ARCHIVED REPORTS_MONITORING WELL INSTALLATION REPORT 2010

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Monitoring Well Installation Report April 15, 2010 Former Nestle USA, Inc. Facility, Ripon, CA poorly sorted sands and silty sands. The borehole was terminated at 42 feet bgs. The lithologic log for M-52B is located in Appendix C. 4.5.2 GROUNDWATER SAMPLING The Simulprobe°sampler was able to successfully retrieve groundwater samples at 32.5 feet, 36.5 feet, and 40.5 feet bgs. As with the samples collected in M-53B, these discrete intervals were targeted to collect samples in the B Zone of the Upper Aquifer at intervals where previous borings at this location indicated a significant water-bearing sand zone exists in the B Zone. These samples were labeled M-52B-32.5, M-52B-36.5', and M-52B-40.5', and were immediately placed in a cooler on ice for containment until transport to TestAmerica for analysis of VOCs by EPA Method 8260B. Results of analysis are discussed in Section 7. 4.5.3 WELL COMPLETION DETAILS Monitoring well M-52B was completed to a depth of 42 feet bgs on December 20, 2009. The well was constructed of two-inch PVC Schedule 40 casing with 20 feet of 0.020-slot screen from approximately 22 to 42 feet bgs. Well completion details are illustrated in Appendix D and on Table 1. 5 WELL DEVELOPMENT The newly constructed wells were developed in the week of December 21, 2009, to remove fine particles from the well casing, screen and filter pack. The wells were developed by surging the water inside the well screen with a surge block to pull fine material out of the filter pack and screen. Water and sediment were pumped and/or bailed from each well. The well development was considered complete when the monitored purge water met the following conditions for each well: ■ A measurement of 50 (or less) nephelometric turbidity units (NTUs), ■ A pH change of less than 0.1 pH units, ■ A temperature change of 1' F or less, and ■ A conductivity change of 5% or less. 6 WELL SURVEY INFORMATION Bedesen-Cardoza & Associates, Inc. (BCA) surveyed the new well locations and elevations with respect to the State Plane Coordinate system on January 19, 2010. Top of Casing (TOC) elevations were determined to within +/-0.01 feet using the North American Vertical Datum of 1988 (NAVD88). The well latitudes and longitudes were surveyed into the existing geodetic network using the North American Datum of 1983 (NAD83). Both the TOC, which is the measuring point for depth-to-water measurements, and the ground surface adjacent to each well were surveyed for elevation using NAVD88 coordinate system. Table 2 provides post-development depth to water and groundwater elevation data for all five new wells. 7