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15 May 2019 <br />AGE Project No. 14-3002 <br />Page 14 of 17 <br />included in Appendix H. Laboratory EDF files will be QA/QC checked and uploaded to the <br />State Water Board GeoTracker site. <br /> <br /> <br />5.6. GROUNDWATER ELEVATION, FLOW DIRECTION AND GRADIENT <br /> <br />Groundwater elevation data was collected from wells MW-1 through MW-4 on 03 April <br />2019. The groundwater elevation was calculated by subtracting the depth to water from <br />the surveyed casing elevation. Groundwater flow direction was inferred, and gradient was <br />calculated from the data collected from wells MW -1 through MW-4. Depth to groundwater <br />ranged between 12.52 feet (MW -2) and 14.29 feet (MW -1) below the top of casings (btoc) <br />in the wells. Groundwater elevations ranged between 5.21 feet (MW -2) and 5.37 feet <br />(MW -1) above NAVD88. The monitoring wells were constructed with the well casings <br />extending approximately 2.5 feet above the surface and stove pipe well monuments <br />installed over the wells. Therefore, the depths to groundwater are not measurements from <br />near surface grade. Additionally, groundwater samples were not collected from the <br />monitoring wells during this investigation. <br /> <br />Groundwater was inferred to be flowing toward the southwest at an average hydraulic <br />gradient of 0.003 foot per foot (ft/ft) across the entire site (Figure 10). Depth to water and <br />groundwater elevations are summarized in Table 8 and the well monitoring field log is <br />provided in Appendix I. <br /> <br /> <br />6.0. SUMMARY AND CONCLUSIONS <br /> <br />Based upon the environmental activities completed, AGE provides the following summary <br />and conclusions: <br />• Lithology at the site consists of silty sand and sand from near surface grade to <br />approximately 14 feet bsg and clay from 14 to 15 feet bsg in most locations. Sands <br />extended deeper in the former power plant area and clay was only encountered in <br />one boring at 17 feet bsg due to the elevated surface grade of the former power <br />plant (Appendix D and Figures 6 through 9). <br />• Two significant waste cells composed of glass processing waste were located and <br />identified during the investigation: 1) Waste Cell No. 1 was encountered along the <br />eastern property boundary adjacent to the former North Waste Cell at 17100 <br />Murphy Parkway. Waste Cell No. 1 is approximately 3,300 square feet, 7 to 9 feet <br />thick, and the limits of the cell are defined by borings B13, B15, B17, B21 and B22 <br />(Figures 3, 6 and 7); and, 2) Waste Cell No. 2 was encountered in the southeastern <br />area of the former power plant area. Waste Cell No. 2 is approximately 3,900 <br />square feet, 5 to 8 feet thick, and the limits of the cell are defined by borings B36, <br />B39, B41, and B42 (Figures 4, 5, 8, 9). <br />• Arsenic was the only CAM 17 metal detected above environmental screening <br />levels in soil and waste samples analyzed; environmental screening levels for