Round Valley
Round Valley is an earth dam located in Lassen County, California, built in 1892. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Round Valley
The primary purpose of Round Valley 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 Jack And Thomas Swickard (private). It impounds the Round Val Cr.
The dam stands 45 feet tall and stretches 220 feet across, creates a reservoir covering 420 acres, has a maximum storage capacity of 5,500 acre-feet, and collects water from a drainage area of 10 square miles. Completed in 1892, 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 09/22/2025.
At 45 feet, this dam is taller than 91% of dams nationwide.
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Location
| State | California |
| County | Lassen |
| River/Stream | Round Val Cr |
| Coordinates | 40.51540, -120.66060 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 45 ft |
| Dam Height | 45 ft |
| Dam Length | 220 ft |
| Year Completed | 1892 (134 years old) |
Storage & Hydraulics
| NID Storage | 5,500 acre-ft |
| Max Storage | 5,500 acre-ft |
| Surface Area | 420 acres |
| Drainage Area | 10 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Jack and Thomas Swickard |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/22/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00509 |
| Federal ID | CA00509 |
| More Info | State Dam Safety Program |