Quarry Pits is an earth dam located in Alameda County, California, built in 1997. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 26 ft26 ft tall and 9,150 ft long, taller than 55% 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 Quarry Pits
The primary purpose of Quarry Pits is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by Alameda County Water District (local government). It impounds the Old Alameda Creek near Fremont.
The dam stands 26 feet tall and stretches 9,150 feet across, creates a reservoir covering 330 acres, has a maximum storage capacity of 3,360 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1997, the structure is 29 years 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 10/31/2024.
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 | Alameda |
| Nearest City | Fremont |
| River/Stream | Old Alameda Creek |
| Coordinates | 37.57900, -122.00680 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 26 ft |
| Dam Height | 26 ft |
| Dam Length | 9,150 ft |
| Year Completed | 1997 (29 years old) |
Storage & Hydraulics
| NID Storage | 3,360 acre-ft |
| Max Storage | 3,360 acre-ft |
| Surface Area | 330 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Tailings |
| Owner | Alameda County Water District |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/31/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA01422 |
| Federal ID | CA01422 |
| More Info | State Dam Safety Program |