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2012 Monitoring Well Installation Work Plan November 8, 2012 <br /> FormerNestic USA, Inc. Facility <br /> 1 INTRODUCTION <br /> Environmental Cost Management, Inc. (ECM) has prepared this 2012 Monitoring Well <br /> Installation Work Plan (Work Plan) on behalf of Nestl6 USA, Inc. (Nestle). This Work Plan <br /> presents three well locations agreed upon during a meeting with the California Central Valley <br /> Regional Water Quality Control Board (RWQCB) on October 2, 2012. The three new monitoring <br /> wells will provide monitoring data near the lateral extent of contaminants of concern (COCs), <br /> previously delineated during the December 2011 Cone Penetrometer Test(CPT) investigation. <br /> 2 MONITORING WELL PLACEMENT AND DESIGN <br /> The proposed monitoring wells will be named M-55A, M-56A, and M-57A because they will each <br /> be screened in the Upper Aquifer in the A zone. This Work Plan presents approximate locations <br /> and screen intervals for the proposed wells based on the lithology characterized at nearby CPT <br /> borings and co-located depth-discrete groundwater samples. The well locations and screen <br /> intervals may be adjusted based on access constraints and the lithology encountered in each <br /> borehole. <br /> 2.1 LOCATION <br /> Figure 7 presents the proposed well locations, shown with respect to historic CPT boring <br /> locations and nearby existing monitoring wells. The table below details the information used to <br /> site these wells: <br /> PROPOSED LOCATION PURPOSE AND RATIONALE <br /> WELL <br /> To provide a well screened in the Lower <br /> West of CPT-34, located near well A zone in the vicinity of M-1 3A (a C Zone <br /> M-55A M-13A and CPT-39. Alley south of well). Hydropunch samples at CPT-34 <br /> West Main Street and Locust. and CPT-39 both contained CDCs above <br /> MCLs in the Lower A zone. <br /> To monitor groundwater downgradient of <br /> the impacted area recently delineated in <br /> M-56A Northeast of CPT-36 and CPT-37. the Upper A and Lower A zones. COC <br /> M-57A Terminus of frontage road north of concentrations were non-detect or at <br /> Pine Street. trace levels in groundwater samples at <br /> CPT-36 and CPT-37 in the Upper, <br /> Middle, and Lower A zones. <br /> 2.2 SCREEN INTERVALS <br /> The target depth interval for the proposed well screen for M-56A is in the Upper A zone of the <br /> Upper Aquifer. The target depth interval for the proposed well screens for M-55A and M-57A is <br /> the Lower A zone of the Upper Aquifer. The Upper A zone is a stratigraphic interval <br /> encountered from approximately 50 to 80 feet below ground surface (bgs). The lithology of the <br /> Upper A zone is characterized by predominantly coarse sands with occasional fine-grained <br /> interbeds. The Lower A zone is a stratigraphic interval encountered from approximately 95 to <br /> 120 feet bgs and is similar to the Upper A zone, though generally has fine-grained sand, as <br /> Page 1 of 4 <br />