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Water Quality Monitoring Report <br /> Forward Landfill <br /> analyses were completed within required holding times. Based on the results of the <br /> laboratory QA/QC analyses, it is concluded that the laboratory data generated for the <br /> second quarter 2016 monitoring period are acceptable and the water quality samples <br /> collected from the Forward Unit appear to be representative of water quality at the site. <br /> 2.1.3 Groundwater Elevations and Contours <br /> Prior to purging and sampling, each well was sounded for water depth using a weighted <br /> electronic sounder to an accuracy of 0.01 foot, and the static water level was recorded <br /> on a Well Data Sheet (Appendix F). The groundwater elevations were calculated for <br /> each well by subtracting the depth-to-water measurement from the top-of-casing <br /> reference elevation. The current groundwater elevation data for the Forward Unit is <br /> summarized in Table 2-3. <br /> The groundwater elevation data obtained on May 16, 2016, were used to generate the <br /> groundwater elevation contour map shown on Figure 2-1 for the second quarter 2016 <br /> monitoring period, which depicts groundwater beneath the Forward Unit generally <br /> flowing to the south at a hydraulic gradient of 0.001 ft/ft. <br /> To calculate the approximate linear groundwater flow velocity for the Forward Unit, <br /> conservative assumptions were used, including a hydraulic conductivity of 875 gallons <br /> per day per square foot (0.04 cm/sec) and an estimated effective porosity of 35 percent <br /> (CH2M Hill, 2000). An estimated groundwater flow velocity was calculated using Darcy's <br /> Law: <br /> Ki cm 0.001 sec— ft <br /> V = —= f(O.04—)* ]*2835 = 0.324 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=0.001 during the second quarter 2016. <br /> ne= Effective porosity(ne=0.35); an estimated value. <br /> The maximum groundwater flow rate is calculated to be 0.324 feet per day (118 <br /> feet/year). <br /> 2.1.4 Detection Monitoring Program <br /> Field and laboratory results for the Forward Unit groundwater monitoring wells for the <br /> second quarter 2016 monitoring period are summarized in Table 2-2. <br /> M:\2016.0007\FA 2Q16.docx 6 <br />