Green Oaks #1 is an earth dam located in San Mateo County, California, built in 1936. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 39 ft39 ft tall and 880 ft long, taller than 85% 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 Green Oaks #1
Green Oaks #1 is a dam in San Mateo, California. The dam is owned by New Year's LLC (private). It impounds the Green Oaks Creek.
The dam stands 39 feet tall and stretches 880 feet across, creates a reservoir covering 22 acres, has a maximum storage capacity of 322 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1936, the structure is well-established, with more than 75 years of service.
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 03/19/2025.
At 39 feet, this dam is taller than 85% of dams nationwide.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | California |
| County | San Mateo |
| River/Stream | Green Oaks Creek |
| Coordinates | 37.12750, -122.31740 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 880 ft |
| Year Completed | 1936 (90 years old) |
Storage & Hydraulics
| NID Storage | 322 acre-ft |
| Max Storage | 322 acre-ft |
| Surface Area | 22 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | New Year's LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/19/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01010 |
| Federal ID | CA01010 |
| More Info | State Dam Safety Program |