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------------ -- - " k L E I N F E L D E R 5 DISCUSSION OF FINDINGS 5.1 GROUNDWATER ELEVATION FINDINGS Based on surveyed elevations of the four monitoring wells at the site and two depth to groundwater surveys, Kleinfelder has evaluated depth to groundwater, groundwater flow direction and gradient. Based on a survey conducted on October 29, 2003, depth to groundwater was found to be between approximately 55 to 60 feet bgs with a groundwater flow direction to the southwest at a gradient of 0.012 ft./ft. Because a groundwater pumping test was being performed north of the site during this survey a second survey was conducted on December I8, 2003. Depth to groundwater was found to be between approximately 55 to 58 feet bgs with a groundwater flow direction to the southwest at a gradient of 0.010 ft./ft. Data from the two surveys were found to be consistent in depth to groundwater, groundwater flow direction and gradient. A summary of the groundwater elevation data is summarized in Table 1 located in the Appendix. Based on these findings the subject site appears to be down -gradient of the northern offsite property (Former Shell Station) and partially downgradient to cross -gradient from the trucking operation located east of the site. The CalTrans maintenance yard located south of the site appears to be down -gradient from the subject site. 5.2 ANALYTICAL RESULTS Based on the requested soil and groundwater analytical analyses summarized in Section 4, four groundwater samples, six composite soil samples and 22 discrete soil samples were analyzed for various analyses as listed in Section 4. The groundwater sampling results are summarized on Table 2 and the soil sampling results are summarized in Tables 3 through 8 located in the Appendix. 5.2.1 Groundwater Sampling Results Three perimeter monitoring wells (MW1, MW -3 and MW -4) were installed along the subject site boundaries to the north, east and south to assess potential offsite sources of concern from nearby industrial and commercial operations. Monitoring well MW -2 was installed adjacent to a former onsite UST area to assess potential impacts to groundwater from the former USTs. The four groundwater samples collected from these wells were analyzed for various petroleum constituent, including fuel oxygenates (See Section 4.5). Based on the analytical results no requested petroleum constituents or volatile organic compounds (EPA 8260 analytes) were detected from two of the perimeter groundwater samples 362741 ST03R1919 Page 1 1 of 19 c 206=1 Kleinfelder, Inc. January 5, 2004