Halsey Afterbay
Halsey Afterbay is a rockfill dam located in Placer County, California, built in 1913. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Halsey Afterbay
The primary purpose of Halsey Afterbay is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Pacific Gas And Electric Company (private). It impounds the Dry Creek near Baxter.
The dam stands 40 feet tall and stretches 222 feet across, creates a reservoir covering 9 acres, has a maximum storage capacity of 106 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1913, the structure is over a century 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 08/07/2023.
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 | Placer |
| Nearest City | Baxter |
| River/Stream | Dry Creek |
| Coordinates | 38.95600, -121.04310 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 40 ft |
| Dam Height | 38 ft |
| Dam Length | 222 ft |
| Year Completed | 1913 (113 years old) |
Storage & Hydraulics
| NID Storage | 106 acre-ft |
| Max Storage | 106 acre-ft |
| Normal Storage | 60 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 3 sq mi |
| Max Discharge | 2,830 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Pacific Gas and Electric Company |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/07/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00348 |
| Federal ID | CA00348 |
| More Info | State Dam Safety Program |