Sonoma Hills
Sonoma Hills is an earth dam located in Sonoma County, California, built in 1991. It carries a Low hazard potential classification and has a satisfactory condition assessment.
About Sonoma Hills
The primary purpose of Sonoma Hills 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 Fred Cline (private). It impounds the Tr Tolay Creek.
The dam stands 38 feet tall and stretches 323 feet across, creates a reservoir covering 29 acres, has a maximum storage capacity of 240 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1991, the structure is 35 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 04/23/2025.
At 38 feet, this dam is taller than 85% of dams nationwide.
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Location
| State | California |
| County | Sonoma |
| River/Stream | Tr Tolay Creek |
| Coordinates | 38.21580, -122.50900 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 38 ft |
| Dam Height | 38 ft |
| Dam Length | 323 ft |
| Year Completed | 1991 (35 years old) |
Storage & Hydraulics
| NID Storage | 240 acre-ft |
| Max Storage | 240 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Fred Cline |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/23/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01321 |
| Federal ID | CA01321 |
| More Info | State Dam Safety Program |