James H. Turner
James H. Turner is an earth dam located in Alameda County, California, built in 1964. It carries a High hazard potential classification and has a satisfactory condition assessment.
About James H. Turner
The primary purpose of James H. Turner is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City And County Of San Francisco (local government). It impounds the San Antonio Creek near Sunol.
The dam stands 193 feet tall and stretches 2,160 feet across, creates a reservoir covering 825 acres, has a maximum storage capacity of 50,500 acre-feet, and collects water from a drainage area of 39 square miles. Completed in 1964, 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 11/21/2024.
At 193 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 | Alameda |
| Nearest City | Sunol |
| River/Stream | San Antonio Creek |
| Coordinates | 37.57590, -121.84620 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 193 ft |
| Dam Height | 193 ft |
| Dam Length | 2,160 ft |
| Year Completed | 1964 (62 years old) |
Storage & Hydraulics
| NID Storage | 50,500 acre-ft |
| Max Storage | 50,500 acre-ft |
| Surface Area | 825 acres |
| Drainage Area | 39 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City and County of San Francisco |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/21/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00132 |
| Federal ID | CA00132 |
| More Info | State Dam Safety Program |