Dawson Ranch #1 is an earth dam located in Cascade County, Montana, built in 1948. It carries a Low hazard potential classification.
Dam profile
NID height · 30 ft30 ft tall and 250 ft long, taller than 68% 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 Dawson Ranch #1
The primary purpose of Dawson Ranch #1 is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Dawson Ranch Inc (private). It impounds the Tr-big Otter Creek near Armington.
The dam stands 30 feet tall and stretches 250 feet across, has a maximum storage capacity of 55 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1948, the structure is well-established, with more than 75 years of service.
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 | Cascade |
| Nearest City | Armington |
| River/Stream | Tr-big Otter Creek |
| Coordinates | 47.35250, -110.82970 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 250 ft |
| Year Completed | 1948 (78 years old) |
Storage & Hydraulics
| NID Storage | 55 acre-ft |
| Max Storage | 55 acre-ft |
| Normal Storage | 22 acre-ft |
| Drainage Area | 1 sq mi |
| Max Discharge | 30 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Dawson Ranch Inc |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT03294 |
| Federal ID | MT03294 |
| More Info | State Dam Safety Program |