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approximately 45 to 65 feet bgs. A sand pack was placed in the annulus of MW 11 R extending from the bottom of the well screen to approximately two feet above the well screen. Approximately three ' feet of bentonite were placed on top of the sand pack and hydrated to form an annular seal. Cement grout was tremmied on top of the bentonite and the well was completed at grade with a watertight, flush-mounted traffic rated vault. MW11R was installed approximately five feet west of MW11. The ' location of MW11R is shown on Figure 12. MW11 was destroyed and grouted to the ground surface. Well construction details for MW11R and lithological descriptions associated with destroyed monitoring well MW 11 are included in Attachment 3. 1 On April 18, 2005, MW11R was developed and sampled and the top of the casing was surveyed for elevation. MW l 1 R was developed by pumping approximately 38 gallons (approximately 17 well casing volumes). Following development of the well, a groundwater sample was collected with a disposable bailer and delivered to Argon Laboratories for analyses of the analytes previously mentioned. The groundwater well purge and sample log for MW11R is included in Attachment 1. ' 1,2-DCA was detected in the groundwater sample collected from MW11R on April 18, 2005, at a concentration of 1.1 µg& None of the other analytes were detected at or above the laboratory reported detection limits. The analytical results of the groundwater sample are summarized in Table ' 2. Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2. SECOND QUARTER 2005 SAMPLING ACTIVITIES r� On June 27, 2005, groundwater samples were collected from MW through MW 10, MW11R, and MW 12. Prior to collection of groundwater samples,the depth to water was measured in the wells and ' the pH, electrical conductivity, and temperature were measured in groundwater purged from the monitoring wells and recorded. A minimum of three well casing volumes were purged from each monitoring well prior to sampling. The wells were allowed to recover and samples were collected from each well using disposable polyethylene bailers. The groundwater samples collected from each well were submitted to Argon Laboratories for analyses of the analytes previously mentioned. Groundwater well purge and sample logs are included in Attachment 1. 1 SECOND QUARTER 2005 GROUNDWATER FLOW DIRECTION Water levels were measured in monitoring wells MW through MW10, MW11R, and MW12 on June 27, 2005. Water levels in the shallow zone (MWI, MW2, MW3, MW8, MW9, MW10, and MW1IR) ranged from 47.80 to 49.56 feet below the tops of the well casing elevations. Water levels in the intermediate zone wells (MW4, MW5, MW6, and MW12) ranged from 48.86 to 49.72 feet below the tops of the well casing elevations. The water level in the deep zone well,MW7, was 49.41 feet below the top of the well casing elevation. The water level data were used to develop the groundwater ' elevation contour maps shown in Figures 13 and 14. Groundwater flow in the shallow zone was variable with eastward and northward components flowing toward the center of the site. Groundwater flow in the intermediate zone was towards the south. The average hydraulic gradient in the 1 intermediate zone on June 27, 2005, was calculated to be 0.0007 ft/ft or approximately 4 ft/mile. A summary of groundwater monitoring data is presented in Table 1. ' r s:lenviromental1283491reports12005 1&2 QMR,doc 4 ATC Associates Inc.