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Water Quality Monitoring Report <br /> Forward Landfill <br /> ® Based on the results of the laboratory blank and duplicate analyses, it is concluded that <br /> acceptable QA/QC procedures were exercised and the water quality samples collected <br /> from the Austin Unit appear to be representative of water quality at the site. <br /> 3.1.3 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 E). The groundwater elevations were calculated for each well by subtracting <br /> the depth-to-water measurement from the top-of-casing reference elevation. The <br /> current groundwater elevation data for the Austin Unit are summarized in Table 3-6. <br /> The groundwater elevation data obtained during this quarterly monitoring period were <br /> used to generate the groundwater elevation contour map shown on Figure 3-1, which <br /> indicates that groundwater flows in a radial pattern from a groundwater high located in <br /> the vicinity of the infiltration pond along the northern perimeter of the Austin Unit. The <br /> hydraulic gradients vary from of 0.001 to 0.004 ft/ft. <br /> To calculate the approximate linear groundwater flow velocity for the site, conservative <br /> assumptions were used, including a hydraulic conductivity of 875 gallons per day per <br /> square foot (0.04 cm/sec) and an estimated effective porosity of 35 percent (CH21VI Hill <br /> ® 2000). An estimated groundwater flow velocity was calculated using Darcy's Law: <br /> Ki cm 0.004 sec— ft <br /> V = —= [(0.04—)* ]*2835 1.296 ft/day <br /> ne sec 0.35 cm —day <br /> where:V= Groundwater flow velocity. <br /> K= Hydraulic conductivity of the water-bearing unit (0.04 cm/sec). <br /> i= Hydraulic gradient: i�z 0.004 at the site during the first quarter 2015. <br /> ne= Effective porosity(ne=0.35); an estimated value. <br /> The maximum groundwater flow rate is calculated to be 1.3 feet/day(473 feet/year). <br /> 3.1.4 Detection Monitoring Program <br /> Field and laboratory results for the Austin Unit DMP wells for the first quarter 2015 are <br /> summarized in Table 3-1. <br /> Non-Statistical Data Analysis <br /> During the first quarter 2015 monitoring period, the CNSDAM was performed for VOCs <br /> ® detected in the DMP wells. As shown in Table 3-1, non-statistical indications of a <br /> release were identified at well AMW-6 as a result of a quantifiable concentrations of <br /> M:\2015.0014\FA 1Q15.docx 10 <br /> 4/27/2015,Rev.0 <br />