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Kansas Geological Survey, Open-file Report 88-39
Great Plains and Cedar Hills Aquifers--Page 11 of 25

6.0 Regional Ground-water Geochemistry

6.1 Types of Chemical Data Collected and Examined

Chemical data were collected for Barton, Russell, Ellis, Rush, Rooks, Trego, Graham, part of Ellsworth counties. A general survey of ground- water chemistry was made using sixty samples collected in June, 1987, from domestic, stock, and municipal wells. Selection of the sampling points was based on data from the USGS WATSTORE file, KGS reports for the various counties, and the water-well record file at the KGS. The wells were selected on the basis of depth, location in the county, and availability of information on the screened interval. Some of the wells could not be located in the field and alternative sampling sites were used where available. Some of the samples had high nitrate concentrations indicating either recharge from the surface through the well bore or else a gravel pack in the well from the zone of interest to the surface. Sample data from these wells were not used for the general evaluation of water chemistry. Chemical determinations were also made for samples from the three monitoring sites in the Upper and Lower Dakota Formations, Cheyenne Sandstone, and Cedar Hills Sandstone.

Oil-field brines were collected from wells producing oil from the Arbuckle and Kansas City Groups. These wells were chosen either to evaluate possible sources of saltwater near Cheyenne Bottoms, or were used as examples of brines that are currently being disposed in the Cedar Hills Sandstone. Other oil-field brine data with accurate chemical determinations were selected from the files of D. Whittemore for Russell County. Procedures for sample collection and types of constituent determinations made in the current study are given in the section on methods of study (3.0).

In addition to chemical analyses made by the KGS, data for the Dakota Formation (Great Plains aquifer) were selected from the USGS WATSTORE data file for the counties in the study area. The data were evaluated using the computer model WATEQF for aqueous chemical equilibria written by Plummer et al. (1976) to determine whether the cation-anion balance was correct to within + or - 5%. Data meeting this criteria were used in further evaluations of water chemistry. A summary of analyses used in the study are presented in Appendices A and B.

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Kansas Geological Survey, Dakota Project
Original document dated December, 1988
Electronic version placed online April 1996
Scientific comments to P. Allen Macfarlane
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