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k' ■ KLEtNFELDER Laboratory Analysis The water samples collected were analyzed for the following metals: boron, calcium, magnesium, iron, potassium, and sodium. The water samples were also analyzed for alkalinity, hardness, pH, specific conductance, total dissolved solids, chloride, nitrate as NO3, orthophosphate, sulfate as SO4, and silica. The samples were analyzed by Sequoia Analytical of Sacramento, California. Sequoia is certified by the State of California Department of Health Services (DHS) to perform the requested analysis. Groundwater Results In summary, the groundwater samples collected from all the wells (DW-1 , DW-3, and DOM-1) showed generally consistent results compared to past sampling and monitoring events conducted at the site. Table 2 attached to this report summarizes the detected concentrations of each analyte. For a complete listing of the analytes, analysis conducted, and QA/QC please refer to the attached laboratory reports included in Appendix A. Groundwater Levels in Vicinity of Quarry The depths to groundwater in the wells have been measured and recorded back to 1999 (with the exception of DW-2 which was measured back to 2001). Table 1 attached to this report details the water level, recorded for the site by others and Kleinfelder. DW-1 is located centrally along the quarry's western boundary, approximately 600 feet northeast of the California Aqueduct. The depth to groundwater in DW-1 has ranged from 169 feet (February 2000) to 253 feet (March 2001). The water levels in DW-1 have increased since February 2003, based on the annual monitoring events. DW-3 is located approximately 300 feet east of the Delta Mendota Canal, less than 700 feet east of the quarry boundary and approximately 2,500 feet north/northeast of the California Aqueduct. The depth to groundwater in DW-3 has ranged from 113 feet (December 2005) to 175 feet (December 2004). The water levels in DW-3 during the December 2005 were the highest since monitoring began (December 1999). An onsite domestic well (DOM-1) is located near the southwest corner of the quarry, north of the California Aqueduct. The depth to groundwater in the domestic well has ranged from 154 feet (February 1999) to 171 feet (February 2002). In December 2005, the domestic well was sampled but no depth to water level was taken due to the lack of an available measuring point. In summary, depth to groundwater had remained relatively consistent in deep wells DW- I and DW-3 since 2001 with a general trend of decreasing groundwater elevations. The depths to groundwater noted during the December 2005 sampling event were less than 29131.E01/ST06R838/FB:Iv Page 2 of 4 ©2006 Kleinfelder, Inc, August 1,2006