Data and Methods
Rainfall
Gauge Data Links:
Threshold Data Links:
Rainfall data explained:
These USGS rain gauges use tipping buckets to collect real-time rainfall accumulation data every 15 minutes. The Poamoho gauge shows mauka rainfall, while the Waiahole gauge shows makai rainfall. The last hour of rainfall accumulation is used to determine the severity of the rainfall event. The hourly rainfall return period statistics are used to show the severity of the event. The minor rainfall is represented by the 2-year return period, while the 10-year return period represents a more major rainfall event.
Tides
Gauge Data Links:
Threshold Data Links:
Tide data explained:
The Waikane tides are predicted water levels modeled from the Mokouloe tide gauge station. The water level observed at the Mokouloe station is not shown here, so actual water levels may deviate from the predictions NOAA offers. The water levels are referenced to the mean lower low water level datum, similar to other tide forecast charts. The minor and major floods for tides were based on the datums and extreme water level statistics of the Mokouloe station. Residents reported that backwater flooding at the Waikane bridge occurs frequently during high tides and extreme rainfall. The 1-year return period of an extreme water level was used as the minor threshold while a 2-year return period marked the major threshold.
Streams
Gauge Data Links:
Threshold Data Links:
Stream data explained:
USGS stream gauges provides the real-time water level height of the streams. NOAA’s dashboard includes the water level heights at which minor and major flood events occur. These water level heights were used for the minor and major thresholds. It is important to note the water level height that contributes to minor or major flooding can change after large flood events. Large floods can alter the shape or geometry of the river channel, which changes the water level height where flooding occurs.