Horsepen Dam
Horsepen Dam is an earth dam located in Loudoun County, Virginia. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Horsepen Dam
The primary purpose of Horsepen Dam 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 Metro-washington Airport Authority (public utility). It impounds the Horsepen Run.
The dam stands 50 feet tall and stretches 600 feet across, creates a reservoir covering 18 acres, has a maximum storage capacity of 15,200 acre-feet, and collects water from a drainage area of 22 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 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 07/20/2021.
At 50 feet, this dam is taller than 93% 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 | Loudoun |
| River/Stream | Horsepen Run |
| Coordinates | 38.98950, -77.46520 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 50 ft |
| Dam Height | 50 ft |
| Dam Length | 600 ft |
Storage & Hydraulics
| NID Storage | 15,200 acre-ft |
| Max Storage | 15,200 acre-ft |
| Normal Storage | 129 acre-ft |
| Surface Area | 18 acres |
| Drainage Area | 22 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Metro-Washington Airport Authority |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/20/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | VA107007 |
| Federal ID | VA107007 |
| More Info | State Dam Safety Program |