Moynihan Lake Dam
Moynihan Lake Dam is an earth dam located in St. Francois County, Missouri, built in 1956. It carries a High hazard potential classification.
About Moynihan Lake Dam
The primary purpose of Moynihan Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Harold Moynihan (private). It impounds the Tr-wolf Creek near Knob Lick.
The dam stands 30 feet tall, creates a reservoir covering 8 acres, has a maximum storage capacity of 128 acre-feet, and collects water from a drainage area of 170 square miles. Completed in 1956, 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.
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 | St. Francois |
| Nearest City | Knob Lick |
| River/Stream | Tr-wolf Creek |
| Coordinates | 37.78528, -90.36806 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 128 acre-ft |
| Max Storage | 128 acre-ft |
| Normal Storage | 80 acre-ft |
| Surface Area | 8 acres |
| Drainage Area | 170 sq mi |
Ownership & Safety
| Purpose | Recreation |
| Owner | HAROLD MOYNIHAN |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not Rated |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MO30279 |
| Federal ID | MO30279 |
| More Info | State Dam Safety Program |