SITE HISTORY_FILE 2 - Laserfiche WebLink

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2.0 SITE INFORMATION 2.1 Site Description The site is located on the eastern side of South Harlan Road between J Street and Thomsen Road in the City of Lathrop, San Joaquin County, California (Figure 1). The site is currently developed as a retail motor fuel service facility and truck stop with four fuel dispensers to service automobiles and light trucks, twelve dispensers to service heavy commercial trucks, a truck wash, and a retail store building containing a mini-mart and a sandwich shop. According to Mr. Dhoot, the site has operated as a motor fuel dispensing facility since 1954. Several generations of underground storage tanks (USTs) and aboveground storage tanks (ASTs) have been installed at the site during the subsequent years. Currently, there are three gasoline USTs (12,000, 10,000, and 4,000 gallons) and one diesel UST (4,000 gallons) that supply the automobile dispenser islands, and four 10,000-gallon diesel ASTs that supply the heavy truck dispensers. The current station configuration is shown on Figure 2a. Topography in the vicinity of the site is generally flat, at an elevation of approximately 14 feet above mean sea level. Most of the site is covered either by the building or asphalt paving. Several planters are situated along the western property boundary along S. Harlan Road. The area surrounding the property is mixed commercial and residential. Properties adjoining the site to the north and south are a Storage Pro facility and a Best Western Plaza Inn and Suites, respectively. Single family homes are located on properties adjoining the site to the east (along Lisa Lane and Patricia Place). 2.2 Previous Environmental Investigations Environmental investigations at the site began in January 1997, when petroleum-hydrocarbon impact was identified during pre-UST removal characterization activities. Since that time, more than sixty vertical soil borings have been drilled at the property and in surrounding areas to evaluate the lateral and vertical extent of soil and groundwater impact beneath the site. Of these borings, twenty-two borings were converted to permanent groundwater monitoring wells screened across three intervals of water-bearing strata beneath the site. Quarterly groundwater monitoring and sampling was initiated in February 2000, and is currently ongoing. A summary of well construction details is included as Table 1. Historical soil and grab groundwater analytical results from all previous assessment conducted at the site are summarized on Tables 2 and 3, respectively. Historical quarterly groundwater gauging and analytical results are summarized in Tables 4 and 5, respectively. A compilation of all historic soil boring/well construction logs are provided in Appendix A. The following narrative provides a chronological account of all previous environmental work at the site from January 1997 to September 2009. Page 6 5 rKALU5