Tivoli Lake Spillway
Tivoli Lake Spillway is a concrete dam located in Rockland County, New York, built in 1908. It carries a Significant hazard potential classification and has a poor condition assessment.
About Tivoli Lake Spillway
The primary purpose of Tivoli Lake Spillway is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Pierson Lake Homeowners Association (private). It impounds the Tr-ramapo River near Sloatsburg.
The dam stands 5 feet tall and stretches 205 feet across, creates a reservoir covering 103 acres, has a maximum storage capacity of 1,100 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1908, the structure is over a century old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 08/28/2024.
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Location
| State | New York |
| County | Rockland |
| Nearest City | Sloatsburg |
| River/Stream | Tr-ramapo River |
| Coordinates | 41.14611, -74.20528 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 5 ft |
| Dam Height | 5 ft |
| Dam Length | 205 ft |
| Year Completed | 1908 (118 years old) |
Storage & Hydraulics
| NID Storage | 1,100 acre-ft |
| Max Storage | 1,100 acre-ft |
| Normal Storage | 800 acre-ft |
| Surface Area | 103 acres |
| Drainage Area | 2 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | PIERSON LAKE HOMEOWNERS ASSOCIATION |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 08/28/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | NY14640 |
| Federal ID | NY14640 |
| More Info | State Dam Safety Program |