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Water Quality Monitoring Report <br /> French Camp Landfill <br /> Based on the results of the laboratory QA/QC analyses, it is concluded that acceptable QA/QC <br /> procedures were exercised, and the water quality samples collected from the French Camp <br /> Landfill appear to be representative of water 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 (Appendix Q. <br /> The groundwater elevations were calculated for each well by subtracting the depth-to-water <br /> measurement from the top-of-casing reference elevation. The current and historical <br /> groundwater elevation data for the French Camp Landfill is summarized in Table 5. <br /> The groundwater elevation data obtained during the monitoring period were used to generate <br /> the groundwater elevation contour maps shown on Figures 1 and 2, which indicate that <br /> groundwater generally flows to the southeast, converging near wells MW-9A and MW-9B at a <br /> hydraulic 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 estimated <br /> effective porosity of 35 percent (CH2M Hill, 2000). The estimated groundwater flow velocity <br /> was calculated using Darcy's Law: <br /> AIML <br /> Ki cin0.002 sec <br /> V = —_ [(0.014 —)* ]* 2835 0.227 .fi /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 = Maximum hydraulic gradient: i z 0.002 for the site during the monitoring <br /> period. <br /> ne= Effective porosity(ne=0.35); an estimated value. <br /> The groundwater flow rate is calculated to be 0.227 feet/day(83 feet/year). <br /> 4.4 Detection Monitoring Program <br /> Field and laboratory results from the current monitoring period for DMP monitoring wells(MW- <br /> 6A, MW-7A, MW-8A, MW-9A, MW-9B, and MW-10A) are summarized in Table 2 and time- <br /> series concentration plots are presented in Appendix D. <br /> 4.4.1 Concentration Limits <br /> For DMP monitoring wells at the French Camp Landfill, concentration limits (CLs) provided in <br /> WDR 115-2007-0046 are used for the water quality protection standards (WQPS). All CLs are <br /> Project No.2016.0007 3 <br />