Russel W. Plume Toby L. Welborn 2009 vector digital data U.S. Geological Survey Scientific Investigations Map SIM2009-3063 Reston, VA U.S. Geological Survey https://water.usgs.gov/lookup/getspatial?sim3063_Tahoe_Geophysical Russell W. Plume, Mary L. Tumbusch, and Toby L. Welborn 2008 pdf document Scientific Investigations Map SIM2009-3063 Reston, Virginia U.S. Geological Survey https://pubs.usgs.gov/sim/3063/ These data present a ground-water inventory of existing geospatial data and other information needed to determine the extent and characteristics of the aquifers in the Tahoe Basin. Geospatial and other data include geologic maps and soil surveys of the entire basin and for specific watersheds within the basin at the best available scales; vegetation remote-sensing datasets; well information from various local, state, and federal agencies; geophysical surveys; and results of available ground-water studies. The compilation and development of a ground-water inventory geospatial database will assist the United States Forest Service in better assessing the present and future impacts on ground-water resources within the Lake Tahoe Basin. These data were developed in support of the Lake Tahoe ground-water inventory. The intended uses of this data set include, but are not limited to, natural resource modeling, mapping, and visualization applications. 1988 1992 publication date Complete None planned -120.223895 -119.946799 39.255711 38.850791 USGS Thesaurus Geophysics Seismic Inland waters USGS Metadata Identifier USGS:5cc0d194-0502-48fb-b23a-cbdd463817bd Geographic Names Information System Lake Tahoe Nevada California None 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. These data are not intended to be used as a survey product and are for reference purposes only. U.S. Geological Survey Nevada Water Science Center Public Information Officer mailing and physical address

