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The groundwater elevation data obtained on September 23, 2013 were used to generate the groundwater elevation contour map shown on Figure 2-1 for the third quarter 2013 monitoring period, which indicates that groundwater beneath the southern and central portions of the Forward Unit generally flows to the northeast at a hydraulic gradient of 0.003 ft/ft,while groundwater beneath the northeast corner of the Forward Unit flows to the southwest at a hydraulic gradient of 0.01 ft/ft. This southwest gradient was first noted during the May 2011 monitoring event and is believed to be related to groundwater mounding, as a result of agricultural activities east of the site. To calculate the approximate linear groundwater flow velocity for the Forward Unit, conservative assumptions were used, including a hydraulic conductivity of 875 gallons per day per square foot(0.04 cm/sec) and an estimated effective porosity of 35 percent (CH2M Hill 2000). An estimated groundwater flow velocity was calculated using Darcy's Law: Ki cm 0.003 sec– ft V = — _ [(0.04—)* ]*2835 ;zz 0.972 ft/day ne sec 0.35 cm – day where: V=Groundwater flow velocity. K=Hydraulic conductivity of the water-bearing unit(0.04 cm/sec). i=Hydraulic gradient: i�z 0.003 for the site during the third quarter 2013. ne=Effective porosity(ne=0.35);an estimated value. AAftk The maximum groundwater flow rate is calculated to be 0.972 feet per day (355 feet/year). Detection Monitoring Program Field and laboratory results for the Forward Unit groundwater monitoring wells for the third quarter 2013 monitoring period are summarized in Table 2-2. Non-Statistical Data Anal The non-statistical VOC wa,analysis was performed on the DMP well data during the third quarter 2013. Review of the analytical data indicates that there was a non-statistical indication of release identified at well MW-2A as a result of the detection of diisopropyl ether(DIPE) above the PQL. Trend analyses indicate that there is a statistically significant increasing temporal trend for DIPE at well MW-2A. Trend analyses are included in Appendix D. The occurrence of DIPE in well MW-2A coincides with the groundwater gradient reversal noted in the northeast corner of the Forward Unit beginning in May 2011 and is believed to be related to an offsite source, since it has not been detected in leachate at the Forward Unit. With the exception of DIPE, only one estimated trace concentration of trichlorofluoromethane was measured in the samples collected from the Forward Unit. On behalf of Forward Inc., GLA prepared a letter report dated February 14, 2001 C:\2013-0021TA_3Q13.doc 5 Geo-Logic Associates