Clearwell Phase 2
Clearwell Phase 2 is an earth dam located in Contra Costa County, California, built in 1977. It carries a Low hazard potential classification and has a satisfactory condition assessment.
About Clearwell Phase 2
The primary purpose of Clearwell Phase 2 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 Central Contra Costa Sanitary District (public utility). It impounds the Grayson Creek.
The dam stands 30 feet tall and stretches 2,090 feet across, creates a reservoir covering 6 acres, and has a maximum storage capacity of 100 acre-feet. Completed in 1977, the structure is 49 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 02/27/2025.
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Location
| State | California |
| County | Contra Costa |
| River/Stream | Grayson Creek |
| Coordinates | 38.00380, -122.06740 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 2,090 ft |
| Year Completed | 1977 (49 years old) |
Storage & Hydraulics
| NID Storage | 100 acre-ft |
| Max Storage | 100 acre-ft |
| Surface Area | 6 acres |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Central Contra Costa Sanitary District |
| Owner Type | Public Utility |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 02/27/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01109 |
| Federal ID | CA01109 |
| More Info | State Dam Safety Program |