Upper Occoquan Sewage Authority Dam
Upper Occoquan Sewage Authority Dam is an earth dam located in Fairfax County, Virginia. It carries a High hazard potential classification and has a fair condition assessment.
About Upper Occoquan Sewage Authority Dam
Upper Occoquan Sewage Authority Dam is a dam in Fairfax, Virginia. The dam is owned by Uosa (local government). It impounds the Tr-bull Run.
The dam stands 41 feet tall and stretches 1,680 feet across, creates a reservoir covering 54 acres, has a maximum storage capacity of 1,130 acre-feet, and collects water from a drainage area of 0 square miles.
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 09/22/2022.
At 41 feet, this dam is taller than 88% 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 Virginia 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 | Virginia |
| County | Fairfax |
| River/Stream | Tr-bull Run |
| Coordinates | 38.80260, -77.45720 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 41 ft |
| Dam Height | 41 ft |
| Dam Length | 1,680 ft |
Storage & Hydraulics
| NID Storage | 1,130 acre-ft |
| Max Storage | 1,130 acre-ft |
| Normal Storage | 515 acre-ft |
| Surface Area | 54 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | UOSA |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 09/22/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | VA059024 |
| Federal ID | VA059024 |
| More Info | State Dam Safety Program |