Mill Picayune Watershed Site N-2 is an earth dam located in Shelby County, Iowa, built in 1972. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 39 ft39 ft tall and 834 ft long, taller than 85% of U.S. dams with a recorded height. 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 Mill Picayune Watershed Site N-2
The primary purpose of Mill Picayune Watershed Site N-2 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 Shelby County Swcd (local government). It impounds the Tr-north Picayune Creek near Woodbine.
The dam stands 39 feet tall and stretches 834 feet across, creates a reservoir covering 13 acres, has a maximum storage capacity of 448 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1972, the structure is well into its service life at over 50 years old.
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 09/04/2024.
At 39 feet, this dam is taller than 85% of dams nationwide.
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Location
| State | Iowa |
| County | Shelby |
| Nearest City | Woodbine |
| River/Stream | Tr-north Picayune Creek |
| Coordinates | 41.80270, -95.54620 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 834 ft |
| Year Completed | 1972 (54 years old) |
Storage & Hydraulics
| NID Storage | 448 acre-ft |
| Max Storage | 448 acre-ft |
| Normal Storage | 95 acre-ft |
| Surface Area | 13 acres |
| Drainage Area | 2 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Shelby County Swcd |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/04/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA00985 |
| Federal ID | IA00985 |
| More Info | State Dam Safety Program |