Rocky Crossing Reservoir is an earth dam located in Chouteau County, Montana, built in 1950. It carries a Significant hazard potential classification.
Dam profile
NID height · 12 ft12 ft tall and 3,100 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 Rocky Crossing Reservoir
The primary purpose of Rocky Crossing Reservoir is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Joseph Schmit (private). It impounds the Big Sandy Creek near Box Elder.
The dam stands 12 feet tall and stretches 3,100 feet across, has a maximum storage capacity of 721 acre-feet, and collects water from a drainage area of 471 square miles. Completed in 1950, the structure is well-established, with more than 75 years of service.
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 | Chouteau |
| Nearest City | Box Elder |
| River/Stream | Big Sandy Creek |
| Coordinates | 48.26480, -110.06890 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 3,100 ft |
| Year Completed | 1950 (76 years old) |
Storage & Hydraulics
| NID Storage | 721 acre-ft |
| Max Storage | 721 acre-ft |
| Normal Storage | 491 acre-ft |
| Drainage Area | 471 sq mi |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Joseph Schmit |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT03665 |
| Federal ID | MT03665 |
| More Info | State Dam Safety Program |