Happy Valley Flood Prevention
Happy Valley Flood Prevention is an earth dam located in Maui County, Hawaii, built in 1980. It carries a High hazard potential classification.
About Happy Valley Flood Prevention
The primary purpose of Happy Valley Flood Prevention 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 Maui County (local government). It impounds the Iao Offstream near Puuohala Village.
The dam stands 18 feet tall and stretches 140 feet across, has a maximum storage capacity of 4 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1980, the structure is 46 years 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. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 08/21/2014. That was 11 years ago — unusually long for a high-hazard dam, which typically requires more frequent inspections.
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 | Puuohala Village |
| River/Stream | Iao Offstream |
| Coordinates | 20.89557, -156.51393 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 18 ft |
| Dam Height | 16 ft |
| Dam Length | 140 ft |
| Year Completed | 1980 (46 years old) |
Storage & Hydraulics
| NID Storage | 4 acre-ft |
| Max Storage | 4 acre-ft |
| Normal Storage | 0 acre-ft |
| Drainage Area | 0 sq mi |
| Max Discharge | 445 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | MAUI COUNTY |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Not Rated |
| Last Inspection | 08/21/2014 |
| Emergency Action Plan | No |
Identifiers
| NID ID | HI00125 |
| Federal ID | HI00125 |
| More Info | State Dam Safety Program |