Faunt, Claudia C. 2012 vector digital data Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?pp1766_hobs Faunt, Claudia C. (editor) 2009 Professional Paper 1766 Reston, Virginia U.S. Geological Survey 3 chapters, 1 appendix Online_Linkage: http://pubs.usgs.gov/pp/1766/PP_1766.pdf This digital dataset defines the well locations for hydraulic-head observations used in the calibration of the transient hydrologic model of the Central Valley flow system. The Central Valley encompasses an approximate 50,000 square-kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the USGSs numerical modeling code MODFLOW-FMP (Schmid and others, 2006). This application is referred to here as the Central Valley Hydrologic Model (CVHM) (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The USGS and DWR maintain databases of key wells in the Central Valley that are web-accessible (http://waterdata.usgs.gov and http://www.water.ca.gov/waterdatalibrary/, respectively). These data were combined to form a database of available water levels throughout the Central Valley from 1961 to 2003. More than 850,000 water-level altitude measurements from more than 21,400 wells have been compiled by the USGS or DWR and have been entered into their respective databases. However, only a small proportion of these wells have both sufficient construction information to determine the well-perforation interval and water-level measurements for the simulation period. For model calibration, water-level altitude data were needed that were (1) distributed spatially (both geographically and vertically) throughout the Central Valley, from the valley trough to the foothills; (2) distributed temporally throughout the simulation period (1961-2003); and (3) available during both wet and dry climatic regimes. From the available wells records, a subset of comparison wells was selected on the basis of perforation depths, completeness of record, climatic intervals, and locations throughout the Central Valley. Water-level altitude observations (19,725) for 206 comparison wells were used as calibration targets during parameter estimation. The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS).The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details). The well locations, perforated intervals, and time series of water levels are used as input to MODFLOW-FMP, the USGS 3-dimensional finite-difference code used to simulate flow in the CVHM. In particular, the water-levels are used as observations to calibrate the model. The CVHM is a tool that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system. The hydraulic-head observation dataset is one of many layers in a geospatial database supporting the USGS Central Valley Groundwater Availability Project. Regional groundwater availability studies quantify current groundwater resources, evaluate how those resources have changed through time, and provide tools that decision makers can use to predict system responses to future development and climate variability and change. To provide information to stakeholders addressing these issues, the USGS made a detailed assessment of groundwater availability of the Central Valley aquifer system, which includes: (1) the present status of groundwater resources; (2) characterization of how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at various scales. Data from these previous studies were the foundation of the Central Valley geospatial database. These and other data were re-examined through a series of regional-scale hydrologic investigations to provide updated and spatially consistent interpretations for the Central Valley Groundwater Availability study. In some cases, new data were collected to augment existing information. Data compiled from the studies include geology (in particular, borehole lithology and the extent and thickness of the Corcoran Clay Member of the Tulare Formation), topography, remote sensing, climate (precipitation and temperature), geophysics, vegetation and land use, vegetation properties, hydrology (stream network and flows), groundwater levels, subsidence, chemistry, and soils. Digital elevation models, geologic maps, borehole information, cross sections, and other 3-dimensional models were used to develop the texture model which represents the properties and geometry of the Central Valley alluvial deposits. The resulting geospatial database supports characterization and conceptualization of the Central Valley hydrologic system between 1961 and 2003, construction of 3-dimensional hydrogeologic framework and hydrologic flow models, and visualization of analysis and model results. 2009 publication date Complete None planned -122.429470 -118.778823 40.390176 35.021853 ISO 19115 Topic Category inlandWaters geoscientificinformation American Geological Institute Glossary of Geology (http://glossary.agiweb.org/dbtw-wpd/glossary/search.aspx) hydrology hydrogeology model groundwater hydraulic head water level none Central Valley Hydrologic Model Flow Model CVHM Texture Model CV-RASA Groundwater Availability of the Central Valley Aquifer Central Valley Aquifer U.S. Board of Geographic Names (BGN) and Geographic Names Information System (GNIS) California Central Valley Trinity County Shasta County Tehama County Humboldt County Butte County Mendocino County Glenn County Yuba County Lake County Nevada County Colusa County Sutter County Placer County El Dorado County Yolo County Sonoma County Napa County Sacramento County Amador County Solano County Calaveras County Tuolumne County San Joaquin County Contra Costa County Stanislaus County Alameda County Mariposa County Madera County Merced County Fresno County Santa Clara County San Benito County Monterey County Tulare County Kings County Kern County San Luis Obispo County Santa Barbara County Ventura County Sacramento Valley San Joaquin Valley Central Valley, California 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 dataset in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology. Claudia C. Faunt U.S. Geological Survey Hydrologist mailing and physical address

