In cooperation with the State of Hawaii Department of Transportation, the U.S. Geological Survey (USGS) has computed a series of basin characteristic rasters for Hawaii to be implemented into the USGS StreamStats application (https://streamstats.usgs.gov/ss/). The basin characteristics, along with geospatial datasets for watershed delineation published as a separate USGS data release (https://doi.org/10.5066/P9N61WJ7), were used to delineate watersheds and determine basin characteristics in StreamStats for Hawaii.

This U.S. Geological Survey (USGS) data release record consists of topographic data themes that cover the Hawaiian Geospatial Fabric (HIGF) domain. The 30-meter (m) raster data sets included under Topographic Derivatives are: digital elevation (dem.tif) , topographic wetness index (TWI, twi.tif), slope (rise over run, slope.tif), aspect (asp.tif), flow accumulation (fac.tif), and flow direction (fdr.tif). All file formats are in GeoTIFF (Geographic Tagged Imaged Format).

The U.S. Geological Survey (USGS), in cooperation with the Puerto Rico Environmental Quality Board, has compiled a series of geospatial datasets for Puerto Rico to be implemented into the USGS StreamStats application (https://streamstats.usgs.gov/ss/). These geospatial datasets, along with basin characteristics datasets for Puerto Rico published as a separate USGS data release (https://doi.org/10.5066/P9HK9SSQ), were used to delineate watersheds and develop the peak-flow and low-flow regression equations used by StreamStats.

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 two geographic information system (GIS) shapefiles, one of polygons representing the extents of the drainage basins of 238 selected streamgages operated by the USGS in the State of Hawaiʻi, and the other of polygons representing the extents of flood-regression regions in the State of Hawaiʻi. The 238 selected streamgages 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). Also included is a comma-separated values (.csv) text file containing the physical, land-cover, and climatic characteristics of the basin polygons corresponding to each of the 238 selected streamgages. The data supporting the basin delineations and basin characteristics were previously published as separate data releases: https://doi.org/10.5066/P9N61WJ7, and https://doi.org/10.5066/P9TOQANM.

This dataset consists of a personal geodatabase containing several vector datasets. These datasets may be used with the ArcHydro Tools, developed by ESRI in partnership with the U.S. Geological Survey, StreamStats Development Team. The datasets, together with the ArcHydro Tools and the ArcHydro 8-digit HUC datasets for an area of interest, allow users to delineate watersheds and compute several watershed characteristics.

This dataset consists of a personal geodatabase containing several vector datasets. These datasets may be used with the ArcHydro Tools, developed by ESRI in partnership with the U.S. Geological Survey, StreamStats Development Team. The datasets, together with the ArcHydro Tools and the ArcHydro 8-digit HUC datasets for an area of interest, allow users to delineate watersheds and compute several watershed characteristics.

This data release consists of a comma-delimited ascii file with attributes for 21 U.S. Geological Survey streamgage sites in Hawai‘i and Southeast Alaska selected to enable assessment of how floods might change in a future climate. Floods in Hawai‘i and Southeast Alaska have led to loss of human life; damage to agricultural crops, cultural and biological resources, infrastructure, and property; threats to public health; and conditions that are highly disruptive to residents and visitors. Floods are generated by atmospheric and terrestrial processes that may be enhanced or depressed in response to climate change. Understanding the mechanisms that generate floods can be useful for assessing how floods may change in future climates and developing adaptive-management strategies to cope with future floods. Key to improved understanding of floods in Hawai‘i and Southeast Alaska is identifying sites that are affected by known flood-generating mechanisms and that can be used to potentially assess the effects of these mechanisms on the magnitude and frequency of floods, both historically and in a future climate. Stakeholders representing scientific, public-safety, cultural, and ecologic perspectives from government, academic, and private institutions provided input for developing and refining site-selection criteria and selecting sites. The site-selection criteria were: (1) the site contributes to representing the primary flood-generating mechanisms in the study area, (2) the site's available annual peak-streamflow record contains a minimum of 10 years of record during the 1980-2020 period, with a preference for longer records, (3) streamflow at the site during 1980-2020 was not substantively affected by regulation, urban areas, and basin land-use change, which could confound interpretation of the relation between floods and flood-generating mechanisms, (4) concurrent water years of annual peak-streamflow and daily mean streamflow records are available, which enables assessment of antecedent flood conditions, and (5) the site is preferably currently (2022) active, which indicates current relevance of the site’s data that could continue to be relevant in the future. The 21 selected sites are representative of classes of spatial climatic variations for Hawai‘i and seasonal and other flow regimes for Southeast Alaska. For Hawai‘i, selected sites consist of at least one site each from the drier (leeward) and wetter (windward) side of each of the five largest islands (Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i). For Southeast Alaska, selected sites consist of at least one site each from five seasonal streamflow regimes variously controlled by rain, snowmelt, and high-elevation melt (Curran and Biles, 2021), and one site each from flow regimes controlled by large basins and glacial lake outburst floods.

