Manley #2 is an earth dam located in Powell County, Montana, built in 1964. It carries a Significant hazard potential classification.
Dam profile
NID height · 25 ft25 ft tall and 500 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 Manley #2
The primary purpose of Manley #2 is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by John Manley (private). It impounds the Douglas Creek near Helmville.
The dam stands 25 feet tall and stretches 500 feet across, has a maximum storage capacity of 93 acre-feet, and collects water from a drainage area of 16 square miles. Completed in 1964, 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 | Powell |
| Nearest City | Helmville |
| River/Stream | Douglas Creek |
| Coordinates | 46.78780, -113.11630 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 500 ft |
| Year Completed | 1964 (62 years old) |
Storage & Hydraulics
| NID Storage | 93 acre-ft |
| Max Storage | 93 acre-ft |
| Normal Storage | 55 acre-ft |
| Drainage Area | 16 sq mi |
| Max Discharge | 646 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | John Manley |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT01228 |
| Federal ID | MT01228 |
| More Info | State Dam Safety Program |