Deering Reservoir Dam

PISCATAQUOG RIVER· Hillsborough, New Hampshire· Built 1940· Earth· 25 ft tall
High Hazard Recreation State Government

Key Takeaway

Deering Reservoir Dam is classified as high hazard in New Hampshire. It was completed in 1940 and is 86 years old. Its primary use is recreation. 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 25 ft (taller than 80.2% in NH)
Dam Length873 ft
Dam TypeEarth
Max Storage3.1K acre-ft
Normal Storage2.7K acre-ft
Surface Area323 acres
Drainage Area4 sq mi
Max Discharge3,839 cfs
Year Completed1940 (86 years old)
Year Modified2007
NID IDNH00282

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: June 9, 2022
State Regulated: Yes
Regulatory Agency: NH DES

Ownership

NH DES WATER DIVISION

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Deering Reservoir Dam?

Deering Reservoir Dam 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 Deering Reservoir Dam?

Deering Reservoir Dam is owned by NH DES WATER DIVISION (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Deering Reservoir Dam built?

Deering Reservoir Dam was completed in 1940, making it 86 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 Deering Reservoir Dam?

Deering Reservoir Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Deering Reservoir Dam?

Deering Reservoir Dam has a dam height of 25 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 Deering Reservoir Dam last inspected?

Deering Reservoir Dam was last inspected on June 9, 2022. 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.