South Anna Dam #4
South Anna Dam #4 is an earth dam located in Louisa County, Virginia, built in 1981. It carries a High hazard potential classification and has a satisfactory condition assessment.
About South Anna Dam #4
The primary purpose of South Anna Dam #4 is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Thomas Jefferson Soil And Water Conservation District (local government). It impounds the Tr-south Anna.
The dam stands 32 feet tall and stretches 830 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 2,100 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1981, the structure is 45 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 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 12/07/2021.
At 32 feet, this dam is taller than 76% 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 | Louisa |
| River/Stream | Tr-south Anna |
| Coordinates | 38.03190, -78.19110 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 32 ft |
| Dam Height | 32 ft |
| Dam Length | 830 ft |
| Year Completed | 1981 (45 years old) |
Storage & Hydraulics
| NID Storage | 2,100 acre-ft |
| Max Storage | 2,100 acre-ft |
| Normal Storage | 84 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 4 sq mi |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Thomas Jefferson Soil and Water Conservation District |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 12/07/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | VA109032 |
| Federal ID | VA109032 |
| More Info | State Dam Safety Program |