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' k`■ KLEINFELDER A total of eight soil samples were collected for potential chemical analyses from the samples collected above groundwater (samples collected at 4 and 7 feet bgs from each well boring). ' Chemical analysis was subsequently conducted on 4 soil samples, one from each well boring collected at depths of 4 or 7 feet. ' Soil cuttings and decontamination water generated while drilling were placed on the large stockpiled soil located adjacent and south of Large Excavation C. ' 4.2.3 Measurement of Water Levels ' A groundwater level survey was conducted prior to sampling the four temporary monitoring wells TW-1 through TW-4. The wells were sounded on July 6, 2001 prior to groundwater purging and sampling and on July 11, 2001 prior to well destruction. The well casing was vented during installation therefore equilibrated at least 24 hours prior to measurement of water levels. The depth-to-water was measured in each well according to the general protocol described in Appendix B. Depth to groundwater measurement field sheets are located in Appendix D. ' Delta Survey hic of Lodi, California surveyed the top of casing elevations relative to a local bench ' mark in the area. The depth-to-water measurements were then converted to relative groundwater elevations based on surveyed well data. Groundwater elevations and related data are summarized on Table 5. ' Depth to water was relatively consistent ranging from 8 to 10 feet below ground surface. Groundwater flow direction during both sounding events was towards the northeast at a gradient of ' 0.0028 ft./ft. Groundwater contour gradient maps are illustrated on attached Plates 3 and 4. 4.2.4 Collection of Groundwater Samples A total of 4 groundwater samples were collected on July 6, 2001. The samples were collected from temporary monitoring wells TW-1 through TW-4 (Plate 2). The wells were purged and sampled using disposable bailers and as generally described in Appendix B. Copies of the monitoring well sampling logs are included in Appendix D. ' 4.3 SAMPLE COLLECTION AND HANDLING Soil samples were collected within the various excavations, potholes and stockpiles using the following methods described in Section 4.3.1. Sample handling was conducted similarly for both soil and groundwater samples as described in Section 4.3.2. Kleinfelder's Typical Field Protocol ' is described further in Appendix B. 4.3.1 Soil Sample Collection tSoil samples collected from within the three excavations were collected by slide hammering a 2- inch diameter by 6-inch long stainless steel tube into the soil. Extensions were used as necessary 20-4341-I1.E01/2011R959 Page 14 of 31 Copyright 2001,Kleinfelder,Inc. August 21,2001