O'neill Forebay Dike is an earth dam located in Merced County, California, built in 1967. It carries a Low hazard potential classification.
Dam profile
NID height · 20 ft20 ft tall and 1,120 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About O'neill Forebay Dike
The primary purpose of O'neill Forebay Dike 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 Bureau of Reclamation (federal). It impounds the San Luis Creek Os near Volta.
The dam stands 20 feet tall and stretches 1,120 feet across, creates a reservoir covering 2,250 acres, and has a maximum storage capacity of 64,800 acre-feet. Completed in 1967, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 05/17/2023.
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Location
| State | California |
| County | Merced |
| Nearest City | Volta |
| River/Stream | San Luis Creek Os |
| Coordinates | 37.10860, -121.05700 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 16 ft |
| Dam Length | 1,120 ft |
| Year Completed | 1967 (59 years old) |
Storage & Hydraulics
| NID Storage | 64,800 acre-ft |
| Max Storage | 64,800 acre-ft |
| Normal Storage | 56,430 acre-ft |
| Surface Area | 2,250 acres |
| Spillway Type | None |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Bureau of Reclamation |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 05/17/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA10171 |
| Federal ID | CA10171S001 |
| More Info | State Dam Safety Program |