Minnetonka Lake Dam
Minnetonka Lake Dam is an other dam located in Washington County, Missouri, built in 1957. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Minnetonka Lake Dam
The primary purpose of Minnetonka Lake 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 Lake Forest Farms (private). It impounds the Trib-ditch Creek near Richwoods.
The dam stands 74 feet tall and stretches 1,100 feet across, creates a reservoir covering 90 acres, has a maximum storage capacity of 2,500 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1957, 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 11/10/2022.
At 74 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 | Richwoods |
| River/Stream | Trib-ditch Creek |
| Coordinates | 38.16788, -90.79482 |
Physical Characteristics
| Dam Type | Other |
| NID Height | 74 ft |
| Dam Height | 74 ft |
| Dam Length | 1,100 ft |
| Year Completed | 1957 (69 years old) |
Storage & Hydraulics
| NID Storage | 2,500 acre-ft |
| Max Storage | 2,500 acre-ft |
| Normal Storage | 2,130 acre-ft |
| Surface Area | 90 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 2,300 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Tailings |
| Owner | LAKE FOREST FARMS |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/10/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO30727 |
| Federal ID | MO30727 |
| More Info | State Dam Safety Program |