Randell J. Laczniak 2006 map Digital geospatial data sets for the hydrogeologic framework and transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California hobs_ss Henderson, Nevada U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?sir045205_hobs_ss Belcher, W.R. and Sweetkind, D.S. (editors) 2010 U.S. Geological Survey Professional Paper 1711 Reston, Virginia U.S. Geological Survey 6 chapters, 2 appendices, 2 plates, 403 p. http://pubs.er.usgs.gov/publication/pp1711 Belcher, W.R. (editor) 2004 U.S. Geological Survey Scientific Investigations Report 2004-5205 Reston, Virginia U.S. Geological Survey 6 chapters, 2 appendices, 2 plates, 408 p. http://pubs.usgs.gov/sir/2004/5205/ This digital geospatial data set contains the locations, values, and uncertainties of 700 hydraulic-head observations used in the steady-state, prepumped period of the transient model of the Death Valley regional ground-water flow system (DVRFS), a 100,000-square-kilometer region of southern Nevada and California. Hydraulic-head observations, which are the composite of one or more water-level measurements made at a well, are used to calibrate ground-water flow models. To develop hydraulic-head observations for the DVRFS ground-water flow model, nearly all available water levels for the DVRFS region through 2004 were compiled in Ground-Water Site Inventory (GWSI), the ground-water component of the U.S. Geological Survey (USGS) National Water Information System (NWIS) database. Water levels suitable for developing hydraulic-head observations representative of regional, steady-state ground-water flow conditions were identified through analyses. The resulting water levels were averaged for each well to produce one hydraulic-head observation value at each of 700 wells. The uncertainty of each hydraulic-head observation was statistically quantified from the values of uncertainties associated with well altitude and location, nonsimulated transient stress, and measurement accuracy. The hydraulic-head observations and associated uncertainties in this data set represent regional, steady-state (not affected by pumping) ground-water conditions in the DVRFS transient ground-water flow model. Head observations and their uncertainties are an input file to MODFLOW-2000, the USGS 3D finite-difference code used to simulate ground-water flow in the DVRFS. The steady-state, hydraulic-head observation data set is one of many layers in a geospatial database supporting the USGS DVRFS project. During this 5-year (1998-2004) project the USGS, in cooperation with DOE and other Federal, State, and local agencies, developed this geospatial database for a regional-scale, 3D hydrogeologic framework model (HFM) and a ground-water flow model. The models are intended to address water-resource issues and the potential movement of radioactive material from the Nevada Test Site and the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Data from two previous ground-water flow models of the greater Death Valley region (see "Larger Work Citation", Chapter A, p. 7) were the foundation of the DVRFS geospatial database. Those and other data were reexamined through a series of regional-scale hydrologic investigations to provide updated and spatially consistent interpretations for the DVRFS study. In some cases, new data were collected to augment the existing information. Data compiled from the studies include natural ground-water discharge occurring through evapotranspiration and spring flow; ground-water pumping for the period 1913-98; ground-water recharge simulated as net infiltration; ground-water inflow and outflow at lateral model boundaries; hydraulic conductivity and its relation to depth and other rock properties; and the estimation of water levels representative of prepumped and pumped conditions in the region. Digital elevation models, geologic maps, borehole information, cross sections, and other 3D models were used to develop the HFM which represents the geometry of 27 hydrogeologic units and structural features. The resulting geospatial database supports characterization and conceptualization of the DVRFS, construction of 3D hydrogeologic framework and ground-water flow models, and visualization of analysis and model results. 1907 2004 ground condition Complete None planned -117.389566 -115.174867 37.905350 35.635253 USGS Water Basics Glossary. Accessed May 3, 2005 at http://capp.water.usgs.gov/GIP/h2o_gloss/; American Geological Institute Glossary of Geology Death Valley regional ground-water flow system flow model ground water hydraulic head hydraulic-head observation hydrogeology hydrology MODFLOW-2000 observation uncertainty steady state ground-water model transient ground-water model water level water well U.S. Board of Geographic Names (BGN) and Geographic Names Information System (GNIS) Amargosa Desert Ash Meadows California Valley Chicago Valley China Ranch Clark County Clayton Valley Coal Valley Death Valley eastern California Esmeralda County Eureka Valley Franklin Lake Franklin Well Garden Valley Inyo County Kern County Las Vegas Valley Lincoln County Mesquite Valley Mineral County Mono County Nevada Nevada Test Site Nye County Oasis Valley Owlshead Mountains Pahranagat Range Pahrump Valley Panamint Range Penoyer Valley Railroad Valley Resting Spring Saline Valley San Bernardino County Sarcobatus Flat Sheep Range Shoshone Silurian Valley southern Nevada Spring Mountains Stewart Valley Stone Cabin Valley Tecopa Yucca Mountain None Data have been checked to ensure the accuracy of the data. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology. U.S. Geological Survey Randell J. Laczniak mailing and physical address

160 N. Stephanie Street

