Lower Ridge
Lower Ridge is an earth dam located in Westmoreland County, Pennsylvania, built in 1915. It carries a High hazard potential classification and has a poor condition assessment.
About Lower Ridge
The primary purpose of Lower Ridge 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 Derry Borough Municipal Authority (local government). It impounds the Mcgee Run.
The dam stands 20 feet tall and stretches 200 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 6 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1915, the structure is over a century 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 10/14/2020.
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 | Westmoreland |
| River/Stream | Mcgee Run |
| Coordinates | 40.32611, -79.28722 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 200 ft |
| Year Completed | 1915 (111 years old) |
Storage & Hydraulics
| NID Storage | 6 acre-ft |
| Max Storage | 6 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | DERRY BOROUGH MUNICIPAL AUTHORITY |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/14/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA01347 |
| Federal ID | PA01347 |
| More Info | State Dam Safety Program |