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Water Quality Monitoring Report Forward Landfill The groundwater elevation data obtained on November 17 and 18, 2014, were used to generate the groundwater elevation contour map shown on Figure 2-1 for the fourth quarter 2014 monitoring period, which indicates that groundwater beneath the eastern and southeastern portions of the Forward Unit flows to the west-northwest at a hydraulic gradient of 0.001 ft/ft, while groundwater beneath the northern, western, and central portions of the Forward Unit flows to the south and southeast at a hydraulic gradient of 0.001 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 0.001 sec — ft V = — _ [( 0.04 —) * ] * 2835 = 0.324 ft l 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 �zz 0.001 at the site during the fourth quarter 2014. ne= Effective porosity (ne = 0.35); an estimated value. The maximum groundwater flow rate is calculated to be 0.324 feet per day (118 feet/year) to the west-northwest and south-southeast. 2.1.4 Detection Monitoring Program Field and laboratory results for the Forward Unit groundwater monitoring wells for the fourth quarter 2014 monitoring period are summarized in Table 2-2. As shown in Table 2-2, diisopropyl ether (DIPS) was measured at a quantifiable concentration in the sample collected from well MW -2A and an estimated trace concentrations of chloroform was also measured in the sample collected from well MW -17. No other VOCs were measured in the Forward Unit groundwater wells during the monitoring period. 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 2014 monitoring period, non -statistical indications of a release was identified at M:\ 2014.0012\FA_4Q14.docx 6 1/28/2015, Rev. 0