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Phase II Environmental Site Assessment Manteca Multimodal Station Project, Southeast of Moffat Boulevard and Main Street,Manteca, California several of its major tributaries namely,the Stanislaus, and Calaveras, and Mokelumne Rivers. The San Joaquin River flows northward into the Sacramento and San Joaquin Delta and discharges into the San Francisco Bay. According to the RWQCB Water Quality Control Plan for the Central Valley Region, the site lies within Groundwater Subbasin B4 of the San Joaquin River Basin hydrologic study area. Beneficial uses for the groundwater resources within this hydrologic area include municipal and domestic supply, irrigation, stock watering, industrial process, and service supply. Based on the previous assessment conducted at the site by Wm. J. Hunter and Associates in 1992,the depth to groundwater beneath the site was approximately 25 feet below grade and the anticipated groundwater flow direction in the vicinity of the site was north to northeast. In addition, the following groundwater data are based on documents maintained by the SWRCB on their GeoTracker website for several nearby properties: • Groundwater beneath 151 S. Main Street(former Diamond Lumber), located about 120 feet to the northwest of the site, is encountered at between about 10 and 20 feet below grade and flows to the northwest to north-northeast. • Groundwater beneath 419 S. Main Street(Boyette Petroleum), located about 350 feet to the south-southwest of the site, is encountered at between 14 and 23 feet below grade and flows to the northwest. • Groundwater beneath 210 E. Wetmore Street(Manteca City Corporation Yard), located about 200 feet to the southeast of the site, is encountered at between 15 and 23 feet below grade and flows to the northwest. During the current assessment, groundwater was encountered between 18 and 22 feet below grade in the five soil borings advanced to 25 feet below grade. METHODOLOGY On December 6 and 7, 2010, a total of 22 soil borings were completed at the site. The borings were advanced using a Geoprobe direct push rig operated by Vironex, Inc. of Concord, California, under the direction of Rincon. All sampling was performed under the oversight of a California Professional Geologist. Photographs taken during sampling are in Figure 3. Sampling methodologies are as follows. SOIL AND GROUNDWATER SAMPLING Standard Oil Company Supply Station and Industrial Adjacent Land Uses On December 6, 2010, five soil borings (B1 through 135)were completed along the southern boundary of the subject property as depicted in Figure 2. The five borings were advanced to a maximum depth of 25 feet below grade using a Geoprobe direct push rig operated by Vironex. Soil samples were obtained from depths of 5, 10, 15, 20, and 25 feet below grade. Samples collected using the Geoprobe sampling system were obtained by driving a hydraulic hammer or vibrator into the soil. As the probe was advanced, soil was driven into a 1-inch diameter, 2-foot long acetate sleeve. After being driven to the necessary depth,the rods were removed from the borehole. The acetate sleeve containing the soil was then removed from the probe. A 6-inch long section was cut and sealed with Teflon tape and end caps. The samples were labeled and Rincon Consultants 7