San Marcos
High HazardSatisfactory ConditionEmergency Action Plan: Yes
Location
| County | San Luis Obispo |
| Nearest City | None |
| River/Stream | San Marcos Creek |
| Coordinates | 35.67400, -120.81300 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 42 ft |
| Dam Height | 42 ft |
| Dam Length | 502 ft |
| Year Completed | 1964 (62 years old) |
Storage & Hydraulics
| NID Storage | 325 acre-ft |
| Max Storage | 325 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 7 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | Harry E. Blythe Jr. |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/21/2025 |
| Emergency Action Plan | Yes |