Mossyrock
Washington, Lewis County, Cowlitz River
Location
| State | Washington |
| County | Lewis |
| River | Cowlitz River |
| Coordinates | 46.53460, -122.42500 |
Physical Characteristics
| NID Height | 606 ft |
| Dam Height | 366 ft |
| Dam Length | 1,750 ft |
| NID Storage | 1,900,000 acre-ft |
| Max Storage | 1,900,000 acre-ft |
| Surface Area | - |
Safety Classification
| Hazard Potential | High |
| Condition Assessment | Unsatisfactory |
| EAP Status | Yes |
| Last Inspection | August 20, 2025 |
| Inspection Frequency | 1 |
Dam Information
| Year Completed | 1968 |
| Primary Purpose | Hydroelectric |
| Dam Type | Arch |
| Owner Type | Public Utility |
| Owner | City of Tacoma |
Location Map
About This Dam Record
Dam safety data is maintained by the Army Corps of Engineers National Inventory of Dams (NID). High-hazard dams are those where failure could cause loss of life or major property damage downstream.