Lake St. Louis Dam
Lake St. Louis Dam is an earth dam located in St. Charles County, Missouri, built in 1973. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Lake St. Louis Dam
The primary purpose of Lake St. Louis Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Lake St Louis Comm Assoc (private). It impounds the Peruque Creek near O'fallon.
The dam stands 47 feet tall and stretches 900 feet across, creates a reservoir covering 563 acres, has a maximum storage capacity of 14,650 acre-feet, and collects water from a drainage area of 56 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 10/05/2022.
At 47 feet, this dam is taller than 92% 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 | St. Charles |
| Nearest City | O'fallon |
| River/Stream | Peruque Creek |
| Coordinates | 38.80179, -90.76519 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 47 ft |
| Dam Height | 47 ft |
| Dam Length | 900 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 14,650 acre-ft |
| Max Storage | 14,650 acre-ft |
| Normal Storage | 6,300 acre-ft |
| Surface Area | 563 acres |
| Drainage Area | 56 sq mi |
| Max Discharge | 36,700 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | LAKE ST LOUIS COMM ASSOC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/05/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO10545 |
| Federal ID | MO10545 |
| More Info | State Dam Safety Program |