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+i I � Y Geological Tecwa Inc. Page 3 Groundwater Monitoring Report Project No. 750.2 i May 15,2003 water table between the wells. The calculation considers the slope of the water table and the distance in a down-gradient direction between the two wells used in the calculations. Figure 2 shows the location of the well cluster used for calculating groundwater groundwater gradient in this report, MW-1 and MW-101. Table 1 shows a Summary of Water Level and ` Gradients Slope and Bearing and Table 3 shows the calculated vertical gradients. The L 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 + • vertical head: [(head of deep well) - (head of shallow+ correction)=vertical head] { • vertical gradient: [(vertical head) / (vertical distance) =vertical gradient] i j For the March 6, 2003, groundwater measurement, the vertical gradient was calculated for Cthe MW-1/1\4W-101 pair. The vertical gradient was positive (a upward direction). However, i it was insignificant as head difference between MW-1 and MW-101 was only 0.02-feet. Generally, the magnitude of the vertical gradient has progressively decreased since February 2001. 4 As required under AB2886, the depth to groundwater data was submitted electronically to i GeoTracker on May 5, 2003,with confirmation number 7676319718 1.2 Groundwater Sampling Procedure On March 6, 2003, Don Light of Del-Tech mobilized to the site to conduct a groundwater-; monitoring event. The wells were first sounded for depth to water and then they were purged of at least three well volumes of stagnant water using a dedicated Waterra pump. Purging I� :. p p g g continued until the temperature, conductivity and pH of the groundwater stabilized (<10% 'l variation among three readings) indicating that formation water representative of aquifer conditions was entering the well. 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 during the filling of the VOA vials. Once the sample containers were filled and capped, the bottles were inverted, tapped and checked for headspace bubbles. Each sample container was identified and labeled with a unique rdesignation, inserted into foam holders and placed in a chilled ice chest for transport to the 6,+ laboratory. All non-disposable sampling equipment was decontaminated using a steam cleaner before and between uses. Disposable gloves were used by the technician to collect all rsamples and were changed with each sampling event. I