Johnson Reservoir is an earth dam located in Dawson County, Montana, built in 1937. It carries a Low hazard potential classification.
Dam profile
NID height · 21 ft21 ft tall and 1,500 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 Johnson Reservoir
The primary purpose of Johnson Reservoir is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by State of Montana, D.f.w.p. (state). It impounds the Deer Creek near Intake.
The dam stands 21 feet tall and stretches 1,500 feet across, creates a reservoir covering 35 acres, has a maximum storage capacity of 351 acre-feet, and collects water from a drainage area of 17 square miles. Completed in 1937, 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. The most recent inspection on record was 07/17/2024.
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Location
| State | Montana |
| County | Dawson |
| Nearest City | Intake |
| River/Stream | Deer Creek |
| Coordinates | 47.31420, -105.09740 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 21 ft |
| Dam Height | 21 ft |
| Dam Length | 1,500 ft |
| Year Completed | 1937 (89 years old) |
Storage & Hydraulics
| NID Storage | 351 acre-ft |
| Max Storage | 351 acre-ft |
| Normal Storage | 208 acre-ft |
| Surface Area | 35 acres |
| Drainage Area | 17 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | State of Montana, D.f.w.p. |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 07/17/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT00110 |
| Federal ID | MT00110 |
| More Info | State Dam Safety Program |