Helemano 6 Reservoir dam
Helemano 6 Reservoir
Helemano 6 Reservoir, located in Honolulu, Hawaii, was completed in 1915 and serves a primary purpose of irrigation. This private reservoir stands at a structural height of 38 feet, with a dam height of 36 feet and a hydraulic height of 30 feet. It has a storage capacity of 80 acre-feet, with a normal storage level of 66 acre-feet and a surface area of 4.6 acres. The reservoir is situated near the North Pomoho Stream, making it a vital water resource for the surrounding area.
Despite its age, Helemano 6 Reservoir is in poor condition with a high hazard potential, as indicated by its last inspection in 2020. The spillway type is uncontrolled with a width of 10 feet, and the dam is classified as an earth dam with a buttress core type. The reservoir is regulated by the Department of Land and Natural Resources (DLNR) in Hawaii, with state jurisdiction and permitting in place. The risk assessment for the reservoir is moderate, highlighting the importance of ongoing maintenance and management measures to ensure its safety and functionality for irrigation purposes.
In light of its historical significance and critical role in providing irrigation water, Helemano 6 Reservoir stands as a testament to the enduring importance of water resources in the face of climate challenges. As efforts continue to assess and address the reservoir's condition and safety, its value as a sustainable water source in Honolulu, Hawaii, remains paramount for the local community and agricultural operations in the region.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Helemano 6 Reservoir -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Opaeula Str Nr Wahiawa | 3 cfs | → |
| Kamananui Str At Pupukea Mil Rd | 4 cfs | → |
| Kamananui Str At Maunawai | 5 cfs | → |
| Sf Kaukonahua Str At E Pump | 8 cfs | → |
| Nf Kaukonahua Str Abv Rb | 4 cfs | → |
| Makaha Str Nr Makaha | · | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Helemano 6 Reservoir.
Track Helemano 6 Reservoir in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Helemano 6 Reservoir
Where does the data for Helemano 6 Reservoir come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the High hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Helemano 6 Reservoir.