J. LaRue Smith Toby L. Welborn 2006 raster digital data http://water.usgs.gov/lookup/getspatial?sir2006-5100_dtwnv_g Thomas J. Lopes Susan G. Buto J. LaRue Smith Toby L. Welborn 2006 document U.S. Geological Survey Scientific Investigations Report 2006-5100 http://pubs.water.usgs.gov/sir2006-5100 This is a raster-based, depth to ground-water data set for the State of Nevada. The source of this data set is a statewide water-table contour data set constructed from water-table contours collected from 1947 to 2004 and published in 38 reports from 1961 to 2004, depth to ground water contours from Static Ground Water Levels of Nevada published in 1974, and depth to ground water contours from Diamond Valley published in 2006. 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. The data set was created as part of an effort to provide statewide information on depth to ground water and water-table levels in Nevada. One variable that may control the susceptibility of ground water to contamination and determines contamination transport is depth to water (Lopes and others, 2006). The intended uses of this data set include, but are not limited to, natural resource modeling, mapping, and visualization applications. Reference Cited Lopes, T.J., Buto, S.G., Smith, J.L., and Welborn, T.L., 2006, Water-table levels and gradients, Nevada, 1947-2004: U.S. Geological Survey Scientific Investigations Report 2006-5100, 27 p. All source maps were of ground-water altitude, except Diamond Valley and Rush (1974), which had depth to ground water contours. The Diamond Valley and Rush (1974) contours were processed with the National Elevation Dataset (NED) to determine ground-water altitude. 1947 2004 ground condition at the time of water-level measurement or the publication date of the source Complete None planned -120.304400 -113.694808 42.040375 34.962960 None depth to ground water ground water depth to ground-water surface inlandWaters None Nevada Great Basin none These data are not intended to be used as a survey product and are for reference purposes only. Although this Federal Geographic Data Committee (FGDC) 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 Public Information Assistant mailing and physical address

