Napili 2-3 Desilting Basin dam
Napili 2-3 Desilting Basin
Napili 2-3 Desilting Basin, also known as Structure #1, is a vital flood risk reduction infrastructure situated in Napili, Maui, Hawaii. Owned by the local government and regulated by the Department of Land and Natural Resources (DLNR), this desilting basin was designed by the USDA NRCS and completed in 1988. With a dam height of 39 feet and a hydraulic height of 40 feet, the basin serves the primary purpose of flood risk reduction for the NAPILI 2-3 river or stream, covering a drainage area of 0.46 square miles.
This earth dam structure has a structural height of 43 feet and a length of 660 feet, with a storage capacity of 57 acre-feet. The basin's spillway type is uncontrolled, with a width of 12 feet, allowing for a maximum discharge of 1030 cubic feet per second. Despite being classified as having a high hazard potential, the condition assessment of the desilting basin is currently rated as fair. Regular inspections are conducted, with the last one completed in March 2021, ensuring its operational readiness and effectiveness in mitigating flood risks for the surrounding area.
Enthusiasts of water resource management and climate resilience will find the Napili 2-3 Desilting Basin an intriguing case study in flood risk reduction infrastructure. Its strategic location in Napili, Maui, along with its significant storage capacity and controlled discharge capabilities, make it a critical asset in managing flood events in the area. The basin's fair condition assessment and regular inspections reflect a commitment to maintaining its operational integrity and safeguarding the community from potential flood hazards. With its design by the USDA NRCS and state regulation by the DLNR, this desilting basin stands as a testament to collaborative efforts in ensuring water resource sustainability and climate resilience in Hawaii.
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 Napili 2-3 Desilting Basin -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Honokohau Stream Near Honokohau | 28 cfs | → |
| Kahakuloa Stream Near Honokohau | 17 cfs | → |
| Waihee River At Dam Near Waihee | 55 cfs | → |
| Iao Stream At Kepaniwai Park Nr Wailuku | 87 cfs | → |
| Halawa Stream Near Halawa | 15 cfs | → |
| Kaunakakai Gulch At Altitude 75 Feet | · | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Napili 2-3 Desilting Basin.
Campgrounds
- Camp Olowalu - Maui
- Camp Olowalu
- Papalau Camping
- Kanaha Beach Park - Maui
- Maybe Camping
- Chemin Vers La Côte
Track Napili 2-3 Desilting Basin 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 Napili 2-3 Desilting Basin
Where does the data for Napili 2-3 Desilting Basin 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 Napili 2-3 Desilting Basin.