John C Youngman
John C Youngman is an earth dam located in Lycoming County, Pennsylvania, built in 1951. It carries a High hazard potential classification and has a fair condition assessment.
About John C Youngman
The primary purpose of John C Youngman 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 Williamsport Municipal Water Authority (local government). It impounds the Mosquito Creek.
The dam stands 101 feet tall and stretches 600 feet across, creates a reservoir covering 61 acres, has a maximum storage capacity of 2,581 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1951, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 10/14/2020.
At 101 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 | Lycoming |
| River/Stream | Mosquito Creek |
| Coordinates | 41.15389, -77.07833 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 101 ft |
| Dam Height | 101 ft |
| Dam Length | 600 ft |
| Year Completed | 1951 (75 years old) |
Storage & Hydraulics
| NID Storage | 2,581 acre-ft |
| Max Storage | 2,581 acre-ft |
| Normal Storage | 1,627 acre-ft |
| Surface Area | 61 acres |
| Drainage Area | 2 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | WILLIAMSPORT MUNICIPAL WATER AUTHORITY |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 10/14/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00353 |
| Federal ID | PA00353 |
| More Info | State Dam Safety Program |