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Project No 034-98081 Appendix B METHODOLOGY i The methods used to accomplish the purpose and scope of the September 1998 monitoring well installation are listed below The assessment activities were accomplished in accordance with the Regional Water Quality Control Board (RWQCB) Tri-Regional Board guidelines and the requirements listed in the "Recommendations for Preliminary Investigation and Evaluation of Underground Storage Tank Sites " A copy of the workplan was submitted to the SJCEHD for review and written approval before commencing the field investigation September 1998 Phase Il Assessment • Three groundwater monitoring wells were installed during this assessment The ' locations of the wells are shown on Figure 2 The total depths of the wells were based on the existing depth to groundwater, which is approximately 35 feet bgs, and on the anticipated vertical seasonal fluctuations of the water table The wells are approximately 50 feet in depth The wells are constructed of 2-inch diameter Schedule 40 PVC water well casing and screen The screen interval has 0 020-inch diameter slot size The screen interval was designed to extend from 15 feet below, and from 5 to 10 feet above, the water table The screened interval extends from between 25-30 to 50-52 feet bgs (well dependent) A filter pack, consisting of rounded 20 x 16 mesh washed, bagged sand was placed into the annular space to a depth of approximately two feet above the ' screen interval A two foot thick seal, consisting of hydrated bentonite pellets, was placed above the filter pack The remaining annular space was filled with 21-sack neat grout The grout was introduced into the annular space by a tremae pipe or equivalent i system depending on the depth of the open annular space of the boreholes A flush- mounted, traffic-rated well vault was emplaced to provide access to the wellhead The well vault was set above existing site grade to promote positive drainage away from the wellhead Well construction specifications are diagramatically presented on soil boring logs in Appendix E • During the drilling of monitoring wells, the drill cuttings (soil) were subjectively analyzed for odor and discoloration Additionally, the soil were field scicened with a portable pliotoionization detector(PID) The PID readings were recorded on field notes The PID is a direct reading real-time analyzer that can detect most of the volatile hydrocarbon constituents present in the vapor phase of petroleum-affected soils • Soil samples from the soil borings were obtained for logging purposes at five foot intervals, beginning at grade Soils were logged in accordance with the Unified Soil Classification System • Soil samples from the proposed soil borings were collected from the capillary fringe (� 32 feet bgs) and submitted for analysis of BTEX and TPH-G at a laboratory certified by the State of California for analysis of hazardous waste KRAZAN & ASSOCIATES, INC Ten Offices Serving the Western United States 3498081 SG2