Chino Ranch #1
Chino Ranch #1 is an earth dam located in San Bernardino County, California, built in 1918. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Chino Ranch #1
The primary purpose of Chino Ranch #1 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 Tres Hermanos Conservation Authority (public utility). It impounds the Tonner Canyon Cr.
The dam stands 22 feet tall and stretches 460 feet across, creates a reservoir covering 20 acres, and has a maximum storage capacity of 137 acre-feet. Completed in 1918, the structure is over a century 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 06/10/2025.
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Location
| State | California |
| County | San Bernardino |
| River/Stream | Tonner Canyon Cr |
| Coordinates | 33.98990, -117.78670 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 460 ft |
| Year Completed | 1918 (108 years old) |
Storage & Hydraulics
| NID Storage | 137 acre-ft |
| Max Storage | 137 acre-ft |
| Surface Area | 20 acres |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Tres Hermanos Conservation Authority |
| Owner Type | Public Utility |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/10/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00755 |
| Federal ID | CA00755 |
| More Info | State Dam Safety Program |