Hemund is an earth dam located in Madison County, Montana, built in 1974. It carries a Significant hazard potential classification.
Dam profile
NID height · 20 ft20 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 Hemund
The primary purpose of Hemund is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by George Armstrong Jr (private). It impounds the Dogtown Sewer near Sappington.
The dam stands 20 feet tall and stretches 600 feet across, and has a maximum storage capacity of 173 acre-feet. Completed in 1974, 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.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Montana |
| County | Madison |
| Nearest City | Sappington |
| River/Stream | Dogtown Sewer |
| Coordinates | 45.75990, -111.86560 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 600 ft |
| Year Completed | 1974 (52 years old) |
Storage & Hydraulics
| NID Storage | 173 acre-ft |
| Max Storage | 173 acre-ft |
| Normal Storage | 107 acre-ft |
| Max Discharge | 300 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | George Armstrong Jr |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT01582 |
| Federal ID | MT01582 |
| More Info | State Dam Safety Program |