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<br />June 3, 1992 <br />Page 4 <br />STEFF~OBERTSON AND KIRSTEN <br />that 10~ cm/sec. To compare the significance of variation in hydraulic head aver the geomembrane <br />liner and soil liner permeability, the following table is illustrative. <br />Soil Liner Permeability <br />(cm/sec) Hydraulic Head <br />(n) Total Seepage <br />(gallons/yr) <br />10"` 1 4,740 <br />10' 2 9,840 <br />10~ 10 47,400 <br />10"' 1 474 <br />10"' 2 948 <br />10'' 10 4,740 <br />10~ 1 47.4 <br />10-0 2 94.8 <br />10-0 10 474 <br />Considering the probable average hydraulic head conditions over the liner of 1 foot and the <br />measured soil liner permeability of less than 10~ crrt/sec, a theoretical seepage rate of 47.4 gallons <br />per year would result from liner flaws over the entire facility. <br />The equivalent hydraulic conductivity of the synthetic liner, based on the manufacturer's testing, is <br />1 x 10-" cm/sec. The mechanism for water migration through the synthetic material is one of <br />molecular diffusion. The material has the same equivalent permeability to that of a drinking glass. <br />Therefore, no significant rate of seepage is anticipated through intact liner. <br />EM/RD/mlp <br />Attachment <br />