Kehalani Offsite Retention Basin
Kehalani Offsite Retention Basin is an earth dam located in Maui County, Hawaii, built in 2003. It carries a High hazard potential classification and has a poor condition assessment.
About Kehalani Offsite Retention Basin
The primary purpose of Kehalani Offsite Retention Basin is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Heona Investments Llc, Rcfc Kehalani, Llc (private). It impounds the Waikapu Stream near Wailuku.
The dam stands 30 feet tall and stretches 2,300 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 490 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 2003, the structure is relatively new.
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 04/22/2025.
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 | Maui |
| Nearest City | Wailuku |
| River/Stream | Waikapu Stream |
| Coordinates | 20.85811, -156.49669 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 2,300 ft |
| Year Completed | 2003 (23 years old) |
Storage & Hydraulics
| NID Storage | 490 acre-ft |
| Max Storage | 490 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 2,076 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Heona Investments LLC, RCFC Kehalani, LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 04/22/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | HI00141 |
| Federal ID | HI00141 |
| More Info | State Dam Safety Program |