PeakFQ inputs and selected outputs for 238 selected streamgages in Hawaiʻi through water year 2020

The U.S. Geological Survey (USGS), in cooperation with the State of Hawaiʻi Department of Transportation, estimated flood magnitudes for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEP) for unregulated streamgages in Kauaʻi, Oʻahu, Molokaʻi, Maui, and Hawaiʻi, State of Hawaiʻi, using data through water year 2020. Regression equations which can be used to estimate flood magnitude and associated frequency at ungaged streams were developed. The methods and results of the study are published in a separate report (https://doi.org/10.3133/sir20235014).
This data release includes peak-flow, specification, output, and export files from version 7.3 of USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006) for 238 streamgages operated by the USGS in the State of Hawaiʻi and a summary of data from the output and export files. Within PeakFQ software, the Expected Moments Algorithm (EMA) was used to conduct frequency analysis to estimate stream discharges corresponding to the 0.5, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 AEPs (otherwise known as the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods, respectively). Results of the frequency analysis were used to develop a regional flood skew with Bayesian weighted least squares/Bayesian generalized least squares (B-WLS/B-GLS) regression and were used in generalized least-squares (GLS) regression to generate equations that predict stream discharges corresponding to selected AEPs at ungaged locations on streams in the State of Hawaiʻi (Mitchell and others, 2023).