Dams in Honolulu County, Hawaii
13Total Dams
12High Hazard
0Significant
Dam Safety in Honolulu County, Hawaii
Honolulu County has 13 dams tracked in the National Inventory of Dams. Of these, 12 are classified as high hazard — meaning failure would probably cause loss of human life. Currently, 8 dams have a condition assessment of poor or unsatisfactory.
The average dam in Honolulu County is 97 years old. The most common purpose is irrigation. The tallest dam is Wahiawa Dam at 98 ft.
Explore more: Oldest dams in Hawaii · Tallest dams · High risk dams · Largest reservoirs
Data note: Hazard potential describes the consequences if a dam failed; it does not predict the likelihood of failure. Inspection, condition, and emergency-plan fields can be incomplete or delayed. Check state dam-safety officials and local emergency managers for official guidance.
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| Wahiawa Dam | High | Poor | 98 | Irrigation | 1906 |
| Ku Tree Reservoir | High | Unsatisfactory | 90 | Other | 1925 |
| Kaneohe Dam | High | Fair | 83 | Flood Risk Reduction | 1980 |
| Nuuanu Dam No. 4 | High | Fair | 73 | Flood Risk Reduction | 1910 |
| Opaeula 01 Reservoir | High | Fair | 71 | Irrigation | 1910 |
| Waimanalo 60 Mg Reservoir | High | Fair | 65 | Irrigation | 1993 |
| Upper Helemano Reservoir | High | Poor | 51 | Irrigation | 1912 |
| Helemano 6 Reservoir | High | Poor | 38 | Irrigation | 1915 |
| Nuuanu Reservoir No. 1 | High | Poor | 34 | Flood Risk Reduction | 1905 |
| Maunaolu Reservoir | High | Fair | 27 | Irrigation | 1966 |
| Kemoo 5 Reservoir | High | Poor | 25 | Irrigation | 1920 |
| Oahu Reservoir 155 | High | Poor | 25 | Irrigation | 1916 |
| Koolau Reservoir | Low | Unsatisfactory | 70 | Other | 1919 |