Hopkinton Dam - Dike H-2 Reservoir Report
Nearby: Hopkinton Dam Hoague - Sprague
Last Updated: December 16, 2025
Hopkinton Dam - Dike H-2, also known as Hopkinton Dike Elm Brook H2, is a federally owned structure located in Hopkinton, New Hampshire.
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Summary
Built in 1962 by the US Army Corps of Engineers, this earth dam stands at a towering height of 77 feet and serves the primary purpose of flood risk reduction along Elm Brook. With a storage capacity of 131,000 acre-feet and a surface area of 220 acres, the dam plays a crucial role in managing water levels and preventing flooding in the area.
Despite its high hazard potential, the dam is regularly inspected and monitored by the US Army Corps of Engineers to ensure its structural integrity and mitigate any potential risks. The agency works closely with local emergency managers to develop and update emergency action plans, as well as engage with the public to raise awareness and preparedness for dam-related emergencies. Through ongoing risk management measures and maintenance efforts, the USACE is committed to safeguarding the surrounding communities and ensuring the effective operation of Hopkinton Dam - Dike H-2 for years to come.
Year Completed |
1962 |
Dam Length |
5220 |
Dam Height |
77 |
River Or Stream |
Elm Brook |
Primary Dam Type |
Earth |
Surface Area |
220 |
Hydraulic Height |
71.1 |
Drainage Area |
382 |
Nid Storage |
131000 |
Structural Height |
77 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
77 |
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.
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