Faunt, Claudia C. 2012 vector digital data Professional Paper 1766 Reston, Virginia U.S. Geological Survey https://water.usgs.gov/lookup/getspatial?pp1766_corcoran_clay_depth_feet Faunt, Claudia C. 2009 Professional Paper 1766 Reston, VA U.S. Geological Survey 3 Chapters, 5 Plates https://pubs.usgs.gov/pp/1766/PP_1766.pdf This digital dataset defines the depth of the Corcoran Clay Member of the Tulare Formation. The complex hydrologic system of the Central Valley is simulated using the USGS numerical modeling code MODFLOW-FMP (Schmid and others, 2006b). This simulation 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. Numerous lenses of fine-grained sediments are distributed throughout the southern Central Valley (San Joaquin Valley) and generally constitute more than 50 percent of the total thickness of the valley fill. Generally, these lenses are discontinuous and not vertically extensive or laterally continuous. However, the Corcoran Clay is a low-permeability, areally extensive, lacustrine deposit (Johnson and others, 1968) as much as 200-ft thick (Davis and others, 1959; Page, 1986). This continuous clay divides the groundwater-flow system of the western San Joaquin Valley into an upper semi-confined zone and a lower confined zone (Williamson and others, 1989; Belitz and Heimes, 1990; Burow and others, 2004). The extent and distribution of the Corcoran Clay was defined for use in the CVHM because the unit is one of the few deposits in the Valley that can be regionally mapped. 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 depth of the Corcoran Clay Member of the Tulare Formation is used to help define the 3-dimensional extent of the Corcoran Clay for the CVHM. In the CVHM flow simulation, the Corcoran Clay is generally a fine-grained confining layer and is simulated separately by layers 4 and 5. 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 depth of the Corcoran Clay 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 -121.504203 -118.758069 37.793811 35.004248 ISO 19115 Topic Category geoscientificinformation American Geological Institute Glossary of Geology (http://glossary.agiweb.org/dbtw-wpd/glossary/search.aspx) hydrology hydrogeology model groundwater USGS Thesaurus inlandWaters Central Valley Aquifer Central Valley Hydrologic Model Flow Model CVHM Texture Model CV-RASA Groundwater Availability of the Central Valley Aquifer Corcoran Clay discretization USGS Metadata Identifier USGS:2eedd7e1-0522-465f-9478-c47e5263a46e U.S. Board of Geographic Names (BGN) and Geographic Names Information System (GNIS) California Central Valley San Joaquin County Stanislaus County Merced County Madera County Fresno County Tulare County Kings County Kern County 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 US Geological Survey Hydrologist mailing and physical address

4165 Spruance Road, Suite 200

San Diego CA 92101 USA 6192256142 ccfaunt@usgs.gov https://water.usgs.gov/GIS/browse/pp1766_corcoran_clay_depth.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 Johnson, A. I. Moston, R. P. Morris, D. A. 1968 atlas Professional Paper 497-A Reston, VA U.S. Geological Survey https://pubs.usgs.gov/pp/0497a/report.pdf Schmid, Wolfgang Hanson, R. T. Maddock, Thomas, III Leake, S. A. 2006b Techniques and Methods 6-A17 Sacramento, CA USGS California Water Science Center https://pubs.usgs.gov/tm/2006/tm6A17/ Davis, G. H. Green, J. H. Olmsted F. H. Brown, D. W. 1959 Water Supply Paper 1469 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/wsp/1469/report.pdf Page, R. W. 1986 Professional Paper 1401-C Reston, VA U.S. Geological Survey https://pubs.usgs.gov/pp/1401c/report.pdf Williamson, A. K. Prudic, D. E. Swain, L. A. 1989 Professional Paper 1401-D Reston, VA U.S. Geological Survey https://pubs.usgs.gov/pp/1401d/report.pdf Belitz, Kenneth R. Heimes, Frederick J. 1990 Water Supply Paper 2348 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/wsp/2348/report.pdf Burow, Karen R. Shelton, Jennifer L. Hevesi, Joseph A. Weissmann, Gary S. 2004 Scientific Investigations Report 2004-5232 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/sir/2004/5232/ 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. Lines forming polygons join at endpoints to completely enclose defined areas. Lines not enclosing areas do not intersect. No duplicate line features exist and all nodes are represented by a single coordinate pair which indicates the beginning or end of a line. All vertices that define the shape of the line are represented by a unique coordinate pair. The line features in this dataset are computer-generated and represent the Corcorcan Clay depth layers in the Central Valley Hydrologic Model. The dataset is complete and is not anticipated to change. Horizontal positional accuracy of line features in the dataset was tested by visually comparing to digital source maps by using a GIS system. Faunt, C. C. Hanson, R.T. Belitz, K. 2009 document U.S. Geological Survey Professional Paper 2009-1766 Reston, Virginia U.S. Geological Survey https://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) See Professional Paper 1766 - Groundwater Availability of the Central Valley Aquifer, California. Page, R. W. 1986 Professional Paper 1401-C Reston, VA U.S. Geologic Survey http://ngmdb.usgs.gov/Prodesc/proddesc_4831.htm online 2009 publication date Page (1986) Corcoran Clay depth linework and cuntour values The 1:500,000 scale plate of the contour lines was scanned into a 300 dots per inch .tiff image A GIS was used to georeference and trace/digitize the contour lines by hand into a shapefile. Each contour-line attribute was populated with the depth (in feet) of the Corcoran Clay. Page (1986) Unknown 08303600 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 String 220 Albers Conical Equal Area 29.500000 45.500000 -120.000000 23.000000 0.000000 0.000000 coordinate pair 100 100 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 corcoran_clay_depth_feet Depth to top of Corcoran Clay, in feet dataset originator FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. COR_DEPTH Depth to top of Corcoran Clay, in feet Page (1986) 50 900 Feet 50 There are 220 records in this shapefile. It has 2 attributes that are generated by the GIS (FID, and Shape) for internal software purposes. The remaining attribute was assigned by the author (dataset Originator) to define and describe the depth to the top of the Corcoran Clay layer in feet. These data were used for analysis and for developing input files for the CVHM textural model and numerical ground-water flow model. none. U.S. Geological Survey Michael Ierardi IT Specialist mailing and physical

445 National Center

Reston Virginia 20192 USA 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov 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 0.0388183594 https://water.usgs.gov/GIS/dsdl/pp1766_CorcoranClay.zip None. This dataset is provided by the USGS as a public service. 2011 20201117 U.S. Geological Survey Michael Ierardi IT Specialist mailing and physical address

445 National Center

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