Galivan Retarding Basin is an earth dam located in Orange County, California, built in 2000. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 14 ft14 ft tall and 600 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 Galivan Retarding Basin
The primary purpose of Galivan Retarding Basin 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 County of Orange (local government). It impounds the Oso Creek.
The dam stands 14 feet tall and stretches 600 feet across, creates a reservoir covering 17 acres, has a maximum storage capacity of 169 acre-feet, and collects water from a drainage area of 13 square miles. Completed in 2000, the structure is 26 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 09/23/2025.
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Location
| State | California |
| County | Orange |
| River/Stream | Oso Creek |
| Coordinates | 33.56320, -117.67620 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 600 ft |
| Year Completed | 2000 (26 years old) |
Storage & Hydraulics
| NID Storage | 169 acre-ft |
| Max Storage | 169 acre-ft |
| Surface Area | 17 acres |
| Drainage Area | 13 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | County of Orange |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/23/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01427 |
| Federal ID | CA01427 |
| More Info | State Dam Safety Program |