Tivoli Lake Dam

TR-RAMAPO RIVER· Rockland, New York· Built 1908· Concrete· 29 ft tall

High Hazard Recreation Water Supply Private

Key Takeaway

Tivoli Lake Dam is classified as high hazard in New York. It was completed in 1908 and is 118 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	29 ft (taller than 77.5% in NY)
Dam Length	140 ft
Dam Type	Concrete
Max Storage	1.1K acre-ft
Normal Storage	800 acre-ft

Surface Area	103 acres
Drainage Area	2 sq mi
Year Completed	1908 (118 years old)
NID ID	NY00052

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: July 28, 2020

State Regulated: Yes

Regulatory Agency: NYS DEC

Ownership

PIERSON LAKE HOMEOWNERS ASSOCIATION

Private

Nearby Dams

Tivoli Lake Spillway

Rockland, NY

Significant Hazard 5 ft

Potake Lake Dam

Rockland, NY

High Hazard 22 ft

Pine Grove Lake Dam

Rockland, NY

High Hazard 12 ft

Shepherd Lake Dam

Passaic, NJ

Low Hazard 18 ft

Bear Swamp Pond Dam

Bergen, NJ

Low Hazard 14 ft

Mcmillan Reservoir Dam

Bergen, NJ

Low Hazard 21 ft

Sterling Forest Lake Dam

Orange, NY

High Hazard 30 ft

Cupsaw Lake Dam

Passaic, NJ

High Hazard 35 ft

Frequently Asked Questions

What is the hazard classification of Tivoli Lake Dam?

Tivoli 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 Tivoli Lake Dam?

Tivoli Lake Dam is owned by PIERSON LAKE HOMEOWNERS ASSOCIATION (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Tivoli Lake Dam built?

Tivoli Lake Dam was completed in 1908, making it 118 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 Tivoli Lake Dam?

Tivoli Lake Dam serves the following purposes: Recreation, Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Tivoli Lake Dam?

Tivoli Lake Dam has a dam height of 29 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 Tivoli Lake Dam last inspected?

Tivoli Lake Dam was last inspected on July 28, 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.