Hopkinton Dam - Dike H-3 Reservoir Report
Last Updated: December 16, 2025
Hopkinton Dam - Dike H-3, also known as Hopkinton Flood Control Spillway H3, 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 height of 66 feet and spans a length of 4400 feet. Its primary purpose is flood risk reduction, with a normal storage capacity of 700 acre-feet and a maximum discharge of 58,000 cubic feet per second.
Managed by the US Army Corps of Engineers, Hopkinton Dam - Dike H-3 serves to mitigate flooding along Cressey's Brook by controlling water levels and releasing excess water downstream when necessary. The dam's hazard potential is rated as high, prompting regular inspections and risk management measures to ensure its structural integrity and public safety. While the dam is equipped with an uncontrolled spillway and has a moderate risk assessment, ongoing monitoring and maintenance efforts are in place to address any potential issues that may arise during severe weather events or periods of increased water flow.
As part of the broader flood risk reduction strategy, the US Army Corps of Engineers collaborates with local emergency managers and stakeholders to raise awareness about the dam's function and potential hazards. Through the development of emergency action plans and regular maintenance activities, the agency aims to minimize the risk of dam-related emergencies and ensure the community is prepared to respond effectively in the event of a flood. While the dam's risk management measures are continuously updated, further details specific to Hopkinton Dam - Dike H-3 are expected to be provided in the future to enhance public understanding and safety protocols.
Year Completed |
1962 |
Dam Length |
4400 |
Dam Height |
66 |
River Or Stream |
Cressey's Brook |
Primary Dam Type |
Earth |
Surface Area |
220 |
Hydraulic Height |
60.1 |
Drainage Area |
382 |
Nid Storage |
131000 |
Structural Height |
66 |
Hazard Potential |
High |
Foundations |
Rock, Soil |
Nid Height |
66 |
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.
Hopkinton Dam - Dike H-3
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