J. LaRue Smith 2004 raster digital data Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?nv_hlrnv_g Douglas K. Maurer Thomas J. Lopes Rose L. Medina J. LaRue Smith 2004 document U.S. Geological Survey Scientific Investigations Report 2004-5131 Reston, VA U.S. Geological Survey http://pubs.water.usgs.gov/sir2004-5131 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. This data set was created as part of a U.S. Geological Survey study, done in cooperation with the Nevada Division of Environmental Protection, to evaluate the susceptibility and vulnerability of ground water to anthropogenic contamination. Hydrologic landscape regions group areas in Nevada according to their similarity in landscape and climate characteristics. The landscape and climate characteristics represent factors assumed to affect hydrologic processes in the environment. The intended uses of this data set include, but are not limited to, natural resource modeling, mapping, and visualization applications. 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 (GIS) tools and statistical methods including cluster analysis. One use of the hydrologic landscape regions was to select water quality sample sites throughout the state. The data layers of hydrogeology, precipitation, soil permeability, land surface slope and aspect were used to identify the hydrologic landscape regions. Hydrogeology and soil permeability describe the geologic texture, land-surface slope and aspect describe the land surface form, and precipitation describes the climatic setting. For more information on the hydrogeologic landscape region process and theory see Maurer and others (2004). To identify hydrologic landscape regions the input data layers were generalized and then converted to raster format. A raster processing function combined the multiple grids on a cell-by-cell basis such that a unique value is assigned to each unique combination of input values. The resulting attribute table also includes the number of cells with each unique combination, and the values of each input grid. The combination process produced 112 unique combinations which were examined and reduced using cluster analysis. Cluster analysis is an exploratory data analysis tool for solving classification problems. Its objective is to sort cases (things, people, events, etc) into groups, or clusters, so that the degree of association is strong between members of the same cluster and weak between members of different clusters. Each cluster thus describes, in terms of the data collected, the class to which its members belong. Each cluster identifies a hydrologic landscape region. Cluster analysis identified 16 hydrologic landscape regions. The initial 112 combinations were reclassed to the 16 hydrologic landscape regions and a filtering process was used to remove areas smaller than a 4 hectare minimum mapping unit. References Maurer, D.K., Lopes, T.J., Medina, R.L., and Smith, J.L., 2004, Hydrogeology and hydrologic landscape regions of Nevada: U.S. Geological Survey Scientific Investigations Report 2004-5131, 35 p. 1961 2000 ground condition Complete None planned -120.180324 -113.694509 42.039355 34.967066 None hydrologic landscape regions precipitation soil permeability land surface slope land surface aspect hydrogeology inlandWaters None Nevada Great Basin None. The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as ArcGIS format, this metadata file may include some ArcGIS-specific terminology. Acknowledgment of the U.S. Geological Survey and the Nevada Division of Environmental Protection would be appreciated in products derived from these data. U.S. Geological Survey J. LaRue Smith Hydrologist mailing and physical address

333 W. Nye Lane

Carson City NV 89706 USA (775) 887-7630 (775) 887-7629 jlsmith@usgs.gov Compilation of this data set and the associated metadata was done in cooperation with the Nevada Division of Environmental Protection. Technical review of this data set and metadata was provided by Douglas O. Shipley and Brian D. Reece of the U.S. Geological Survey. Microsoft Windows 2000 Version 5.1 (Build 2600) Service Pack 1; ESRI ArcCatalog 8.3.0.800 The raster representation of precipitation, soil permeability, and hydrogeology were compared to their vector data sets graphically on screen or by plotting maps. Land surface slope and aspect were compared with a shaded relief representation of the base elevation data set. When data sets were grouped into a data range, the grouped data value was compared to the original data value at selected areas throughout the state in basin and range areas. Combinations of the five grids were compared to the original data values at selected areas throughout the state. After filtering was performed, the data set was compared to the data set before filtering. All steps were determined to have been performed properly and exactly. Throughout the processing tests of valid values were determined. All areas were completely described. No inconsistencies were determined. Complete for Nevada All attempts were made to compare the raster data representation to the original source data by visual inspection of selected areas. All data is accurate within the 30 meter cell size when converted from vector data. The accuracy of the source data for land surface slope and aspect is