Koolau Reservoir is an earth dam located in Honolulu County, Hawaii, built in 1919. It carries a Low hazard potential classification and has a unsatisfactory condition assessment.
Dam profile
NID height · 70 ft70 ft tall and 270 ft long, taller than 96% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Koolau Reservoir
Koolau Reservoir is a dam in Honolulu, Hawaii. The dam is owned by Schofield Barracks (federal). It impounds the S Fork Kaukonahua near Wahiawa.
The dam stands 70 feet tall and stretches 270 feet across, creates a reservoir covering 4 acres, and has a maximum storage capacity of 138 acre-feet. Completed in 1919, the structure is over a century old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated unsatisfactory, indicating serious safety deficiencies exist that require immediate attention or remedial action. The most recent inspection on record was 06/22/2022.
At 70 feet, this dam is taller than 96% of all dams in the United States.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Hawaii |
| County | Honolulu |
| Nearest City | Wahiawa |
| River/Stream | S Fork Kaukonahua |
| Coordinates | 21.49200, -157.97000 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 70 ft |
| Dam Height | 70 ft |
| Dam Length | 270 ft |
| Year Completed | 1919 (107 years old) |
Storage & Hydraulics
| NID Storage | 138 acre-ft |
| Max Storage | 138 acre-ft |
| Normal Storage | 122 acre-ft |
| Surface Area | 4 acres |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | Schofield Barracks |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Unsatisfactory |
| Last Inspection | 06/22/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | HI00156 |
| Federal ID | HI00156 |
| More Info | State Dam Safety Program |