Mcnab
Mcnab is an earth dam located in Mendocino County, California, built in 1947. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Mcnab
Mcnab is a dam in Mendocino, California. The dam is owned by Fetzer Vineyards (private). It impounds the Mc Nab Creek.
The dam stands 40 feet tall and stretches 830 feet across, creates a reservoir covering 7 acres, has a maximum storage capacity of 96 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1947, 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 06/10/2025.
At 40 feet, this dam is taller than 87% of dams nationwide.
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Location
| State | California |
| County | Mendocino |
| River/Stream | Mc Nab Creek |
| Coordinates | 39.03860, -123.19370 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 830 ft |
| Year Completed | 1947 (79 years old) |
Storage & Hydraulics
| NID Storage | 96 acre-ft |
| Max Storage | 96 acre-ft |
| Surface Area | 7 acres |
| Drainage Area | 2 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | Fetzer Vineyards |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/10/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00561 |
| Federal ID | CA00561 |
| More Info | State Dam Safety Program |