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Quik Stop Market No. 132 July 11, 1991Page 4 Project No. 3-49132-31 0.020-inch slot size. Only flush-threaded couplings were used; no solvents or cements were used during well construction. 'The screened interval of the monitoring well was determined in the field by the Exceltech geologist based on the characteristics of the _. saturated zone being monitored. After the casing was installed,clean No. 2/12 sand was poured through the auger, as the auger was being removed, to fill the annulus between the casing and the borehole wall to approximately 1/2 foot above the screerPd interval in MWAR and 2 feet above the top of the screened interval in MW-5. Approximately 1 foot of 1/4 inch bentonite pellets was then placed on top of the sand and hydrated to form a seal. A cement grout seal was then placed in the remaining annulus to within 1 foot of the surface. A water- tight protective vault was placed over the well at or slightly above ground level and the space around the cover was filled in with concrete. All monitoring wells were equipped with an expansion type well cap(see Monitoring Well Detail - Appendix A). Well Development and Groundwater Sampling On April 5, 1991, the newly installed wells were developed to remove fine-grained material and turbid water, and to improve the hydraulic communication with the surrounding formation. A hand bailer and surge block were used to develop the wells. A minimum of 16 well volumes of groundwater were removed from each well. No surface sheen or other visible signs of contamination characteristic of petroleum hydrocarbons was noted in the groundwater removed. On April 8, 1991, prior to groundwater sampling, ail five monitoring wells were checked for the presence of free-floating petroleum product, using a clear acrylic bailer. Floating product or surface sheen characteristic of petroleum hydrocarbons was not observed in any of the monitoring wells. The wells were then purged of approximately four more wellvolumes bailer. water prior to The wafs� npies fromer each well were les were then collected using a clean teflon poured into the proper laboratory-supplied containers, labeled with a unique sample number, entered onto a chain-of-custody form, and placed in a suitable container chilled with ice. Site Survey The elevations of the PVC well casings and the adjacent ground surface were surveyed on April 1, 1991 by Ron Archer, Civil Engineer, Inc., of Pleasantun, California. The .01 foot on the City of Stockton datum. The elevations were recorded to the nearest 0 reference benchmark was a brass disc set in a standard monument casing located 40 feet -_ - southerly from the centerline intersection of W. Hammer Lane and Mariners Drive with an elevation of 2.619 feet. The property boundaries, the location of the