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analytical certificates indicates that all of the laboratory analyses were completed within <br /> required holding times. Based on the results of the laboratory QA/QC analyses,it is <br /> concluded that acceptable QA/QC procedures were exercised, and the water quality <br /> samples collected from the French Camp Landfill appear to be representative of water <br /> quality at the site. <br /> 4.3 GROUNDWATER ELEVATIONS AND CONTOURS <br /> Prior to purging and sampling, each well was sounded for water depth using a weighted <br /> electronic sounder, and the static water level was recorded on a Well Data Sheet <br /> (Appendix Q. The groundwater elevations were calculated for each well by subtracting <br /> the depth-to-water measurement from the top-of-casing reference elevation. The current <br /> and historical groundwater elevation data for the French Camp Landfill is summarized in <br /> Table 5. <br /> The groundwater elevation data obtained during the monitoring period were used to <br /> generate the groundwater elevation contour maps shown on Figures 1 and 2, which <br /> indicates that groundwater generally flows to the southeast with an average hydraulic <br /> gradient of 0.002 ft/ft. <br /> To calculate the approximate linear groundwater flow velocity for the site,conservative <br /> assumptions were used, including a hydraulic conductivity of 0.014 cm/sec, and an <br /> estimated effective porosity of 35 percent(CH2M Hill, 2000). The estimated <br /> groundwater flow velocity was calculated using Darcy's Law: <br /> Ki cm 0.002 sec– ft <br /> V = —_ [(0.014 —)* ]*2835 = 0.23 ft/day <br /> ne sec 0.35 cm –day <br /> where: V=Groundwater flow velocity. <br /> K=Hydraulic conductivity of the water-bearing unit(0.014 cm/sec). <br /> i=Average hydraulic gradient:i=0.002 for the site during the monitoring period. <br /> ne=Effective porosity(ne=0.35);an estimated value. <br /> The groundwater flow rate is calculated to be 0.23 feet/day(83 feet/year). <br /> 4.4 DETECTION MONITORING PROGRAM <br /> Field and laboratory results from the current monitoring period for DMP monitoring <br /> wells (MW-6A,MW-7A,MW-8A, MW-9A,MW-9B, and MW-lOA) are summarized in <br /> Table 2 and time-series concentration plots are presented in Appendix D. <br /> CA201XW23Wc2sn13.doe 3 Geo-Logic Associates <br />