Pea Ridge Tailings Dam
Pea Ridge Tailings Dam is a rockfill dam located in Washington County, Missouri, built in 1980. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Pea Ridge Tailings Dam
The primary purpose of Pea Ridge Tailings Dam is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by Caldera Holding Llc (private). It impounds the Tr-marys Creek near Morse Mill.
The dam stands 150 feet tall and stretches 1,380 feet across, creates a reservoir covering 80 acres, has a maximum storage capacity of 4,100 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1980, the structure is 46 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 10/05/2021.
At 150 feet, this dam is taller than 99% 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 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 | Washington |
| Nearest City | Morse Mill |
| River/Stream | Tr-marys Creek |
| Coordinates | 38.13264, -91.03646 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 150 ft |
| Dam Height | 150 ft |
| Dam Length | 1,380 ft |
| Year Completed | 1980 (46 years old) |
Storage & Hydraulics
| NID Storage | 4,100 acre-ft |
| Max Storage | 4,100 acre-ft |
| Normal Storage | 4,100 acre-ft |
| Surface Area | 80 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 3,275 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Tailings |
| Owner | CALDERA HOLDING LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/05/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO30473 |
| Federal ID | MO30473 |
| More Info | State Dam Safety Program |