37Total Dams
9High Hazard
0Significant
Dam Safety in San Juan County, Washington
San Juan County has 37 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. Currently, 1 dam has a condition assessment of poor or unsatisfactory.
The average dam in San Juan County is 57 years old. The most common purpose is recreation. The tallest dam is Spencer Lake at 42 ft.
Explore more: Oldest dams in Washington · Tallest dams · High risk dams · Largest reservoirs
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| Trout Lake Storage Dam | High | Fair | 37 | Recreation | 1929 |
| Buck Mountain Reservoir Dam No 2 | High | Fair | 32 | Water Supply | 1985 |
| Boyd Lower Reservoir Dam | High | Fair | 24 | Irrigation | 1960 |
| Cascade Lake Dam | High | Poor | 21 | Hydroelectric | 1915 |
| Buck Mountain Reservoir Dam No 3 | High | Fair | 20 | Water Supply | 1985 |
| Mountain Lake Dam | High | Fair | 17 | Recreation | 1905 |
| Buck Mountain Reservoir Dam No 1 | High | Fair | 17 | Water Supply | 1985 |
| Roche Harbor Lake Dam | High | Satisfactory | 15 | Water Supply | 2013 |
| Jays Pond Dam | High | Fair | 8 | Recreation | 1973 |
| Spencer Lake | Low | Satisfactory | 42 | Hydroelectric | 1983 |
| Ayer Reservoir Dam | Low | Not assessed | 32 | Recreation | 1964 |
| Sundstrom Dam No 2 | Low | Not assessed | 28 | Irrigation | 1984 |
| Goodrow Dam | Low | Not assessed | 27 | Recreation | 1964 |
| Zylstra Dam No 2 | Low | Not assessed | 25 | Irrigation | 1963 |
| Blazing Tree Ranch Pond 6 Dam | Low | Not assessed | 25 | Irrigation | 1977 |
| Blazing Tree Ranch Pond 5 South Dam | Low | Not assessed | 25 | Irrigation | 1965 |
| Blazing Tree Ranch Pond 5 North Dam | Low | Not assessed | 25 | Irrigation | 1965 |
| Durhack Dam No 1 | Low | Not assessed | 23 | Recreation | 1968 |
| Durhack Dam No 4 | Low | Not assessed | 21 | Recreation | 1968 |
| Woods Reservoir Dam | Low | Not assessed | 20 | Irrigation | 1972 |
| Thorald Dam | Low | Not assessed | 19 | Irrigation | 1988 |
| Limekiln Dam | Low | Not assessed | 19 | Recreation | 1976 |
| Durhack Dam No 3 | Low | Not assessed | 18 | Recreation | 1968 |
| Lawson Lake Dam | Low | Fair | 17 | Irrigation | 1948 |
| Helsell Dam | Low | Not assessed | 16 | Recreation | 1999 |
| Sundstrom Dam No 1 | Low | Not assessed | 16 | Irrigation | 1970 |
| Utter Dam | Low | Not assessed | 16 | Recreation | 1971 |
| Heidenreich Dam | Low | Not assessed | 16 | Recreation | 1972 |
| Jefferts Dam | Low | Not assessed | 15 | Irrigation | 1988 |
| Durhack Dam No 5 | Low | Not assessed | 15 | Recreation | 1972 |
| Fowler Reservoir Dam | Low | Not assessed | 15 | Irrigation | 1960 |
| Burton & Louthan Dam | Low | Not assessed | 14 | Fire Protection, Stock, Or Small Fish Pond | 1973 |
| Erickson Dam No 2 | Low | Not assessed | 14 | Recreation | 1964 |
| Martins Lake Dam | Low | Not assessed | 13 | Recreation | 1962 |
| Erickson Dam No 1 | Low | Not assessed | 13 | Recreation | 1964 |
| Durhack Dam No 2 | Low | Not assessed | 10 | Recreation | 1968 |
| Sportsman Lake Dam | Low | Not assessed | 7 | Irrigation | 1960 |