Lower Mountain Lake Dam

WATERMAN BROOK· Grafton, New Hampshire· Built 1967· Earth· 33 ft tall
Significant Hazard Recreation Local Government

Key Takeaway

Lower Mountain Lake Dam is classified as significant hazard in New Hampshire. It was completed in 1967 and is 59 years old. Its primary use is recreation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 33 ft (taller than 89.6% in NH)
Dam Length850 ft
Dam TypeEarth
Max Storage376 acre-ft
Normal Storage191 acre-ft
Surface Area41 acres
Drainage Area4 sq mi
Max Discharge1,650 cfs
Year Completed1967 (59 years old)
Year Modified2015
NID IDNH00195

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

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

Emergency Action Plan: Yes
Last Inspection: April 27, 2021
State Regulated: Yes
Regulatory Agency: NH DES

Ownership

MOUNTAIN LAKES VILLAGE DISTRICT

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lower Mountain Lake Dam?

Lower Mountain Lake Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lower Mountain Lake Dam?

Lower Mountain Lake Dam is owned by MOUNTAIN LAKES VILLAGE DISTRICT (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lower Mountain Lake Dam built?

Lower Mountain Lake Dam was completed in 1967, making it 59 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 Lower Mountain Lake Dam?

Lower Mountain Lake 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 Lower Mountain Lake Dam?

Lower Mountain Lake Dam has a dam height of 33 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 Lower Mountain Lake Dam last inspected?

Lower Mountain Lake Dam was last inspected on April 27, 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.