San Antonio Dam
San Antonio Dam is an earth dam located in San Bernardino County, California, built in 1956. It carries a High hazard potential classification.
About San Antonio Dam
The primary purpose of San Antonio Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - Los Angeles District (federal). It impounds the San Antonio Creek near Claremont.
The dam stands 160 feet tall and stretches 3,850 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 11,880 acre-feet, and collects water from a drainage area of 27 square miles. Completed in 1956, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 03/15/2021.
At 160 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 | San Bernardino |
| Nearest City | Claremont |
| River/Stream | San Antonio Creek |
| Coordinates | 34.15730, -117.67707 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 160 ft |
| Dam Height | 160 ft |
| Dam Length | 3,850 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 11,880 acre-ft |
| Max Storage | 11,880 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 27 sq mi |
| Max Discharge | 53,700 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Los Angeles District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 03/15/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA10023 |
| Federal ID | CA10023 |
| More Info | State Dam Safety Program |