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1 v 1 v <br /> CLEARWkTER <br /> G R O U P, I N C <br />' 1.0 INTRODUCTION <br />' This report presents the results fourth quarter 1994 groundwater monitoring <br /> performed by Clearwater Group, Inc (Clearwater) on December 29, 1994 at 1702 <br /> Jackson Street in Escalon, California (Figure 1). The tasks performed during this <br />' phase of work included groundwater gauging, well purging and groundwater <br /> sample collection <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 /> surroundmg'land is essentially flat Subsurface investigation conducted at the site <br /> indicates that encountered soils consist predominantly of unconsolidated sands and <br /> silts A layer of lean clay is present at a depth interval of 75 to 82 feet below grade <br />' surface (bgs) Depth to groundwater varies seasonally from approximately 48 5 to 51 <br /> 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 RESNA's recommendations was prepared b <br /> P P P P Y <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 4Q94 1 February 3, 1995 <br />