Briones is an earth dam located in Contra Costa County, California, built in 1964. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 273 ft273 ft tall and 2,100 ft long, taller than 99% of U.S. dams with a recorded height. Height is drawn to scale against the Statue of Liberty, 305 ft ground to torch; the profile is a generic embankment section and the water level is illustrative.
About Briones
Briones is a dam in Contra Costa, California. The dam is owned by East Bay Municipal Utility District (public utility). It impounds the Bear Creek.
The dam stands 273 feet tall and stretches 2,100 feet across, creates a reservoir covering 735 acres, has a maximum storage capacity of 67,520 acre-feet, and collects water from a drainage area of 8 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 10/24/2024.
At 273 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 | Contra Costa |
| River/Stream | Bear Creek |
| Coordinates | 37.91480, -122.21240 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 273 ft |
| Dam Height | 273 ft |
| Dam Length | 2,100 ft |
| Year Completed | 1964 (62 years old) |
Storage & Hydraulics
| NID Storage | 67,520 acre-ft |
| Max Storage | 67,520 acre-ft |
| Surface Area | 735 acres |
| Drainage Area | 8 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | East Bay Municipal Utility District |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/24/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00172 |
| Federal ID | CA00172 |
| More Info | State Dam Safety Program |