Penacook Upper Falls Reservoir Report
Last Updated: December 18, 2025
Penacook Upper Falls, located in Boscawen, New Hampshire, is a private hydroelectric dam on the Contoocook River.
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Summary
Completed in 1987, this concrete dam stands at a height of 23 feet with a length of 243 feet, providing a storage capacity of 71 acre-feet and a maximum discharge of 35,000 cubic feet per second. The dam's primary purpose is hydroelectric generation, making it a significant contributor to the region's renewable energy resources.
Managed by the NHDES Dam Bureau and regulated by the Federal Energy Regulatory Commission, Penacook Upper Falls is subject to regular state inspections and enforcement to ensure its safe operation. With a low hazard potential and a very high risk assessment rating, the dam's emergency action plan is in compliance with guidelines, although the condition assessment is currently not available. The dam features a controlled spillway with a width of 235 feet and six slide (sluice gate) outlet gates, demonstrating a commitment to safety and efficient water management practices.
For water resource and climate enthusiasts, Penacook Upper Falls represents a vital piece of infrastructure that harnesses the power of the Contoocook River for clean energy production. Its strategic location and design contribute to the region's water storage capacity and regulatory framework, highlighting the importance of sustainable dam operation in mitigating flood risks and ensuring a reliable water supply for surrounding communities. As a key player in the state's hydroelectric sector, Penacook Upper Falls serves as a model for responsible water resource management and environmental stewardship in New Hampshire.
Year Completed |
1987 |
Dam Length |
243 |
Dam Height |
23 |
River Or Stream |
Contoocook River |
Primary Dam Type |
Concrete |
Surface Area |
11.4 |
Drainage Area |
766 |
Nid Storage |
71 |
Outlet Gates |
Slide (sluice gate) - 6 |
Hazard Potential |
Low |
Nid Height |
23 |
Seasonal Comparison
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Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
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