Loyalhanna Dam

LOYALHANNA CREEK· Westmoreland, Pennsylvania· Built 1942· Gravity·

High Hazard Flood Risk Reduction Other Recreation Federal Government

Key Takeaway

Loyalhanna Dam is classified as high hazard in Pennsylvania. It was completed in 1942 and is 84 years old. Its primary use is flood risk reduction. 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 Length	960 ft
Dam Type	Gravity
Max Storage	127.6K acre-ft
Normal Storage	2.0K acre-ft

Surface Area	210 acres
Drainage Area	290 sq mi
Max Discharge	106,800 cfs
Year Completed	1942 (84 years old)
NID ID	PA00106

Safety Information

High Hazard

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?

Emergency Action Plan: Yes

Last Inspection: July 30, 2020

State Regulated: No

Ownership

USACE - Pittsburgh District

Federal Government

Nearby Dams

Mannitto

Westmoreland, PA

Low Hazard 18 ft

Conemaugh Dam

Westmoreland, PA

High Hazard

Greenwalt

Westmoreland, PA

Significant Hazard 27 ft

Keystone State Park

Westmoreland, PA

Significant Hazard 45 ft

David Mine Sedimentation Pond No 2

Armstrong, PA

High Hazard 35 ft

David Mine Equalization Pond No 3

Armstrong, PA

Significant Hazard 21 ft

Beaver Run

Westmoreland, PA

High Hazard 92 ft

Thorn Run

Westmoreland, PA

Low Hazard 22 ft

Frequently Asked Questions

What is the hazard classification of Loyalhanna Dam?

Loyalhanna Dam 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 Loyalhanna Dam?

Loyalhanna Dam is owned by USACE - Pittsburgh District (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Loyalhanna Dam built?

Loyalhanna Dam was completed in 1942, making it 84 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 Loyalhanna Dam?

Loyalhanna Dam serves the following purposes: Flood Risk Reduction, Other, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Loyalhanna Dam last inspected?

Loyalhanna Dam was last inspected on July 30, 2020. 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.