Mason Dam
Mason Dam is a rockfill dam located in Baker County, Oregon, built in 1968. It carries a High hazard potential classification.
About Mason Dam
The primary purpose of Mason Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Bureau Of Reclamation (federal). It impounds the Powder River near Baker.
The dam stands 173 feet tall and stretches 895 feet across, creates a reservoir covering 2,235 acres, has a maximum storage capacity of 95,500 acre-feet, and collects water from a drainage area of 164 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/10/2020.
At 173 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 Oregon 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 | Oregon |
| County | Baker |
| Nearest City | Baker |
| River/Stream | Powder River |
| Coordinates | 44.67180, -117.99960 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 173 ft |
| Dam Height | 167 ft |
| Dam Length | 895 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 95,500 acre-ft |
| Max Storage | 95,500 acre-ft |
| Normal Storage | 78,500 acre-ft |
| Surface Area | 2,235 acres |
| Drainage Area | 164 sq mi |
| Max Discharge | 1,210 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 09/10/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | OR00577 |
| Federal ID | OR00577 |
| More Info | State Dam Safety Program |