Prairie Lake Dam
Prairie Lake Dam is an earth dam located in Cass County, Illinois, built in 1999. It carries a High hazard potential classification.
About Prairie Lake Dam
The primary purpose of Prairie Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Illinois Department Of Natural Resources (state). It impounds the Trib Cox Creek near Chandlerville.
The dam stands 68 feet tall and stretches 820 feet across, creates a reservoir covering 210 acres, has a maximum storage capacity of 6,085 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1999, the structure is 27 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. An emergency action plan is in place for this dam. The most recent inspection on record was 04/19/2023.
At 68 feet, this dam is taller than 96% 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 Illinois 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 | Illinois |
| County | Cass |
| Nearest City | Chandlerville |
| River/Stream | Trib Cox Creek |
| Coordinates | 39.99641, -90.05851 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 68 ft |
| Dam Height | 68 ft |
| Dam Length | 820 ft |
| Year Completed | 1999 (27 years old) |
Storage & Hydraulics
| NID Storage | 6,085 acre-ft |
| Max Storage | 6,085 acre-ft |
| Normal Storage | 3,381 acre-ft |
| Surface Area | 210 acres |
| Drainage Area | 3 sq mi |
| Max Discharge | 9,846 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | ILLINOIS DEPARTMENT OF NATURAL RESOURCES |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 04/19/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL50417 |
| Federal ID | IL50417 |
| More Info | State Dam Safety Program |