Maui Reservoir 21
Maui Reservoir 21 is an earth dam located in Maui County, Hawaii, built in 1913. It carries a High hazard potential classification and has a poor condition assessment.
About Maui Reservoir 21
The primary purpose of Maui Reservoir 21 is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Mp East B, Llc (private). It impounds the Fed By Irrigation Gulch near Upper Paia.
The dam stands 22 feet tall and stretches 950 feet across, creates a reservoir covering 6 acres, has a maximum storage capacity of 72 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1913, 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 01/30/2025.
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 | Upper Paia |
| River/Stream | Fed By Irrigation Gulch |
| Coordinates | 20.88786, -156.34380 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 950 ft |
| Year Completed | 1913 (113 years old) |
Storage & Hydraulics
| NID Storage | 72 acre-ft |
| Max Storage | 72 acre-ft |
| Normal Storage | 57 acre-ft |
| Surface Area | 6 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 175 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | MP East B, LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 01/30/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | HI00071 |
| Federal ID | HI00071 |
| More Info | State Dam Safety Program |