Johnson
Johnson is a dam located in Franklin County, Idaho, built in 1860. It carries a Significant hazard potential classification and has a fair condition assessment.
About Johnson
The primary purpose of Johnson is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is private-owned. It impounds the Worm Creek Cub River near Preston.
The dam stands 28 feet tall and stretches 450 feet across, creates a reservoir covering 40 acres, has a storage capacity of 396 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1860, the structure is one of the older dams in the region, with over a century and a half 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 07/13/2018.
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Location
| State | Idaho |
| County | Franklin |
| Nearest City | Preston |
| River/Stream | Worm Creek Cub River |
| Coordinates | 42.10620, -111.80590 |
Physical Characteristics
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 450 ft |
| Year Completed | 1860 (166 years old) |
Storage & Hydraulics
| NID Storage | 396 acre-ft |
| Normal Storage | 396 acre-ft |
| Surface Area | 40 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 07/13/2018 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | ID00069 |
| Federal ID | ID00069 |
| More Info | State Dam Safety Program |