Lower Ridge
Key Takeaway
Lower Ridge is classified as high hazard in Pennsylvania. It was completed in 1915 and is 111 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 20 ft (taller than 43.1% in PA) |
| Dam Length | 200 ft |
| Dam Type | Earth |
| Max Storage | 6 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 1 sq mi |
| Year Completed | 1915 (111 years old) |
| NID ID | PA01347 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
DERRY BOROUGH MUNICIPAL AUTHORITY
Local Government
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What is the hazard classification of Lower Ridge?
Lower Ridge is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Lower Ridge?
Lower Ridge is owned by DERRY BOROUGH MUNICIPAL AUTHORITY (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lower Ridge built?
Lower Ridge was completed in 1915, making it 111 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 Lower Ridge?
Lower Ridge serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lower Ridge?
Lower Ridge has a dam height of 20 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 Lower Ridge last inspected?
Lower Ridge was last inspected on October 14, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.