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xK sv' ,� ••'a«:y a Quik Stop Market No, 132 August 28, 1990 Job No. 349132-31 Page 4 The geologist will prepare a log of the subsurface conditions encountered during drilling and will classify the soils according to the Unified Soil Classification System and Munsell Soil Color Charts. All drilling logs will be reviewed by a certified engineering geologist, Groundwater Monitoring Well Construction After the soil sampling is completed, Exceltech will install a groundwater monitoring wells in each designated exploratory boring. Exceltech will construct the monitoring wells in accordance with all permit requirements of San Joaquin County. The wells will be constructed of 2-inch•diameter, Schedule 40, flush-threaded polyvinyl chloride (PVC) blank and slotted casing; no glues or solvents will be used. After drilling the boring to the desired depth, the PVC casing will be installed through the hollow-stem auger. The screened interval of the casing will extend sufficiently above the water table so that the presence of free floating product can investigated. As the auger is withdrawn, sand will be slowly poured down the borehole annulus to approximately 2 feet above the slotted screen section. Bentonite pellets will be placed on top of the sand and hydrated to form an annular seal. The remaining portion of the annular space will be sealed with a neat cement and bentonite grout. The top of the well will be set in a waterproof traffic-rated vault box slightly above grade with a locking cover to provide security and protect the PVC wellhead. A concrete surface seal will u be installed to complete the well construction. Survey f The wells will be surveyed by a licensed land surveyor, 'Me wells will be located both horizontally and vertically (to the nearest .01 feet MSL). A site plan will be prepared at a reasonable scale so that the data can be portrayed in a uwful manner. Well Development After construction,each well will be developed using a surge block to agitate and set the rs sand pack around the annulus of the well casing. A baiter will be used to remove water manually after each surge. Well development (a) removes residual silts and clays left from the drilling and (b) improves the hydraulic Conductivity between the wells and the natural formation, After development, the well will be allowed to recharge with water from the surrounding formation (approximately 24 hours), enabling Exceltech to collect a representative water sample and to, measure the thickness of any floating praduct encountered All water collected during well developnmont will be placed in DOT 17E drums and Ieft z on-site until laboratory analyses are complete. At that time, the drums and water may be properly disposed of by Quik Stop. t' J5fHD31333X3 LL:00 061 U� 5nU