Shay Dam is an earth dam located in Toole County, Montana, built in 1915. It carries a Significant hazard potential classification.
Dam profile
NID height · 15 ft15 ft tall and 600 ft long. 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 Shay Dam
The primary purpose of Shay Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Hellinger Bros (private). It impounds the Tr-willow Creek near Devon.
The dam stands 15 feet tall and stretches 600 feet across, and has a maximum storage capacity of 31 acre-feet. Completed in 1915, the structure is over a century 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.
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Location
| State | Montana |
| County | Toole |
| Nearest City | Devon |
| River/Stream | Tr-willow Creek |
| Coordinates | 48.51800, -111.44240 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 600 ft |
| Year Completed | 1915 (111 years old) |
Storage & Hydraulics
| NID Storage | 31 acre-ft |
| Max Storage | 31 acre-ft |
| Normal Storage | 16 acre-ft |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Hellinger Bros |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT00400 |
| Federal ID | MT00400 |
| More Info | State Dam Safety Program |