John Orr is an earth dam located in Amador County, California, built in 1959. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 20 ft20 ft tall and 590 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 John Orr
The primary purpose of John Orr is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Chris H. and Fay E. Gansberg (private). It impounds the Tr Jackson Cr.
The dam stands 20 feet tall and stretches 590 feet across, creates a reservoir covering 36 acres, has a maximum storage capacity of 152 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1959, 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 03/18/2025.
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Location
| State | California |
| County | Amador |
| River/Stream | Tr Jackson Cr |
| Coordinates | 38.29750, -120.97320 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 590 ft |
| Year Completed | 1959 (67 years old) |
Storage & Hydraulics
| NID Storage | 152 acre-ft |
| Max Storage | 152 acre-ft |
| Surface Area | 36 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Chris H. and Fay E. Gansberg |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/18/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA00615 |
| Federal ID | CA00615 |
| More Info | State Dam Safety Program |