Hopkinton Dam - Dike H-2

Elm Brook· Merrimack, New Hampshire· Built 1962· Earth· 77 ft tall
High Hazard Flood Risk Reduction Recreation Federal Government

Key Takeaway

Hopkinton Dam - Dike H-2 is classified as high hazard in New Hampshire. It was completed in 1962 and is 64 years old. Its primary use is flood risk reduction. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 77 ft (taller than 98.3% in NH)
Dam Length5,220 ft
Dam TypeEarth
Max Storage131.0K acre-ft
Normal Storage700 acre-ft
Surface Area220 acres
Drainage Area382 sq mi
Max Discharge58,000 cfs
Year Completed1962 (64 years old)
NID IDNH00726

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: November 2, 2021
State Regulated: Yes
Regulatory Agency: NH DES

Ownership

USACE - New England District

Federal Government

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Frequently Asked Questions

What is the hazard classification of Hopkinton Dam - Dike H-2?

Hopkinton Dam - Dike H-2 is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Hopkinton Dam - Dike H-2?

Hopkinton Dam - Dike H-2 is owned by USACE - New England District (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Hopkinton Dam - Dike H-2 built?

Hopkinton Dam - Dike H-2 was completed in 1962, making it 64 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Hopkinton Dam - Dike H-2?

Hopkinton Dam - Dike H-2 serves the following purposes: Flood Risk Reduction, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Hopkinton Dam - Dike H-2?

Hopkinton Dam - Dike H-2 has a dam height of 77 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Hopkinton Dam - Dike H-2 last inspected?

Hopkinton Dam - Dike H-2 was last inspected on November 2, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.