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04 October 2005 . AGE-NC Project No 98-0432 Page 2 of 6 Based on the General Soil Map from the San Joaquin County Soil Survey,published by the United States Department of Agriculture Soil Conservation Service in 1992, the site is situated within an area of Capay clay soil Capay clay is located in interfan basin or alluvial fan areas, and generally consists of very deep, moderately well-drained grayish brown and dark grayish brown clay formed in alluvium derived from mixed rock sources The nearest surface water feature in the vicinity of the property is the Stanislaus River, located approximately 5 miles south of the site Ground water at the site is currently encountered at a depth of approximately 14 feet to 20 feet below surface grade (bsg), and typically flows toward the west- northwest Ground water over the majority of the site occurs in a stratigraphic layer generally consisting of silty sand extending from surface grade to approximately 25 feet bsg,and from surface grade to approximately 15 feet bsg in the southern portion of the site Ground water elevation data from January 2000 to July 2005 is presented in Table 1 Histonc ground water elevation maps are included in Appendix A 22 WELL SURVEY In April 2000,AGE conducted a sensitive receptor survey to locate potential vertical conduits within a 2,000-foot radius of the site The survey located an a nPrJestence to4aJ1 well l 750 fe sou as of este at the Van Ryan Nut processing facility and�twod�a gen` s One domestic water weel was c�` observed 1,800 feet southwest of the site on Industrial Park Drive Additionally, one commercial/agricultural well was located down-gradient approximately 2,200 feet northwest at a pickling processor Results of the investigation were reported in the AGE-prepared Well Survey, dated 20 April 2000 2 3 UNDERGROUND STORAGE TANK REMOVAL AND OVER-EXCAVATION On 10 September 1998,four USTs,including one 4,000-gallon and two 3,000-gallon gasoline USTs and one 12,000-gallon diesel UST,two dispenser islands,and associated product lines were removed from the site These tanks were in operation at the site for approximately 20 years The former UST locations are depicted on Figure 2 During the removal of the USTs and fueling system, AGE performed interim soil remediation, approximately 350 cubic yards of soil were removed from two UST excavations and four dispenser excavations On 15 September 1998,the interim soil remediation included removal of an additional 100 cubic yards of significantly diesel-impacted soil from the bottom of the diesel UST excavation Soil was excavated from the diesel UST excavation at the central area of the site to a depth of 20 feet . bsg One grab water sample was collected from the northern edge of the diesel UST over-excavation Advanced GeoEnnronmentai,Inc