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. 0 108 ft/ft Groundwater flow in the upper water bearing zone has been to the south, south-southeast, and southeast during previous quarters GRO and benzene were reported in wells MW-4 and VW-3 Benzene was also reported in well VW-2 The highest concentrations of GRO (280,000 µg/L) and benzene (3,800 pg/L)were reported in well MW-4 MTBE, TBA, TAME, DIPE, ETBE, EDB, 1,2-DCA, or ethanol were not reported in any of the upper zone wells Analytical results for the first quarter 2006 are generally consistent with previous quarters GRO, benzene, and MTBE analytical data for the samples collected on March 28, 2006, are presented in Figure 5 Analytical data were submitted to the State Water Resources Control Board as required by AB2886 The electronic delivery receipt is attached in Appendix C Lower Water Bearing Zone (Sand Zone 2 During the site visits conducted during the first quarter 2006, a product sheen was found in well MW-1, and free product was measured in well MWA5 at thicknesses ranging from 0 04 and 0 56 feet Approximately 11 gallons of product/water mixture were bailed during the first quarter 2006 from wells MWA and MW-15 Approximately 207 gallons (MW-1) and 44 gallons (MW-15) of productlwater mixture have been bailed to date Product thickness measurements and volumes of liquid balled are summarized in Table 1 At the time of the first quarter 2006 monitoring event, groundwater levels had increased between 0 15 and 1 14 feet in wells MWA, MW-9, MWA 0, MWA 2, and MW-15 since the previous monitoring event (December 19, 2005) Depth-to-water measurements were normalized to mean sea level (MSL) and used to construct a groundwater elevation contour map (Figure 4) Wells that contained less than 1 foot of water are interpreted to be dry and are indicated as "dry" on Figure 4 Groundwater flow was generally to the southeast at an average gradient of 0 175 ft/ft Groundwater flow has been to the southeast, east-southeast, and east during previous quarters GRO and benzene were reported in wells MW-9, MW-10, and MW-12 The highest concentrations of GRO (42,000 pg/L) and benzene (11,000 gg/L) were reported in well MW-12 TBA (280 [tg/L), 1,2-DCA (72 pglL), and EDB (9 7 µg/L) were reported in well MW-9 1,2-DCA (56 µg/L) was also reported in well MW-10 MTBE, TAME, DIPE, ETBE, or ethanol were not reported in any of the lower zone wells Analytical results for the first quarter 2006 are generally consistent with previous quarters GRO, benzene, and MTBE analytical data for the samples collected on March 28, 2006, are presented in Figure 5 Analytical data were submitted to the State Water Resources Control Board as required by AB2886 The electronic delivery receipt is attached in Appendix C Domestic Well GRO, BTEX, MTBE, TBA, TAME, DIPE, ETBE, EDB, 1,2-DCA, or ethanol were not reported above method detection limits in the domestic well GRO, benzene, and MTBE analytical data are presented in Figure 5 These analytical results for the first quarter 2006 are consistent with historical data System Description Soil Vapor Extraction System The Solleco 500 cfm SVE system consists of a 500 cfm rated thermal oxidizer with a 40 hp liquid ring blower Upon system start-up (May 16, 2005), petroleum hydrocarbon laden soil vapors were extracted from wells VW-1, VW-3, VW-4, VW-8, VW-14, MW-2, MW-8, and MW-9 using the 40 hp blower package capable of producing up to 28 "Hg vacuum The extracted soil vapors were abated in the thermal oxidizer prior to discharge to the atmosphere The SVE system has a built-in hour meter that is used to determine the operational uptime Sample ports (influent, system-influent, and effluent) are designated to collect air samples Since the influent petroleum hydrocarbon concentrations (measured using PID) from well MW-2 K\Bp-Arca for URS\6100\Quarterly\2006\Arco_6I00_IQ06 doc 5TKATUS