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Chevron Products Company 4 Former Chevron Station 9-5775, 301 W Kettleman Lane, Lodi, CA July 24,2000 • southwest, at an approximate gradient of 0 003 Quarterly monitoring and sampling is ongoing at the site Additionally, sampling of the municipal well located approximately 350 feet southwest of the site was initiated in 1996 (San Joaquin Co Public Works Department, Frank Beeler verbal communication July 2000) The well was sampled annually in 1996 and 1997, quarterly during 1998, and monthly in 1999 and 2000 No detectable concentrations of hydrocarbons or fuel oxygenates have been reported in this well (City of Lodi and G -R) RECENT ASSESSMENT ACTIVITIES AND FINDINGS Well Installation and Soil Borings Between June 14 and July 7, 2000, ten groundwater monitoring wells (MW -513, MW -8B, MW - 10A and B, MW -11A and B, MW -12A and B, MW -13, and MW -14) were drilled and installed at the site by Cascade Drilling Monitoring wells MW -5B, MW -8B, MW -10B, MW -11B, and MW -12B were drilled and completed to approximately 90 feet bgs Monitoring wells MW - 10A, MW -11A, MW -12A, MW -13, and MW -14 were drilled and completed to approximately 65 feet bgs Borehole logs and well construction details are presented in Attachment D Geology and Hydrogeology . Based on observations during drilling activities, the site vicinity is underlain primarily by silty sands and sandy silts in varying amounts Soil encountered in the borings for MW -8B, MW - 5B, MW -3, SB -1, and MW -4 consists primarily of near surface sandy silts, extending in some locations to 35 feet bgs, with discontinuous sand and clay lenses The sandy silt layer is underlain by a silty sand layer, which in some locations extends to 43 feet bgs A sandy silt to clayey silt layer was encountered in some locations extending to the water -bearing zone at a depth of approximately 55 feet bgs A water -bearing zone consisting of a mixture of clayey silts, sandy silts, clayey sands, and silty sands was encountered at approximately 55 bgs A silty sand layer (extending to 60 feet bgs) underlain by a sandy -silt layer (extending to approximately 65 feet bgs) was encountered in some locations A cross section location map and a geologic cross section for the site are provided as Figures 2 and 3, respectively Monitoring data from July 18, 2000, (Table 1) indicates depth to water in shallow zone wells ranging from 55 to 57, and from 56 to 59 feet bgs in deeper zone wells Groundwater flow direction is to the west in the shallow zone wells at an approximate gradient of 0 005 and to the southwest in deeper zone wells at a approximate gradient of 0 003 Groundwater contour maps for shallow and deeper water -bearing zone wells are provided as Figures 4 and 5, respectively 077 41991 04319-5775PAR doc