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In the following discussion, ground water chemistry will be analyzed by aquifer. Possible • <br />seasonal variations in water qualii;y are addressed, and suspect water chemistry data are <br />noted. As with other hydrologic analyses contained in this PAP, all ground water quality <br />data collected through water year 1989 are incorporated in the analyses below. However, <br />water quality analyses from October, 1989 have also been included to provide a larger data <br />base for the more recently compl e~:ed monitoring wells. Statistical summaries of water <br />quality data by aquifer and schoeller diagrams for each aquifer are presented in the <br />discussions below. Water chemistry information for each well (raw water quality data, <br />statistical summaries, and trilinear diagrams) can be found in Appendix 7-4. <br />Suspect Ground Water Chemistry. A list of ground water chemistry data that is suspected <br />to be inaccurate is shown in Table 7-9. A total of nine wells are believed to have <br />erroneous chemistry. Due to well construction failure, the entire water chemistry data <br />sets for two Wadge coal wells, GW-S2W-1W and -SW, are considered suspect. The remaining <br />wells listed in Table 7-9 have, on the sample dates indicated, chemistry data that is <br />obviously not representative when compared with other chemistry measured at these sites. <br />Although it is difficult to assess why this chemical data is not representative, we <br />surmise that since all of the atypical data is from the first sampling of the wells, the • <br />suspect data can probably be attributed to incomplete well development and/or residual <br />drilling fluids in the formation or well bore. These suspect data are presented in <br />Appendix 7-4, but they are not used in the analyses performed below (e.g., water type <br />classifications, statistical analyses, etc.). <br />Alluvial Aquifers. seaeca II-W alluvial water quality has been monitored at six wells. <br />Wells GW-52W-BA1 and CW-S2W-9A1 have monitored the Watering Trough Culch alluvium; water <br />quality monitoring at -8A1 was discontinued in 1984, and only water levels are currently <br />monitored at this well. Both wells are located quite near each other and, as would be <br />' expected, they display very similar water chemistry. Water quality analyses from each <br />' well indicate that the Watering Trough Culch alluvium has a CaMg-HC03 water type (Table <br />~ 7-10). Field pH values for this aquifer range from 6.80-8.10 (average value 7.19), <br />indicating that this water is slightly alkaline (Table 7-11). With an average hardness of <br />464.46 mg/1 of CaC03, the Watering Trough Gulch alluvium contains water that is very hard. <br />Concentrations of numerous trace elements have been detected at the two wells, including <br />A1, As, Ba, B, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Mo, Ni, Se, Ag, and Zn. Most trace elements <br />have concentrations less than 1.0 mg/1, and the highest trace element concentration was a • <br />manganese measurement of 3.19 mg/1 recorded at GW-S2W-8A1. Total dissolved solids (TDS) <br />36 <br />