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Water Quality Monitoring Report French Camp Landfill primary samples collected during the monitoring period. In addition, a trace concentration of calcium were measured in a laboratory method blank, though, the detection was at a very low,trace concentration that did not affect the interpretation of primary sample results. A duplicate sample was collected from well MW-10A and was labeled DUP. Duplicate test results are presented along with the primary data in Table 2. Comparison of the primary and duplicate sample results,when both results are measurable concentrations above the practical quantitation limit (PQL), indicates good agreement with a relative percent difference of less than ten percent. 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 indicates that groundwater generally flows to the south and southeast with hydraulic gradients ranging between 0.001 ft/ft and 0.002 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 (CH21VI Hill, 2000). The estimated groundwater flow velocity was calculated using Darcy's Law: Ki cm 0.002 sec— ft V = —=[(0.014 —)* ]*2835 = 0.23 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=0.002 for the site during the monitoring period. ne=Effective porosity(n,=0.35);an estimated value. The groundwater flow rate is calculated to be 0.23 feet/day(83 feet/year). M:\2014.0012\FC iSA14.doc 3 7/10/2014,Rev.0