Mill Run
Mill Run is an earth dam located in Blair County, Pennsylvania, built in 1957. It carries a High hazard potential classification and has a poor condition assessment.
About Mill Run
The primary purpose of Mill Run is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Altoona Water Authority (local government). It impounds the Mill Run.
The dam stands 100 feet tall and stretches 1,200 feet across, creates a reservoir covering 42 acres, has a maximum storage capacity of 3,320 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1957, the structure is well into its service life at over 50 years old.
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. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 09/23/2020.
At 100 feet, this dam is taller than 98% 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 | Blair |
| River/Stream | Mill Run |
| Coordinates | 40.51917, -78.45222 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 100 ft |
| Dam Height | 100 ft |
| Dam Length | 1,200 ft |
| Year Completed | 1957 (69 years old) |
Storage & Hydraulics
| NID Storage | 3,320 acre-ft |
| Max Storage | 3,320 acre-ft |
| Normal Storage | 2,990 acre-ft |
| Surface Area | 42 acres |
| Drainage Area | 4 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | ALTOONA WATER AUTHORITY |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 09/23/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00533 |
| Federal ID | PA00533 |
| More Info | State Dam Safety Program |