Hadley Falls Reservoir Report

Last Updated: December 17, 2025

Hadley Falls, also known as Bobbin Shop Dam, is a state-owned structure located in Goffstown, New Hampshire, along the Piscataquog River.


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Summary

Built in 1922, this concrete gravity dam stands at a height of 20 feet and spans a length of 230 feet, with a storage capacity of 150 acre-feet. The dam serves primarily for hydroelectric purposes but also supports fire protection, stock, small fish pond, and recreational activities.

Managed by the New Hampshire Department of Environmental Services Dam Bureau, Hadley Falls is regulated, permitted, inspected, and enforced by state authorities. The Federal Energy Regulatory Commission also plays a role in oversight. With a spillway type of uncontrolled and a spillway width of 176 feet, the dam has a significant hazard potential and a moderate risk rating. Emergency action plans have been prepared, although the condition assessment is not currently available.

Water resource and climate enthusiasts will appreciate the historical significance and engineering feat of Hadley Falls, as it harnesses the power of the Piscataquog River for renewable energy generation. The dam not only provides electricity but also contributes to the local ecosystem and recreational opportunities. Ongoing monitoring and maintenance ensure the safety and integrity of this vital infrastructure, supporting sustainable water management practices in the region.

Year Completed

1922

Dam Length

230

Dam Height

20

River Or Stream

Piscataquog River

Surface Area

24

Drainage Area

197

Nid Storage

150

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

Significant

Nid Height

20
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.