Patterson
California — Alameda County — Offstream
Location
| State | California |
| County | Alameda |
| River | Offstream |
| Coordinates | 37.69850, -121.68360 |
Physical Characteristics
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 1,275 ft |
| NID Storage | 104 acre-ft |
| Max Storage | 104 acre-ft |
| Surface Area | 4 acres |
Safety Classification
| Hazard Potential | High |
| Condition Assessment | Fair |
| EAP Status | Yes |
| Last Inspection | November 17, 2025 |
| Inspection Frequency | 1 |
Dam Information
| Year Completed | 1962 |
| Primary Purpose | Water Supply |
| Dam Type | Earth |
| Owner Type | State |
| Owner | California Department of Water Resources |
Location Map
About This Dam Record
Dam safety data is maintained by the Army Corps of Engineers National Inventory of Dams (NID). High-hazard dams are those where failure could cause loss of life or major property damage downstream.