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Monitoring Well Installation Report April 15, 2010 <br /> Former Nestle USA, Inc. Facility, Ripon, CA <br /> 3) Installing one groundwater monitoring well to the southwest of the Stockton <br /> Avenue site to verify and monitor the COC concentration in Intermediate Aquifer <br /> (C zone)from the City of Ripon municipal lagoons. <br /> 2.1 DRILLING METHODS <br /> The wells were installed using two different methods of drilling due to the lithology in the <br /> investigation area. The presence of heaving sands, particularly at deeper intervals, <br /> required the use of the rotosonic (sonic) drilling method to install deeper well M-54C. <br /> Shallower wells M-50A, M-51 A, M-5213, and M-53B were successfully installed using the <br /> hollow stem auger drilling method. <br /> 2.2 GROUNDWATER SAMPLING METHODS <br /> The MaxiProbe® Simulprobe® sampler was utilized in conjunction with hollow stem <br /> auger drilling to collect soil core and groundwater samples from the drilling locations at <br /> M-50A, M-51A, M-5213, and M-5313. However, during the drilling of well M-50A, the <br /> Simulprobe° sampler became immobilized at a depth of 44 feet bgs due to heaving <br /> sands. As a result, hydropunch sampling using a one-foot screen interval was employed <br /> for the sample collected at a depth of 45 to 46 feet bgs in M-50A. Passive diffusion bag <br /> (PDB) samplers were placed to collect samples at depth-specific intervals from well M- <br /> 54C after its completion and development. <br /> 3 FIELD PREPARATION <br /> The following sections provide a summary of activities completed prior to commencing <br /> drilling operations. <br /> 3.1 PERMITTING <br /> Prior to drilling, ECM obtained well installation permits (Appendix A) from the San <br /> Joaquin County Environmental Health Department (EHD) for all five wells. In addition, <br /> ECM obtained a City of Ripon Encroachment Permit (Appendix B) for well M-54C, due <br /> to the proposed location of the boring in a City of Ripon street right-of-way. <br /> 3.2 ACCESS <br /> Nestle has an on-going access agreement with California Freight Company (Cal <br /> Freight), the current owner of the 230 Industrial Avenue parcel. ECM contacted Cal <br /> Freight in advance of drilling operations to notify the owners of the pending field <br /> investigation. <br /> 3.3 SUBSURFACE UTILITY CLEARANCE <br /> ECM obtained utility mark-out tickets for all three parcels (230 Industrial Avenue, 519 <br /> South Stockton Avenue, and Fifth Street) from Underground Service Alert (USA) for <br /> utility clearance (USA #s 360868, 360879, 360879). In addition, Gregg Drilling obtained <br /> tickets for their work at 230 Industrial Avenue and 519 South Stockton Avenue (USA #s <br /> 380081 and 380108). <br /> ECM also contracted Subtronic Corporation (Subtronic), a private locating company to <br /> complete a private property subsurface utility screening. Subtronic completed initial <br /> 2 <br />