Longley
Key Takeaway
Longley is classified as low hazard in California. It was completed in 1910 and is 116 years old. Its primary use is hydroelectric.
Physical Details
| Dam Height | 27 ft (taller than 26.1% in CA) |
| Dam Length | 120 ft |
| Dam Type | Earth |
| Max Storage | 178 acre-ft |
| Normal Storage | 178 acre-ft |
| Surface Area | 11 acres |
| Max Discharge | 300 cfs |
| Year Completed | 1910 (116 years old) |
| NID ID | CA00447 |
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
Southern California Edison Company
Private
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Longley?
Longley 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 Longley?
Longley is owned by Southern California Edison Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Longley built?
Longley was completed in 1910, making it 116 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 Longley?
Longley serves the following purposes: Hydroelectric, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Longley?
Longley has a dam height of 27 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 Longley last inspected?
Longley was last inspected on August 22, 2018. Inspection dates indicate when a formal review occurred, not the results of that inspection.