Twin Reservoirs
Twin Reservoirs is an earth dam located in Kauai County, Hawaii, built in 1920. It carries a High hazard potential classification and has a unsatisfactory condition assessment.
About Twin Reservoirs
Twin Reservoirs is a dam in Kauai, Hawaii. The dam is owned by County Of Kauai - Department Of Public Works, Green Aloha Real Estate, Llc, Kapaa 382, Kulana Home Owners Association, Leonard Kaui, Meghan Ornellas, Outbound Llc, Troy & Renee Johnston, Waipouli Manoa, Llc (local government). It impounds the Tr-waikaea Canal Offstream near Wailua.
The dam stands 49 feet tall and stretches 1,810 feet across, creates a reservoir covering 16 acres, has a maximum storage capacity of 520 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 unsatisfactory, indicating serious safety deficiencies exist that require immediate attention or remedial action. An emergency action plan is in place for this dam. The most recent inspection on record was 10/04/2024.
At 49 feet, this dam is taller than 92% of dams nationwide.
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 | Wailua |
| River/Stream | Tr-waikaea Canal Offstream |
| Coordinates | 22.08223, -159.34886 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 49 ft |
| Dam Height | 49 ft |
| Dam Length | 1,810 ft |
| Year Completed | 1920 (106 years old) |
Storage & Hydraulics
| NID Storage | 520 acre-ft |
| Max Storage | 520 acre-ft |
| Normal Storage | 162 acre-ft |
| Surface Area | 16 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,800 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | County of Kauai - Department of Public Works, Green Aloha Real Estate, LLC, Kapaa 382, Kulana Home Owners Association, Leonard Kaui, Meghan Ornellas, Outbound LLC, Troy & Renee Johnston, Waipouli Manoa, LLC |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Unsatisfactory |
| Last Inspection | 10/04/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | HI00062 |
| Federal ID | HI00062 |
| More Info | State Dam Safety Program |