2730 N. Deer Run Road

Carson City NV 89701 USA (775)887-7600 (775)887-7629 https://water.usgs.gov/GIS/browse/sim3063.jpg Map of the Hydrogeology of the Lake Tahoe Basin, California and Nevada jpg Acknowledgment of the U.S. Geological Survey and the U.S.Forest Service would be appreciated in products derived from these data. Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 Markiewicz, R.D. 1992 document Denver, CO Bureau of Reclamation As part of the Technical Assistance to The States Program, the Bureau of Reclamation initiated and conducted a series of geophysical surveys consisteing of seismic reflection and electrical resistivity measurements at verious location with the Lake Tahoe Basin, California and Nevada. The purpose of the geophysical surveys was twofold. First, the surveys were designed to help determine the location of granitic bedrock at selected sites within the basin. Second, the surveys were designed to provide any information obtainable avout the relative grain sizes of alluvial and reworked glacial (glacial-fluvial) materials. The depth to granitic bedrock and hence the total glacio-fluvial thickness is related to the amount of saturated section to be expected at a water well site. the relative grain size of glacio-fluvial materical is an indicator of how much water the well will ultimately produce for a given saturated section, clean sands and gravels producing relatively more and clays and silts producing relatively less water. Niblack, Robert L. 1988 document Ward Creek drains a 31Km^2 basin on the west side of Lake Tahoe. Ground water from the basin flows directly into Lake Tahoe. In order to determine the quantity of ground water flowing from the aquifer into the lake, surface geophysical methods were proposed to determine the configuration of the Ward Valley aquifer. 28 vertical electrical soundings (VES) were completed in the Ward Valley area in an attempt to define the aquifer limits, the resulting apparent resistivity data were inverted for resistivity depth structure. The aquifer boundaries were considered to be the contact between an impervious igneous basement rock and unconsolidated sediments or lake bed deposits. Results of the VES survey indicate that the aquifer depth at the interface with Lake Tahoe is greater than 50 meters below the lake surface, and the unconsolidated sediments probably overlie a low resistivity volcanic formation. Water bearing properties of the volcanicformation may be intermediate between the unconsolidated sediments, and a nearly impermeable bedrock. The resistivity value of olivine latite ocurring in the study area, which is the highest resistivity of any subsurface formation identified in this study, is from 700 to 900 ohm-meters. The olivine latite flow at Paige Meadows, in the north central study area is underlain by a low resistivity formation which probably consists of oldervolcanic rocks. A meadow in the Ward Creek delta is underlain by a high resistivity volcanic flow formation which may be an estension of the olivine latite. Surface resistivity values greater than 10,000 ohm-meters are typical for hillside settings surrounding Ward Valley. Verification was done by interactive on-screen review. Frequency tests were performed on all feature class attributes to check that no features were unlabeled, misspelled, or inconsistent. Corrections were made until one visual comparison, combined with on-screen review, determined 100 percent of the digital attribute data was correct. Consistent with source data. Complete Errors resulting from source data quality, automation processes, and scale resolution can impact the accuracy of data. These data are derived from 1:100,000-scale sources. National Map Accuracy Standards (NMAS) established for the United States in 1947 (U.S. Geological Survey, 1988) state that no more than 10 percent of features shall be more than 1/50th of an inch from their intended location on maps of scale smaller than 1:20,000. National Standards for Spatial Data Accuracy (NSSDA) published by the Federal Geographic Data Committee (FGDC) in 1998 relate the NMAS to the digital geospatial data standard by multiplying the NMAS accuracy by a factor of 1.1406 resulting in expected error in the geospatial data at standard mapping scales as follows: 1: 24,000-scale map - 14 meters 1: 62,500-scale map - 36 meters 1: 100,000-scale map - 58 meters 1: 250,000-scale map - 145 meters 1: 500,000-scale map - 290 meters 1:1,000,000-scale map - 579 meters References Cited FGDC, Subcommittee for Base Cartographic data, 1998, Geospatial Positioning Accuracy Standards, Part 3: National Standard for Spatial Data Accuracy, FGDC-STD-007.3-1998, last accessed 03/29/2007 at URL http://www.fgdc.gov/standards/projects/FGDC-standards-projects/accuracy/part3/chapter3 U.S. Geological Survey, 1988, National mapping program technical instructions - Part 2: Specifications, Standards for Digital Line Graphs: U.S. Geological Survey, 56 p. 58 meters These data were derived from documents with unknown scale based on 1:24,000 USGS digital raster graphics (DRG). Due to the lack of knowledge about the source data, a maximum estimated horizontal accuracy is derived using associated data sets with the file based geodatabase. The error inherent from the 1:100,000 scale is at least 58 meters on the X-Y. Markiewicz, R.D. 1992 document Unknown Bureau of Reclamation As part of the Technical Assistance to The States Program, the Bureau of Reclamation initiated and conducted a series of geophysical surveys consisteing of seismic reflection and electrical resistivity measurements at verious location with the Lake Tahoe Basin, California and Nevada. The purpose of the geophysical surveys was twofold. First, the surveys were designed to help determine the location of granitic bedrock at selected sites within the basin. Second, the surveys were designed to provide any information obtainable avout the relative grain sizes of alluvial and reworked glacial (glacial-fluvial) materials. The depth to granitic bedrock and hence the total glacio-fluvial thickness is related to the amount of saturated section to be expected at a water well site. the relative grain size of glacio-fluvial materical is an indicator of how much water the well will ultimately produce for a given saturated section, clean sands and gravels producing relatively more and clays and silts producing relatively less water. paper 1992 publication date Markiewicz, 1992 Geosphysical survey locations Niblack, Robert L. 1988 document Davis, CA University of California, Davis Masters Thesis paper 1988 publication date Niblack, 1988 Geophysical survey locations Geophysical surveys were digitized from figures in Markiewicz, R.D., 1992. Markiewicz, 1992 20070629 Tahoe_Geophysical_Data Geophysical surveys were digitized from figures in Niblack, 1988. Niblack, 1988 Unknown Tahoe_Geophysical_Data Vector String 13 Universal Transverse Mercator 10 0.999600 -123.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000100 0.000100 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 North American Vertical Datum of 1988 0.000100 meters Explicit elevation coordinate included with horizontal coordinates Tahoe_Geophysical_Data Geophysical survey transect locations U.S. Geological Survey OBJECTID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. Seismic_Nm Published geophysical suvey line name Markiewicz, 1992; Niblack, 1988 Name of feature from Markiewicz, 1992 or Niblack, 1988 Seismic_Cd Unique survey line code U.S. Geological survey Unique polyline identifier Source Source of geophysical transect. U.S. Geological Survey Abbreviated citation for source of geophysical survey line SHAPE_Length Length of feature in internal units. ESRI Length in meters U.S. Geological Survey Michael Ierardi IT Specialist mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov Downloadable Data Although these data have 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. File Geodatabase12 9.2 File Geodatabase Spatial and attribute information WinZip 40.7 mb https://water.usgs.gov/GIS/dsdl/SIM3063.zip File Shape 9.2 File Shape Spatial and attribute information WinZip 34.890 mb https://water.usgs.gov/GIS/dsdl/SIM3063_Shapefile.zip XML Workspace Document 2008 Spatial and attribute information WinZip 35.5 mb https://water.usgs.gov/GIS/dsdl/SIM3063_XML.zip This dataset is provided by the USGS as a public service. 20081222 20201117 20081019 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

507 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998