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Borehole drill cuttings, decontamination water, cement mixing and cleanup water will be placed into closed top drums, labeled and left at the Client specified location onsite. 4.0 Groundwater Monitoring Well Installation and Sampling 4.1 Monitoring Well Design and Installation Three monitoring wells will be constructed using threaded Sch. 40 PVC casing; glues will not be used. Final well design will be modified to the site-specific conditions encountered in the borehole during drilling. Once the aquifer strata are defined, the casing will be lowered to the bottom of the borehole, leaving a short sand pack interval above the occurrence of groundwater to observe for floating product. The slotted interval will use a 0.020-inch slot and the annular space around the slots will be backfilled with 2/12-size sand. The sand pack will be placed to a point about two feet above the slots. Previous experience has shown this to be a reliable well design in fine grained and stratified depositional environments in this area. A bentonite seal will be placed atop the sand pack, and a cement grout seal (cement mix witnessed and approved by the SJC/EHD representative in the field prior to sealing) will be placed atop the bentonite using a tremie line, filling from the bottom to top of the borehole. A traffic-rated wellhead access box and security device will complete each well. 4.2 Monitoring Well Head Survey All wells will be scheduled for a location and elevation survey to a known datum. The well survey will also be performed so that well location and elevation are plotted for inclusion for regulatory reporting. 4.3 Monitoring Well Sampling The wells will be developed after waiting at least 72 hours for the well cement grout seals to set, and then purged and sampled after development. Each monitoring well will be purged using calculated well volumes based upon the depth to water in each casing. Depth to groundwater measurements will be made to the nearest one-one hundredth of one foot, and also checked for the presence of separate phase product. As each purge volume is removed, measurements of pH, electrical conductivity, turbidity, and temperature will be taken until these parameters stabilize over two measurements, which are interpreted to indicate aquifer water entering the casing. The well will be allowed to stabilize to about 80%of its initial water level before sampling. Each groundwater sample will be carefully collected with a clean disposable PVC bailer and poured with minimum cavitation and minimum headspace into the appropriate laboratory prepared container. Each water sample will be labeled, logged onto a chain-of-custody form, and placed in a chilled ice chest on crushed ice. Upon completion of well sampling, each well will be closed and locked. Well purge water will be stored onsite in labeled, closed top 55-gallon steel drums. The purge water will then be appropriately disposed.