Big Casino Creek Dam
Big Casino Creek Dam is an earth dam located in Fergus County, Montana, built in 1976. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Big Casino Creek Dam
The primary purpose of Big Casino Creek Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by City Of Lewistown (local government). It impounds the Big Casino Creek near Lewistown.
The dam stands 80 feet tall and stretches 1,056 feet across, creates a reservoir covering 72 acres, has a maximum storage capacity of 2,063 acre-feet, and collects water from a drainage area of 19 square miles. Completed in 1976, the structure is 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 06/15/2020.
At 80 feet, this dam is taller than 97% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Montana dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Montana |
| County | Fergus |
| Nearest City | Lewistown |
| River/Stream | Big Casino Creek |
| Coordinates | 47.03680, -109.43010 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 80 ft |
| Dam Height | 68 ft |
| Dam Length | 1,056 ft |
| Year Completed | 1976 (50 years old) |
Storage & Hydraulics
| NID Storage | 2,063 acre-ft |
| Max Storage | 2,063 acre-ft |
| Normal Storage | 124 acre-ft |
| Surface Area | 72 acres |
| Drainage Area | 19 sq mi |
| Max Discharge | 16,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | CITY OF LEWISTOWN |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/15/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT01569 |
| Federal ID | MT01569 |
| More Info | State Dam Safety Program |