Long Lake
Long Lake is a rockfill dam located in Plumas County, California, built in 1938. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Long Lake
The primary purpose of Long Lake 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 Graeagle Land And Water Company (private). It impounds the Gray Eagle Creek.
The dam stands 12 feet tall and stretches 110 feet across, creates a reservoir covering 141 acres, has a maximum storage capacity of 1,478 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1938, the structure is well-established, with more than 75 years 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 08/14/2025.
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Location
| State | California |
| County | Plumas |
| River/Stream | Gray Eagle Creek |
| Coordinates | 39.70650, -120.67890 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 110 ft |
| Year Completed | 1938 (88 years old) |
Storage & Hydraulics
| NID Storage | 1,478 acre-ft |
| Max Storage | 1,478 acre-ft |
| Surface Area | 141 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Graeagle Land and Water Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/14/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00534 |
| Federal ID | CA00534 |
| More Info | State Dam Safety Program |