This U.S. Geological Survey (USGS) metadata record consists of 17 different spatial layers in GeoTIFF format for the Hawaii. They are: 1) average water capacity (awc.zip), 2) percent sand (sand.zip), 3) percent silt (silt.zip), 4) percent clay (clay.zip), 5) soil texture (TEXT_PRMS.zip), 6) land use/land cover (LULC.zip), 7) snow values (snow.zip), 8) summer rain values (SRain.zip), 9) winter rain values (WRain.zip), 10) leaf presence values (keep.zip), 11) leaf loss values (loss.zip), 12) percent tree canopy (CNPY.zip), 13) percent impervious surface (imperv.zip), 14) snow depletion curve numbers (CV_INT.zip), 15) rooting depth (RootDepth.zip), 16) permeability values (Lithology_exp_Konly_Project.zip), and 17) water bodies. All data cover the National Hydrologic Model's (NHM) version 1.1 Alaskan domain. The NHM is a modeling infrastructure consisting of three main parts: 1) an underlying geospatial fabric of modeling units (hydrologic response units and stream segments) with an associated parameter database, 2) a model input data archive, and 3) a repository of the physical model simulation code bases (Regan and others, 2014). The NHM has been used for a variety of applications since its initial development.The 250-meter (m) raster data sets for soils are derived from the OpenGeoHub's LandGIS data (Hengl, 2018). The 30-meter raster of land use and land cover data are a simplified re-classification version of the North American Land-Change Monitoring System (NALCMS, Latifovic and others, 2012) data following the guidance and crosswalk table (CrossWalk.xslx) in Viger and Leavesley (2007). This layer was used to derive rasters representing dominant vegetative cover type, snow, summer and winter rain interception values, leaf cover and loss, and rooting depth. The impervious data was compiled from the Global Man-made Impervious Surface (GMIS) Dataset from Landsat, v1 (NASA, 2010). The tree canopy data was compiled from MOD44B MODIS/Terra Vegetation Continuous Fields Yearly L3 Global 250m SIN Grid V006, (Carroll and others, 2017). The snow depletion data was compiled from data by Liston and others (2009) and further processed using methods provided in a snow depletion table (SDC.xslx) by Sexstone and others (2020). All file formats are in GeoTIFF (Geograhpic Tagged Imaged Format).

This dataset consists of a workspace (folder) containing 41 gridded datasets and a personal geodatabase. The gridded datasets consist of 28 precipitation-frequency grids, a mean annual precipitation grid, eight land cover grids, two soil permeability grids, a synthetic stream grid, and a region grid used in the Hawaii StreamStats application for peak flow estimates. The personal geodatabase contains a polygon feature class of exclusion polygons, which identify areas in which use the StreamStats application is restricted.

These datasets each consist of a folder containing a personal geodatabase of the NHD, and shapefiles used in the HydroDEM process. These files are provided as a means to document exactly which lines were used to develop the HydroDEMs. Each folder contains a line shapefile named for the 8-digit HUC code, containing the NHD flowlines that comprise the coastline for that island. The “hydrolines.shp” shapefile contains the lines that were burned into the DEM. These lines were selected from the NHD flowlines, with some minor editing in places. The “wbpolys.shp” shapefile contains the water-body polygons that were selected from the NHD and used in the bathymetric gradient process. The folders for HUCs 20010000 (Hawaii) and 20020000 (Maui) also contain a “walls.shp” shapefile, which contains the lines that were superimposed on the surface as “walls.”