Big Creek Diversion Dam
Big Creek Diversion Dam is a gravity dam located in Polk County, Iowa, built in 1970. It carries a High hazard potential classification.
About Big Creek Diversion Dam
The primary purpose of Big Creek Diversion 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 - Rock Island District (federal). It impounds the Big Creek near Polk City.
The dam stands 80 feet tall and stretches 1,750 feet across, creates a reservoir covering 885 acres, has a maximum storage capacity of 27,500 acre-feet, and collects water from a drainage area of 76 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 12/06/2022.
At 80 feet, this dam is taller than 97% 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 Iowa 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 | Iowa |
| County | Polk |
| Nearest City | Polk City |
| River/Stream | Big Creek |
| Coordinates | 41.79307, -93.73018 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 80 ft |
| Dam Height | 80 ft |
| Dam Length | 1,750 ft |
| Year Completed | 1970 (56 years old) |
Storage & Hydraulics
| NID Storage | 27,500 acre-ft |
| Max Storage | 27,500 acre-ft |
| Normal Storage | 7,600 acre-ft |
| Surface Area | 885 acres |
| Drainage Area | 76 sq mi |
| Max Discharge | 355 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Rock Island District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 12/06/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IA00014 |
| Federal ID | IA00014 |
| More Info | State Dam Safety Program |