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' 3.0 GROUNDWATER INVESTIGATION 3.1 INSTALLATION OF ONE GROUNDWATER MONITORING WELL ' On September 29 1 p 992, one two-inch diameter monitoring well (MW-2) was ' constructed at the location shown on Figure 1 The monitoring well was constructed in an eight-inch diameter boring to a depth of 16 feet The boring was completed using a hollow-stem auger rig Soil samples were obtained for logging purposes at a minimum of every five feet using a California Modified split spoon sampler The soil samples were logged by a qualified geologist according to the USCS classification system and a completed boring log is included in Appendix A ' The well was constructed according to Central Valley Regional Water Quality Control Board (CVRWQCB) and SJCPHS guidelines with Schedule 40, flush-joint ' threaded PVC casing and 0 020-inch slotted PVC screen A sand pack of Monterey #2/12 sand was placed from a depth of 16 to 5 5 feet The screened interval extended from 6 to 16 feet in depth based on anticipated groundwater level fluctuations The ' well seal consists of 0 5 feet of hydrated bentonite transition seal and a bentonite- grout seal to the surface The well was completed with a flush monument, capped and locked A well completion detail is included with the boring log of MW-2 in Appendix A Soils logged in MW-2 indicate a clayey silt with trace sand to a depth of approximately eight feet with a zone of sand with some gravel extending from S to 16 feet in depth This profile is consistent with borings H-1, H-2, H-3 and the borings completed as part of the initial site investigation as documented in the April 1991 Report of Findings A survey was completed by BAI staff of the three existing site wells to obtain relative elevations of the well casings The casing and monument elevations are included on Table 2 ' On October 2, 1992, the monitoring well (MW-2) was developed using a surge block and subsequently bailing 20 casing volumes of water from the well Groundwater ' was monitored for changes in color, temperature, conductivity, and pH to establish when an equilibrium state has been achieved All water from the development ' process was stored on-site in appropriately labelled California DOT approved 55- gallon drums 3.2 GROUNDWATER SAMPLING ' On September 6, 1992 groundwater was sampled in wells MW-1, MW-2 and P-2 This sampling was performed as the third event of a quarterly groundwater monitoring program , 5