Henderson Nevada 89074 USA (702) 564-4603 (702) 564-4600 rlaczni@usgs.gov http://water.usgs.gov/GIS/browse/sir045205_hobs_ss.jpg Illlustration of data set jpg Spatial data sets supporting the Death Valley regional ground-water flow system (DVRFS) project were developed in cooperation with the U.S. Department of Energy (DOE) National Nuclear Security Administration/Nevada Site Office (NNSA/NSO) Underground Test Area (UGTA) project of the Office of Environmental Management, the NNSA/NSO Hydrologic Resource Management Program (HRMP), the Office of Civilian Radioactive Waste Management (OCRWM) Yucca Mountain Project (YMP), the NNSA/NSO Maintenance of Test Capability (MTC) program, and the National Park Service (NPS). Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 Attributes in this data set were derived either from the USGS GWSI database or the data set author (Point of Contact). The transfer of attributes from the USGS GWSI database was validated through manual comparison and cross checking. The accuracy of GWSI attribute information is indicated by accuracy codes which reflect the accuracy of the original source. Attributes added by the data set author were checked routinely by inspection using queries, hardcopy printouts, and visually using a GIS. In addition, attributes were checked and evaluated as part of the review process associated with the publication of the source report (Larger Work Citation). Points represent real-world well locations. Coincident points represent the locations of multiple piezometers in a single well, multiple completions within a single well, or a well that has been recompleted to a new depth. All accessible water-level and well-completion data through 2004 for the region were obtained from Nye County, Nevada; the States of Nevada and California; U.S. Geological Survey (USGS); National Park Service; U.S. Fish and Wildlife Service; Department of Energy Yucca Mountain Project and Underground Test Area Program; and local mining operations. The resulting compilation of nearly 40,000 water-level measurements in about 2,100 wells was transferred to the USGS GWSI database. Temporal and spatial gaps in the water-level data were addressed by making additional field measurements or by compiling previously omitted measurements. Analyses to assess the suitability of measurements for developing regional, steady-state head observations for the DVRFS flow model reduced the data set to about 12,000 water levels in 700 wells.Wells having insufficient information for determining an open interval were omitted. The water levels suitable for estimating steady-state (not affected by pumping) head observations at each well were averaged to produce one hydraulic-head observation value at each of the 700 observation wells represented in this data set. The accuracy of a well location is indicated by the coordinate accuracy code reported in GWSI. Coordinate accuracy codes vary according to methods used to locate a well. Latitude and longitude coordinate accuracy codes given in GWSI for wells in the DVRFS region typically range from about 0.1 to 100 seconds. Higher accuracy is associated with high-precision surveying methods, such as spirit level or differential global positioning system (GPS) surveying; and lower accuracy with coordinates determined solely on the basis of a given map. The accuracy of land-surface altitude at a well location is indicated by the altitude accuracy code reported in GWSI. Altitude accuracy codes are expressed as a plus/minus (±) range related directly to the method by which the altitude was determined. Ranges vary from about ±0.03 m for high-precision methods, such as spirit level and GPS surveying, to about ±25 m for estimates determined from topographic maps having large (50 m) contour intervals. USGS 20040810 tabular digital data Source is a USGS National water-resources database http://waterdata.usgs.gov/nwis/gwsi online 20040810 Extraction date GWSI Source database from which water levels were retrieved SQL queries were used to extract all water-level and well-completion information for the DVRFS study area through August 10, 2004 from the USGS GWSI database. The resulting data set of nearly 40,000 water levels measured in about 2,100 wells was stored in an intermediate Microsoft Access project database. Wells having insufficient information for determining an open interval were omitted. Each water-level measurement was assigned attributes to assess its suitability for developing hydraulic-head observations that were representative of regional, steady-state conditions. These attributes were determined by analyzing hydrographs, reviewing reports, and evaluating the well location relative to centers of pumping and underground nuclear tests. Open-interval depth information for wells also was evaluated to assess whether measured fluctuations result from precipitation variations or evapotranspiration. About 12,000 water levels in 700 wells were attributed as appropriate for use in developing regional, steady-state hydraulic-head observations. The head observation was computed as the average of all regional, steady-state water levels at each well. Values of errors for the well location and altitude, nonsimulated transient stress, and water-level measurement methods were used to statistically quantify the value of uncertainty for each hydraulic-head observation. The average water levels, uncertainty values, and attribute information required to construct a MODFLOW-2000 input file were transferred from the intermediate Microsoft Access database to a GIS (ArcMap) to create this digital data set. GWSI 2004 Point Entity point 700 Universal Transverse Mercator 11 0.999600 -117.