Walnut Canyon
Walnut Canyon is an earth dam located in Orange County, California, built in 1968. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Walnut Canyon
The primary purpose of Walnut Canyon 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 City Of Anaheim (local government). It impounds the Walnut Canyon near Anaheim.
The dam stands 187 feet tall and stretches 930 feet across, creates a reservoir covering 47 acres, has a maximum storage capacity of 2,570 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1968, 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 12/16/2025.
At 187 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 | Orange |
| Nearest City | Anaheim |
| River/Stream | Walnut Canyon |
| Coordinates | 33.84120, -117.75250 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 187 ft |
| Dam Height | 187 ft |
| Dam Length | 930 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 2,570 acre-ft |
| Max Storage | 2,570 acre-ft |
| Surface Area | 47 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Anaheim |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 12/16/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA00869 |
| Federal ID | CA00869 |
| More Info | State Dam Safety Program |