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TECHNICAL MEMORANDUM <br />AmerAlia, lnc. <br />October 19, 1999 <br />Page S <br />2.3 Water Quality <br />The alluvial aquifers are localized water bodies occurring along streams. Ground water in the alluvial <br />aquifer as measured in the C-a Tract wells is generally of a sodium sulfate type, with a neutral pH. <br />Average concentration of TDS exceeds agricultural water standards. Alluvial wells are possibly <br />dominated by organic content (Meglen and Sistko 1986). Piper diagrams for these waters are presented <br />in Appendix B. <br />Upper Aquifer ground water is influenced by both the Uinta formation and the upper part of the Green <br />River Formation (Weeks et al. 1974; Saulnier, 1978; as seen in Saulnier 1999). Waters in the Parachute <br />Creek Member of the Green River Formation are higher in bicarbonate, waters from the Uinta formation <br />are generally higher in sulfate and dissolved solids (Saulnier 1999). The ground water in the upper <br />aquifer as measured in wells near the project site is of a sodium bicarbonate type with an alkaline pH, <br />and high concentrations of sulfate. Piper diagrams are presented in Appendix B. Concentrations of <br />fluoride and TDS and pH exceed Colorado agricultural water standards. This is proven by data from <br />wells TH 75 -7A and 7-B on the project site, as well as by data from WRN. Ground water data for the <br />upper aquifer from the C-a Tract wells also indicate a mixed sodium sulfate and bicarbonate type, with <br />alkaline pH. Iron, lead, and manganese and sulfate values for the upper aquifer are higher in the C-a <br />Tract wells than in the WRN or TH75 wells and lead and sulfate exceed agricultural water standards in <br />the C-a Tract wells. Based on data from the WRN, conductivity, pH, or TDS do not exhibit any seasonal <br />or long-term trends in the upper aquifer. Graphs for conductivity, pH, and TDS measurements and <br />graphs and tables for monthly averages are contained in Appendix C. <br />Ground water in the lower aquifer is influenced by the Parachute Creek member. The water quality has <br />been measured in TH 75-B and four WRN wells. Waters in the lower aquifer are of a sodium <br />bicarbonate type. In these water-bearing zones the pH is highly alkaline, with the value for TH75-7-B of <br />8.2 and the median value for the WRN wells of 92. Agricultural standards are exceeded by fluoride, <br />TDS and pH, and by 3rd quartile value of boron, and by some high values for cadmium and copper. <br />Piper diagrams are presented in Appendix B. Based on data from the WRN, conductivity, pH, or TDS do <br />not exhibit any seasonal or long-term trends in the Power aquifer. Monthly averages in the lower aquifer <br />are fairly constant, and no long-term changes are present. Graphs for conductivity, pH, and TDS <br />measurements and graphs and tables for monthly averages are contained in Appendix C. <br />2ndFinelTecMicel Memo Aoc 10/19/99 TRC HYDRO-GEO CONSULTANTS <br />