This data release presents two datasets including waterbodies (reservoirs, lakes, ponds, wetlands, etc.) and flowlines (stream reaches) from the high-resolution National Hydrography Dataset Plus (NHDPlus HR) that are potentially observable from Landsat images for the United States (excluding Alaska). To determine where National Hydrography Dataset Plus high resolution (NHDPlus HR; USGS 2019) features intersect locations with observed water, a workflow was developed using the Global Surface Water Extent dataset (GSWE; Pekel et al. 2016) to specify where water was observed by Landsat from 1984 to 2019. The workflow determines where the extent of NHDPlus HR water features (waterbodies and areas) overlaps the maximum extent of Landsat-observed water (as defined by GSWE), then removes edge pixels to determine if any pure water pixels are observable by Landsat within a water feature’s extent. Each pure-water pixel within NHDPlus HR area features (i.e. rivers represented by polygons) was associated with the nearest NHDPlus HR flowline. The result identifies flowlines and waterbodies (as defined by NHDPlus HR) that contain at least one estimated pure-water pixel from the GSWE and are thus ‘potentially resolvable’. The resulting datasets can be linked to the NHDWaterbodies and NHDFlowline layers of NHDPlus HR to identify waterbodies where remote sensing may be a suitable monitoring method.

This data release documents the data used for the associated publication "Evaluating hydrologic region assignment techniques for ungaged watersheds in Alaska, USA" (Barnhart and others, 2022) The data sets within this release are stored in 14 files: (1) Streamflow observations and sites used. (2) Statistically estimated streamflow values computed for each site. (3) Streamflow statistics computed from observed and estimated streamflow values at each site, basin characteristics for each site, and hydrologic regions (clusters) for each site. (4) A dataset describing the optimal number of hydrologic regions into which the considered sites were grouped. (5) P-values from a multiple comparisons analysis testing for statistical differences between clusters for each basin characteristic and streamflow statistic. (6) A matrix of zeros and ones describing the performance of each hydrologic region assignment technique considered in the publication associated with this release. (7) A dataset of variable importance generated by random forest modeling-based hydrologic region assignment techniques evaluated. (8-14) Daily datasets of simulated SnowModel (Liston and Elder, 2006) runoff (snowmelt + rainfall), precipitation, glacial melt, snow water equivalent, snow covered area, liquid precipitation, and air temperature for Alaska, USA at a 1 km grid cell size.

This data release documents the data used for the associated publication "Evaluating hydrologic region assignment techniques for ungaged watersheds in Alaska, USA" (Barnhart and others, 2022) The data sets within this release are stored in 14 files: (1) Streamflow observations and sites used. (2) Statistically estimated streamflow values computed for each site. (3) Streamflow statistics computed from observed and estimated streamflow values at each site, basin characteristics for each site, and hydrologic regions (clusters) for each site. (4) A dataset describing the optimal number of hydrologic regions into which the considered sites were grouped. (5) P-values from a multiple comparisons analysis testing for statistical differences between clusters for each basin characteristic and streamflow statistic. (6) A matrix of zeros and ones describing the performance of each hydrologic region assignment technique considered in the publication associated with this release. (7) A dataset of variable importance generated by random forest modeling-based hydrologic region assignment techniques evaluated. (8-14) Daily datasets of simulated SnowModel (Liston and Elder, 2006) runoff (snowmelt + rainfall), precipitation, glacial melt, snow water equivalent, snow covered area, liquid precipitation, and air temperature for Alaska, USA at a 1 km grid cell size.

The National Hydrography Dataset (NHD) High Resolution flowlines were used as a base to provide additional information on the connectivity of the stream network for the hydrographic basins in and around Montana. In addition to the attributes that are published as part of the NHD data, two fields were added to the attribute table to associate streams that do not have a Geographic Names Information System (GNIS) name with the GNIS name and NHD reachcode of the nearest downstream named flowline. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. NHD data were originally developed at 1:100,000-scale and exists at that scale for the whole country. This high-resolution NHD, generally developed at 1:24,000/1:12,000 scale, adds detail to the original 1:100,000-scale NHD. Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee. This dataset is NHD Model version 2.2.1. For more information on the NHD High Resolution dataset, see Model Diagram at: http://ftp.geoinfo.msl.mt.gov/Data/Spatial/MSDI/Hydrography.

The National Hydrography Dataset (NHD) High Resolution flowlines were used as a base to provide additional information on the connectivity of the stream network for the hydrographic basins in and around Montana. In addition to the attributes that are published as part of the NHD data, two fields were added to the attribute table to associate streams that do not have a Geographic Names Information System (GNIS) name with the GNIS name and NHD reachcode of the nearest downstream named flowline. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. NHD data were originally developed at 1:100,000-scale and exists at that scale for the whole country. This high-resolution NHD, generally developed at 1:24,000/1:12,000 scale, adds detail to the original 1:100,000-scale NHD. Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee. This dataset is NHD Model version 2.2.1. For more information on the NHD High Resolution dataset, see Model Diagram at: http://ftp.geoinfo.msl.mt.gov/Data/Spatial/MSDI/Hydrography.

This tabular data set represents the presence of six National Hydrography Dataset (NHD) high resolution waterbody types compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. The six types of waterbodies presented here are: playa, ice mass, lake/pond, reservoir, swamp/marsh, and estuary. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the NHDPlus high resolution waterbodies produced by USGS , 2015. Units are percent. Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).

This tabular data set represents the presence of six National Hydrography Dataset (NHD) high resolution waterbody types compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. The six types of waterbodies presented here are: playa, ice mass, lake/pond, reservoir, swamp/marsh, and estuary. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the NHDPlus high resolution waterbodies produced by USGS , 2015. Units are percent. Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).