based on the National Elevation Dataset (NED) which is variable. See ftp://edcftp.cr.usgs.gov/pub/data/ned/documents/NED_Release_Notes_Dec03.pdf for a complete description of digital elevation model horizontal data accuracy. The accuracy of the source data for precipitation is based on the original specification of the Defense Mapping Agency 1 degree digital elevation models (DEM). The stated accuracy of the DEM is 130 meter circular error with 90 percent probability. The accuracy of the source data for hydrogeology is based on the 1:500,000-scale map product and deductively estimated at 260 meters. The accuracy of the source data for soil permeability is based on the 1:250,000-scale map product and deductively estimated at 130 meters. See ftp://edcftp.cr.usgs.gov/pub/data/ned/documents/NED_Release_Notes_Dec03.pdf for a complete description of digital elevation model vertical data accuracy. Chris Daly, Oregon State University George Taylor, Oregon Climate Service at Oregon State University 199705 vector digital data Portland, Oregon Water and Climate Center of the Natural Resources Conservation Service http://www.wcc.nrcs.usda.gov/gis/precip.html/ 250,000 online 1961 1990 publication date precip precipitation spatial data U.S. Geological Survey 1999 raster digital data http://ned.usgs.gov/ CD-ROM unknown publication date of source DEM NED elevation spatial data G.E. Schwarz R.B. Alexander 19950901 1.1 vector digital data Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ussoils 250,000 online 1994 publication date of original STATSGO data base USSOILS soil spatial data Rose L. Medina Douglas K. Maurer Thomas J. Lopes 2004 vector digital data Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?nv_hydgeolnv_p 500,000 online 2004 publication date NVHYDGEO hydrogeologic spatial data U.S. Geological Survey Unknown vector digital data Reston, VA U.S. Geological Survey http://edcsns17.cr.usgs.gov/EarthExplorer/ 100,000 CD-ROM unknown publication date DLG hydrology DLG The precipitation vector contour data was converted to ArcGIS TIN format using the ArcGIS createtin command. The contour value was used to create the TIN Z value. The TIN was converted to the GRID format with the ArcGIS tinlattice command using a linear interpolation maintaining an integer value. The precipitation data set was resampled to 30 meter cell size by setting the ArcGIS GRID environment variables setcell and setwindow to the NED. 200111 The attribute PERM was added to the USSOILS data set by relating the supplied data table based on the attribute MUID and populating the field with the permeability field. The data set was converted to raster using the ArcGIS GRID polygrid function based on the attribute PERM and setting the environment variables setcell and setwindow to the NED. 200307 Percent slope was calculated from the NED data using the ArcGIS GRID slope function. 200301 Aspect was calculated from the NED data using the ArcGIS GRID aspect function. 200301 The attribute GRID-CODE was added to the NVHYDGEOL data set. It was populated with a value of 0 for high conductivity or 1 for low conductivity based on the attribute HYDGEOL. High conductivity included unconsolidated formations except playas and the carbonate and basalt formations. Low conductivity included rhyolite, andesite, breccia/tuff, intrusive/metamorphic, sandstone, siltstone, and tertiary sedimentary formations and playas. The data set was converted to raster format using the ArcGIS GRID polygrid function based on the attribute GRID-CODE and setting the environment variables setcell and setwindow to the NED. 200405 The input grids, except for hydrogeolgy, were grouped into more general categories using the ArcGIS GRID reclass function. Lookup tables were created for soil permeability, precipitation, slope, and aspect data sets. Soil permeability was grouped into the ranges of 0 to 5 feet per day, greater than 5 to 10 feet per day, and greater than 10 feet per day. The soil permeability data set also had a unique code for waterbodies or no data. Precipitation was grouped into 0 to 8 inches, greater than 8 to 16 inches, and greater than 16 inches. Slope was grouped into 0 to 3 percent, greater than 3 percent to 25 percent, and greater than 25 percent. Aspect was grouped into 60 to 330 degrees or southerly facing slopes and the ranges of 331 to 360 and 0 to 59 degrees or northerly facing slopes. There was also a code for aspect if the cell had a level slope. If the slope at a cell was less than 3 percent, the aspect was considered not significant and was coded as level aspect. 200405 The five grids were combined using the ArcGIS GRID combine function. The value attribute table indicated a unique value for each unique combination, the number of cells with each value, and the input values of the five data sets. The table was exported as a DBASE format file for input into the SAS statistical package for cluster analysis. 200405 See Maurer and others (2004) for a description of the cluster analysis. A table was created from the results of the cluster analysis processing identifying the input combination number and the output cluster number. A lookup table was created for use in the ArcGIS GRID reclass function which mapped the 112 combinations to 16 cluster numbers. 