Monthly twelve-digit hydrologic unit code aggregations of the National Hydrologic Model Precipitation-Runoff Modeling System modeling application for Hawaii, 1980-2021

This data release contains 16 variables from the National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System (NHM-PRMS) modeling application forced with Daymet version 4 (Rosa and others, 2025) from 1980 through 2021 that are summarized to a monthly time step and a twelve-digit hydrologic unit code for the spatial extent of Hawaii. The following fluxes and storages are included: total monthly precipitation, evapotranspiration, lateral flow, surface runoff, quickflow, interflow, recharge, groundwater flow, and the average monthly snow water equivalent, interflow storage, groundwater storage, total storage, and soil moisture. These data can be found in the “HI_huc12_monthly_nhmprms_daymet_1980_2021.nc” file.

Additionally, two supplementary files are also included in this data release. The first file (“HI_weights_hru_to_huc12_nhmprms_daymet.csv”) contains the spatial weights or fraction that is used to “weight” the modeling output in the area-weighting process. The second file (“HI_summed_weights_per_huc12_nhmprms_daymet.csv”) contains the total fractional area within each twelve-digit hydrologic unit code that is covered by the modeling output and is important for filtering results in the data file (where a fractional coverage may be less than one).

In the version 2.0 data release update, a new variable was added to the “HI_huc12_monthly_nhmprms_daymet_1980_2021.nc” file. Additionally, several new netCDF files were added that contain data summarizations from a different production run (output data referenced as "byPOIobs") within the model application data release by Rosa and others (2025). Two of the three files added contain daily estimates of soil moisture fraction ("HI_byPOIobs_huc12_daily_soil_moisture_fraction_nhmprms_daymet_1980_2021.nc") and daily estimates of snow water equivalent ("HI_byPOIobs_huc12_daily_pkwater_equiv_nhmprms_daymet_1980_2021.nc") at the twelve-digit hydrologic unit code spatial regions. The third file added contains monthly estimates of 16 variables from the "byPOIobs" modeling application production run ("HI_byPOIobs_huc12_monthly_nhmprms_daymet_1980_2021.nc"). See the file, “revision_history_nhmprms_daymet_PR.txt” for a full description of the revisions.

First release: 2024
Revised: June 2025 (ver. 2.0)