National Hydrologic Model v1.0 water budget components aggregated to 10 and 12-digit Hydrologic Unit Code boundaries

This data release contains the output of the National Hydrologic Hydrologic Model (NHM) version 1.0 aggregated to twelve-digit and ten-digit Hydrologic Unit Code (HUC) boundaries contained in the NHDPlus v2.1 dataset. The data are intended to provide "local" water budgets for each HUC boundary as total aggregated streamflow across HUC boundaries is not included. The HUC boundaries are periodically updated; this data release uses HUC boundaries downloaded on 10-26-2020. The NHM outputs aggregated in this release are calibrated using a step-wise calibration procedure to determine optimal parameter set and utilize the Muskingum routing (referred to as byHRU Musk-Obs). See Hay and LaFontaine (2020) for additional information regarding calibration. A spatial weighting technique is used to aggregate the smaller hydrologic response units to the larger HUC boundaries. In this study, spatial weighting functions were adapted from Blodgett (2020) and Blodgett (2019). Because factors such as topography, land use, and flow routing are not included in aggregation, these aggregated values should be viewed as estimates of the spatial mean and used with caution. For instance, calculating flow volumes at the HUC pour points from the spatial mean runoff values would be an approximation due to the lack of routing information.

This data release contains:
1) The centroid coordinates for HUC10 and HUC12 boundaries in files named hucXXcoords.csv, where XX indicates the two-digit identifier
2) The area weights for HUC10 and HUC12 boundaries in files named hucXXarea_weights.csv, where XX indicates the two-digit identifier
3) The aggregated monthly and water year budget components for HUC10 and HUC12 boundaries in files named YY_hucXX_budgets.csv, where YY indicates monthly or water year and XX indicates the two-digit identifier
4) a zip folder containing processing scripts called nhm_hru_to_huc12.zip

This data release compliments the following related data releases:
Blodgett, D.L., 2020, Twelve-digit hydrologic unit actual evapotranspiration and snowpack water equivalent storage from the National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System 1980-2016: U.S. Geological Survey data release, https://doi.org/10.5066/P9IH7CB8.
Blodgett, D.L., 2019, Twelve digit hydrologic unit soil moisture and recharge from the National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZZAWK4.

This data release uses the following sources of information:
1) NHM 1.0 Geospatial fabric, accessed here: http://dx.doi.org/doi:10.5066/F7542KMD GIS Features of the Geospatial Fabric for National Hydrologic Modeling
2) NHM 1.0 daily simulation outputs, accessed from the "byHRU_musk_obs.tar" file in this data release: Hay, L.E., and LaFontaine, J.H., 2020, Application of the National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System (NHM-PRMS),1980-2016, Daymet Version 3 calibration: U.S. Geological Survey data release, https://doi.org/10.5066/P9PGZE0S.
3) The HUC boundaries, downloaded on 10-26-2020, which are accessible here: https://www.sciencebase.gov/catalog/file/get/60cb5edfd34e86b938a373f4?n….