Duncan
Duncan is an earth dam located in Modoc County, California, built in 1919. It carries a Low hazard potential classification and has a satisfactory condition assessment.
About Duncan
The primary purpose of Duncan 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 Milano Land And Cattle Company, Llc (private). It impounds the Tr Pit River.
The dam stands 19 feet tall and stretches 900 feet across, creates a reservoir covering 353 acres, has a maximum storage capacity of 2,575 acre-feet, and collects water from a drainage area of 11 square miles. Completed in 1919, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 05/29/2025.
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Location
| State | California |
| County | Modoc |
| River/Stream | Tr Pit River |
| Coordinates | 41.51790, -120.94200 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 19 ft |
| Dam Height | 19 ft |
| Dam Length | 900 ft |
| Year Completed | 1919 (107 years old) |
Storage & Hydraulics
| NID Storage | 2,575 acre-ft |
| Max Storage | 2,575 acre-ft |
| Surface Area | 353 acres |
| Drainage Area | 11 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Milano Land and Cattle Company, LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/29/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA00480 |
| Federal ID | CA00480 |
| More Info | State Dam Safety Program |