SITE INFORMATION AND CORRESPONDENCE_FILE 1

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Three soil borings are proposed to confirm that the former piping has been removed. The location of these borings are shown on Figure 4. The nearest surface water is Fivemile Creek, approximately 3,000 feet to the northwest. Fivemile Creek flows southwest toward Fivemile Slough, which flows into the San Joaquin Delta. Site elevation is approximately 15 feet above mean sea level (MSL); regional ground- water flow is to the southwest. Groundwater elevations in the Stockton area have declined in recent years and poor quality groundwater from the San Joaquin Delta has migrated east toward Stockton. Water quality in the Stockton area has been affected and groundwater- supply wells have been abandoned in the western part of the region. New wells have been drilled in the eastern part of the city and groundwater use has been supplemented by supplies from the Calaveras River. A well survey (Sierra 1992) was performed for the site using data from the California State Department of Water Resources. Using these data, 30 water wells were identified within 1/2 mile of the site. Two of the wells identified in the well survey, a domestic well and a municipal well, are potentially downgradient of the site. These wells are both more than 1/4 mile southeast of the site. 2.2 Primary Source Data regarding the primary source of the petroleum hydrocarbon residuals beneath the site are limited. Available data (groundwater monitoring and site soil chemistry) indicate that the primary sources of petroleum hydrocarbons were the former product storage and distribution facilities. Additionally, a relatively recent source of hydrocarbons at the site appears to be associated with product delivery activities and specifically the fill containment buckets. These conditions were rectified in December 1993 by replacing the fill containment buckets with updated models. Based on available information, it appears that there are no existing primary sources of hydrocarbons at the site. 2.3 Secondary Source Secondary sources of residual petroleum hydrocarbons beneath the site were identified as: groundwater and potentially the capillary fringe containing weathered dissolved petroleum hydrocarbons. Although not addressed by this CAP, it should be noted that chlorinated compounds have been identified beneath the site. The source of these chlorinated compounds is presumably located within Lincoln Center, as previously discussed. Previous investigation has included seven soil borings (converted to Wells MW-I through MW-7), seven soil samples (collected from beneath the former USTs), and seven soil vapor probes (VP-1 through VP-7) (Figure 4). To further investigate the potential for residual 3201357B/CAPREVI 3 June 29, 1995