Mahoning Creek Dam
Mahoning Creek Dam is a gravity dam located in Armstrong County, Pennsylvania, built in 1941. It carries a High hazard potential classification.
About Mahoning Creek Dam
The primary purpose of Mahoning Creek Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - Pittsburgh District (federal). It impounds the Mahoning Creek near Putneyville.
The dam stands 162 feet tall and stretches 926 feet across, creates a reservoir covering 280 acres, has a maximum storage capacity of 94,000 acre-feet, and collects water from a drainage area of 340 square miles. Completed in 1941, the structure is well-established, with more than 75 years of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 11/10/2022.
At 162 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Pennsylvania dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Pennsylvania |
| County | Armstrong |
| Nearest City | Putneyville |
| River/Stream | Mahoning Creek |
| Coordinates | 40.92179, -79.27805 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 162 ft |
| Dam Length | 926 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 94,000 acre-ft |
| Max Storage | 94,000 acre-ft |
| Normal Storage | 9,550 acre-ft |
| Surface Area | 280 acres |
| Drainage Area | 340 sq mi |
| Max Discharge | 103,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Pittsburgh District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 11/10/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00107 |
| Federal ID | PA00107 |
| More Info | State Dam Safety Program |