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Monitoring Well Installation Report April 15, 2010 <br /> Former Nestle USA, Inc. Facility, Ripon, CA <br /> 4.3.1 STRATIGRAPHIC CHARACTERIZATION <br /> Silty sands and clays were observed at shallower depths in M-5313, while silty sands with <br /> fine to coarse grained sands were observed intermittently at deeper intervals. The <br /> borehole for this well was terminated at 42 feet bgs. The lithologic log for M-53B is <br /> provided in Appendix C. <br /> 4.3.2 GROUNDWATER SAMPLING <br /> An attempt was made to collect a groundwater sample with the Simulprobe® sampler at <br /> a depth of 29.67 feet bgs. However, no sample was recovered in the Simulprobe® <br /> water canister. Dampness in the canister and in the soil core recovered suggested there <br /> was water present in the surrounding lithology, but potentially the hydraulic head was not <br /> sufficient enough for water to enter and fill the canister. <br /> The Simulprobe°sampler successfully retrieved groundwater samples at approximately <br /> 31 feet, 34 feet, and 40 feet bgs. These discrete intervals were targeted to collect <br /> samples in the B Zone of the Upper Aquifer at intervals where previous borings at this <br /> location indicated a significant water-bearing sand zone in the B Zone. These samples <br /> were labeled M-53B-31.33', M-53B-34.42', and M-53B-40.17', and were immediately <br /> placed in a cooler on ice for containment until transport to TestAmerica for analysis of <br /> VOCs by EPA Method 8260B. Results of analysis are discussed in Section 7. <br /> 4.3.3 WELL COMPLETION <br /> Monitoring well M-53B was completed to a depth of 42 feet bgs. The well was <br /> constructed of two-inch PVC Schedule 40 casing with 20 feet of 0.020-slot screen from <br /> approximately 22 to 42 feet bgs. Well completion details are illustrated in Appendix D <br /> and on Table 1. <br /> 4.4 MONITORING WELL M-50A <br /> The following subsections detail the installation activities for Upper Aquifer monitoring <br /> well M-50A located on the 230 Industrial Avenue site. <br /> 4.4.1 INITIAL BORING LOCATION <br /> The initial boring location selected for well M-50A was in the driveway located on the <br /> northwestern end of the 230 Industrial Avenue site. <br /> The original boring location for well M-50A was marked-out under USA Ticket#s 360879 <br /> and 380081. Additionally, Subtronic completed an underground utility survey in this <br /> location and provided mark-outs for the private property and driveway. <br /> Drilling activities for this location initially commenced on the afternoon of December 15, <br /> 2009. However, due to the discovery of an unmarked City of Ripon sanitary sewer line, <br /> drilling activities were terminated at this location the same evening. The top and top- <br /> side of the 8-foot deep City of Ripon sewer line received damage during advancement of <br /> the auger tools and was further damaged when the augers were removed from the hole. <br /> The City of Ripon was contacted as well as the San Joaquin County EHD Inspector <br /> upon discovery of the sewer line. The County EHD Inspector granted permission to <br /> immediately grout the 40 foot borehole in order to prevent any potential contamination of <br /> groundwater from the sewer line. Representatives from the City of Ripon arrived onsite <br /> 5 <br />