Lake Cohasset Upper Dam

ARDEN BROOK· Orange, New York· Built 1924· Concrete· 25 ft tall
High Hazard Recreation State Government

Key Takeaway

Lake Cohasset Upper Dam is classified as high hazard in New York. It was completed in 1924 and is 102 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 69.7% in NY)
Dam Length150 ft
Dam TypeConcrete
Max Storage373 acre-ft
Normal Storage373 acre-ft
Surface Area37 acres
Drainage Area2 sq mi
Year Completed1924 (102 years old)
NID IDNY00042

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 22, 2019
State Regulated: Yes
Regulatory Agency: NYS DEC

Ownership

NYSOPRHP - PALISADES INTERSTATE PARK COMMISSION

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lake Cohasset Upper Dam?

Lake Cohasset Upper 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 Cohasset Upper Dam?

Lake Cohasset Upper Dam is owned by NYSOPRHP - PALISADES INTERSTATE PARK COMMISSION (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lake Cohasset Upper Dam built?

Lake Cohasset Upper Dam was completed in 1924, making it 102 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 Cohasset Upper Dam?

Lake Cohasset Upper 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 Cohasset Upper Dam?

Lake Cohasset Upper 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 Lake Cohasset Upper Dam last inspected?

Lake Cohasset Upper Dam was last inspected on October 22, 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.