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collect samples to confirm the vapor results The results of the investigation were presented in the Soil Assessment Report prepared by Upgradient in April 1998 Subsequently, one of the borings was converted to groundwater monitor well VM-4 In August 1999, Upgradient installed two remediation test wells within the mapped zone of soil contamination However, no hydrocarbons were detected in any of the soil samples collected from these wells One of the wells (VT-1) was screened with 4-inch PVC casing from 15 to 30 feet for future use in soil vapor extraction testing The other well (SW-1), was screened with 2-inch PVC casing from 29 5 to 31 5 feet for potential use as an air sparging well Groundwater monitoring, which began after the installation of VM-1 and has been conducted on a regular quarterly schedule since June 1998, has shown that VM-1 and VM-2 are consistently impacted with gasoline and VM-3 and VM-4 are occasionally impacted It has thus been apparent that the contamination extends off site, but difficulties in obtaining an Encroachment Permit from the City of Stockton to drill on City property north and west of the site have prevented attempts to further delineate the extent of contamination until recently The necessary pernlits were obtained in March 2003, and four wells were drilled in April This report presents the results of that work, as well as the results of groundwater monitoring activities that took place after the new wells were installed 3.0 PROCEDURES 3.1 Drilling and Sampling V&W Drilling mobilized a hollow-stem auger drilling rig to the site on April 1 and drilled three borings The fourth boring (VM-8) was drilled on April 15, after Underground Services Alert was re-contacted to confirm that no underground utilities were present at the proposed location Three of the borings (VM-b, VM-7, and VM-8) were drilled to a depth of 40 feet and sampled at 5- foot intervals (Figure 2) Boring logs (Appendix A) were prepared during drilling, and the borings were terminated within the low-permeability silty clay that underlies the first aquifer at the site This aquifer consists of fine to coarse-grained sand The top of this bed varies in depth from less than 15 to more than 20 feet in various borings, but the base is generally near 33 feet However, in VM-5 the base was at 30 feet, therefore, this boring was terminated at 35 feet A faint hydrocarbon odor was detected in some samples from VM-7 during drilling, and four samples were preserved for laboratory analysis No odors were evident in the other borings, so only samples near and below the soil-water interface were preserved from these borings A total of ten samples weie transported to Excelchem Environmental Laboratory for analysis r 3.2 Groundwater Monitoring and Surveying The depth to groundwater was measured and water samples were collected on April 15 The wells were opened and allowed to equalize with atmospheric pressure before the depth to groundwater 3