Merrimack (Lower) River Watershed Assessment Study

The Merrimack River is formed by the confluence of the Pemigewasset and Winnipesaukee Rivers in Franklin, New Hampshire.  The river flows southward for approximately 78 miles in New Hampshire before crossing the New Hampshire/Massachusetts border and flowing in a northeasterly direction for approximately another 50 miles before discharging to the Atlantic Ocean at Newburyport, Massachusetts.  The final 22 miles of the river, downstream of Haverhill, Massachusetts, are tidally influenced. 

The watershed study was designed to develop a comprehensive understanding of the existing water quality conditions of the river, the pollution sources impairing designated uses along the river, and the water quality benefits of different water quality management scenarios. The overall goal of the study is to develop a comprehensive watershed assessment to guide water quality related investments in the basin.

The Non-Federal sponsor for study that  focused on the Lower Merrimack River watershed, was the City of Lowell in partnership with Manchester and Nashua, New Hampshire; Haverhill, Massachusetts; and GLSD, Massachusetts.  Collectively, these communities formed the Merrimack River Basin Community Coalition.

The Environmental Protection Agency, Massachusetts Department of Environmental Protection, New Hampshire Department of Environmental Services,  U.S. Geological Survey have all provided technical assistance to the U.S. Army Corps of Engineers New England District for this study. This study is authorized by Section 729 of Water Resources Development Act (WRDA) of 1986 entitled “Study of Water Resources Needs of River Basins and Regions” as amended.” 

The study area for the Lower Merrimack Study stretched from the Hookset Dam in New Hampshire (above Manchester) to the estuary at Newburyport and Salisbury, Mass.

The study included sampling and analysis of water quality and river flows and development of a watershed/river computer simulation model.  The three major components of the model are: watershed runoff and loading, hydraulic routing, and water quality simulation.

Phase I  was completed in September 2006.  Available Phase I reports are provided under the Menu bar on this website.   The USACE is preparing a draft Watershed Assessment report that will be available for public review in fall 2019.

For more information, please contact the Project Manager, by email.

Updated June 14, 2019