Cheshire Mills Lower Dam

About Cheshire Mills Lower Dam

The primary purpose of Cheshire Mills Lower Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Historic Harrisville Inc (private). It impounds the Nubanusit Brrok near Harrisville.

The dam stands 18 feet tall and stretches 50 feet across, creates a reservoir covering 0 acres, has a maximum storage capacity of 1 acre-feet, and collects water from a drainage area of 10 square miles. Completed in 1848, the structure is one of the older dams in the region, with over a century and a half of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 08/25/2022.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New Hampshire dam safety program can provide more specific information about emergency planning for this structure.

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