Patterson
High HazardFair ConditionEmergency Action Plan: Yes
Location
| County | Alameda |
| Nearest City | Livermore |
| River/Stream | Offstream |
| Coordinates | 37.69850, -121.68360 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 1,275 ft |
| Year Completed | 1962 (64 years old) |
Storage & Hydraulics
| NID Storage | 104 acre-ft |
| Max Storage | 104 acre-ft |
| Surface Area | 4 acres |
Ownership & Safety
| Purpose | Water Supply |
| Owner | California Department of Water Resources |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 11/17/2025 |
| Emergency Action Plan | Yes |