Assabet Headwaters

Click here for a map of the Assabet Headwaters in Westborough.
Click here for a map of the surficial geology of the Assabet Headwaters.

The true headwaters of the Assabet is the Assabet swamp (left) in Westborough that feeds the reservoir above the George H. Nichols dam (right). The dam was built by the Soil Conservation Service in 1970 as part of the SuAsCo Flood Control Project, to prevent the kind of flooding that occured with Hurricane Diane in 1955.
The 380-acre pond is known variously as the Mill Pond, Stump Pond, or A1 Impoundment/reservoir. The reservoir is popular for boating, fishing, and skating, and provides habitat for wildlife.
The standing dead trees - left when the reservior was formed - are ideal nesting sites for great blue heron and osprey. You're also likely to see tree swallows, kingfisher, cormorants, gulls, mute swans, ducks, geese, mergansers, and red-tailed hawks. The shallow pond itself supports fish like large mouth bass, yellow perch, pumpkinseeds, and white suckers. The Headwaters Conservation Area borders the reservoir.
Assabet River - as a named river - starts just below the dam and runs across the open field before slipping into the trees and running through a quiet neighborhood. At times during the summer there is no flow from the dam and the top of the stream is virtually dry.
The river runs under Mill Street, Fisher Street, and Maynard Street in quick succession before it is joined by a small stream from Hocomonco Pond. Just before the river reaches Route 9, it recieves its first discharge of treated wastewater (the Westborough municipal wastewater treatment facility). The stream runs along the Northborough/ Westborough border until as it passes under Milk Street.