Mayfield
High HazardUnsatisfactory ConditionEmergency Action Plan: Yes
Location
| State | Washington |
| County | Lewis |
| Nearest City | Toledo, WA |
| River/Stream | Cowlitz River |
| Coordinates | 46.50330, -122.58830 |
Physical Characteristics
| Dam Type | Arch |
| NID Height | 250 ft |
| Dam Height | 200 ft |
| Dam Length | 850 ft |
| Year Completed | 1963 (63 years old) |
Storage & Hydraulics
| NID Storage | 184,194 acre-ft |
| Max Storage | 184,194 acre-ft |
| Normal Storage | 133,718 acre-ft |
| Surface Area | 2,250 acres |
| Drainage Area | 1,392 sq mi |
| Max Discharge | 313,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | City of Tacoma |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Unsatisfactory |
| Last Inspection | 08/21/2025 |
| Emergency Action Plan | Yes |