East Blacktail is an earth dam located in Rosebud County, Montana, built in 1952. It carries a Significant hazard potential classification.
Dam profile
NID height · 25 ft25 ft tall and 2,825 ft long, taller than 50% 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 East Blacktail
The primary purpose of East Blacktail is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Jack Galt (private). It impounds the East Blacktail Creek near Forsyth.
The dam stands 25 feet tall and stretches 2,825 feet across, has a maximum storage capacity of 947 acre-feet, and collects water from a drainage area of 46 square miles. Completed in 1952, 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.
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Location
| State | Montana |
| County | Rosebud |
| Nearest City | Forsyth |
| River/Stream | East Blacktail Creek |
| Coordinates | 46.65500, -107.03260 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 2,825 ft |
| Year Completed | 1952 (74 years old) |
Storage & Hydraulics
| NID Storage | 947 acre-ft |
| Max Storage | 947 acre-ft |
| Normal Storage | 561 acre-ft |
| Drainage Area | 46 sq mi |
| Max Discharge | 2,000 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Jack Galt |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT00057 |
| Federal ID | MT00057 |
| More Info | State Dam Safety Program |