Mann Creek Dam
Mann Creek Dam is an earth dam located in Washington County, Idaho, built in 1967. It carries a High hazard potential classification.
About Mann Creek Dam
The primary purpose of Mann Creek Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Bureau Of Reclamation (federal). It impounds the Mann Creek near Weiser.
The dam stands 148 feet tall and stretches 1,176 feet across, creates a reservoir covering 283 acres, has a maximum storage capacity of 12,536 acre-feet, and collects water from a drainage area of 55 square miles. Completed in 1967, 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 05/10/2022.
At 148 feet, this dam is taller than 99% 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 Idaho 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 | Idaho |
| County | Washington |
| Nearest City | Weiser |
| River/Stream | Mann Creek |
| Coordinates | 44.39200, -116.89550 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 148 ft |
| Dam Height | 148 ft |
| Dam Length | 1,176 ft |
| Year Completed | 1967 (59 years old) |
Storage & Hydraulics
| NID Storage | 12,536 acre-ft |
| Max Storage | 12,536 acre-ft |
| Surface Area | 283 acres |
| Drainage Area | 55 sq mi |
| Max Discharge | 3,840 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 05/10/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | ID00285 |
| Federal ID | ID00285 |
| More Info | State Dam Safety Program |