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1 Creologecalw4ficcsW Page 3 GW Monitoring Report Ted Peters -AST Project No 701 2 July 31, 2002 ' are offset by 90° when compared to the southwesterly directions noted on July 30, 1999, and February 17, 2000 The northeasterly flow direction in February 2001 is anomalous to ' the dominant westerly direction observed for the other monitoring events The field technician has previously noted that free product was present in well MW-5, but it was not observed for this event Groundwater elevation data for MW-5 is anomalous for the ' June 2002 event and are omitted from the contour diagram included in Figure 2 Groundwater gradient was also calculated from the three wells installed at the front of the site to investigate the UST area The gradient in this area was 0 001 ft/ft flowing N70°W This is consistent with the other monitoring events completed during the investigation The gradient has consistently trended to west to northwest in the past ' An examination of the AST area indicates that for the last four events the gradient was northwesterly This suggests that previous calculations were affected by the spatial orientation of the AST wells, the presence of free product in MW-5, or a combination of ' both It is also possible the local domestic wells located west of this property are influencing the gradients at the site A domestic well survey within 2,000 feet of the site was completed on August 16, 2000 The survey efforts resulted in the identification of numerous domestic wells on the residential properties to the southwest, west and northwest of the site Ten wells were located in the properties to the immediate west of the subject site and their locations are N identified in our "Well Receptor Report" dated September 11, 2000, (submitted to the SJC- PHS/EHD and the CRWQCB-CVR) ' 2.2 Groundwater Sampling Procedure On June 19, 2002, Don Light of Del Tech Geotechnical Support arrived on-site, opened the ' wells and measured the depth to water with an electrically actuated sounding tape The watei level reading was recorded to an accuracy of 0 01 foot The wells were then purged of at least 3 well volumes of stagnant water using a centrifugal ' pump Purging continued until the temperature, conductivity and pH of the groundwater had stabilized (<10% 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 The logs are included in Appendix C A stainless steel bailer or dedicated Wattera gibing was used to collect a sample from each ' well Care was taken to minimize sample agitation from the initial filling of the bailer to the transfer of the sample to the VOA vial and glass amber liter bottles Once the sample container was filled and capped, the bottle was then inverted, tapped and checked for ' headspace bubbles The sample container was then identified and labeled with a unique designation, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the 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 samples and were changed after each sample was collected I 1