Pony Creek Watershed Site 21
Pony Creek Watershed Site 21 is an earth dam located in Mills County, Iowa, built in 1971. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Pony Creek Watershed Site 21
The primary purpose of Pony Creek Watershed Site 21 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 Pony Creek Drainage District (local government). It impounds the Pony Creek near Pacific Junction.
The dam stands 75 feet tall and stretches 968 feet across, creates a reservoir covering 83 acres, has a maximum storage capacity of 3,660 acre-feet, and collects water from a drainage area of 13 square miles. Completed in 1971, 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 07/05/2023.
At 75 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 | Mills |
| Nearest City | Pacific Junction |
| River/Stream | Pony Creek |
| Coordinates | 41.06960, -95.79080 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 75 ft |
| Dam Height | 75 ft |
| Dam Length | 968 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 3,660 acre-ft |
| Max Storage | 3,660 acre-ft |
| Normal Storage | 1,122 acre-ft |
| Surface Area | 83 acres |
| Drainage Area | 13 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Pony Creek Drainage District |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/05/2023 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IA00675 |
| Federal ID | IA00675 |
| More Info | State Dam Safety Program |