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' PROJECT STATUS AND MONITORING REPORT USA PETROLEUM STATION#110 - STOCKTON JANUARY, 1996 3.0 SUMMARY OF MONITORING WELL INSTALLATION Two borings were drilled on September 25 and 26, 1995 and completed as monitoring wells s (MW-4-P and MW-6-P) MW-5-P was drilled and completed as a monitoring well on October 30, 1995 MW-4-P was originally planned to be located in front of the abandoned Arco service station on Manposa Road Due to overhead utilities the well was relocated to a position southwest of the proposed position on the Arco site MW-5 was intended to be located in front of the Montezuma School However, due to underground utilities, the boring was moved to a position on the south side of Farmington Road on the USA site MW-6 was moved from its originally proposed position to the parking lot in front of the shopping center at 2101 East Manposa Road, as shown in Figure 2. Detailed descriptions of the monitoring well construction are presented in the December, 1995, "Well Construction Report",prepared by this office 4.0 SUMMARY AND CONCLUSIONS ' 4.1 Results of Groundwater Laboratory Analyses TPH G was only detected in monitoring wells MW-2-P and MW-3-P at 530 and 270 rrucrograms ' per liter(�ig/l),respectively TPH G was non-detect for all other monitored wells TPH D was non-detect for all samples analyzed Samples from MW-4-P and MW-1-P were not analyzed for diesel BTEX compound concentrations ranged from non-detect to a high of 51 icg/l for benzene in MW-2-P No detected levels of total lead were reported in any of the wells Analytical results are summarized in Table 3 Groundwater laboratory results for September, 1992 September, 1993 M P p arch, August, and December, 1994, and March and June, 1995 are also summanzed in Table 3 Certified laboratory ' reports and COC documents for the most recent sampling event are included in Appendix B ' 4.2 Groundwater Conditions Recent groundwater data collected at the site indicate groundwater is present at depths ranging ' from 71 51-feet to 72 56-feet below ground surface (bgs) The groundwater elevation ranges from a high of 46 14-feet below MSL to a low of 46 69-feet below MSL The most recent groundwater data indicates that groundwater is flowing to the northeast with a hydraulic gradient ' of approximately 0 0027-feet/feet A review of the historical field data suggests that the groundwater generally flows to the east and has fluctuated slightly to the north and south several tunes during the period of record Graphic presentations of the flow beneath the site are ' presented in Figure 3 1