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C7eolo kal TWk dcs l/u Page 2 <br /> Groundwater Mon tonng Report <br /> Project No 662 2 <br /> February 15, 2005 <br /> 1 wells A dual phase extraction/aquifer pumping test was completed on December 6 — 10, <br /> 2004 A report on these activities is forthcoming <br /> ' On November 19, 2004 all of the site's wells were surveyed in accordance with Geotracker <br /> requirements <br /> 1.0 GROUNDWATER MONITORING <br /> ' 1.1 Hydrogeology of Site <br /> ' The dominant soil type in the upper 40 feet of the subsurface geologic soils investigated is <br /> sand, fine to course grained, interbedded with thinner units of plastic clay The average <br /> groundwater elevation on November 26, 2004 was approximately 12 32 feet above MSL, <br /> ' which is about 27 feet below ground surface This represents an increase of 3 26 feet since <br /> the August 2004 monitoring event <br /> ' A groundwater gradient was calculated for the event and the groundwater was found to flow <br /> N2$°E at 0 001 ft/ft Groundwater elevation and gradient data are summarized in Table 1, <br /> N Appendix A Gradient direction is shown on Figure 2 Gradient Map, and Figure 3 <br /> Groundwater Gradient Rose Diagram <br /> ' 1.2 Groundwater Sampling Procedure <br /> On November 26, 2004, Don Light of Del-Tech mobilized to the site to conduct groundwater <br /> ' monitoring of the four monitoring wells on site <br /> Before sampling was performed the wells were sounded for depth to water The wells were <br /> ' purged of at least three well volumes of stagnant water using a centrifugal pump Purging <br /> continued until the temperature, conductivity, and pH of the groundwater stabilized (c10% <br /> variation between three readings) indicating that formation water representative of aquifer <br /> ' conditions was entering the wells These water quality parameters were measured at intervals <br /> of each well volume purged <br /> ' Once purging was complete, a water sample was collected using a dedicated Waterra check- <br /> ball assembly and 1/z inch tubing Care was taken to minimize sample agitation Once the <br /> sample container was filled and capped, the bottle was inverted, tapped, and checked for <br /> ' headspace bubbles The sample container was identified and labeled with a unique <br /> designation, inserted into foam holders and placed in an ice chest cooled to 4°C for transport <br /> to the laboratory <br /> I <br />