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.
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
Miller, Jerry, 1994, Major Bedrock Aquifers Within 300 Feet of Ground Surface: ISGS GIS Database GISDB_HYDRO.IL_Maj_Bedrock_Aq_Lt_300_Ft_Py, Illinois State Geological Survey, Champaign, Illinois.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
CODE - Discriminates polygon on basis of water quality 0 - Major bedrock aquifer absent 1 - Major bedrock aquifer present
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.
Miller, J.R., R.C. Berg, T.M. Johnson, A. Weh, 1985 (not published), Siting a Low-Level Radioactive Waste Disposal Facility in Illinois: Statewide Criteria - Description of maps: Compilation, Database, and Intended Use.: Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C., and J.P. Kempton, 1984, Potential for contamination of shallow aquifers by land burial of municipal wastes: Illinois State Geological Survey Map same as title, Illinois State Geological Survey, Champaign, Illinois.
Bergstrom, R.E., K. Cartwright, K. Piskin, and M, 1968, Groundwater resources of the Quaternary deposits of Illinois; in the Quaternary of Illinois - a symposium in observance of the centennial of the University of Illinois: Illinois State Geological Survey, Champaign, Illinois.
Bergstrom, R.E., and A.J. Zeizel, 1957, Ground-water geology in western Illinois, south part - A preliminary geologic report: Illinois State Geological Survey Circular 232, Illinois State Geological Survey, Champaign, Illinois.
Kempton, J.P., W.H. Johnson, P.C. Heigold, and, 1991, Mahomet bedrock valley in east-central Illinois; topography, glacial drift stratigraphy, and hydrology: Geological Society of America Special Paper 258.
Pryor, W.A., 1956, Groundwater geology in southern Illinois - A preliminary geologic report: Illinois State Geological Survey Circular 212, Illinois State Geological Survey, Champaign, Illinois.
Selkregg, L.F., and J.P. Kempton, 1957, Groundwater geology in south-central Illinois - A preliminary geologic report: Illinois State Geological Survey Circular 225, Illinois State Geological Survey, Champaign, Illinois.
Selkregg, L.F., and J.P. Kempton, 1958, Groundwater geology in east-central Illinois - A preliminary geologic report: Illinois State Geological Survey Circular 248, Illinois State Geological Survey, Champaign, Illinois.
Visocky, A.P., M.G. Sherrill, and K. Cartwrigh, 1985, Geology, hydrology, and water quality of the Cambrian and Ordovician systems in northern Illinois: Illinois State Geological Survey Cooperative Groundwater Resources Report 10, Illinois State Geological Survey, Champaign, Illinois.
Willman, H.B., E. Atherton, T.C. Buschback, C., 1975, Handbook of Illinois stratigraphy: Illinois State Geological Survey Bulletin 95, Illinois State Geological Survey, Champaign, Illinois.
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.
Person who carried out this activity:
, ISGS Terms of Use.Online Links:
, University of Illinois Web Privacy Notice.Online Links:
, University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).Online Links:
, Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.Online Links:
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.
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.
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.
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.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- 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.
- Use_Constraints:
- 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.
217-333-4747 (voice)
isgs@isgs.illinois.edu
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.
Illinois Natural Resources Geospatial Data Clearinghouse
Generated by mp version 2.8.25 on Wed Apr 08 08:29:05 2009