200405 The filter process was achieved in multiple steps. The ArcGIS GRID regiongroup function recorded for each cell in the output the identity of the connected region to which it belongs within the analysis window assigning a unique number to each region. A mask grid was created by setting to null values those regions with less than 44 pixels or approximately 4 hectares, the minimum mapping unit. The ArcGIS GRID nibble function was used with the mask grid which replaced areas in the original grid, identified by the mask grid null values, with the values of the nearest neighbors based upon Euclidean distance. Due to computer program memory limitations, the filtering process was done in pieces based on 1:100,000-scale map quadrangle boundaries and then mosaicked back together. The quadrangle boundaries were buffered by 1500 meters using the ArcGIS buffer command and converted to grid format using the ArcGIS GRID polygrid function. This buffer represented more than the length a linear string of pixels could occupy and still have 44 contiguous pixels. After filtering an area represented by the buffered map quadrangle, the processing environment mask was set to the original 1:100,000-scale map quadrangle boundary, in grid format, and clipped the buffered area to the original map quadrangle boundary. All 1:100,000-scale map quadrangle grids were mosaicked back together using the ArcGIS GRID merge function. Null values, resulting from the clipping, masking and mosaicking process, in the resulting hydrologic landscape region grid were replaced with an adjacent pixel value. Values were calculated for the null values using the GRID focalmajority function with a 3-by-3 neighborhood. Using the ArcGIS GRID condition function, if a null value was found in the hydrologic landscape region grid, it was replaced with the result of the focalmajority function. 200405 A waterbody data set of selected lakes and reservoirs of the state was created. Waterbodies include Lake Mead, Lake Tahoe, Pyramid Lake, Walker Lake, Washoe Lake, Ruby Lake, Summit Lake, Toulon Lake, Humboldt Lake, Artesia Lake, Pahranaget Lakes, Lahontan Reservoir, Weber Reservoir, Rye Patch Reservoir, Wildhorse Reservoir, Adams-McGill Reservoir, and Topaz Reservoir. Most waterbodies came from the USSOILS data except the Pahranagat Lakes, Adams-McGill Reservoir, Weber Reservoir, Toulon Lake, and Wild Horse Reservoir which came from the USGS digital line graphs (DLG). The lakes were selected from each data set and combined into one data set using ArcGIS commands. The waterbodies were then converted to raster format using ArcGIS GRID polygrid command and setting the environment variables setcell and setwindow to the NED. The waterbodies were inserted into the final data set as null values using the ArcGIS GRID condition function. 200405 Raster Grid Cell 26021 17908 1 Transverse Mercator 0.999600 -117.000000 0.000000 500000.000000 0.000000 row and column 30.000000 30.000000 meters North American Datum of 1927 Clarke 1866 6378206.400000 294.978698 hlrnv_g.vat value attribute table ESRI ObjectID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Value Hydrologic landscape region number Statistical Analysis Software (SAS) 0 Waterbodies from USSOIL or no data for permeability USSOIL 1 The region has high precipitation: >16 in/yr; low soil permeability: <=5 ft/day; moderate slope: >3-25 percent; southerly aspect. Predominate distributions include Owyhee Upland, Modoc Plateau, and most ranges throughout Nevada. This region occures in 14,390 square miles of the State or 13.1 percent of the land. user-defined 2 The region has low precipitation: <=8 in/yr; low soil permeability: <=5 ft/day; moderate slope: >3 to 25 percent; southerly aspect. Predominate distributions include playas in Black Rock Desert and Smoke Creek Desert, Carson Sink, and southwestern Nevada. This region occurs in 8,110 square miles of the State or 7.4 percent of the land. user-defined 3 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: <5 to 10 ft/day; high slope: >25 percent; southerly aspect. Predominate distributions include Ranges in central and southeastern Nevada. This region occurs in 6,750 square miles of the State or 6.1 percent of the land. user-defined 4 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: >5 to 10 ft/day; low slope: <=3 percent; southerly aspect. Predominate distributions include playas in Desert Valley and central eastern Nevada. This region occurs in 5,700 square miles of the State or 5.2 percent of the land. user-defined 5 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: >5 to 10 ft/day; moderate slope: >3 to 25 percent; northerly aspect. Predominate distributions include small, scattered areas in consolidated rock throughout Nevada . This region occurs in 2,840 square miles of the State or 2.6 percent of the land. user-defined 6 The region has mostly moderate precipitation: >8 to 16 in/yr; mostly moderate soil permeability: >5 to 10 ft/day; high slope: >25 percent; northerly aspect. Predominate distributions include small, scattered areas in consolidated rock throughout Nevada. This region occurs in 2,660 square miles of the State or 2.4 percent of the land. user-defined 7 The region has low precipitation: <=8 in/yr; high soil permeability: >10 ft/day; mostly moderate slope: >3 to 25 percent; mostly southerly