Great Works River

The Great Works River runs 24.5 miles and changes 520 feet in elevation from the headwaters in downtown Sanford to its confluence with the Salmon Falls River in South Berwick. The watershed drains the towns of Sanford, Wells, York, Berwick, North Berwick, and South Berwick, Maine. It consists of the main stem of the Great Works River, Estes Brook, West Brook, and numerous small tributaries, as well as dozens of ponds and wetlands. 


Drainage: 84 square miles
Drinking water source for:  None
Receives wastewater from: North Berwick
Significant water features: Estes Brook, West Brook

Watershed Description

The upper reaches of the watershed in Sanford and North Berwick are characterized by scattered agricultural land and large forest blocks interspersed with large areas of developed land. Downstream from Sanford, a series of small ponds form an area of significant habitat for inland waterfowl, wading birds, and the endangered Northern Black Racer.

The middle portion of the Great Works River Watershed includes areas of dense development, yet several large blocks of mixed forest and agricultural land surround two tributaries of the watershed.

In the Southern and Eastern portion of the watershed, a vast area of wetlands, forests, and agricultural land make up one of the most significant natural areas in the region. Several tracts of conservation land are located here, surrounding Mt. Agamenticus. These include private and state held preserves and easements which provide recreation and important resource protection. Vast exemplary natural communities of oak forests provide thousands of acres of significant habitat for wildlife including the endangered Northern Black Racer, the vulnerable Ringed Boghaunter, and the threatened Swamp Darter, as well as important deer wintering habitat and inland waterfowl and wading bird habitat. The final stretch of the watershed includes the developed area around Leighs Mill village in South Berwick. 

Local Information

Towns in Watershed

Berwick, North Berwick, Sanford, South Berwick, Wells, York

Piscataqua Regions Estuary Partnership (PREP)

The mission of Piscataqua Region Estuaries Partnership (PREP) is to protect and improve the water quality and overall health of the region’s two estuaries – Great Bay & Hampton-Seabrook. We monitor and research the region’s water ways, encourage all who live, work and play on the Seacoast to take actions to help protect and preserve the places we love, support development patterns that protect water quality, maintain open spaces and important habitat, and restore estuarine resources.

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