Winchester is an earth dam located in Placer County, California, built in 1999. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 39 ft39 ft tall and 400 ft long, taller than 85% of U.S. dams with a recorded height. 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 Winchester
The primary purpose of Winchester 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 Duncan Golf Management (private). It impounds the Tr Orr Creek.
The dam stands 39 feet tall and stretches 400 feet across, creates a reservoir covering 6 acres, has a maximum storage capacity of 58 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1999, the structure is 27 years old.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 04/16/2025.
At 39 feet, this dam is taller than 85% of dams nationwide.
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Location
| State | California |
| County | Placer |
| River/Stream | Tr Orr Creek |
| Coordinates | 38.98460, -121.04480 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 400 ft |
| Year Completed | 1999 (27 years old) |
Storage & Hydraulics
| NID Storage | 58 acre-ft |
| Max Storage | 58 acre-ft |
| Surface Area | 6 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Duncan Golf Management |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/16/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01418 |
| Federal ID | CA01418 |
| More Info | State Dam Safety Program |