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1117 Lone Palm Avenue, Suite 201 AV Modesto, California 95351 Wr kTc209-579-2221 ENVIRONMENTAL - GEOTECHNICAL Fax: 209-579-2225 BUILDING SCIENCES • MATERIALS TESTING approximate locations shown on Figure 3. ATC anticipates the borings will be installed in the sidewalk or the roadway depending on the potential presence of utilities and municipal requirements. The two proposed soil borings will be advanced using cone penetration test (CPT) methods. CPT borings are proposed in lieu of monitoring wells as a cost saving measure. Drilling will be conducted by a State-licensed (C57) drilling company. The CPT borings will be advanced to an estimated depth of approximately 90 feet. The borings will advanced using a direct CPT rig that will log soil lithology from approximately five feet bgs to the maximum depth explored. A groundwater sample will be collected from a separate borehole advanced adjacent to each of the CPT borings using a modified Hydropunch® sampler. Prior to groundwater sampling, a water level meter will be used to confirm that the drive rods do not contain water. The sampler will then be driven to approximately three feet below the desired sampling depth and then retracted three feet to expose the disposable Schedule 20 polyvinyl chloride (PVC) screen and allow groundwater to enter the Hydropunch® sampler. The water samples will be collected by lowering a 3/4-inch diameter stainless steel bailer through the drive rods to groundwater. The groundwater will be bailed from the drive rods and decanted into 40-milliliter glass vials. Following the collection of the samples, the drive rods will be retracted, leaving the disposable drive tip and four-foot length of PVC well screen in the hole. Following completion, the CPT borings will be grouted through the drive rods from the total depth explored to surface grade with neat cement. Sample Analyses Groundwater samples collected from the borings will be submitted under chain-of-custody procedures to a State-certified laboratory. The groundwater samples will be analyzed for total petroleum hydrocarbons quantified as gasoline (TPHg) utilizing EPA Method 8015B; and benzene, toluene, ethylbenzene, and xylenes (BTEX), methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPE), tertiary amyl ether (TAME), tertiary butyl alcohol (TBA), 1,2- dichloroethane (1,2-DCA), 1,2-dibromoethane (EDB), and naphthalene utilizing EPA Method 8260B. Report Preparation Upon completion of the field activities, a report will be prepared describing the field activities and laboratory analytical results and will include an assessment of the extent of the petroleum hydrocarbon release along with recommendations for additional investigation activities if warranted. The report will be prepared in general accordance with CRWQCB reporting guidelines. The work described in this workplan will be performed under the direction of a California Registered Professional Engineer or California Registered Geologist. All work will be performed in accordance with ATC's Site Specific Health and Safety Plan (HASP). Proiected Schedule Once approval of this workplan has been received, ATC will work to obtain an access agreement to install the proposed off-site wells to the southeast and confirm a schedule for drilling activities. ATC will notify the SJCEHD at least 48 hours prior to beginning any field activities. The summary report s:\enviromental\28349\reports\2020 Offsite WP CPT.doc 5 ATC