Lock 4 - Stillwater
Lock 4 - Stillwater is a concrete dam located in Rensselaer County, New York, built in 1955. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Lock 4 - Stillwater
The primary purpose of Lock 4 - Stillwater 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 New York State Canal Corporation (state). It impounds the Hudson River near Stillwater.
The dam stands 5 feet tall and stretches 820 feet across, creates a reservoir covering 1,500 acres, has a maximum storage capacity of 3,150 acre-feet, and collects water from a drainage area of 3,745 square miles. Completed in 1955, the structure is well into its service life at over 50 years 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/20/2022.
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Location
| State | New York |
| County | Rensselaer |
| Nearest City | Stillwater |
| River/Stream | Hudson River |
| Coordinates | 42.93660, -73.65360 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 5 ft |
| Dam Height | 5 ft |
| Dam Length | 820 ft |
| Year Completed | 1955 (71 years old) |
Storage & Hydraulics
| NID Storage | 3,150 acre-ft |
| Max Storage | 3,150 acre-ft |
| Normal Storage | 3,150 acre-ft |
| Surface Area | 1,500 acres |
| Drainage Area | 3,745 sq mi |
| Max Discharge | 200,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | New York State Canal Corporation |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/20/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NY00162 |
| Federal ID | NY00162 |
| More Info | State Dam Safety Program |