Shelbyville Dam
Shelbyville Dam is a concrete dam located in Shelby County, Illinois, built in 1970. It carries a High hazard potential classification.
About Shelbyville Dam
The primary purpose of Shelbyville Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - St. Louis District (federal). It impounds the Kaskaskia River near Shelbyville.
The dam stands 138 feet tall and stretches 3,025 feet across, creates a reservoir covering 11,100 acres, has a maximum storage capacity of 1,026,546 acre-feet, and collects water from a drainage area of 1,054 square miles. Completed in 1970, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 05/25/2023.
At 138 feet, this dam is taller than 99% 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 | Shelby |
| Nearest City | Shelbyville |
| River/Stream | Kaskaskia River |
| Coordinates | 39.40912, -88.78038 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 138 ft |
| Dam Height | 108 ft |
| Dam Length | 3,025 ft |
| Year Completed | 1970 (56 years old) |
Storage & Hydraulics
| NID Storage | 1,026,546 acre-ft |
| Max Storage | 1,026,546 acre-ft |
| Normal Storage | 207,832 acre-ft |
| Surface Area | 11,100 acres |
| Drainage Area | 1,054 sq mi |
| Max Discharge | 162,500 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - St. Louis District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 05/25/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00118 |
| Federal ID | IL00118 |
| More Info | State Dam Safety Program |