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Water Quality Monitoring Report Forward Landfill (CH2M Hill, 2000). An estimated groundwater flow velocity was calculated using Darcy's Law: Ki cm 0.002 sec – ft V = — _ [( 0.04 —) * ) * 2835 1 - 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 = Maximum hydraulic gradient: i - 0.002 during the fourth quarter 2015. ne= Effective porosity In, = 0.35); an estimated value. The maximum groundwater flow rate is calculated to be 0.648 feet per day (237 feet/year). 2.1.4 Detection Monitoring Program Field and laboratory results for the Forward Unit groundwater monitoring wells for the fourth quarter 2015 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 fourth quarter 2015 monitoring period, non -statistical indications of a release was identified at well MW -16 as a result of a quantifiable concentration of diisopropyl ether (DIPE); and at well MW -17 as a result of quantifiable concentrations of chloroform and carbon tetrachloride. In a letter dated August 13, 2015, similar concentrations of these VOCs were reported to the RWQCB for the second quarter 2015 and confirmed in retest samples collected on July 29, 2015. It should be noted that these confirmed VOCs are well below state and/or federal maximum contaminant levels (MCLS), and were placed in "tracking mode" and are being evaluated quarterly for temporal trends. Historically, low-level concentrations of VOCs have been detected in the samples collected from the Forward Unit. 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 continued to minimize gas related impacts to groundwater by preventing ponding of water through regular site maintenance. Furthermore, in accordance with CCR Title 27, Section 20937, Forward continues to install additional landfill gas extraction wells, M:\ 2015.0014\FA_4Q15.docx 7 1/29/2016, Rev. 0