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Water Quality Monitoring Report Forward Landfill gradient of 0.002 ft/ft, while groundwater beneath the northern, western, and central portions of the Forward Unit flows to the southeast at a hydraulic gradient of 0.002 ft/ft. 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 0.002 sec— ft V =—_ [(0.04—)* ]*2835 = 0.648 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=0.002 at the site during the third quarter 2014. ne= Effective porosity(ne=0.35); an estimated value. The maximum groundwater flow rate is calculated to be 0.648 feet per day (237 feet/year)to the northwest and southeast. 2.1.4 Detection Monitoring Program Field and laboratory results for the Forward Unit groundwater monitoring wells for the third quarter 2014 monitoring period are summarized in Table 2-2. Non-Statistical Data Analysis The California Non-Statistical Data Analysis Method (CNSDAM) was performed for VOCs detected less than 10 percent of the time in background samples. Under the CNSDAM, a measurably significant indication of release occurs in a given sample when: two or more VOCs exceed their respective Method Detection Limits (MDLs); or one or more VOCs equals or exceeds its respective practical quantitation limit (PQL). During the third quarter 2014 monitoring period, non-statistical indications of a release were identified at well MW-2A as a result of a quantifiable concentration of diisopropyl ether (DIPE) (0.92 µg/L), and at well MW-17 as a result of trace-level concentrations of chloroform (0.22j µg/L) and trichlorofluoromethane (TCFM) (0.19j µg/L). In a letter dated October 1, 2014, the RWQCB was notified of these exceedances and retesting is scheduled for October 2014. The results of the verification sampling will be reported under separate cover. On behalf of Forward Inc., GLA prepared a letter report dated February 14, 2001 (RWQCB Case No. 2209),to assess the source and potential impacts of low-level VOCs in groundwater adjacent to the Forward Landfill. The letter report concluded that the sporadic detection of low-level VOCs in groundwater (and lysimeter samples) at the Forward Unit are most likely due to landfill gas from unlined unit WMU-B. Forward has M:\2014.0012\FA_3Q14.docx 6 10/31/2014,Rev.0