Hydrologic landscape regions group areas according to their similarity in landscape and climate characteristics. These characteristics represent variables assumed to affect hydrologic processes in the environment. Hydrologic landscape regions in Nevada were delineated using geographic information system tools and statistical methods including cluster analysis. The data layers of hydrogeology, precipitation, soil permeability, land surface slope and aspect were used to identify the hydrologic landscape regions. Sixteen hydrologic landscape regions were identified through cluster analysis. The hydrologic landscape regions are noncontiguous in nature and can range from small areas which tend to be in the mountain ranges to very large areas in the basins.

The U.S. Geological Survey (USGS), in cooperation with the Air Force Civil Engineer Center (AFCEC), has compiled Geographic Information Systems (GIS) datasets. The spatial data layers provided in this data release are hydrography data derived from high-resolution lidar digital elevation models (DEM). They include a hydroline polyline shapefile used to hydro-enforce the high-resolution lidar DEM; a stream network centerline polyline shapefile derived from the hydro-enforcement that shows stream location; a sub-basin polygon shapefile derived from the hydro-enforcement representing watershed areas for all stream network centerline polylines; a flow direction raster, predicting the direction of flow based on direction of steepest drop; and a flow accumulation raster, predicting the number of upstream cells flowing into each one-meter cell. Field verification was conducted for locations where the high-resolution lidar digital elevation models were unclear on hydraulic connection. Photographs were captured to confirm the conveyance of flow. The datasets are provided in separate child items.

The Geopspatial Fabric provides a consistent, documented, and topologically connected set of spatial features that create an abstracted stream/basin network of features useful for hydrologic modeling.The GIS vector features contained in this Geospatial Fabric (GF) data set cover the lower 48 U.S. states, Hawaii, and Puerto Rico. Four GIS feature classes are provided for each Region: 1) the Region outline ("one"), 2) Points of Interest ("POIs"), 3) a routing network ("nsegment"), and 4) Hydrologic Response Units ("nhru"). A graphic showing the boundaries for all Regions is provided at http://dx.doi.org/doi:10.5066/F7542KMD. These Regions are identical to those used to organize the NHDPlus v.1 dataset (US EPA and US Geological Survey, 2005). Although the GF Feature data set has been derived from NHDPlus v.1, it is an entirely new data set that has been designed to generically support regional and national scale applications of hydrologic models. Definition of each type of feature class and its derivation is provided within the section of this metadata document. The first entry in that section provides an overview of the delineation process, with each subsequent corresponding to one of the four types of feature. These entries describe the derivation of feature types in the order in which they are created. Minimal attribution (feature size, location, and routing connectivity) is provided for the feature classes within the GF Feature data set. More extensive feature attribution is published separately as individual tables of attributes(for example, http://dx.doi.org/doi:10.5066/F7RX9937) or via entire configurations of tables engineered to satisfy particular watershed models (for example, http://dx.doi.org/doi:10.5066/F7WM1BF7).

The Geographic Information Retrieval and Analysis System (GIRAS) was developed in the mid 70s to put into digital form a number of data layers which were of interest to the USGS. One of these data layers was the Hydrologic Units. The map is based on the Hydrologic Unit Maps published by the U.S. Geological Survey Office of Water Data Coordination, together with the list descriptions and name of region, subregion, accounting units, and cataloging unit. The hydrologic units are encoded with an eight- digit number that indicates the hydrologic region (first two digits), hydrologic subregion (second two digits), accounting unit (third two digits), and cataloging unit (fourth two digits). The data produced by GIRAS was originally collected at a scale of 1:250K. Some areas, notably major cities in the west, were recompiled at a scale of 1:100K. In order to join the data together and use the data in a geographic information system (GIS) the data were processed in the ARC/INFO GUS software package. Within the GIS, the data were edgematched and the neatline boundaries between maps were removed to create a single data set for the conterminous United States. NOTE: A version of this data theme that is more throughly checked (though based on smaller-scale maps) is available here: https://water.usgs.gov/lookup/getspatial?huc2m HUC, GIRAS, Hydrologic Units, 1:250 For the most current data and information relating to hydrologic unit codes (HUCs) please see http://water.usgs.gov/GIS/huc.html. The Watershed Boundary Dataset (WBD) is the most current data available for watershed delineation. See http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/water/watersheds/dataset

