Knowles Pond Dam

TR WILLIAMS BROOK· Merrimack, New Hampshire· Built 1935· Earth· 11 ft tall
Low Hazard Recreation Local Government

Key Takeaway

Knowles Pond Dam is classified as low hazard in New Hampshire. It was completed in 1935 and is 91 years old. Its primary use is recreation.

Physical Details

Dam Height 11 ft (taller than 23.8% in NH)
Dam Length350 ft
Dam TypeEarth
Max Storage237 acre-ft
Normal Storage182 acre-ft
Surface Area56 acres
Drainage Area0 sq mi
Year Completed1935 (91 years old)
Year Modified2008
NID IDNH00367

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

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

Emergency Action Plan: No
Last Inspection: September 5, 2019
State Regulated: Yes
Regulatory Agency: NH DES

Ownership

TOWN OF NORTHFIELD

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Knowles Pond Dam?

Knowles Pond Dam is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Knowles Pond Dam?

Knowles Pond Dam is owned by TOWN OF NORTHFIELD (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Knowles Pond Dam built?

Knowles Pond Dam was completed in 1935, making it 91 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 Knowles Pond Dam?

Knowles Pond 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 Knowles Pond Dam?

Knowles Pond Dam has a dam height of 11 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 Knowles Pond Dam last inspected?

Knowles Pond Dam was last inspected on September 5, 2019. 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.