The Assabet River is located in eastern Massachusetts, approximately 20 miles west of Boston. The Assabet River has a length of about 32 miles, and drains a watershed of approximately 177 square miles, flowing through the towns of Westborough, Northborough, Marlborough, Berlin, Hudson, Stow, Maynard, Acton, and Concord, Masss. The Assabet River joins the Sudbury River in Concord to form the Concord River.

This is a Planning Assistance to the States study, and the purpose of this study is to provide planning assistance to the Massachusetts Department of Environmental Protection (MassDEP). MassDEP in conjunction with EPA and watershed stakeholders are investigating and implementing measures to improve water quality and the aquatic ecosystem of the Assabet River in order to meet its Class B water quality standard (fishable and swimmable). The study's role in this effort is to provide scientific and engineering information that will inform the decision making process by MassDEP and stakeholders.

The Corps study considered the potential measures of sediment and dam removal to reduce internal recycling of phosphorus (sediment phosphorus flux) in the Assabet River. The first part of the study focused on reductions in sediment phosphorus flux from sediment for sediment and dam removal measures. The second part of the study focused on engineering and environmental considerations for hypothetical dam removal. 

If in the future a proponent steps forward who wishes to pursue dam removal, then there would be detailed environmental assessments and permitting involved at all levels of government – local, state and Federal.