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..+ KLEINFELDER EXPECT MORE Task E2 Advancement of Push Probes and Groundwater Analysis Six (6) push probes will be advanced adjacent to the chlorine contact basin at the Stockton RWCF. The proposed locations were chosen by OMIfThames Water Stockton (Plate 1). The probes are proposed to collect groundwater samples to evaluate the potential presence of chlorine in groundwater. The push probes will be advanced with a truck mounted Geoprobe machine equipped with stainless steel sampling equipment. We propose to advance the borings to a total maximum depth of approximately 25-feet below ground surface (bgs). All equipment used in the drilling and installation procedures will be cleaned and/or decontaminated with a steam cleaner or Liquinox cleaning solution. Prior to the advancement of the pushprobes, the first four feet will be hand-augered to assess potential underground utilities. The six pushprobes will be advanced using a pneumatically driven steel probe. Kleinfelder proposes to use a continuous core technique at the first boring location to describe the lithology and assess the depth to groundwater. In the first location, soil samples will be obtained by inserting a sample barrel, lined with acetate liners into the probe. The sample barrel will be lowered to the desired sampling depth and driven into the soil. Soil samples will be collected continuously during the advancement of the pushprobes at depths ranging from 4-feet to the proposed maximum depth of 25 feet bgs. During the advancement of the initial boring, soil samples will be continuously collected for lithologic classification based on the Unified Soil Classification System (USCS). The initial push probe will be advanced approximately four feet into groundwater. A temporary PVC well screen and casing will be installed in the initial probe location. A groundwater sample will be collected from the temporary well in accordance with Kleinfelder's typical field sampling protocols (Appendix B). Groundwater samples will be obtained from the five additional locations using the hydropunch technique in which a steel drive point attached to a stainless steel barrel with an internal PVC slotted screen, is driven 3 to 4 feet into groundwater. The barrel is connected to the surface using clean, 2-inch diameter hollow steel rods. The barrel is then pulled back 1 to 2 feet exposing the internal PVC screen to the soil. Groundwater then enters the barrel through the screen under hydrostatic pressure and is brought to the surface with a clean, Teflon or stainless steel bailer. After collection, the groundwater samples will immediately be for the analyzed for chlorine by colorimetric methods consistent with the Standard Method 4500-C1. After groundwater sample collection the borings will be filled with neat-cement slurry using a tremmie pipe. 02002PROP.ENV/ST07P083R Page 2 of 6 0 2007 Kleinfelder May 17, 2007