Great Falls Dam, Lock No. 20
Key Takeaway
Great Falls Dam, Lock No. 20 is classified as low hazard in Maryland. It was completed in 1850 and is 176 years old. Its primary use is recreation.
Physical Details
| Dam Height | 8 ft (taller than 1.2% in MD) |
| Dam Type | Earth |
| Max Storage | 51 acre-ft |
| Year Completed | 1850 (176 years old) |
| Year Modified | 1980 |
| NID ID | MD00368 |
Safety Information
No probable loss of human life and low economic/environmental losses expected.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
US Army Corps of Engineers,Washington Aqueduct Div
Federal Government
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High Hazard 25 ftFrequently Asked Questions
What is the hazard classification of Great Falls Dam, Lock No. 20?
Great Falls Dam, Lock No. 20 is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Great Falls Dam, Lock No. 20?
Great Falls Dam, Lock No. 20 is owned by US Army Corps of Engineers,Washington Aqueduct Div (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Great Falls Dam, Lock No. 20 built?
Great Falls Dam, Lock No. 20 was completed in 1850, making it 176 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 Great Falls Dam, Lock No. 20?
Great Falls Dam, Lock No. 20 serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Great Falls Dam, Lock No. 20?
Great Falls Dam, Lock No. 20 has a dam height of 8 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 Great Falls Dam, Lock No. 20 last inspected?
Great Falls Dam, Lock No. 20 was last inspected on September 30, 1996. Inspection dates indicate when a formal review occurred, not the results of that inspection.