1987-12-01_PERMIT FILE - C1981017 (94)

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of precipitation and/or influent seepage from streams can sig- nificantly recharge the outwash deposits. From July, 1983 to July, 1984, five ground water samples were obtained from borehole W-1 and four samples each from E-1 and E-2. The results of chemical analyses of these samples are presented in Tables 2, 3, and 4, for boreholes W-1, E-1, and E-2, respectively. Since the analyses were performed by several different laboratories , measured chemical parameters are not entirely consistent between samples. Chemical results from samples taken in July - August , 1983 are somewhat questionable since they were obtained shortly after completion of drilling . For example, the July, 1983 sample from borehole E-1 seems to be enriched in sodium chloride and depleted in calcium/magnesium sulfate compared to samples taken at other times. The July, 1983 sample from E-2 has unusually high concentrations of iron and magnesium. These anomalous concentrations may be related to the chemistry of invaded drilling fluids that were not completely removed from the formation during well development. The concentration of total dissolved solids is generally regarded as an indicator of ground water quality. Measured values of total dissolved solids for samples taken in W-1, E-1, and E-2, are plotted in Figures 1, 2, and 3, respectively. For the 10 samples analyzed, the mean concentration is 388 mg/l with a standard deviation of 101 mg/l. The highest value (602 mg/1) was measured in the October , 1983 sample from borehole W-1 , coinciding with generally low ground water levels during the dry part of the year. Typically low values of total dissolved solids were observed in ground water samples obtained in May, 1984, a period of increased precipitation /runoff and high ground water levels. Although water quality records do not cover an entire year, it is reasonable to assume that total dissolved solids in ground water should not substantially exceed the maximum reported value (602 mg/1) or fall significantly below the minimum reported value (235 mg/1 ) . Low concentrations of total dissolved solids are expected to occur in late spring and high concentrations during the fall . 3. 0 SURFACE WATER Stream flows have been measured on a daily basis since October , 1983 at three gaging stations in the vicinity of the Sutey Disposal Site. Stream hydrographs based on monthly mean flow rates are presented in Figures 4, 5, and 6, for Sutey stations 1, 2, and 3, respectively. Stream flow was ephemeral at stations 1 and 2, with dry creek beds prior to February, 1981. During March and April , stream flows at all gaging stations were observed to increase sharply, coinciding with increased 27