Flathead
Flathead is an earth dam located in Washakie County, Wyoming, built in 1979. It carries a Significant hazard potential classification and has a poor condition assessment.
About Flathead
The primary purpose of Flathead is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Buffalo Creek Farms Inc. (private). It impounds the Gomer Gulch near Manderson.
The dam stands 45 feet tall and stretches 1,600 feet across, creates a reservoir covering 29 acres, has a storage capacity of 417 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1979, the structure is 47 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 06/08/2022.
At 45 feet, this dam is taller than 91% of dams nationwide.
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Location
| State | Wyoming |
| County | Washakie |
| Nearest City | Manderson |
| River/Stream | Gomer Gulch |
| Coordinates | 44.16010, -107.57360 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 45 ft |
| Dam Height | 40 ft |
| Dam Length | 1,600 ft |
| Year Completed | 1979 (47 years old) |
Storage & Hydraulics
| NID Storage | 417 acre-ft |
| Normal Storage | 417 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 275 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | BUFFALO CREEK FARMS INC. |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 06/08/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY01653 |
| Federal ID | WY01653 |
| More Info | State Dam Safety Program |