Miller, Jerry 1994 20040401 vector digital data ISGS GIS Database GISDB_HYDRO.IL_Maj_Bedrock_Aq_Lt_300_Ft_Py Champaign, Illinois Illinois State Geological Survey http://www.isgs.illinois.edu/ http://illinois.edu This map shows the distribution of major bedrock aquifer units within 300 feet of ground surface in Illinois. Major aquifers are capable of yielding 70 gallons of water per minute. Potable water contains less than 2,500 milligrams per liter of total dissolved solids. Bedrock aquifers within 300 feet of ground surface cover most of northern Illinois and are commonly overlain only by thin layers of less permeable silts and clays. Many are directly overlain by shallow or major sand and gravel aquifers allowing direct hydrologic communication with shallower aquifer systems. Stratigraphic units considered to be major bedrock aquifers are: Hunton Limestone Megagroup Ancell Group Prairie du Chien Group Ironton-Galesville Sandstone Elmhurst-Mt. Simon Sandstone The scale of these data is 1:500,000. This feature class is intended to identify areas of Illinois where major bedrock aquifers exist. These data are appropriate for use in regional thematic analysis. The data are not appropriate as a geodetic, legal or engineering base. The datasets were not and are not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS, the data have no legal basis in the definition of boundaries or property lines. In April 2004 the source coverage was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated edition 20040401. The source coverage (edition 2.0) was entirely reconstructed from the source hand-drafted map, making the previous version (coverage edition 1.0) obsolete. This edition retains the edition 2.0 data. Some information used to compile this map was obtained from well log data on file at the Illinois State Geological and Water Surveys. A variety of well/boring data were used, including: water wells oil wells (active and abandoned) gas wells (active and abandoned) Secondary and Tertiary oil recovery wells air injection wells service wells waste disposal wells observation wells (disposal sites) observation wells (water resources) gas storage operational wells water test holes coal test holes mineral test holes structure test holes stratigraphic test holes engineering test holes 1986 publication date of sources Complete None planned -91.4244 -87.3840 42.4951 36.9540 none aquifer groundwater water hydrology hydrogeology bedrock none Illinois ISGS information must be obtained directly from the ISGS or from an authorized distributor. Be aware that ISGS information obtained from an unauthorized third party may have been altered subsequent to original distribution, or may no longer be current. Any access to these data, Web sites, computer systems, electronic services, and electronic networks is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section. ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved.  University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is provided in the Cross References section. Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, isgs@isgs.illinois.edu. License fees and a license agreement may be required, depending on the proposed usage. Any use of these data is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section. Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data.  Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor. The data do not replace the need for detailed site-specific studies. Please refer to the Distribution Information section. ArcSDE 9.1 on Oracle 10g http://www.isgs.illinois.edu http://www.vpaa.uillinois.edu/policies/web_privacy.cfm http://www.uillinois.edu/trustees/rules.cfm#sec34 http://www.fs.uiuc.edu/cam/CAM/viii/viii-1.1.html Attributes were extracted from source hand-drafted maps in 1994 and verified by three individuals. Attribute codes are believed to fully representative of the source data. Source data were derived through contouring and interpretation. When in coverage format, this data set was checked for complete chain-node topology (no dangling arcs, except where appropriate), polygon labels (one per polygon, except for universal polygon), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances. There are no known polygon attribute values outside the appropriate value domains. This data set contains major bedrock aquifers as defined in the abstract. There exist other aquifers (associated with other geologic formations or aquifer definitions) not identified on this map. Some examples are sand and gravel aquifers, shallow aquifers, and other aquifers between 50 and 300 feet that are not identified as "major aquifers". Because these data are generalized over a large areal extent, the user needs a good working knowledge of the geologic formations used here in order to derive valid and useful interpretations. Horizontal positional accuracy of this data with respect to the source maps was verified by three individuals by visual comparison (manual