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2.3 Field Investigation The scope of work for this project included an underground utility location survey and the advancement of two soil borings using Cone Penetrometer Testing (CPT) methods Details of the investigation methods are presented in the following sections 2.3.f Underground Utility Location Survey On February 11, 2002, an underground utility location survey was conducted to assess the absence or presence of unreported underground utilities at the site The utility survey was conducted using ground-penetrating radar (GPR) and radio frequency survey equipment The utility survey cleared utilities for the proposed CPT boring locations * 2.3.2 Drilling and Groundwater Sample Collection ■ Two borings were advanced to 30 5 meters (100 feet) using a truck mounted Cone Penetrometer Testing (CPT) rig A boring location map is presented in Figure 2 The boring locations were selected by Caltrans to provide data for determining the vertical extent of contamination The CPT borings were performed to obtain deep lithologic data on the aquifer and to collect discreet groundwater samples As the first boring was advanced, cone bearing tip resistance, sleeve friction, friction ratio, and pore water pressure were measured using the cone penetrometer tip Using the CPT results, subsurface conditions were interpreted in order to determine aquifer zones to collect groundwater samples from The CPT log indicated that potential water bearing zones were located at 19 8 meters (65 feet), 27 4 meters (90 feet), and 30 5 meters (100 feet) The second boring, SC-1, was advanced to obtain groundwater samples from the targeted zones using Hydropunch methods Groundwater samples were collected from each of the zones using Hydropunch methods The samples were collected by advancing approximately 1 meter(3 3 feet) below the targeted zone and raising the probe to expose the 1 5-meter (5-foot) screen New disposable polyethylene and stainless steel bailers were used for groundwater collection The groundwater samples were labeled, packaged with ice, and stored in an insulated chest for transport under chain-of-custody manifest to a California-certified analytical laboratory Groundwater samples were labeled with the boring number, depth, date, time, and initialed For example SC-1-64, where SC-1 is the boring number and 64 is the sample depth in feet Temperature, pH, and conductivity of each ' groundwater sample were recorded on field report forms Drilling and sampling procedures are included in Appendix B Following the last sample, an expendable Hydropunch tip was knocked out and the hole grouted with 20 1 cement/bentonite grout, from the bottom up, during removal of the probe casing x,k—b-rectu,obgrl CRFPI3COMMan&wDPLVWWJBW n.luidbc 2-2 4102