Dams in San Juan County, Washington
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 dams have 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 | 32 | Recreation | 1964 | |
| Sundstrom Dam No 2 | Low | 28 | Irrigation | 1984 | |
| Goodrow Dam | Low | 27 | Recreation | 1964 | |
| Zylstra Dam No 2 | Low | 25 | Irrigation | 1963 | |
| Blazing Tree Ranch Pond 6 Dam | Low | 25 | Irrigation | 1977 | |
| Blazing Tree Ranch Pond 5 South Dam | Low | 25 | Irrigation | 1965 | |
| Blazing Tree Ranch Pond 5 North Dam | Low | 25 | Irrigation | 1965 | |
| Durhack Dam No 1 | Low | 23 | Recreation | 1968 | |
| Durhack Dam No 4 | Low | 21 | Recreation | 1968 | |
| Woods Reservoir Dam | Low | 20 | Irrigation | 1972 | |
| Thorald Dam | Low | 19 | Irrigation | 1988 | |
| Limekiln Dam | Low | 19 | Recreation | 1976 | |
| Durhack Dam No 3 | Low | 18 | Recreation | 1968 | |
| Lawson Lake Dam | Low | Fair | 17 | Irrigation | 1948 |
| Helsell Dam | Low | 16 | Recreation | 1999 | |
| Sundstrom Dam No 1 | Low | 16 | Irrigation | 1970 | |
| Utter Dam | Low | 16 | Recreation | 1971 | |
| Heidenreich Dam | Low | 16 | Recreation | 1972 | |
| Jefferts Dam | Low | 15 | Irrigation | 1988 | |
| Durhack Dam No 5 | Low | 15 | Recreation | 1972 | |
| Fowler Reservoir Dam | Low | 15 | Irrigation | 1960 | |
| Burton & Louthan Dam | Low | 14 | Fire Protection, Stock, Or Small Fish Pond | 1973 | |
| Erickson Dam No 2 | Low | 14 | Recreation | 1964 | |
| Martins Lake Dam | Low | 13 | Recreation | 1962 | |
| Erickson Dam No 1 | Low | 13 | Recreation | 1964 | |
| Durhack Dam No 2 | Low | 10 | Recreation | 1968 | |
| Sportsman Lake Dam | Low | 7 | Irrigation | 1960 |