Dina Bob Lake is an earth dam located in Sonoma County, California, built in 1955. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 33 ft33 ft tall and 635 ft long, taller than 76% 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 Dina Bob Lake
The primary purpose of Dina Bob Lake 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 Robert D. Ogg (private). It impounds the Tr Franz Cr.
The dam stands 33 feet tall and stretches 635 feet across, creates a reservoir covering 14 acres, has a maximum storage capacity of 139 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1955, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. 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 08/14/2025.
At 33 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | California |
| County | Sonoma |
| River/Stream | Tr Franz Cr |
| Coordinates | 38.61660, -122.68910 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 33 ft |
| Dam Height | 33 ft |
| Dam Length | 635 ft |
| Year Completed | 1955 (71 years old) |
Storage & Hydraulics
| NID Storage | 139 acre-ft |
| Max Storage | 139 acre-ft |
| Surface Area | 14 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Robert D. Ogg |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/14/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00991 |
| Federal ID | CA00991 |
| More Info | State Dam Safety Program |