Tiskilwa Structure 1 Dam
Tiskilwa Structure 1 Dam is an earth dam located in Bureau County, Illinois, built in 1960. It carries a High hazard potential classification.
About Tiskilwa Structure 1 Dam
The primary purpose of Tiskilwa Structure 1 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 Village Of Tiskilwa (local government). It impounds the Rocky Run near Tiskilwa.
The dam stands 49 feet tall and stretches 930 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 764 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1960, 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. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 05/06/2025.
At 49 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 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 | Bureau |
| Nearest City | Tiskilwa |
| River/Stream | Rocky Run |
| Coordinates | 41.28411, -89.55382 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 49 ft |
| Dam Height | 49 ft |
| Dam Length | 930 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 764 acre-ft |
| Max Storage | 764 acre-ft |
| Normal Storage | 99 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 1,887 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | VILLAGE OF TISKILWA |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 05/06/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00449 |
| Federal ID | IL00449 |
| More Info | State Dam Safety Program |