overlay) of source maps and hard-copy plots. Arcs within one line-width of source mylars were deemed acceptable. Consult the sources for information on the derivation of aquifer boundaries. Miller, J.R., R.C. Berg, T.M. Johnson, A. Wehrmann 1985 (not published) unpublished report Champaign, Illinois Illinois State Geological Survey ISGS internal document paper 1985 publication date none attribute and data description Berg, R.C., and J.P. Kempton 1984 Illinois State Geological Survey Map same as title Champaign, Illinois Illinois State Geological Survey 500000 paper 1984 publication date none unknown Bergstrom, R.E., K. Cartwright, K. Piskin, and M.R. McComas 1968 Champaign, Illinois Illinois State Geological Survey Bergstrom, R.E. (ed.); p. 157-159 paper 1984 publication date none unknown Bergstrom, R.E., and A.J. Zeizel 1957 Illinois State Geological Survey Circular 232 Champaign, Illinois Illinois State Geological Survey paper 1957 publication date none unknown Kempton, J.P., W.H. Johnson, P.C. Heigold, and K. Cartwright 1991 Geological Society of America Special Paper 258 paper 1991 publication date none unknown Pryor, W.A. 1956 Illinois State Geological Survey Circular 212 Champaign, Illinois Illinois State Geological Survey paper 1956 publication date none unknown Selkregg, L.F., and J.P. Kempton 1957 Illinois State Geological Survey Circular 225 Champaign, Illinois Illinois State Geological Survey paper 1957 publication date none unknown Selkregg, L.F., and J.P. Kempton 1958 Illinois State Geological Survey Circular 248 Champaign, Illinois Illinois State Geological Survey paper 1958 publication date none unknown Visocky, A.P., M.G. Sherrill, and K. Cartwright 1985 Illinois State Geological Survey Cooperative Groundwater Resources Report 10 Champaign, Illinois Illinois State Geological Survey paper 1985 publication date none unknown Willman, H.B., E. Atherton, T.C. Buschback, C. Collinson, J.C. Frye, M.E. Hopkins, J.A. Lineback, and J.A. Simon 1975 Illinois State Geological Survey Bulletin 95 Champaign, Illinois Illinois State Geological Survey paper 1975 publication date none unknown This coverage was originally digitized in ARC/INFO circa 1985 from hand-drafted map compiled by Jerry Miller of the ISGS. The map is pencil on paper in good condition, at a scale of 1:500,000. 1985 In 1994 the coverage underwent extensive Quality Assurance/ Quality Control review. As a result of the QA/QC review, the existing coverage was replaced. The new coverage was digitized from the original paper map, with a maximum RMS of 0.008. The .PAT ITEMS and values were copied from the existing coverage and then manually verified. This processing was subsequently reviewed and verified by ISGS staff. 1994 Source coverage (aqmb300) converted to double precision and reprojected to GCS_NAD83 using Workstation ArcInfo 7.2.1. The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009. Attribute COUNT-FED-FIPS was dropped. It was an unnecessary item leftover from previous processing. Metadata updated. 20040401 Vector G-polygon 84 0.000001 0.000001 Decimal degrees North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 Attribute items are in typical SDE feature class format. Those requiring explanation are: CODE - Discriminates polygon on basis of water quality 0 - Major bedrock aquifer absent 1 - Major bedrock aquifer present Information Office, Illinois State Geological Survey (ISGS), a division of the Institute of Natural Resource Sustainability (INRS) of the University of Illinois mailing and physical address

615 East Peabody Drive

Champaign Illinois 61820 USA 217-333-4747 217-785-0211 isgs@isgs.illinois.edu 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time Refer to the Legal Notices of Terms and Conditions of the University of Illinois Web Privacy Policy (there is a link in the Cross References section) for policy statements regarding the following: Disclaimer of Liability Disclaimer of Warranties and Accuracy of Data Disclaimer of Endorsement Disclaimer for External Links Disclaimer of Duty to Continue Provision of Data Security Choice of Law By obtaining these data you agree to the provisions of the University of Illinois Web Privacy Policy, regardless of the manner in which the information was obtained. The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, ESRI formats can be imported into many different GIS software packages. It is expected that customers who obtain these data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind. 20090224 Please refer to the Distribution Information section. FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time The access constraints as stated for the data apply also to the metadata. Refer to the Access Constraints section of the Identification Information section. The use constraints as stated for the data apply also to the metadata. Refer to the Use Constraints section of the Identification Information section. http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile