Piscataquog Dams Info


The Piscataquog River consists of three branches, the South, Middle, and North, which run through the south-central New Hampshire communities of Deering, Francestown, Lyndeborough, New Boston, Weare, Goffstown, and Manchester. The Piscataquog River has an approximate length of 63 miles and is free-flowing for 96% of its length.

The three branches merge near the Goffstown townline and the River runs from west to east through Goffstown into Manchester. In west Manchester, the Piscataquog passes under the Nazaire Biron Bridge and reaches the Merrimack River just upstream of the Queen City Bridge.

Close to six miles of the Piscataquog River is classified as impounded. Hydroelectric dams include Hadley Falls and Greggs Falls in Goffstown, and Kelley Falls in Manchester. The Gregg Falls project impoundment includes Glen Lake, with an area of approximate open-water area of 137 acres. The Kelley Falls project impoundment includes Namaske Lake, with an approximate open-water area of 192.5 acres. All three dams are owned by the State of NH and the State leases rights to hydroelectric generation facilities. Hadley Falls Dam has not produced hydroelectricity since 2007.

More information about Hadley Falls, Gregg Falls, and Kelley Falls will be collected and made available on this Town of Goffstown website. Specific questions can be directed to Town Hall, Monday through Friday 8 am to 4 pm at 603-497-8990.

Piscataquog River Management Plan Update - 2010 (PDF)

Hadley Falls (P-5379)

Hadley Falls Dam was constructed in 1921 and the State of NH took ownership in 1968. In the mid-1980s Hadley Falls Dam began producing hydroelectric power in partnership between the NH Water Resource Board, NH Department of Environmental Services (NHDES), and Hydro Dynamics Corporation, later Goffstown Hydro Corporation. In 2007 Goffstown Hydro Corporation ceased hydro-electric operations at this location. In 2013 NHDES became the sole licensee of Hadley Falls Project Number 5379 and indicated to the Federal Energy Regulatory Commission (FERC) that the State would seek other hydropower operators. The State continued to seek hydropower operators at Hadley Falls over the last decade, while the Town considered redevelopment of the mill complex on the adjacent property.

In April and May 2023, NHDES notified the Goffstown Select Board of the State's decision to relinquish the FERC License for Hadley Falls to begin the process of removing Hadley Falls Dam.

Gregg Falls (P-3180)

The Gregg Falls Dam was built by the Manchester Traction, Light, and Power Company in 1918. At the time it was the largest dam in the state. The dam was decommissioned as a hydroelectric generator in the 1970s but recommissioned with new turbines and generators in 1985.

Today, the Gregg's Falls power station is a 3,479-kilowatt hydroelectric generating station owned and operated by Eagle Creek Renewable Energy visit the Eagle Creek Renewable Energy website. The facility's two Francis turbines produce approximately 11 million kilowatt-hours of clean energy in a typical year. The Gregg's Falls facility began commercial operation in 1985. The Gregg's Falls facility operates under an exempt license from the Federal Energy Regulatory Commission.

Kelley's Falls (P-3025)

The Kelley's Falls Dam was completed in 1916 and is a concrete and stone masonry dam owned by the state of New Hampshire. The powerhouse was constructed in 1926/1927 and is a masonry, brick, and steel superstructure.

Kelley's Falls Hydroelectric Project (FERC Number 3025) is an existing, licensed hydroelectric project operated by Green Mountain Power Corporation visit the Green Mountain website.

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