Johnson No. 1
Johnson No. 1 is an earth dam located in Niobrara County, Wyoming, built in 1916. It carries a Low hazard potential classification and has a poor condition assessment.
About Johnson No. 1
The primary purpose of Johnson No. 1 is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Cross A Ranch Llc (private). It impounds the Hancock Draw near Edgemont, Sd.
The dam stands 30 feet tall and stretches 460 feet across, creates a reservoir covering 40 acres, and has a maximum storage capacity of 333 acre-feet. Completed in 1916, the structure is over a century 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. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 08/29/2022.
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Location
| State | Wyoming |
| County | Niobrara |
| Nearest City | Edgemont, Sd |
| River/Stream | Hancock Draw |
| Coordinates | 43.23710, -104.48200 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 460 ft |
| Year Completed | 1916 (110 years old) |
Storage & Hydraulics
| NID Storage | 333 acre-ft |
| Max Storage | 333 acre-ft |
| Normal Storage | 239 acre-ft |
| Surface Area | 40 acres |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | CROSS A RANCH LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 08/29/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY00933 |
| Federal ID | WY00933 |
| More Info | State Dam Safety Program |