Big Four Mine Dam
Big Four Mine Dam is an other dam located in Washington County, Missouri, built in 1978. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Big Four Mine Dam
The primary purpose of Big Four Mine 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 private-owned. It impounds the Trib-calico Creek near Fletcher.
The dam stands 73 feet tall and stretches 1,200 feet across, creates a reservoir covering 85 acres, has a maximum storage capacity of 1,980 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1978, the structure is 48 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 10/28/2021.
At 73 feet, this dam is taller than 97% 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 | Fletcher |
| River/Stream | Trib-calico Creek |
| Coordinates | 38.15493, -90.77007 |
Physical Characteristics
| Dam Type | Other |
| NID Height | 73 ft |
| Dam Height | 73 ft |
| Dam Length | 1,200 ft |
| Year Completed | 1978 (48 years old) |
Storage & Hydraulics
| NID Storage | 1,980 acre-ft |
| Max Storage | 1,980 acre-ft |
| Normal Storage | 1,980 acre-ft |
| Surface Area | 85 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 245 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Tailings |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/28/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO30729 |
| Federal ID | MO30729 |
| More Info | State Dam Safety Program |