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CLEARWA' TER <br /> G R O U P, I N C <br /> ' 1.0 INTRODUCTION <br /> This report presents the results of first quarter 1995 activities performed by <br /> ' Clearwater Group, Inc (Clearwater) at 1702 Jackson Street in Escalon, California <br /> (Figure 1) The tasks performed during this phase of work included groundwater <br /> gauging, well purging and groundwater sample collection, and vapor extraction <br /> ' system installation, start-up and morutoring <br />' 2.0 BACKGROUND <br /> The subject site is located in a mixed light industrial, commercial and residential <br />' neighborhood of central Escalon Escalon is a small town lying in the southern <br /> Sacramento Valley of California, a predominantly agricultural region The site is <br /> currently occupied by a former retail fuel facility The topography of the site and <br /> surrounding land is essentially flat Results of a subsurface investigation conducted <br /> at the site indicates that the shallow subsurface consists predominantly of <br />' unconsolidated sandsand silt. A layer of lean clay is present at a depth interval of 75 <br /> to 82 feet below grade surface (bgs) Depth to groundwater varies seasonally from <br /> approximately 48 5 to 51 feet bgs <br /> Results of analysis of soil samples collected during underground storage tank (UST) <br /> removal indicated the presence of moderate to low concentrations of fuel <br />' hydrocarbons Details of UST removal, soil sampling and preliminary site <br /> evaluation have been presented by RESNA in reports entitled Preliminary Report, <br /> Assessment of-Soil Contamination (July 30, 1991) and Problem Assessment Report, <br /> Soil Contamination (December 23, 1991) <br /> A more in depth phase of site characterization was implemented by RESNA <br />' following completion of the preliminary evaluation Four groundwater <br /> monitoring wells and several soil borings were installed/advanced during this <br /> evaluation Results of this phase of activity defined the extent of fuel hydrocarbons <br /> in the vicinity of the former diesel tank, the former gasoline tanks and the gasoline <br /> dispenser island. RESNA proposed and implemented a plan for the excavation of <br /> soil containing diesel components following completion of the comprehensive site <br /> characterization RESNA recommended the implementation of a vapor extraction <br /> program to address residual hydrocarbons beneath the former gasoline UST's and <br /> dispenser island. <br /> A workplan for the implementation of RE ' <br /> P RESNA's recommendations was prepared by <br /> Clearwater and approved by the San Joaquin County Public Health Services/ <br /> Environmental Health Division (PHS/EHD) A slight modification to the original <br /> plan was recommended in this workplan and included the installation of two <br /> D-102 1Q95 1 May 14, 1995 <br /> I <br /> 1 <br />