Waikamoi Dam No. 2 is a concrete dam located in Maui County, Hawaii, built in 1956. It carries a Low hazard potential classification and has a poor condition assessment.
Dam profile
NID height · 35 ft35 ft tall and 98 ft long, taller than 80% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Waikamoi Dam No. 2
The primary purpose of Waikamoi Dam No. 2 is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Maui County, Dept of Water Supply (local government). It impounds the Waikamoi Stream near Kailua.
The dam stands 35 feet tall and stretches 98 feet across, has a maximum storage capacity of 61 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1956, the structure is well into its service life at over 50 years 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 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 06/05/2025.
At 35 feet, this dam is taller than 80% of dams nationwide.
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Location
| State | Hawaii |
| County | Maui |
| Nearest City | Kailua |
| River/Stream | Waikamoi Stream |
| Coordinates | 20.80781, -156.23033 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 35 ft |
| Dam Height | 34 ft |
| Dam Length | 98 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 61 acre-ft |
| Max Storage | 61 acre-ft |
| Normal Storage | 32 acre-ft |
| Drainage Area | 2 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Maui County, Dept of Water Supply |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 06/05/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | HI00046 |
| Federal ID | HI00046 |
| More Info | State Dam Safety Program |