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gWIJguaI7-"kn "I= Page 3 Groundwater Monitoring Report Project No 770 2 . August 27,2004 Figures 2 & 3 show the location of the well clusters, MW-5/105 and MW-61106, used for ' calculating vertical groundwater gradient in this report Table 1 includes Summary of Water Level and-Gradients Water Table Wells, Table 2 includes Summary of Water Level and Gradients Deep Wells, Table 3 shows the calculated vertical gradients, and Table 6 contains ' the well construction details The information used in the calculations is shown below Vertical gradient calculation formulas are as follows • Vertical correction for gradient [(gw gradient slope) x (distance) =vertical correction] e Vertical head. [(head of deep well) - (head of shallow +correction)= vertical head] • Vertical gradient [(vertical head) /vertical distance) =vertical gradient] ' Vertical gradients were calculated for the MW-5/105 & MW-61106 well airs for the 2"d ln' p ' quarter 2004 monitoring events The vertical gradient was negative (a downward direction) for the MW-51105 well pair for all four sounding events completed in 2004. The MW-61106 well pair vertical gradient was positive (an upward direction) on January 22 and February 26, ' and negative (a downward direction) on March 15 and June 7, 2004 - Both positive and negative vertical gradients have been calculated for previous events Similar to the historical lateral directions, the direction of groundwater in the vertical plane also fluctuates at the site The magnitude of vertical groundwater flow direction ranged from —0 02 to 0 0097 for the site investigation 1.2 Groundwater Sampling Procedure ' On June 7, 2004, Del-Tech Geotechnical Support Services staff mobilized to the site to complete the quarterly groundwater monitoring and sampling of the site's monitoring wells Before sampling was attempted the wells were sounded for depth to water and then a clear ' disposable bailer was used to determine if floating product was present The field technician recorded the presence of"sheen/oily droplets" in wells MW-4, and MW-5 The recharge was poor in the wells MW-6, MW-7, and MW-8 The wells were purged of at least three well ' volumes of stagnant water using a dedicated Waterra check-ball assembly and 1/2 inch tubing Purging continued until the temperature, conductivity_an_d pH of the groundwater_stabilized (c10% variation among three readings) indicating that formation water representative of aquifer conditions was entering the wells These water quality parameters were measured at intervals of each well volume purged ' Once purging was complete, a water sample was collected from the Waterra tube Care was taken to minimize sample agitation. Once the sample container was filled and capped, the ' bottle was inverted, tapped and checked for headspace bubbles The sample container was identified and labeled with a unique designation, inserted into foam holders and placed into an ice chest cooled to 4°C for transport to the laboratory