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Geologiut 'ecknks Inc. Page 4 ' Groundwater Monitoring Report Project No.989.2 April 25, 2002 2.2 Laboratory Analyses ' The groundwater samples collected on March 14, 2002, were delivered to Sherwood Labs (Department of Health Services Certification No. 1400), of Hilmar, California, for the 1 following analyses: • Benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020) • Gasoline range petroleum hydrocarbons (TPH-Gasoline by EPA method 8015(m)) ' Fuel oxygenate suite (MTBE, D1PE, ETBE, TAME, and TBA by EPA method 8260) • 1,2-Dibromoethane and 1,2-Dichloro ethane (1,2 DCA and EDB by EPA method 8260) ' The fuel oxygenates, 1,2 DCA and EDB samples were submitted to Entech Analytical Labs of Santa Clara, California (DHS # 2346). ' A Chain of Custody was completed for all samples collected and tracked to ensure sample integrity. Laboratory data sheets with detection limits are included in Appendix C. ' The laboratory data were submitted electronically to GeoTracker as required under AB2886 on March 29, 2002. The confirmation number for the electronic submittal is 1641162216. 3.0 FINDINGS AND DISCUSSION ' 3.1 Hydrology of Site ' On March 14, 2002, the depth to groundwater was measured in all of the wells prior to purging. Depths to groundwater ranged from a high of 7.53-feet below the top of casing to a low of 8.86-feet below the top of casing. The average depth to water was 8.35-feet below tthe top of casing. The wells are screened at 5-feet bgs and groundwater surface continues to be below the tops of the screens in the 6 monitoring wells. Groundwater elevations were calculated and are summarized in Table 2 of Appendix A. I Site-specific groundwater gradient was calculated using MW-1, MW-3 and MW-6, and ' found to be N 17°W at 0.0049 ft/ft. The calculated groundwater gradient is displayed on the groundwater gradient map, Figure 3. Previous groundwater gradient calculations show a consistent bearing of north-northwest. The bearings have been measured between N050W ' and N45°W and the slope averages 0.0062 ft/ft. Groundwater bearing and slope are summarized in Table 2 of Appendix A and are plotted on a Rose Diagram, Figure 4.