aspect. Predominate distributions include playas and consolidated rock in western to southern Nevada. This region occurs in 2,570 square miles of the State or 2.3 percent of the land. user-defined 8 The region has high precipitation: >16 in/yr; high soil permeability: >10 ft/day; moderate slope: >3 to 25 percent; southerly aspect. Predominate distributions include Fortymile Canyon and ranges in northwestern Nevada. This region occurs in 1,100 square miles of the State or 1.0 percent of the land. user-defined 9 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: >5 to 10 ft/day; low slope: <=3 percent; southerly aspect. Predominate distributions include valley floors in east central and north central Nevada. This region occurs in 24,390 square miles of the State or 22.2 percent of the land. user-defined 10 The region has low precipitation: <=8 in/yr; high soil permeability: >10 ft/day; mostly moderate slope: >3 to 25 percent; mostly southerly aspect. Predominate distributions include alluvial slopes from western to southern Nevada. This region occurs in 13,330 square miles of the State or 12.1 percent of the land. user-defined 11 The region has high precipitation: >16 in/yr; low soil permeability: <=5 ft/day; moderate slope: >3 to 25 percent; southerly aspect. Predominate distributions include ranges in central eastern and western Nevada. This region occurs in 10,260 square miles of the State or 9.3 percent of the land. user-defined 12 The region has low precipitation: <=8 in/yr; low soil permeability: <=5 ft/day; moderate slope: >3 to 25 percent; southerly aspect. Predominate distributions include alluvial slopes in southwestern and southern Nevada. This region occurs in 6,750 square miles of the State or 6.1 percent of the land. user-defined 13 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: >5 to 10 ft/day; high slope: >25 percent; southerly aspect. Predominate distributions include ranges in eastern and southern Nevada. This region occurs in 4,200 square miles of the State or 3.8 percent of the land. user-defined 14 The region has moderate precipitation: >8 to 16 in/yr; moderate soil permeability: >5 to 10 ft/day; moderate slope: >3 to 25 percent; northerly aspect. Predominate distributions include Indian Springs Valley, Three Lakes Valley, and small, scattered areas in consolidated rock throughout Nevada. This region occurs in 3,210 square miles of the State or 2.9 percent of the land. user-defined 15 The region has high precipitation: >16 in/yr; high soil permeability: >10 ft/day; moderate slope: >3 to 25 percent; southerly aspect. Predominate distributions include alluvial slopes in eastern and southern Nevada. This region occurs in 2,160 square miles of the State or 2.0 percent of the land. user-defined 16 The region has mostly moderate precipitation: >8 to 16 in/yr; mostly moderate soil permeability: >5 to 10 ft/day; high slope: >25 percent; northerly aspect. Predominate distributions include small, scattered areas in consolidated rock in eastern and southern Nevada. This region occurs in 1,440 square miles of the State or 1.3 percent of the land. user-defined Count Number of 30-by-30 meter pixels with value ESRI 31883 70199118 The field VALUE is a categorical unique number. COUNT is the number of pixels with VALUE. Table characterizing hydrologic landscape regions of Nevada. [HLR, hydrologic-landscape-region number. Precip: precipitation in inches/year. Soil: soil permeability in feet/year. Slope: land surface slope in percent. Aspect: S, 60 to 330 degrees or southerly facing; N, 0 to 59 and 331 to 360 degrees or northerly facing. Area: area in square miles. Percent: percent area of Nevada. >, greater than. <, less than. M, mostly.] The Value 0 has no data for soil permeability. Values 1 to 8 are characterized by low hydraulic conductivity or <40 feet/day. Values 9 to 16 are characterized by high hydraulic conductivity or >40 feet/day. HLR Precip. Soil Slope Aspect Area Percent 1 >16 <=5 >3-25 S 14,390 13.1 2 <=8 <=5 >3-25 S 8,110 7.4 3 >8-16 >5-10 >25 S 6,750 6.1 4 >8-16 >5-10 <=3 S 5,700 5.2 5 >8-16 >5-10 >3-25 N 2,840 2.6 6 M >8-16 M >5-10 >25 N 2,660 2.4 7 <=8 >10 M >3-25 M S 2,570 2.3 8 >16 >10 >3-25 S 1,100 1.0 9 >8-16 >5-10 <=3 S 24,390 22.2 10 <=8 >10 M >3-25 M S 13,330 12.1 11 >16 <=5 >3-25 S 10,260 9.3 12 <=8 <=5 >3-25 S 6,750 6.1 13 >8-16 >5-10 >25 S 4,200 3.8 14 >8-16 >5-10 >3-25 N 3,210 2.9 15 >16 >10 >3-25 S 2,160 2.0 16 M >8-16 M >5-10 >25 N 1,440 1.3 Provided above U.S. Geological Survey Ask USGS - Water Webserver Team mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ARCE in Unix gzip format Full coverage zipped 69.184 http://water.usgs.gov/GIS/dsdl/nv_hlrnv_g.e00.gz Other BIL in WinZip format zipped 24.615 http://water.usgs.gov/GIS/dsdl/nv_hlrnv_g.bil.zip None. This dataset is provided by USGS as a public service. The ArcGIS grid was reformatted to band interleaved by line (BIL). The file was compressed with WinZip. When uncompressed the BIL and associated files will be about 455.06 megabytes in size. The ArcGIS grid was reformatted to ArcGIS interchange file format (.e00). The file was compressed with Unix gzip. When uncompressed the .e00 file will be 6553.675 megabytes in size. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+nv_hlrnv_g FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998