Amoskeag Reservoir Report
Nearby: Dorrs Pond Dam Kelley's Falls
Last Updated: December 18, 2025
Amoskeag is a private hydroelectric dam located in Manchester, New Hampshire, along the Merrimack River.
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Summary
Completed in 1921, this concrete gravity dam stands at a height of 29 feet and has a length of 1075 feet. With a maximum storage capacity of 4320 acre-feet and a drainage area of 2854 square miles, Amoskeag plays a crucial role in generating hydroelectric power in the region.
Managed by the NHDES Dam Bureau and regulated by the Federal Energy Regulatory Commission, Amoskeag poses a high hazard potential due to its uncontrolled spillway type and a maximum discharge capacity of 87,000 cubic feet per second. Despite its age, the dam's risk assessment is moderate, with a focus on implementing risk management measures to ensure the safety and integrity of the structure. The dam's last inspection in May 2019 highlighted the need for regular monitoring and maintenance to address any potential issues.
As a significant hydroelectric facility in New Hampshire, Amoskeag serves as a vital component of the state's energy infrastructure. With its historical significance and ongoing operational challenges, this dam remains a key player in both water resource management and climate resilience efforts in the region.
Year Completed |
1921 |
Dam Length |
1075 |
Dam Height |
29 |
River Or Stream |
Merrimack River |
Primary Dam Type |
Concrete |
Surface Area |
478 |
Drainage Area |
2854 |
Nid Storage |
4320 |
Outlet Gates |
Slide (sluice gate) - 1 |
Hazard Potential |
High |
Nid Height |
29 |
Seasonal Comparison
Weather Forecast
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.
Amoskeag
Heritage Trail Bedford