Johnsonville
Johnsonville is a concrete dam located in Rensselaer County, New York, built in 1909. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Johnsonville
The primary purpose of Johnsonville 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 Erie Boulevard Hydropower, L.p. (private). It impounds the Hoosic River near Johnsonville.
The dam stands 39 feet tall and stretches 529 feet across, creates a reservoir covering 450 acres, has a maximum storage capacity of 6,430 acre-feet, and collects water from a drainage area of 604 square miles. Completed in 1909, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 07/20/2022.
At 39 feet, this dam is taller than 86% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New York dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | New York |
| County | Rensselaer |
| Nearest City | Johnsonville |
| River/Stream | Hoosic River |
| Coordinates | 42.91970, -73.50840 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 529 ft |
| Year Completed | 1909 (117 years old) |
Storage & Hydraulics
| NID Storage | 6,430 acre-ft |
| Max Storage | 6,430 acre-ft |
| Normal Storage | 6,430 acre-ft |
| Surface Area | 450 acres |
| Drainage Area | 604 sq mi |
| Max Discharge | 11,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Erie Boulevard Hydropower, L.P. |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/20/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NY00119 |
| Federal ID | NY00119 |
| More Info | State Dam Safety Program |