Lock 4 - Stillwater

Hudson River· Rensselaer, New York· Built 1955· Concrete· 5 ft tall
Significant Hazard Hydroelectric State Government

Key Takeaway

Lock 4 - Stillwater is classified as significant hazard in New York. It was completed in 1955 and is 71 years old. Its primary use is hydroelectric. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 5 ft (taller than 0.1% in NY)
Dam Length820 ft
Dam TypeConcrete
Max Storage3.2K acre-ft
Normal Storage3.2K acre-ft
Surface Area1,500 acres
Drainage Area3,745 sq mi
Max Discharge200,000 cfs
Year Completed1955 (71 years old)
NID IDNY00162

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: September 20, 2022
State Regulated: No

Ownership

New York State Canal Corporation

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lock 4 - Stillwater?

Lock 4 - Stillwater is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lock 4 - Stillwater?

Lock 4 - Stillwater is owned by New York State Canal Corporation (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lock 4 - Stillwater built?

Lock 4 - Stillwater was completed in 1955, making it 71 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Lock 4 - Stillwater?

Lock 4 - Stillwater serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lock 4 - Stillwater?

Lock 4 - Stillwater has a dam height of 5 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Lock 4 - Stillwater last inspected?

Lock 4 - Stillwater was last inspected on September 20, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.