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Water Quality Monitoring Report French Camp Landfill (RPD) of less than 11 percent when both results are measurable concentrations above the practical quantitation limit (PQL). Review of sampling dates and laboratory analytical certificates indicates that all of the laboratory analyses were completed within required holding times. Based on the results of the laboratory QA/QC analyses, it is concluded that acceptable QA/QC procedures were exercised, and the water quality samples collected from the French Camp Landfill appear to be 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 Q. 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 1 and 2, which indicate that groundwater generally flows to the southeast, converging near wells MW-9A and MW-9B at a hydraulic gradient of 0.009 ft/ft to 0.011 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). The estimated groundwater flow velocity was calculated using Darcy's Law: Ki cm 0.011 sec— ft V = —= [(0.014 —)* ]*2835 = 1.25 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 = Maximum hydraulic gradient: i = 0.011 for the site during the monitoring period. ne= Effective porosity(ne=0.35); an estimated value. The groundwater flow rate is calculated to be 1.25 feet/day(455 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-10A) are summarized in Table 2 and time- series concentration plots are presented in Appendix D. Project No.2015.0014 3