Johnson Dam
Johnson Dam is an earth dam located in Charles Mix County, South Dakota, built in 1972. It carries a Low hazard potential classification.
About Johnson Dam
The primary purpose of Johnson Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Jay Johnson Living Trust (private). It impounds the Spring Creek-tr.
The dam stands 20 feet tall and stretches 400 feet across, creates a reservoir covering 17 acres, and has a maximum storage capacity of 340 acre-feet. Completed in 1972, the structure is well into its service life at over 50 years old.
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 | South Dakota |
| County | Charles Mix |
| Nearest City | None |
| River/Stream | Spring Creek-tr |
| Coordinates | 43.16645, -98.68744 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 400 ft |
| Year Completed | 1972 (54 years old) |
Storage & Hydraulics
| NID Storage | 340 acre-ft |
| Max Storage | 340 acre-ft |
| Normal Storage | 170 acre-ft |
| Surface Area | 17 acres |
| Max Discharge | 1,600 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Jay Johnson Living Trust |
| Owner Type | Private |
| Hazard Classification | Low |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD02393 |
| Federal ID | SD02393 |
| More Info | State Dam Safety Program |