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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 — ft <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 VOCwater 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 />2A) was measured in samples collected from the Forward Unit. On behalf of Forward <br />M:\ 2014.0012\FA_2Q14.docx 6 <br />7/29/2014, Rev. 0 <br />