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04kTC
<br /> A S S O C I A T E S I N C .
<br /> GROUNDWATER FLOW DIRECTION
<br /> Water level measurements were collected from wells MW 1 through MWS, MW6a, MW6b,
<br /> MW6c, MW7a, MW7b, MW7c, MWS, MW9a, MW9b, MW9c, MW10a, MW10b, MW10c and
<br /> EW1 on June 3, 2004. Water levels in the monitoring wells (MW 1 through MW6a, MW7a,
<br /> MW9a, MW10a, and EWI) screened in the shallow water bearing zone ranged from 65.04 to
<br /> 65.84 feet below the tops of the well casing elevations. The water level data were used to
<br /> develop the groundwater elevation contour maps for the shallow (A), intermediate (B), and deep
<br /> (C) groundwater zones (Figures 3 through 5). Assuming that horizontal isotropic conditions
<br /> prevail, shallow groundwater beneath the site flowed towards the east. The average hydraulic
<br /> gradient in the shallow water bearing zone on June 3, 2004, was calculated to be 0.001 ft/ft or
<br /> approximately 7.5 ft/mile. A summary of groundwater monitoring data is presented in Table 1.
<br /> ANALYTICAL RESULTS
<br /> The groundwater samples collected from wells MW1 through MW4, and EW1 contained
<br /> detectable concentrations of TPHg and BTEX constituents. The groundwater sample collected
<br /> from well MW6a contained a detectable concentration of TPHg but no BTEX constituents.
<br /> None of the groundwater samples from contained detectable concentrations of TPHd.
<br /> Groundwater samples collected from wells MW6b, MW6c, MW7a, MW7b, MW7c MW8
<br /> MW9a, MW9b, MW9c, MW10a, MW10b, and MW10c, contained no detectable concentrations
<br /> of TPHg or BTEX constituents. Groundwater samples collected from MW 1, MW2, MW4,
<br /> MW5, MW6a, MW6b, MW6c, MW7b, MW7c, MW8, MW10b and EW1 contained detectable
<br /> concentrations of MTBE. The groundwater sample collected from well MW6a contained a
<br /> detectable concentration of TBA. Groundwater samples collected from wells MWI, MW2,
<br /> MW4, MW7a, and MW7c contained detectable concentrations of 1,2-DCA. Analytical results of
<br /> groundwater samples are summarized in Table 2. Laboratory data sheets and chain-of-custody
<br /> documentation are contained in Attachment 2. Isoconcentration maps depicting the MTBE
<br /> concentrations in the A, B, and C water bearing zones are presented in Figures 6, 7, and 8,
<br /> respectively.
<br /> GEOTRACKER DATA UPLOAD
<br /> The site facility global ID number is T0607700858. The depth to water data was submitted
<br /> electronically to the State Water Resources Control Board (SWRCB) Geotracker database
<br /> (confirmation number 4702987492) and the laboratory data was also submitted electronically to
<br /> the SWRCB Geotracker .database (confirmation number 1633691728). Documentation of the _ =
<br /> data submittal is contained in Attachment 3.
<br /> ADDITIONAL ACTIVITIES
<br /> On April 21, 2004, monitoring wells MW6c MW I Oa MW
<br /> 10b, and M W 10c were developed by
<br /> pumping several well volumes of water from them with a pneumatic portable pump.
<br /> 5:1268231QM reports12004 2QR.doe 3
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