China Mill Dam

China Mill Dam is a concrete dam located in Merrimack County, New Hampshire, built in 1860. It carries a High hazard potential classification and has a fair condition assessment.

About China Mill Dam

The primary purpose of China Mill 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 Nh Hydro Assoc (private). It impounds the Suncook River near Pembroke.

The dam stands 29 feet tall and stretches 275 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 33 acre-feet, and collects water from a drainage area of 259 square miles. Completed in 1860, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 11/04/2021.

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.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardFair ConditionEmergency Action Plan: Yes

Location

StateNew Hampshire
CountyMerrimack
Nearest CityPembroke
River/StreamSuncook River
Coordinates43.13000, -71.45630

Physical Characteristics

Dam TypeConcrete
NID Height29 ft
Dam Height29 ft
Dam Length275 ft
Year Completed1860 (166 years old)

Storage & Hydraulics

NID Storage33 acre-ft
Max Storage33 acre-ft
Normal Storage22 acre-ft
Surface Area1 acres
Drainage Area259 sq mi
Max Discharge16,770 cfs

Ownership & Safety

PurposeHydroelectric
OwnerNH HYDRO ASSOC
Owner TypePrivate
Hazard ClassificationHigh
Condition AssessmentFair
Last Inspection11/04/2021
Emergency Action PlanYes

Identifiers

NID IDNH00023
Federal IDNH00023
More InfoState Dam Safety Program

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