Lake Topanemus Dam

McGellaird's Brook· Monmouth, New Jersey· Built 1915· Earth· 20 ft tall
High Hazard Recreation Local Government

Key Takeaway

Lake Topanemus Dam is classified as high hazard in New Jersey. It was completed in 1915 and is 111 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 20 ft (taller than 72.4% in NJ)
Dam Length327 ft
Dam TypeEarth
Normal Storage66 acre-ft
Surface Area22 acres
Drainage Area2 sq mi
Max Discharge0 cfs
Year Completed1915 (111 years old)
NID IDNJ00219

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: December 3, 2020
State Regulated: Yes
Regulatory Agency: NJDEP

Ownership

Monmouth County Engineering

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lake Topanemus Dam?

Lake Topanemus 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 Lake Topanemus Dam?

Lake Topanemus Dam is owned by Monmouth County Engineering (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lake Topanemus Dam built?

Lake Topanemus Dam was completed in 1915, making it 111 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 Lake Topanemus Dam?

Lake Topanemus 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 Lake Topanemus Dam?

Lake Topanemus Dam has a dam height of 20 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 Lake Topanemus Dam last inspected?

Lake Topanemus Dam was last inspected on December 3, 2020. 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.