Lake Orinda
Lake Orinda is an earth dam located in Contra Costa County, California, built in 1935. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Lake Orinda
The primary purpose of Lake Orinda 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 Orinda Country Club (private). It impounds the Cascade Creek near Orinda.
The dam stands 45 feet tall and stretches 360 feet across, creates a reservoir covering 9 acres, has a maximum storage capacity of 111 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1935, the structure is well-established, with more than 75 years of service.
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 04/15/2025.
At 45 feet, this dam is taller than 91% of dams nationwide.
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 |
| Nearest City | Orinda |
| River/Stream | Cascade Creek |
| Coordinates | 37.89160, -122.18840 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 45 ft |
| Dam Height | 45 ft |
| Dam Length | 360 ft |
| Year Completed | 1935 (91 years old) |
Storage & Hydraulics
| NID Storage | 111 acre-ft |
| Max Storage | 111 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 474 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Orinda Country Club |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/15/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00659 |
| Federal ID | CA00659 |
| More Info | State Dam Safety Program |