Lois Lake is an earth dam located in Powell County, Montana, built in 1966. It carries a Low hazard potential classification.
Dam profile
NID height · 23 ft23 ft tall and 400 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 Lois Lake
The primary purpose of Lois Lake is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Gary Harrison (private). It impounds the Snowshoe Creek near Avon.
The dam stands 23 feet tall and stretches 400 feet across, creates a reservoir covering 25 acres, has a maximum storage capacity of 288 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1966, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life.
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Location
| State | Montana |
| County | Powell |
| Nearest City | Avon |
| River/Stream | Snowshoe Creek |
| Coordinates | 46.65080, -112.48410 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 23 ft |
| Dam Height | 23 ft |
| Dam Length | 400 ft |
| Year Completed | 1966 (60 years old) |
Storage & Hydraulics
| NID Storage | 288 acre-ft |
| Max Storage | 288 acre-ft |
| Normal Storage | 221 acre-ft |
| Surface Area | 25 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 230 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Gary Harrison |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT01226 |
| Federal ID | MT01226 |
| More Info | State Dam Safety Program |