Big Mac #1 is an earth dam located in Garfield County, Montana, built in 1947. It carries a Low hazard potential classification.
Dam profile
NID height · 35 ft35 ft tall and 500 ft long, taller than 80% 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 Big Mac #1
The primary purpose of Big Mac #1 is fire protection, stock, or small fish pond. The dam maintains a small impoundment used for fire suppression, livestock watering, or as a fish pond. The dam is owned by Macdonald, John J & Sons (private). It impounds the Tr-big Dry Creek near Jordan.
The dam stands 35 feet tall and stretches 500 feet across, has a maximum storage capacity of 157 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1947, 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.
At 35 feet, this dam is taller than 80% of dams nationwide.
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Location
| State | Montana |
| County | Garfield |
| Nearest City | Jordan |
| River/Stream | Tr-big Dry Creek |
| Coordinates | 47.29200, -107.05060 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 35 ft |
| Dam Height | 35 ft |
| Dam Length | 500 ft |
| Year Completed | 1947 (79 years old) |
Storage & Hydraulics
| NID Storage | 157 acre-ft |
| Max Storage | 157 acre-ft |
| Normal Storage | 99 acre-ft |
| Drainage Area | 3 sq mi |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | Macdonald, John J & Sons |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT02664 |
| Federal ID | MT02664 |
| More Info | State Dam Safety Program |