Upper Sand Creek Detention Basin
Upper Sand Creek Detention Basin is an earth dam located in Contra Costa County, California, built in 2014. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Upper Sand Creek Detention Basin
The primary purpose of Upper Sand Creek Detention Basin 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 Contra Costa County Flood Control And Water Conservation District (local government). It impounds the Sand Creek near Brentwood.
The dam stands 40 feet tall and stretches 1,400 feet across, creates a reservoir covering 44 acres, and has a maximum storage capacity of 895 acre-feet. Completed in 2014, the structure is relatively new.
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 01/07/2026.
At 40 feet, this dam is taller than 87% 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 | Brentwood |
| River/Stream | Sand Creek |
| Coordinates | 37.94500, -121.76400 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 1,400 ft |
| Year Completed | 2014 (12 years old) |
Storage & Hydraulics
| NID Storage | 895 acre-ft |
| Max Storage | 895 acre-ft |
| Surface Area | 44 acres |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Contra Costa County Flood Control and Water Conservation District |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 01/07/2026 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA01555 |
| Federal ID | CA01555 |
| More Info | State Dam Safety Program |