Wellington Nap D-21a
Wellington Nap D-21a is an earth dam located in Lafayette County, Missouri, built in 1973. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Wellington Nap D-21a
The primary purpose of Wellington Nap D-21a 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 Lafayette Soil & Water (local government). It impounds the Tr-missouri River near Waterloo.
The dam stands 55 feet tall and stretches 335 feet across, creates a reservoir covering 5 acres, has a maximum storage capacity of 82 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1973, 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 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 11/03/2022.
At 55 feet, this dam is taller than 94% 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 Missouri 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 | Missouri |
| County | Lafayette |
| Nearest City | Waterloo |
| River/Stream | Tr-missouri River |
| Coordinates | 39.12733, -94.04330 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 55 ft |
| Dam Height | 55 ft |
| Dam Length | 335 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 82 acre-ft |
| Max Storage | 82 acre-ft |
| Normal Storage | 54 acre-ft |
| Surface Area | 5 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 897 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | LAFAYETTE SOIL & WATER |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/03/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO12000 |
| Federal ID | MO12000 |
| More Info | State Dam Safety Program |