Lake Oneida is an earth dam located in Butler County, Pennsylvania, built in 1918. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 38 ft38 ft tall and 830 ft long, taller than 84% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Lake Oneida
The primary purpose of Lake Oneida 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 Pa American Water Company (private). It impounds the Connoquenessing Creek.
The dam stands 38 feet tall and stretches 830 feet across, creates a reservoir covering 155 acres, has a maximum storage capacity of 3,350 acre-feet, and collects water from a drainage area of 16 square miles. Completed in 1918, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 06/08/2020.
At 38 feet, this dam is taller than 84% of dams nationwide.
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 | Butler |
| River/Stream | Connoquenessing Creek |
| Coordinates | 40.92417, -79.86944 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 38 ft |
| Dam Height | 38 ft |
| Dam Length | 830 ft |
| Year Completed | 1918 (108 years old) |
Storage & Hydraulics
| NID Storage | 3,350 acre-ft |
| Max Storage | 3,350 acre-ft |
| Normal Storage | 1,762 acre-ft |
| Surface Area | 155 acres |
| Drainage Area | 16 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Pa American Water Company |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/08/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00272 |
| Federal ID | PA00272 |
| More Info | State Dam Safety Program |