L. L. Anderson
L. L. Anderson is an earth dam located in Placer County, California, built in 1965. It carries a High hazard potential classification and has a satisfactory condition assessment.
About L. L. Anderson
The primary purpose of L. L. Anderson is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Placer County Water Agency (local government). It impounds the Middle Fork American River near Auburn.
The dam stands 231 feet tall and stretches 2,700 feet across, creates a reservoir covering 1,430 acres, has a maximum storage capacity of 134,000 acre-feet, and collects water from a drainage area of 47 square miles. Completed in 1965, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. 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 08/22/2023.
At 231 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The California dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | California |
| County | Placer |
| Nearest City | Auburn |
| River/Stream | Middle Fork American River |
| Coordinates | 39.11180, -120.47080 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 231 ft |
| Dam Height | 231 ft |
| Dam Length | 2,700 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 134,000 acre-ft |
| Max Storage | 134,000 acre-ft |
| Normal Storage | 134,000 acre-ft |
| Surface Area | 1,430 acres |
| Drainage Area | 47 sq mi |
| Max Discharge | 16,200 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Placer County Water Agency |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/22/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00856 |
| Federal ID | CA00856 |
| More Info | State Dam Safety Program |