Oak Site is an earth dam located in Santa Cruz County, California, built in 1969. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 43 ft43 ft tall and 290 ft long, taller than 89% of U.S. dams with a recorded height. 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 Oak Site
The primary purpose of Oak Site 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 California Department of Forestry and Fire Protection (state). It impounds the Tr Big Creek.
The dam stands 43 feet tall and stretches 290 feet across, creates a reservoir covering 2 acres, has a maximum storage capacity of 20 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1969, 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 06/25/2025.
At 43 feet, this dam is taller than 89% of dams nationwide.
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Location
| State | California |
| County | Santa Cruz |
| River/Stream | Tr Big Creek |
| Coordinates | 37.12740, -122.17190 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 43 ft |
| Dam Height | 43 ft |
| Dam Length | 290 ft |
| Year Completed | 1969 (57 years old) |
Storage & Hydraulics
| NID Storage | 20 acre-ft |
| Max Storage | 20 acre-ft |
| Surface Area | 2 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | California Department of Forestry and Fire Protection |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/25/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA00051 |
| Federal ID | CA00051 |
| More Info | State Dam Safety Program |