Thunder Bay Lake Dam is an earth dam located in Polk County, Iowa, built in 2010. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 19 ft19 ft tall. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Thunder Bay Lake Dam
The primary purpose of Thunder Bay Lake 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 Prairie Crossing Investments Inc (private). It impounds the Tr-four Mike Creek near Altoona.
The dam stands 19 feet tall, creates a reservoir covering 5 acres, has a maximum storage capacity of 119 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2010, the structure is relatively new.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 05/18/2023.
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Location
| State | Iowa |
| County | Polk |
| Nearest City | Altoona |
| River/Stream | Tr-four Mike Creek |
| Coordinates | 41.65390, -93.51680 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 19 ft |
| Dam Height | 19 ft |
| Year Completed | 2010 (16 years old) |
Storage & Hydraulics
| NID Storage | 119 acre-ft |
| Max Storage | 119 acre-ft |
| Normal Storage | 60 acre-ft |
| Surface Area | 5 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,835 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Prairie Crossing Investments Inc |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/18/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA04174 |
| Federal ID | IA04174 |
| More Info | State Dam Safety Program |