4165 Spruance Road, Suite 200

San Diego CA 92101 USA (619) 225-6142 (619) 225-6101 ccfaunt@usgs.gov http://water.usgs.gov/GIS/browse/pp1766_HOBS.png Illlustration of data set png Spatial datasets supporting the Central Valley Groundwater Availability project were developed primarily by the U.S. Geological Survey's (USGS) Groundwater Resources Program. This program is conducting large-scale multidisciplinary regional studies of groundwater availability. The U.S. Bureau of Reclamation is supporting the updating of the Central Valley datasets and their documentation and release. Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3500 Schmid, Wolfgang Hanson, R. T. Maddock, Thomas, III Leake, S. A. 2006 Techniques and Methods 6-A17 Sacramento, CA USGS California Water Science Center http://pubs.usgs.gov/tm/2006/tm6A17/ National Water Information System 2012 vector digital data Reston, VA U.S. Geological Survey http://waterdata.usgs.gov/nwis California Department of Water Resources 2012 vector digital data Sacramento, CA California Department of Water Resources http://www.water.ca.gov/waterdatalibrary/ Attributes added by the GIS and the data-set author were checked by inspection using a GIS. In addition, attributes were checked and evaluated as part of the review process associated with the publication of the source report. Logical consistency checks were conducted during preparation of the map by visual examination of the positions of plotted symbols on the base map (searching for spurious locations) and cross-checking the tabular locations against their graphical representation. The point features in this dataset represent the head observations in the Central Valley Hydrologic Model. The dataset is complete and is not anticipated to change. Horizontal positional accuracy of point features in the dataset was tested by visually comparing to digital maps in the region by using a GIS system. Faunt, C. C. 2009 document U.S. Geological Survey Professional Paper 2009-1766 Reston, Virginia U.S. Geological Survey http://pubs.usgs.gov/pp/1766/PP_1766.pdf Faunt, C.C. 2009 U.S. Geological Survey Professional Paper 2009-1766 Reston, Virginia U.S. Geological Survey 500000 online 2009 publication date Faunt and others (2009) well locations for hydraulic-head observations From the available well records in the USGS National Water Information System (NWIS) and California Department of Water Resources databases, a subset of comparison wells (206) was selected on the basis of perforation depths, completeness of record, climatic intervals, and locations throughout the Central Valley. Wells are identified and numbered according to their location in the rectangular system for the subdivision of public lands and this ID was taken from the respective database. 2009 Faunt, C.C. USGS Hydrologist mailing and physical address

4165 Spruance Road, Suite 200

San Diego CA 92101 USA (619) 225-6142 ccfaunt@usgs.gov Central Valley, comprised of the Sacramento Valley on the north and the San Joaquin Valley on the south, located in the state of California. Vector Entity point 206 Albers Conical Equal Area 29.500000 45.500000 -120.000000 23.000000 0.000000 0.000000 coordinate pair 1609 1609 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 Head Observations well locations, perforated intervals, and time series of water levels dataset originator FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. OBJECTID Internal feature number. ESRI 1 43218 WELLID Identification number of wells dataset originator 13-character alphanumeric code based on Public Land Survey System location. U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

445 National Center

Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Downloadable Data Digital geospatial datasets for the textural model and numerical model of the hydrogeologic landscape and groundwater flow in California's Central Valley. 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. 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. SHP ESRI Shapefile 0.006 http://water.usgs.gov/GIS/dsdl/pp1766_hobs.zip None. This dataset is provided by the USGS as a public service. 2011 20120824 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing 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+Datase+pp1766_hobs FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998