Second Reservoir Dam
Second Reservoir Dam is an earth dam located in Rockland County, New York, built in 1928. It carries a Significant hazard potential classification and has a poor condition assessment.
About Second Reservoir Dam
The primary purpose of Second Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Nysoprhp - Palisades Interstate Park Commission (state). It impounds the Tr-horse Chock Brook near Thiells.
The dam stands 32 feet tall and stretches 440 feet across, creates a reservoir covering 18 acres, has a maximum storage capacity of 272 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1928, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 04/26/2023.
At 32 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | New York |
| County | Rockland |
| Nearest City | Thiells |
| River/Stream | Tr-horse Chock Brook |
| Coordinates | 41.20861, -74.07139 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 32 ft |
| Dam Height | 32 ft |
| Dam Length | 440 ft |
| Year Completed | 1928 (98 years old) |
Storage & Hydraulics
| NID Storage | 272 acre-ft |
| Max Storage | 272 acre-ft |
| Normal Storage | 198 acre-ft |
| Surface Area | 18 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | NYSOPRHP - PALISADES INTERSTATE PARK COMMISSION |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 04/26/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NY01532 |
| Federal ID | NY01532 |
| More Info | State Dam Safety Program |