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000512 0.000512 meters North American Datum of 1927 (NAD 27) Clarke 1866 6378206.400000 294.978698 well (water) An excavation (pit, hole, tunnel), generally cylindrical in form and often walled in, that is drilled, dug, driven, bored, or jetted into the ground to such a depth as to penetrate water-yielding geologic material and allow the water to flow or to be pumped to the surface. Nevada Division of Water Planning Dictionary, Technical water, water quality, environmental, and water-related terms. Accessed May 3, 2005 at http://water.nv.gov/Water%20planning/dict-1/wwords-w.pdf. FID Environmental Systems Research Institute, Inc. (ESRI) ESRI Sequential unique whole numbers that are automatically generated Shape Feature geometry ESRI Coordinates defining the features SITEID USGS unique well identification number GWSI Unique number identifier for each well SITENAME Name of a well GWSI Unique text identifier for each well OBSNAM Identifier of hydraulic-head observation for MODFLOW model input MODFLOW Unique identifier for each hydraulic-head observation EASTING Easting coordinate of well (UTM coordinates referenced to NAD 27) GWSI 465751.525128 660489.2258379 Meter NORTHING Northing coordinate of well (UTM coordinates referenced to NAD 27) GWSI 3944740.895140 4195107.726580 Meter ALTITUDETO Altitude of top opening of uppermost open interval (in meters referenced to NAVD 88) Author (Point of Contact) -525 2457 Meter ALTITUDEBO Altitude of bottom opening of lowermost open interval (in meters referenced to NAVD 88) Author (Point of Contact) -2307.13 2426.09 Meter HOBS Hydraulic-head observation altitude for each well for MODFLOW input (in meters referenced to NAVD 88) MODFLOW-2000 -85.50 2498.07 Meter IREFSP Stress period used in MODFLOW simulation to which the time of the hydraulic-head observation is referenced MODFLOW-2000 1 Steady state MODFLOW-2000 TOFFSET Time offset from reference stress period in MODFLOW simulation to the time of the hydraulic-head observation (in days) MODFLOW-2000 0 No time offset MODFLOW-2000 NH Total number of hydraulic-head observations used in MODFLOW simulation MODFLOW-2000 Total number of hydraulic-head observations (700) EVH Error variance multiplier for hydraulic-head observations MODFLOW-2000 Error variance multiplier value (1) STAT Hydraulic-head observation error statistic (standard deviation, in meters) MODFLOW-2000 0.76 216.22 Meter IST Statistic code for type of statistic used to represent observation error MODFLOW-2000 1 Standard deviation MODFLOW-2000 PLOT_SYM Plot symbol integer used for graphical analysis MODFLOW-2000 1 Hydraulic-head observation Author (Point of Contact) ROW Model grid row number where hydraulic-head observation is located MODFLOW-2000 16 183 Integer COLUMN Model grid column number where hydraulic-head observation is located MODFLOW-2000 20 149 Integer ROFF Row offset used to locate hydraulic-head observation within a model grid cell MODFLOW-2000 -0.499 0.496 Dimensionless COFF Column offset used to locate hydraulic-head observation within a model grid cell MODFLOW-2000 -0.5 0.5 Dimensionless LAY2_TOP Altitude of top of DVRFS ground-water flow model layer 2 at hydraulic-head observation location (in meters referenced to NAVD 88) Author (Point of Contact) -120.916 2508.418 Meter LAYTOP Topmost layer of flow model penetrated by hydraulic-head observation well Author (Point of Contact) 1 14 Integer LAYBOT Bottommost layer of flow model penetrated by hydraulic-head observation well Author (Point of Contact) 1 16 Integer LAYTOT Number of flow model layers penetrated by hydraulic-head observation well Author (Point of Contact) 1 15 Integer RESIDUAL Difference between the observed and model simulated value of a head observation Author (Point of Contact) -320.2328 439.5044 Meter WRESIDUAL Weighted difference between the observed and model simulated value of a head observation Author (Point of Contact) -17.89954 54.47909 Meter Each point feature has 27 attributes. Two attributes are automatically generated by the GIS (FID, Shape) for internal software purposes. The remaining attributes were assigned by the authors (Citation Originators) for analysis and[or] descriptive purposes. U.S. Geological Survey, 2004, User's manual for the national water information system of the U.S. Geological Survey: Ground-water site-inventory system, Version 4.3: U.S. Geological Survey Open-File Report 2004-1238, 275 p. Accessed May 2, 2005, at http://water.usgs.gov/pubs/of/2004/1238/. Hill, M.C., Banta, E.R., Harbaugh, A.W., and Anderman, E.R., 2000, MODFLOW-2000, The U.S. Geological Survey modular ground-water flow model user guide to the observation, sensitivity, and parameter-estimation processes and three post-processing programs: U.S. Geological Survey Open-File Report 00-184, 209 p. Accessed May 2, 2005, at http://water.usgs.gov/nrp/gwsoftware/modflow2000/modflow2000.html U.S. Geological Survey Ask USGS - Water Webserver Team mailing and physical address

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Reston VA 20192 USA 1-888-275-8747 http://water.usgs.gov/user_feedback_form.html Contact via email or phone. Digital geospatial data sets for the transient ground-water flow model and hydrogeologic framework model, Death Valley regional ground-water flow system, Nevada and California Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. These data should be directly acquired from a U.S. Geological Survey server, and not indirectly through other sources that may have altered the data in some way. Shapefile 1.0 unzip 100 Kilobytes http://water.usgs.gov/GIS/dsdl/hobs_ss.zip None 20050228 U.S. Geological Survey mailing address

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Reston Virginia 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+sir045205_hobs_ss FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998