333 W. Nye Lane

Carson City NV 89706 USA (775) 887-7600 (775) 887-7629 GS-W-NVpublic-info@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 C. Amanda Garcia of the U.S. Geological Survey. Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 1; ESRI ArcCatalog 9.0.0.580 J. LaRue Smith Toby L. Welborn 2006 raster digital data http://water.usgs.gov/lookup/getspatial?sir2006-5100_wanv_g The attribute value is the depth to ground water derived from the published water-table contour lines. All generated surfaces were compared to their vector representation and appeared representative of the original contour lines. Tests of valid surfaces were run throughout processing. 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 after every hydrographic area was processed. The horizontal positional accuracy is dependent on the scale of the source map. The horizontal error can range from 12 meters at 1:24,000-scale to 508 meters at 1:1,000,000-scale. See Buto (2006) error estimates for each set of contours used to generate this data set. All attempts were made to compare the raster data representation to the original source data after every hydrographic area was processed. Vertical accuracy of the source data can vary. Vertical datum differences were disregarded based on the relative inaccuracy of the input and output data. Vertical accuracy of the conversion to a raster surface can produce errors. The date the source data were generated can produce vertical error. The vertical error throughout the data set can vary. U.S. Geological Survey 1999 raster digital data http://gisdata.usgs.gov/NED CD-ROM unknown publication date of source DEM NED elevation and spatial information Susan G. Buto David M. Evetts Sienna Smith-Sager 2006 vector digital data http://water.usgs.gov/lookup/getspatial?sir2006-5100_wanv_l variable online 1947 2004 ground condition at the time of water-level measurement or the publication date of the source wanv_l mass points for surface generation Douglas K. Maurer Susan G. Buto 2006 vector digital data http://water.usgs.gov/lookup/getspatial?sir2006-5100_dtwha153_l online 200103 200104 ground condition dtwha153nv_l mass points for surface generation J. LaRue Smith Toby L. Welborn 2006 raster digital data http://water.usgs.gov/lookup/getspatial?sir2006-5100_wanv_g online 1947 2004 ground condition at time of water-level measurement or the publication date of the source wanv_g mass points for surface generation Susan G. Buto Sienna Smith-Sager 2006 vector digital data http://water.usgs.gov/lookup/getspatial?nv_dtw750nv_l 1:750,000 online 1974 publication date dtw750nv_l mass points for surface generation Rose L. Medina Douglas K. Maurer Thomas J. Lopes 2004 vector digital data http://water.usgs.gov/lookup/getspatial?nv_hydgeolnv_p 1978 1986 1994 1999 publication date of the source data hydgeolnv_p spatial and attribute data Lorri A. Peltz Rose L. Medina Susan G. Buto 2005 vector digital data http://water.usgs.gov/lookup/getspatial?nv_ha750nv 1948 2000 publication date of source map and additional attribute information ha750nv spatial and attribute data J. LaRue Smith Unpublished material vector digital data unknown unknown publication date lakenv_p spatial and attribute data Rush (1974) depth to water contours (dtw750nv_l) were used to supplement the water-table contour lines (wanv_l). Dtw750nv_l contours were selected and edited if they did not directly contradict with wanv_l values and if they filled in data gaps for each hydrographic area (HA) or group of HAs. Dtw750nv_l contours were trimmed in areas where contours overlapped wanv_l in ArcEdit workstation. dtw750nv_l 200504 rush_l Diamond Valley depth to water contours (dtwha153_l) were appended to the selected Rush (1974) depth to water contours (rush_l) using the append function in ArcToolbox. ArcToolbox > Data Management Tools > General/Append rush_l dtwha153_l 200505 rush_l The National Elevation Dataset (NED) elevation raster was resampled from 30 m to 300 m to provide a snapping base at a 1:250,000-scale. Resampling was done using the Spatial Analyst extension in ArcGIS 9.0. Options were set to the extent of elev30g and a cell size of 300 m. elev300g = [elev30g] NED 200505 elev300g Rush_l was converted from vector to raster using the Spatial Analyst extension. The extent and cell size were set to elev300g. Spatial Analyst > Convert > Features to Raster rush_l 200505 rush_g Rush_g was converted from depth to water to water-table by subtracting it from elev300g using the Raster Calculator in the Spatial Analyst extension. Rush_g was set as the mask and the extent and cell size were set to elev300g. Vertical datum differences were disregarded based on the relative inaccuracy of the input and output data. rushwa_g = [elev300g] - [rush_g] rush_g 200505 rushwa_g Wanv_l lines were converted from vector to raster using the Spatial Analyst extension. The extent and cell size were set to elev300g. Spatial Analyst > Convert > Feature to Raster wanv_l 200506 wa_g Wa_g and rushwa_g were merged together using the Raster Calculator in the Spatial Analyst extension. Vertical datum differences were disregarded based on the relative inaccuracy of the input and output data. ttlwa_g = MERGE ([wa_g], [rushwa_g]) wa_g rushwa_g 200506 ttlwa_g Ttlwa_g values were converted to points, where the centroid of each 300 m cell contained one point with the cell's water-table value, using the Spatial Analyst extension. Spatial Analyst > Convert > Raster to Feature ttlwa_g 200506 wa300_x A polygon defining the