard, Acton, and finally Concord where it merges with the Sudbury River at Egg Rock to form the Concord River. The energy in that 320 feet has been tapped by dams along the Assabet's length: mill dams to power the original sawmills and woolen mills, and, more recently, flood control dams. These dams not only changed the character of the river but also the nature of human habitation along its banks. Farms gave way to manufacturing plants, towns sprouted up, and the river became an engine of commerce in the 18th and 19th centuries.

Naturalist Ann Zwinger paddled the length of the Assabet with fellow naturalist Edwin Teale. In their book "A Conscious Stillness" Ann writes about the Assabet River's history, both natural and manmade. The two are intertwined, for good and bad. The Assabet is a "working river" and Ann observed that from the air the river appeared to be "stapled to the landscape by bridges." Over its 31-mile course, over 40 bridges now cross or previously crossed the river.

The Future of the Assabet
While the river is a natural treasure, a history marked with industrial and municipal pollution has left the Assabet with an abundance of nutrients that cause excessive plant growth in the river during the summer months. This damages the river's habitat and recreational value, causing it to fall short of its potential as a haven for fish and other wildlife.

It's that potential that makes the Assabet worth the efforts of OARS members and staffers. After 250-plus years of human use and abuse, it's time to make sure the Assabet's beauty and vitality will be protected and enjoyed by generations to come. But change takes time . . .

Like ripples in a pool, the actions that we take to protect the Assabet and its watershed today will spread beyond the river's banks and into our future.

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

Political Boundaries: The Assabet watershed is divided between Massachusetts' 2nd and 3rd 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, the 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 mainstem 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.

Wastewater Discharges: 4 municipal wastewater treatment plants: Westborough, Marlborough, Hudson, Maynard (all with total phosphorus summertime discharge limits of 0.1 mg/L and winter discharge limits of 1.0 mg/L), 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, bicycling.

Notable Features: The river starts at the outflow of the Nichols Dam in Westborough. It flows through the Assabet River National Wildlife Refuge in Stow.