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• • Kennedy/Jenks Consultants The estimated depth of the wells in the new LAA is approximately 100 feet below ground surface (bgs). Groundwater elevations have declined by approximately 15 feet since 2005, or about 1.5 feet per year. The well screens will be set to approximately 30 feet below first encountered groundwater. 3.2.1.2 Construction A schematic of the proposed well construction details is provided on Figure 5. The well will be constructed of 4-inch diameter, Schedule (SCH) 40 PVC casing. The screened interval will consist of 30 feet of 0.010-inch slotted casing, or other appropriate slot size for the lithology encountered, based on the lithologic log from the soil boring. A threaded end cap will be installed at the bottom of the screen. The remainder of the well above the screened section will consist of flush-threaded, 4-inch diameter, Schedule 40 PVC blank casing. 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 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 two to three feet above the screened section. The wells will be pre-developed after the filter pack is installed and prior to the bentonite seal is installed. A three-to-five foot layer of protective bentonite clay chips or pellets will be placed above the filter pack to minimize downward migration of the grout seal into the filter pack. Cement grout will be placed above the bentonite seal 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 the grouting. If the wells can be drilled out of roadways, the casing will extend approximately 1.5 feet above ground surface and will be protected with a locking steel standpipe monument. If the wells must be completed in a roadway the casing will be cut off just below ground surface and a traffic-rated flush monument will be constructed. Well construction guidelines are presented in the SOG for Well Construction and Development (Appendix C). 3.2.1.3 Development After waiting a minimum of 48 hours to allow curing of the grout and concrete, the monitoring well will be developed by bailing, surging, and pumping until: the water removed from the well is sediment; no further improvement in water quality is observed; or 10 casing volumes have been purged. Field parameters of pH, temperature, and conductivity will be recorded. Procedures are outlined in the SOG for Well Construction and Development (Appendix C). The monitoring wells will be allowed to recover for a minimum of 72 hours following well development, prior to monitoring and sampling. Development water will be discharged on the ground at the well site in a way that does not interfere with site safety. 3.2.1.4 Surveying The location and well casing elevations of the new monitoring wells will be horizontally and vertically surveyed by a licensed land surveyor. The ground surface and top of well casing elevation will be surveyed to the nearest 0.01 foot relative to mean sea level. The ground surface and top of casing will be surveyed to the National Geodetic Vertical Datum (NGVD) 1988, relative to the nearest benchmark for the Site. The horizontal location of the new well will also be surveyed relative to the California Coordinate system to 0.1 foot precision. As Monitoring Well Installation Work Plan, Page 4 Barrel Ten Quarter Circle Land Company, Escalon, California 11SFDGroupOS-Group'Admin Wob1031030118.27_8TQC LC109-Reports\MW-InstaIMP Imtext.doc