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Kennedy/Jenks Consultants • Contract with a California licensed (C-57) drilling contractor to perform fieldwork. • Select a state-certified laboratory to conduct laboratory analytical services. 5.2.2 Installation and Development of Monitoring Wells Following completion of the pre-field activities, a licensed drilling subcontractor will advance the subsurface borings and install the monitoring wells at the selected locations. The soil borings will be drilled using a truck-mounted drill rig equipped with 8-inch hollow stem augers. The borings will be advanced the entire thickness of the water-bearing zone, or approximately 20 feet into the groundwater, whichever is smaller. Soil samples for logging and soil characterization will be collected continuously using a split spoon sampler. A continuous core record will be gathered for all borings. The soil cuttings will be lithologically logged using the USCS (ASTM D-2488-93) system under the direction of a California Professional Geologist who has expertise in lithologic logging. Field documentation will include the completion of boring logs that record the soil encountered during drilling of each borehole, soil sampling intervals, depth and thickness of the saturated zones, and well construction details. Following completion of the wells, well construction logs will be prepared. General procedures for sampling and logging are presented in Kennedy/Jenks' Standard Operating Guideline— Borehole Logging (Appendix C). The monitoring wells will be constructed with 2-inch diameter Schedule 40 polyvinyl chloride (PVC) flush-threaded casing. For the screened interval, 0.010-inch slots or other appropriate slot size for the lithologies encountered will be selected based upon the lithologic logs from the soil borings. The bottom of the screen will be fitted with either a flush-thread cap or a cap secured with stainless steel screws. The remainder of each well above the screened section will consist of flush-threaded, 2-inch-diameter, Schedule 40 PVC blank casing. The wells will typically be screened the entire thickness of the water bearing zone, or 20 feet into the water bearing zone, whichever is smaller, and the screen will extend 3 to 5 feet above the water bearing zone, however, the screened interval may be modified in response to observed subsurface conditions. A continuous filter pack will be placed in the annular space between the screened section and the wall of the boring. The filter pack will consist of washed, packaged sand that is sized accordingly for the well screen slot size selected (#2/12 or equivalent for 0.010-inch slots). The filter pack will extend upwards from the bottom of the boring to one to two feet above the screened section. All wells will be pre-developed after the filter pack is installed, and prior to the bentonite seal being installed. A 2-to 5-foot layer of protective bentonite clay pellets will be placed above the filter pack to minimize downward migration of the grout seal into the filter pack. A cement/bentonite grout will be placed so as to extend continuously from the top of the bentonite pellet layer to less than one foot below grade. In accordance with local regulations, a San Joaquin County representative will be onsite to observe or approve of the grouting. A locking expansion cap and well-housing enclosure will be installed to control access to the well opening. Wells will be completed abovegrade and furnished with a protective, locking steel casing. After waiting a minimum of 48 hours to allow curing of the grout and concrete, the monitoring wells will be developed by surging, bailing, and pumping until the water removed from the wells is sediment-free or until no further improvement in water quality is observed. The wells will be allowed to recover for a minimum of 72 hours following well development, prior to monitoring Work Plan for Improved Detection Monitoring Program Page 13 Musco Family Olive Company, Tracy, California er:�,00uamm`roem2e2a+oaoo m �ou�ens,.w��+uva_22 dm of d.�.m,Veport text-09-26.doc