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dichlorethane, dichlorodifluoromethane,tetrachloroethane, and trichloroethene)were detected in the duplicate sample but not in the primary sample. Historically VOCs have not been detected in well MW-2 at the French Camp Landfill and it is believed that the duplicate samples were confused with another site (Forward Landfill) which was sampled on the same day because many of duplicate sample results correlate with another site's well. Review of sampling dates and laboratory analytical certificates indicates that all of the laboratory analyses were completed within required holding times. With the exception of the duplicate sample mix-up, either by the samplers or the laboratory, based on the results of the laboratory QA/QC analyses, it is concluded that generally acceptable QA/QC procedures were exercised. The water quality samples collected from the French Camp Landfill appear to be generally representative of water quality at the site. 4.3 GROUNDWATER ELEVATIONS AND CONTOURS Prior to purging and sampling, each well was sounded for water depth using a weighted electronic sounder, and the static water level was recorded on a Well Data Sheet (Appendix C). The groundwater elevations were calculated for each well by subtracting the depth-to-water measurement from the top-of-casing reference elevation. The current and historical groundwater elevation data for the French Camp Landfill is summarized in Table 5. The groundwater elevation data obtained during the monitoring period were used to generate the groundwater elevation contour maps shown on Figures I and 1B, which indicates that groundwater generally flows to the south with an average hydraulic gradient of 0.005 ft/ft. To calculate the approximate linear groundwater flow velocity for the site, conservative assumptions were used, including a hydraulic conductivity of 0.014 cm/sec, and an estimated effective porosity of 35 percent(CH2M Hill 2000). An estimated range in groundwater flow velocity was calculated using Darcy's Law: Ki cm 0.005 sec– ft V = —= [(0.014 —)* ]*2835 0.567 ft/day ne sec 0.35 cm – day where: V=Groundwater flow velocity. K=Hydraulic conductivity of the water-bearing unit(0.014 cm/sec). i=Hydraulic gradient: i;t�0.005 for the site during the monitoring period. ne=Effective porosity(ne=0.35);an estimated value. The groundwater flow rate is calculated to be 0.567 feet/day(207 feet/year). 4.4 DETECTION MONITORING PROGRAM Field and laboratory results from the current monitoring period for DMP monitoring wells (MW-6A, MW-7A, MW-8A,MW-9A, MW-9B, and MW-lOA) are summarized in Table 2 and time-series plots are presented in Appendix D. As shown in the time-series D:12010-0030\FC_2SA10.doc 3