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Water Quality Monitoring Report <br /> Forward Landfill <br /> ® dates and required holding times indicates that all samples were submitted and analyzed within <br /> the required holding times during the first quarter 2017. Based on the results of the laboratory <br /> blank and duplicate analyses, it is concluded that acceptable QA/QC procedures were exercised <br /> and the water quality samples collected from the Austin Unit appear to be representative of <br /> 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 (Appendix F). <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 groundwater elevation <br /> data for the Austin Unit are summarized in Table 3-6. <br /> The groundwater elevation data obtained during this quarterly monitoring period were used to <br /> generate the groundwater elevation contour map shown on Figure 3-1, which indicates that <br /> groundwater along the northern perimeter of the Austin unit generally flows in a north- <br /> northeast direction with a hydraulic gradient varying from 0.003 to 0.007 ft/ft, while <br /> groundwater beneath the central and southern perimeter generally flows to the southeast. <br /> To calculate the approximate linear groundwater flow velocity for the site, conservative <br /> assumptions were used, including a hydraulic conductivity of 255 feet per day and an estimated <br /> effective porosity of 35 percent (CDM, 1997). An estimated groundwater flow velocity was <br /> calculated using Darcy's Law: <br /> V = Ki = (255 f �* 0.005 3.64 ft/day <br /> ne day 0.35 <br /> where: V=Groundwater flow velocity. <br /> K=Hydraulic conductivity of the water-bearing unit(0.04 cm/sec). <br /> i=Average hydraulic gradient:i gt�0.005 during the first quarter 2017. <br /> ne=Effective porosity(ne=0.35);an estimated value. <br /> The estimated groundwater flow rate is calculated to be 3.64 feet/day (1330 feet/year). <br /> 3.1.4 Detection Monitoring Program <br /> Field and laboratory results for the Austin Unit DMP wells for the first quarter 2017 are <br /> summarized in Table 3-1. <br /> Project No.5017.1030 I Water Quality Monitoring Report 10 <br /> April 2017 <br />