Okinawa Reservoir
Okinawa Reservoir is an earth dam located in Kauai County, Hawaii, built in 1920. It carries a High hazard potential classification and has a poor condition assessment.
About Okinawa Reservoir
The primary purpose of Okinawa Reservoir is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Grove Farm Company (private). It impounds the Unnamed Gulch near Kapaia.
The dam stands 29 feet tall and stretches 470 feet across, creates a reservoir covering 14 acres, has a maximum storage capacity of 142 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1920, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 02/11/2025.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Hawaii dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Hawaii |
| County | Kauai |
| Nearest City | Kapaia |
| River/Stream | Unnamed Gulch |
| Coordinates | 22.00632, -159.36506 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 29 ft |
| Dam Height | 25 ft |
| Dam Length | 470 ft |
| Year Completed | 1920 (106 years old) |
Storage & Hydraulics
| NID Storage | 142 acre-ft |
| Max Storage | 142 acre-ft |
| Normal Storage | 84 acre-ft |
| Surface Area | 14 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Grove Farm Company |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 02/11/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | HI00014 |
| Federal ID | HI00014 |
| More Info | State Dam Safety Program |