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Water Quality Monitoring Report <br /> Forward Landfill <br /> The groundwater elevation data obtained on April 16, 2014, were used to generate the <br /> groundwater elevation contour map shown on Figure 2-1 for the second quarter 2014 <br /> monitoring period, which indicates that groundwater beneath the southern and central <br /> portions of the Forward Unit generally flows to the northeast at a hydraulic gradient of <br /> 0.003 ft/ft, while groundwater beneath the northeast corner of the Forward Unit flows <br /> to the southwest at a hydraulic gradient of 0.011 ft/ft. This southwest gradient was first <br /> noted during the May 2011 monitoring event and is believed to be related to <br /> groundwater mounding in the vicinity of the front entrance gate due to landscape <br /> irrigation. <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 0.003 sec— fit <br /> V = —_ [(0.04—)* ]*2835 0.972 .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 � 0.003 to 0.011 at the site during the second quarter <br /> 2014. <br /> ne= Effective porosity (ne=0.35); an estimated value. <br /> The maximum groundwater flow rate is calculated to be 0.972 feet per day (355 <br /> feet/year) to the north and northeast and 3.56 feet/day (1,301 feet/year) to the <br /> southwest. <br /> 2.1.4 Detection Monitoring Program <br /> Field and laboratory results for the Forward Unit groundwater monitoring wells for the <br /> second quarter 2014 monitoring period are summarized in Table 2-2. <br /> Non-Statistical Data Analysis <br /> The non-statistical VOCv„ater analysis was performed on the DMP well data during the <br /> second quarter 2014. No non-statistical indications of release were identified during the <br /> second quarter 2014 monitoring period. <br /> Excluding carbon disulfide, which has been flagged as a field/laboratory contaminant, <br /> only one estimated trace concentration of a VOC (diisopropyl ether [DIPS] at well MW- <br /> M:\2014.0012\FA_2Q14rev.docx 6 <br /> 9/5/2014,Rev.1 <br />