Nuuanu Reservoir No. 1 dam
Nuuanu Reservoir No. 1
Nuuanu Reservoir No. 1, located in Honolulu, Hawaii, has been a vital water resource for the local government since its completion in 1905. With a capacity of 63.5 million gallons and a normal storage level of 44 million gallons, this earth dam structure plays a crucial role in water supply management for the region. The reservoir covers a surface area of 6.2 acres and has a drainage area of 0.13 square miles, highlighting its significance in the local hydrological system.
Despite its historical importance, Nuuanu Reservoir No. 1 has faced challenges in recent years, with a poor condition assessment in 2014 and a high hazard potential. The dam's last inspection in February 2021 revealed the need for frequent monitoring and maintenance, with a 5-year inspection frequency in place. The reservoir's spillway type is uncontrolled, with a width of 3 feet, posing additional risks in cases of excessive water inflow. As climate change impacts water resources, the resilience and management of structures like Nuuanu Reservoir No. 1 become increasingly crucial for sustainable water supply and disaster mitigation in the region.
Efforts to address the dam's condition and safety concerns are ongoing, with a risk assessment rating it as moderate. With the potential hazards in mind, stakeholders must prioritize risk management measures and emergency preparedness to ensure the continued functionality and safety of Nuuanu Reservoir No. 1. As water resource and climate enthusiasts, staying informed and involved in the maintenance and regulation of critical infrastructure like this reservoir is essential for safeguarding water security and adapting to changing environmental conditions.
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 Nuuanu Reservoir No. 1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Kalihi Str Nr Honolulu | 5 cfs | → |
| Waihi Stream At Honolulu | 2 cfs | → |
| Waiakeakua Str At Honolulu | 4 cfs | → |
| Moanalua Stream Nr Kaneohe | 1 cfs | → |
| Manoa Str At Kanewai Field | 8 cfs | → |
| Manoa-Palolo Drainage Canal At Moiliili | 22 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Nuuanu Reservoir No. 1.
Track Nuuanu Reservoir No. 1 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 Nuuanu Reservoir No. 1
Where does the data for Nuuanu Reservoir No. 1 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 Nuuanu Reservoir No. 1.