34Total Dams
9High Hazard
6Significant
Dam Safety in Lewis County, Washington
Lewis County has 34 dams tracked in the National Inventory of Dams. Of these, 9 are classified as high hazard — meaning failure would probably cause loss of human life. Another 6 carry a significant hazard classification. Currently, 3 dams have a condition assessment of poor or unsatisfactory.
The average dam in Lewis County is 49 years old. The most common purpose is tailings. The tallest dam is Mossyrock at 606 ft.
Explore more: Oldest dams in Washington · Tallest dams · High risk dams · Largest reservoirs
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| Mossyrock | High | Unsatisfactory | 606 | Hydroelectric | 1968 |
| Mayfield | High | Unsatisfactory | 250 | Hydroelectric | 1963 |
| Centralia Coal Mine Pond 46 Dam | High | Fair | 30 | Flood Risk Reduction | 2004 |
| Carlisle Lake Dam | High | Poor | 19 | Fish and Wildlife Pond | 1920 |
| Centralia Coal Mine Dam No 8a | High | Satisfactory | 18 | Tailings | 1972 |
| Centralia Coal Mine Pond 46a Dam | High | Satisfactory | 16 | Flood Risk Reduction | 2004 |
| Packwood Lake | High | Satisfactory | 14 | Hydroelectric | 1964 |
| Centralia Coal Mine Dam No 8 | High | Satisfactory | 12 | Tailings | 1972 |
| Koppert Pond | High | Fair | 11 | Recreation | 1984 |
| Cowlitz Falls | Significant | Satisfactory | 145 | Hydroelectric | 1994 |
| Centralia Coal Mine Dam No 3b | Significant | Fair | 140 | Tailings | 1980 |
| Centralia Coal Mine Dam No 3c North | Significant | Satisfactory | 134 | Tailings | 1987 |
| Centralia Coal Mine Dam No 3c South | Significant | Satisfactory | 69 | Tailings | 1987 |
| Centralia Coal Mine Dam No 3c East | Significant | Satisfactory | 21 | Tailings | 1987 |
| Chehalis Regional Water Reclamation Pond | Significant | Satisfactory | 17 | Other | 2005 |
| Centralia Coal Mine Dam No 3d | Low | Not assessed | 285 | Tailings | 1988 |
| South Bank Dairy Lagoon Dam | Low | Not assessed | 40 | Other | 1980 |
| Swofford Pond | Low | Satisfactory | 26 | Hydroelectric | |
| Centralia Coal Mine Dam No 5c | Low | Not assessed | 20 | Tailings | 1970 |
| Centralia Coal Mine Dam No 44 | Low | Not assessed | 19 | Tailings | 1975 |
| Koa Dam No 1 | Low | Not assessed | 18 | Recreation | 1965 |
| Long Bell Mill Pond Dam | Low | Not assessed | 18 | Other | 1943 |
| Centralia Coal Mine Dam No 3a | Low | Not assessed | 18 | Tailings | 1970 |
| Barrier Dam | Low | Satisfactory | 16 | Hydroelectric | 1968 |
| Mayfield Plunge Pool Barrier | Low | Satisfactory | 14 | Hydroelectric | 1963 |
| Centralia Coal Mine Dam No 36a | Low | Not assessed | 14 | Tailings | 1989 |
| Centralia Coal Mine Dam No 5 | Low | Not assessed | 14 | Tailings | 1971 |
| Centralia Power Plant Surge Pond Dam | Low | Not assessed | 13 | Water Supply | 1971 |
| Centralia Coal Mine Dam No 36 | Low | Not assessed | 13 | Tailings | 1989 |
| Centralia Coal Mine Dam No 19a | Low | Not assessed | 13 | Tailings | 1977 |
| Centralia Coal Mine Dam No 19 | Low | Not assessed | 13 | Tailings | 1977 |
| Centralia Coal Mine Dam No 6b | Low | Not assessed | 13 | Tailings | 1970 |
| Powell Dam | Low | Not assessed | 11 | Irrigation | 1963 |
| Winlock Waterski Pond Dam | Low | Not assessed | 11 | Recreation | 1990 |