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S <br /> 1 <br /> Mr. Harlin Knoll,SJCEHD June 18,2007 <br /> Well Installation Work Plan <br /> A.Teichert and Sons Property, Stockton,CA <br /> Page 3 <br /> • BCR & Associates, Ltd. (BCR) directed the installation of well MW-14 in March <br /> 1994. This well was then used to perform an SVE test. SVE using well MW-14 <br /> was initiated in December 1994. <br /> • Anderson Consulting Group (Anderson) reconstructed well MW-13 in December <br /> 1994. The well was reconstructed for use as an SVE well. SVE using both wells <br /> MW-13 and MW-14 was initiated in January 1995. <br /> • EMCON installed air sparge well AS-1 in May 1995. SVE in conjunction with <br /> air sparging was initiated in June 1995. <br /> • Town and Country Contractors removed two 20,000-gallon and one 12,000-gallon <br /> USTs (Tanks T-5, T-6, and T-8) and associated dispenser island in March 1999, <br /> and excavated the dispenser area in April 1999. Pinnacle Environmental <br /> Solutions (Pinnacle) collected compliance soil samples during UST, fuel <br /> dispenser, and product line removal activities in March and April 1999. <br /> • Stratus advanced boring B-17 in September 1999. <br /> • Stratus properly destroyed monitoring wells MW-3 through MW-5 and MW-9 <br /> through MW-12 in February 2000. <br /> • Stratus collected compliance soil samples during the removal of a waste oil UST <br /> (Tank T-4)by Savidge Construction in October 2000. <br /> • Bioventing was initiated at the site, using the existing well network, in November <br /> 2004. These activities are ongoing. <br /> • Stratus completed cone penetration testing (CPT) investigations in January and <br /> October 2006. <br /> Site Geology and Hydrogeology <br /> Fine-grained material (silt and clay) comprises the predominant vadose zone soils (from <br /> surface grade to approximately 50 bgs). A laterally continuous sandy stratum <br /> approximately 5 to 15 feet thick was encountered between approximately 20 and 30 feet <br /> bgs. Some sandy strata of limited lateral extent were also encountered within the silt and <br /> clay of the vadose zone. <br /> Saturated soils appear to consist of interbedded fine-grained and sandy soil. Both the <br /> fine-grained and sandy strata appear to be laterally continuous across the site. <br /> Groundwater is first encountered between approximately 55 and 60 feet bgs, within a <br /> sandy stratum approximately 25 to 45 feet thick. This unit appears to thin significantly <br /> and acquire a greater proportion of fine-grained material to the southeast. Based on the <br /> limited number of borings extending deeper than 100 feet bgs, the interbedded <br /> relationship between the sandy and fine-grained strata appears to continue with depth, <br /> K:1Teichertl.Stockton-1031Work PlansAcichert-well install work plan 06-2007.doc 5MIV5 <br />