Introduction

Ground water in the Lake Tahoe basin is the primary source of domestic and municipal water supply and an important source of inflow to Lake Tahoe. Over the past 30–40 years, Federal, State, and local agencies, and research institutions have collected hydrologic data to quantify the ground-water resources in the Lake Tahoe basin. These data are dispersed among the various agencies and institutions that collected the data and generally are not available in a format suitable for basin-wide assessments. To successfully and efficiently manage the ground-water resources throughout the Lake Tahoe basin, the U.S. Geological Survey (USGS) in cooperation with the U.S. Forest Service (USFS) compiled and evaluated the pertinent geologic, geophysical, and hydrologic data, and built a geodatabase incorporating the consolidated and standardized data for the Lake Tahoe basin that is relevant for examining the extent and characteristics of the hydrogeologic units that comprise the aquifers. The Geodatabase can be accessed at http://water.usgs.gov/GIS/dsdl/SIM3063.zip, the shape files can be accessed at http://water.usgs.gov/GIS/dsdl/SIM3063_Shapefile.zip, and the XML Workspace Document can be accessed at http://water.usgs.gov/GIS/dsdl/SIM3063_XML.zip.