Waikoloa Reservoir No. 2 dam
Waikoloa Reservoir No. 2
Waikoloa Reservoir No. 2, also known as Waikoloa 50 Mg Reservoir 2, is a key water resource infrastructure located in Waimea, Hawaii. Completed in 1975, this earth dam stands at a height of 30.5 meters and serves the primary purpose of water supply. With a maximum storage capacity of 190 million gallons and a normal storage of 157 million gallons, this reservoir plays a crucial role in ensuring a reliable water source for the local community.
Situated along the Kohakohau Stream, this reservoir covers a surface area of 7.3 acres and has a drainage area of 0.01 square miles. Despite a high hazard potential due to its structural design, the dam is currently assessed to be in fair condition. Regular inspections are conducted, with the last assessment taking place in March 2020. The reservoir's spillway, with a width of 5 meters, is designed as uncontrolled, allowing for a maximum discharge of 250 cubic feet per second in case of excess water flow.
Managed by the state regulatory agency DLNR, Waikoloa Reservoir No. 2 serves as a vital water supply structure in Hawaii. With its strategic location and significant storage capacity, this reservoir plays a critical role in sustaining water resources for the local community, highlighting the importance of effective management and maintenance of water infrastructure in the face of climate challenges and increasing water demand.
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 Waikoloa Reservoir No. 2 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Kohakohau Stream Above Dws Intake | 1 cfs | → |
| Waikoloa Str At Marine Dam Nr Kamuela | 3 cfs | → |
| Alakahi Stream Near Kamuela | 22 cfs | → |
| Kawainui Stream Nr Kamuela | 27 cfs | → |
| Honolii Stream Nr Papaikou | 162 cfs | → |
| Wailuku River At Piihonoua | 304 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Waikoloa Reservoir No. 2.
Track Waikoloa Reservoir No. 2 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 Waikoloa Reservoir No. 2
Where does the data for Waikoloa Reservoir No. 2 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 Waikoloa Reservoir No. 2.