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Kicm 0.002 sec – ft <br />V = — = [(0.04 —) * ] * 2835 0.65 ft / day <br />ne sec 0.35 cm – day <br />where: V = Groundwater flow velocity. <br />K = Hydraulic conductivity of the water -bearing unit (0.04 cm/sec). <br />i = Hydraulic gradient: i ;ze 0.002 for the site during the current the second quarter 2008. <br />n,= Effective porosity (ne = 0.35); an estimated value. <br />The groundwater flow rate is calculated to be 0.65 feet/day (237 feet/year). <br />3.1.4 Detection Monitoring Program <br />Field and laboratory results for the DMP wells for the second quarter 2008 are <br />summarized in Table 3-1 and time -series plots are presented in Appendix D. As shown <br />in Table 3-1, an estimated trace concentration of DCDFM was measured in the sample <br />collected from well AMW-6. In addition, PCE was measured above the PQL in the <br />sample collected from well AMW-6; PCE and TCE were measured above the PQL in the <br />sample collected from well AMW-13; and DCDFM, PCE, and TCE were measured <br />above the PQL in the sample collected from well AMW-14. <br />For the DMP wells at the Austin Unit, CLs are calculated for the water quality protection <br />standards (WQPS). The CLs shown in Table 3-1 were calculated by Herst & Associates <br />using Sanitas9, a state -approved statistical software program. Based on a comparison of <br />the data obtained during the second quarter 2008 monitoring period, the following <br />analytes were found to exceed a CL. The results of the statistical analyses performed by <br />Herst & Associates are presented in Appendix D. <br />CONSTITUENT <br />Concentration <br />Limit <br />DMP MONITORING WELL <br />AMW-2B AMW-6 AMW-7 AMW-13 <br />AMW-14 <br />ONITORING PARAMETERS (mg/1) <br />Barium <br />0.2445 <br />0.27 <br />Chromium, Hexavalent <br />0.005 <br />0.0052 0.0058 <br />Volatile Petroleum Hydrocarbons <br />25 26' <br />OLATILE ORGANIC COMPOUNDS <br />/l <br />Dichlorodifluoromethane <br />1 0.5 <br />0.94 <br />etrachloroethene <br />0.5 <br />1.1 3.1 <br />22 <br />Trichloroethene <br />0.5 <br />0.65 <br />1 1.8 <br />NOTES: (s) - Background Well. j — Trace Value (between the MDL and PQL). <br />DMP - Trend Analyses <br />In order to evaluate changes in water quality in DMP wells at the Austin Unit, historical <br />trends in groundwater were evaluated beginning in 1994 when the groundwater treatment <br />facility began operation. The observed groundwater quality constituent trends were <br />evaluated using Sen's Slope trend analyses to determine if significant increasing or <br />decreasing trends were evident in the data. Trend analyses, performed by Herst & <br />Associates, are presented in Appendix D and summarized below. Wells and analytes not <br />discussed below either do not show significant trends (rising or falling) or have too few <br />DA2008 0010\FA 2Q08.doc <br />11 Geologic Associates <br />