zone of interpolation, or hull, for each HA or group of HAs was created from the geographic extent of the three contour data sets, wanv_l, dtw750_l, and dtwha153_l. The hull usually consisted of straight lines connecting the ends of each contour. If a contour line had no other contour line that could be logically connected, the hull would be delineated so that all or part of the contour line was not included. The hull was delineated using a shaded-relief map as a backdrop. The shaded relief was used to define the probable extent of ground water based on topography. If topographic high or low features occurred within contoured areas, a boundary was not identified to remove the feature. Hulls were created as coverages using ArcEdit. wanv_l dtw750_l dtwha153_l 200405 - 200505 ha### polygon Hulls were loaded into one personal geodatabase feature class in ArcCatalog. Right Click on the geodatabase in Arc Catalog > Import > Feature Class (multiple) ha### polygon 200506 boundarylines_l Boundarylines_l were modified to reflect changes in contour line work modification with topology rules Must Not Intersect and Must Not Have Dangles. Hulls were built from boundarylines_l using the New Polygon Feature Class from Lines function in ArcCatalog. Right Click on Feature Dataset in Arc Catalog > New > Polygon Featureclass from Lines boundarylines_l 200506 hulls_p Unconsolidated rock was selected from the Hydrogeology of Nevada (hydgeolnv_p) to be used as a mask during the interpolation process. The entire HA was selected for the known deep contours in HAs 42, 43, 44, 45, 48, 49, 50, 51, 52, 61, 62, 64, 147, 160, 227B, 228 and appended to the data set. Selection > Select by Attributes > Set Layer to hydgeolnv_p > 'CONSOL' = 'U' Right Click on Data Set/Export Data To add the select HA: 1. Set edit target to unconsolidated. 2. Selection > Select by Attributes > Set Layer to ha750nv > "HYD_AREA" in ('42', '43', '44', '45', '48', '49', '50', '51', '52', '61', '62', '64', '147', '160', '227B', '228') 3. Right click in ArcMap with the Edit Tool > Copy 4. Paste selection into unconsolidated hydgeolnv_p ha750nv 200506 unconsolidated Unconsolidated was then rasterized and calculated to a value of 1 using the Raster Calculator in the Spatial Analyst extension. Spatial Analyst > Convert > Feature to Raster [unconsolidated_g] = 1 unconsolidated 200506 unconsolidated_g The water-table surface was created using an Inverse Distance Weighted (IDW) interpolation in the Spatial Analyst extension. The unconsolidated_g was set as the mask, wa300_x were the input points, the Z Value was set to the wa300_x ELEV_M field, distance weighting was done to a power of 2, with 12 points defined in the search radius distance, and with boundarylines_l defined as barrier polylines. Spatial Analyst > Interpolation > Inverse Distance Weighted wa300_x boundarylines_l unconsolidated_g 200506 wanv300_g Areas of open water were removed from the data set using the Selected Waterbodies of Nevada (lakenv_p) data set and the Raster Calculator in the Spatial Analyst extension. Spatial Analyst > Convert > Feature to Raster lake1_g = -9999 newmsk_g = merge ([lake1_g], [unconsolidated_g]) Reclass -9999 to NoData: Spatial Analyst > Reclass Set Mask to reclassed raster: wanv300_g2 = [wanv300_g] unconsolidated_g lakenv_p wanv300_g 200506 wanv300_g2 A depth to ground water raster (dtwnv_g) was created by subtracting wanv_g from elev300_g using the Raster Calculator in the Spatial Analyst extension. Vertical datum differences were disregarded based on the relative inaccuracy of the input and output data. dtw300_g = [elev300_g] - [wan300v_g] wanv_g elev300_g 200506 dtw300_g Dtw300_g was converted from meters to feet using the Raster Calculator in the Spatial Analyst extension. dtwnv1_g = [dtw300nv_g] * 3.28083 dtw300nv_g 200506 dtwnv1_g Because of the scale differences in the input contours, several shallow ground-water areas were above land surface elevation. These areas were edited to conform with Office of Water Information Technical Memorandum no. 2002.06 by assigning cell values of one using the Raster Calculator in the Spatial Analyst extension. dtwnv1_g 200506 dtwnv_g Data set was integerized using ArcToolbox. ArcToolbox > Spatial Analyst Tools > Raster Math > Int dtwnv_g 200508 dtwnv_g Raster Grid Cell 26036 18253 1 Universal Transverse Mercator 11 0.999600 -117.000000 0.000000 500000.000000 0.000000 row and column 300.000000 300.000000 meters North American Datum of 1927 Clarke 1866 6378206.400000 294.978698 Unknown Unknown feet Attribute values dtwnv_g.vat value attribute table ESRI ObjectID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Value depth to ground water user-defined 1 3820 feet Count Number of 30-by-30 meter grid cells with the same value ESRI 1 130658 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing and physical address

445 National Center

Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+sir2006-5100_dtwnv_g Downloadable Data 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 these data, software, or related materials. 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. BIL in WinZip format spatial and attribute information WinZip 0.730 http://water.usgs.gov/GIS/dsdl/sir2006-5100_dtwnv_g.bil.zip None. This data set is provided by USGS as a public service. 20060508 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing and physical address

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+sir2006-5100_dtwnv_g FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998