The Geopspatial Fabric provides a consistent, documented, and topologically connected set of spatial features that create an abstracted stream/basin network of features useful for hydrologic modeling.The GIS vector features contained in this Geospatial Fabric (GF) data set cover the lower 48 U.S. states, Hawaii, and Puerto Rico. Four GIS feature classes are provided for each Region: 1) the Region outline ("one"), 2) Points of Interest ("POIs"), 3) a routing network ("nsegment"), and 4) Hydrologic Response Units ("nhru"). A graphic showing the boundaries for all Regions is provided at http://dx.doi.org/doi:10.5066/F7542KMD. These Regions are identical to those used to organize the NHDPlus v.1 dataset (US EPA and US Geological Survey, 2005). Although the GF Feature data set has been derived from NHDPlus v.1, it is an entirely new data set that has been designed to generically support regional and national scale applications of hydrologic models. Definition of each type of feature class and its derivation is provided within the section of this metadata document. The first entry in that section provides an overview of the delineation process, with each subsequent corresponding to one of the four types of feature. These entries describe the derivation of feature types in the order in which they are created. Minimal attribution (feature size, location, and routing connectivity) is provided for the feature classes within the GF Feature data set. More extensive feature attribution is published separately as individual tables of attributes(for example, http://dx.doi.org/doi:10.5066/F7RX9937) or via entire configurations of tables engineered to satisfy particular watershed models (for example, http://dx.doi.org/doi:10.5066/F7WM1BF7).

This data set describes ground-water regions in the United States defined by the U.S. Geological Survey. These ground-water regions are useful for dividing the United States into areas of roughly similar hydrologic characterstics and water-use patterns. Most of these regions are very generalized and were developed from a illustration published at a scale of approximately 1:20 million. The data set also includes polygon features for unconsolidated watercourses taken from 1:7,500,000-scale U.S. Geological Survey map of productive aquifers.

This data set describes ground-water regions in the United States defined by the U.S. Geological Survey. These ground-water regions are useful for dividing the United States into areas of roughly similar hydrologic characterstics and water-use patterns. These regions are very generalized and were developed from a illustration published at a scale of approximately 1:20 million.

This U.S. Geological Survey (USGS) data release consists of two hydrographic datasets with spatial modeling units, two sets of spatial data consistent with the National Hydrologic Model (NHM) Geospatial Fabric for National Hydrologic Modeling (abbreviated within this document as GFv1, Viger and Bock, 2014), and a database of 118 parameters used to run the NHM . These datasets are found as subpages to this landing page as 1) the GIS (geographic information system) features of the United States-Canada Transboundary Geospatial Fabric (TGF, added 08/04/2020), 2) the GIS features of the Geospatial Fabric v1.1 (GFv1.1 or v1_1, added 08/04/2020) which is an update to the GF and includes the TGF, 3) Topographic derivative datasets for the United States-Canada transboundary Geospatial Fabric (added 10/28/2020), 4) Data Layers for the National Hydrologic Model, version 1.1, and 5) National Hydrologic Model's United States-Canada Transboundary Geospatial Fabric Parameter Database (added 11/10/2021). See subpages for more details.

This U.S. Geological Survey (USGS) data release record consists of topographic data themes that cover the United States-Canada Transboundary Geospatial Fabric (TGF) domain. The 30-meter (m) raster data sets included under Topographic Derivatives are: 1) digital elevation (dem.tif) , 2) topographic wetness index (TWI, twi100X.tif) ,3) slope (rise over run, slope100X.tif), 4) aspect (asp100X.tif), and flow direction (fdr.tif). In some instances, values were multiplied by 100 and converted from double precision to integer format to reduce file sizes. All file formats are in GeoTIFF (Geographic Tagged Imaged Format).