Trampas Canyon
Trampas Canyon is an earth dam located in Orange County, California, built in 1975. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Trampas Canyon
Trampas Canyon is a dam in Orange, California. The dam is owned by Santa Margarita Water District (public utility). It impounds the Trampas Canyon near Rancho Mission Viejo.
The dam stands 229 feet tall and stretches 1,300 feet across, creates a reservoir covering 134 acres, has a maximum storage capacity of 5,314 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1975, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. 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 04/03/2025.
At 229 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The California dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | California |
| County | Orange |
| Nearest City | Rancho Mission Viejo |
| River/Stream | Trampas Canyon |
| Coordinates | 33.49880, -117.58370 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 229 ft |
| Dam Height | 229 ft |
| Dam Length | 1,300 ft |
| Year Completed | 1975 (51 years old) |
Storage & Hydraulics
| NID Storage | 5,314 acre-ft |
| Max Storage | 5,314 acre-ft |
| Surface Area | 134 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 2,450 cfs |
Ownership & Safety
| Purpose | Other |
| Owner | Santa Margarita Water District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/03/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA01123 |
| Federal ID | CA01123 |
| More Info | State Dam Safety Program |