Mud Mountain Dam
Mud Mountain Dam is a rockfill dam located in King County, Washington, built in 1948. It carries a High hazard potential classification.
About Mud Mountain Dam
The primary purpose of Mud Mountain 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 Usace - Seattle District (federal). It impounds the White River near Buckley.
The dam stands 425 feet tall and stretches 700 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 106,000 acre-feet, and collects water from a drainage area of 400 square miles. Completed in 1948, the structure is well-established, with more than 75 years of service.
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 05/15/2021.
At 425 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 Washington 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 | Washington |
| County | King |
| Nearest City | Buckley |
| River/Stream | White River |
| Coordinates | 47.14097, -121.93333 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 425 ft |
| Dam Length | 700 ft |
| Year Completed | 1948 (78 years old) |
Storage & Hydraulics
| NID Storage | 106,000 acre-ft |
| Max Storage | 106,000 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 400 sq mi |
| Max Discharge | 156,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Seattle District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 05/15/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00300 |
| Federal ID | WA00300 |
| More Info | State Dam Safety Program |