Philadelphia - Nonoverflow Section
Philadelphia - Nonoverflow Section is a gravity dam located in Jefferson County, New York, built in 1910. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Philadelphia - Nonoverflow Section
The primary purpose of Philadelphia - Nonoverflow Section is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Fortisus Energy Corporation (private). It impounds the Indian River near Philadelphia.
The dam stands 13 feet tall and stretches 45 feet across, creates a reservoir covering 108 acres, has a maximum storage capacity of 89 acre-feet, and collects water from a drainage area of 229 square miles. Completed in 1910, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 06/18/2025.
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Location
| State | New York |
| County | Jefferson |
| Nearest City | Philadelphia |
| River/Stream | Indian River |
| Coordinates | 44.15830, -75.70930 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 45 ft |
| Year Completed | 1910 (116 years old) |
Storage & Hydraulics
| NID Storage | 89 acre-ft |
| Max Storage | 89 acre-ft |
| Normal Storage | 89 acre-ft |
| Surface Area | 108 acres |
| Drainage Area | 229 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | FortisUS Energy Corporation |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/18/2025 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NY12019 |
| Federal ID | NY12019 |
| More Info | State Dam Safety Program |