Tallest Dams in Hawaii
Hawaii has 124 dams with recorded heights. The tallest is Alexander at 141 feet. Taller dams impound more water and carry greater potential energy, which is why height is a key factor in hazard classification and inspection requirements.
| # | Dam | County | Height (ft) | Type | Purpose | Hazard | Year |
|---|---|---|---|---|---|---|---|
| 1 | Alexander | Kauai | 141 | Earth | Hydroelectric | High | 1931 |
| 2 | Puu Lua Reservoir | Kauai | 110 | Earth | Fish and Wildlife Pond | High | 1925 |
| 3 | Wahiawa Dam | Honolulu | 98 | Earth | Irrigation | High | 1906 |
| 4 | Ku Tree Reservoir | Honolulu | 90 | Earth | Other | High | 1925 |
| 5 | Kaneohe Dam | Honolulu | 83 | Earth | Flood Risk Reduction | High | 1980 |
| 6 | Aepo Reservoir | Kauai | 74 | Earth | Irrigation | High | 1901 |
| 7 | Nuuanu Dam No. 4 | Honolulu | 73 | Earth | Flood Risk Reduction | High | 1910 |
| 8 | Opaeula 01 Reservoir | Honolulu | 71 | Earth | Irrigation | High | 1910 |
| 9 | Koolau Reservoir | Honolulu | 70 | Earth | Other | Low | 1919 |
| 10 | Horner Reservoir | Maui | 70 | Earth | Irrigation | High | 1926 |
| 11 | Mimino Reservoir | Kauai | 69 | Earth | Irrigation | High | 1920 |
| 12 | Waimanalo 60 Mg Reservoir | Honolulu | 65 | Earth | Irrigation | High | 1993 |
| 13 | Waikoloi Reservoir | Kauai | 64 | Earth | Irrigation | High | 1958 |
| 14 | Kahoma Reservoir | Maui | 60 | Earth | Irrigation | High | 1918 |
| 15 | Kualapuu Reservoir | Maui | 58 | Earth | Irrigation | High | 1969 |
| 16 | Kahana Nui Dam | Maui | 58 | Earth | Flood Risk Reduction | High | 1984 |
| 17 | Piwai Reservoir | Kauai | 56 | Earth | Irrigation | High | 1916 |
| 18 | Waikoloa Reservoir No. 3 | Hawaii | 54 | Earth | Water Supply | High | 1985 |
| 19 | Kahakapao Reservoirs | Maui | 54 | Earth | Water Supply | High | 1990 |
| 20 | Kapaia Reservoir | Kauai | 53 | Earth | Irrigation | High | 1910 |
| 21 | Waimea 60 Mg Reservoir | Hawaii | 52 | Earth | Irrigation | High | 1957 |
| 22 | Wailuku Water Reservoir 10 | Maui | 52 | Earth | Irrigation | High | 1951 |
| 23 | Upper Helemano Reservoir | Honolulu | 51 | Earth | Irrigation | High | 1912 |
| 24 | Kaneha Reservoir | Kauai | 51 | Earth | Irrigation | High | 1910 |
| 25 | Kaupale Reservoir | Kauai | 50 | Earth | Irrigation | High | 1910 |
| 26 | Ipuolono Reservoir | Kauai | 50 | Earth | Irrigation | High | 1910 |
| 27 | Honokowai - Structure #8 | Maui | 50 | Earth | Flood Risk Reduction | High | 1995 |
| 28 | Twin Reservoirs | Kauai | 49 | Earth | Other | High | 1920 |
| 29 | Papuaa Reservoir | Kauai | 48 | Earth | Irrigation | High | 1914 |
| 30 | Kumano Reservoir | Kauai | 48 | Earth | Irrigation | High | 1902 |
| 31 | Ioleau Reservoir | Kauai | 48 | Earth | Irrigation | Low | 1902 |
| 32 | Huinawai Reservoir | Kauai | 47 | Earth | Irrigation | High | 1902 |
| 33 | Pauwela Reservoir | Maui | 47 | Earth | Irrigation | High | 1904 |
| 34 | Maui Reservoir 40 | Maui | 47 | Earth | Irrigation | High | 1926 |
| 35 | Kaloko Reservoir | Kauai | 46 | Earth | Irrigation | High | 1890 |
| 36 | Manuhonuhonu Reservoir | Kauai | 45 | Earth | Irrigation | High | 1954 |
| 37 | Peahi Reservoir | Maui | 45 | Earth | Irrigation | High | 1924 |
| 38 | Waikoloa Reservoir No. 1 | Hawaii | 44 | Earth | Water Supply | High | 1970 |
| 39 | Haiku Reservoir | Maui | 43 | Earth | Irrigation | High | 1904 |
| 40 | Napili 2-3 Desilting Basin | Maui | 43 | Earth | Flood Risk Reduction | High | 1988 |
| 41 | Aepoeha Reservoir | Kauai | 42 | Earth | Irrigation | High | 1913 |
| 42 | Olinda Reservoir | Maui | 42 | Earth | Water Supply | High | 1918 |
| 43 | Piiholo 50 Mg Reservoir | Maui | 42 | Earth | Water Supply | High | 1971 |
| 44 | Maui Reservoir 20 | Maui | 42 | Earth | Irrigation | High | 1913 |
| 45 | Puu Opae Reservoir | Kauai | 41 | Earth | Irrigation | Low | 1930 |
| 46 | Pa Aalii Reservoir | Hawaii | 40 | Earth | Other | High | 1940 |
| 47 | Halenanahu Reservoir | Kauai | 40 | Earth | Irrigation | High | 1920 |
| 48 | Aepoekolu Reservoir | Kauai | 40 | Earth | Irrigation | High | 1910 |
| 49 | Kepani Reservoir | Kauai | 40 | Earth | Irrigation | High | 1954 |
| 50 | Maui Reservoir 24 | Maui | 39 | Earth | Irrigation | High | 1917 |