Cupsaw Lake Dam

Cupsaw Brook· Passaic, New Jersey· Built 1930· Earth· 35 ft tall
High Hazard Recreation Private

Key Takeaway

Cupsaw Lake Dam is classified as high hazard in New Jersey. It was completed in 1930 and is 96 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 35 ft (taller than 93.2% in NJ)
Dam Length430 ft
Dam TypeEarth
Normal Storage698 acre-ft
Surface Area69 acres
Drainage Area4 sq mi
Max Discharge0 cfs
Year Completed1930 (96 years old)
NID IDNJ00194

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: October 15, 2021
State Regulated: Yes
Regulatory Agency: NJDEP

Ownership

Cupsaw Lake Inprovement Association

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cupsaw Lake Dam?

Cupsaw Lake 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 Cupsaw Lake Dam?

Cupsaw Lake Dam is owned by Cupsaw Lake Inprovement Association (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cupsaw Lake Dam built?

Cupsaw Lake Dam was completed in 1930, making it 96 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 Cupsaw Lake Dam?

Cupsaw 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 Cupsaw Lake Dam?

Cupsaw Lake Dam has a dam height of 35 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 Cupsaw Lake Dam last inspected?

Cupsaw Lake Dam was last inspected on October 15, 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.