Williston Mill Dam (Md 617 Old Harmony Road)
Key Takeaway
Williston Mill Dam (Md 617 Old Harmony Road) is classified as low hazard in Maryland. It was completed in 1936 and is 90 years old. Its primary use is recreation.
Physical Details
| Dam Height | 18 ft (taller than 36.5% in MD) |
| Dam Length | 630 ft |
| Dam Type | Earth |
| Max Storage | 508 acre-ft |
| Normal Storage | 180 acre-ft |
| Surface Area | 52 acres |
| Drainage Area | 8 sq mi |
| Max Discharge | 1,660 cfs |
| Year Completed | 1936 (90 years old) |
| Year Modified | 1936 |
| NID ID | MD00113 |
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
Girl Scouts of the Chesapeake Bay
Private
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Low Hazard 15 ftFrequently Asked Questions
What is the hazard classification of Williston Mill Dam (Md 617 Old Harmony Road)?
Williston Mill Dam (Md 617 Old Harmony Road) 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 Williston Mill Dam (Md 617 Old Harmony Road)?
Williston Mill Dam (Md 617 Old Harmony Road) is owned by Girl Scouts of the Chesapeake Bay (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Williston Mill Dam (Md 617 Old Harmony Road) built?
Williston Mill Dam (Md 617 Old Harmony Road) was completed in 1936, making it 90 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 Williston Mill Dam (Md 617 Old Harmony Road)?
Williston Mill Dam (Md 617 Old Harmony Road) 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 Williston Mill Dam (Md 617 Old Harmony Road)?
Williston Mill Dam (Md 617 Old Harmony Road) has a dam height of 18 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 Williston Mill Dam (Md 617 Old Harmony Road) last inspected?
Williston Mill Dam (Md 617 Old Harmony Road) was last inspected on November 29, 2018. Inspection dates indicate when a formal review occurred, not the results of that inspection.