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Harlin Knoll <br /> San Joaquin County <br /> November 23,2004 <br /> Page 2 of 4 <br /> Permits <br /> Permits for the installation of the soil borings and monitoring wells will be obtained from San <br /> Joaquin County Environmental Health Department and Encroachment permits from The City of <br /> Stockton Public Works Department. <br /> Soil Borings <br /> Delta proposed to use a hollow stem auger drill rig. The shallow boring will be to a depth of <br /> approximately 65 feet below ground surface. The deeper boring will be to a depth of approximately <br /> 85 feet below ground surface.However,depths will be dependent upon field observation at the time <br /> of installation. Soil samples will be collected at five-foot intervals and logged to the total depth <br /> drilled. Soil types encountered will be classified using the Unified Soil Classification System, <br /> Visual/Manual Method, and recorded on a soil boring log. Soil samples collected for lithologic <br /> description will also be field measured for volatile organics using a photo-ionization detector(PID) <br /> and recorded on the boring log. Field methods and procedures to be used by Delta during <br /> installation of the soil boring are summarized in Enclosure A <br /> A minimum of three soil samples will be selected from each boring for chemical analysis based on <br /> field screening results, depth of soil samples and soil lithology. Samples will be submitted to Kiff <br /> Analytical llc,pff Analytical Davis,California for analysis of benzene,toluene,ethylbenzene,and <br /> total xylenes (BTEX), methyl tertiary butyl ether(MTBE), Diisopropyl ether (DIPE), ethyl-t-butyl <br /> ether(ETBE),tert-amyl methyl ether(TAME),tertiarybutyl alcohol(TBA),methanol, ethanol, 1,2- <br /> dichloraethane, and total petroleum hydrocarbons (TPH) in the gasoline range using EPA Method <br /> 8260. Soil samples will be collected using the procedures described in Enclosure A. <br /> Monitoring Well Installation <br /> Monitoring wells will be constructed of 2-inch diameter, flush-threaded, Schedule 40 PVC <br /> casing. Monitoring well MW-18 will be constructed with 5 feet of screen above the water table <br /> and 10 feet beneath the water table approximately 45 to 60 feet below surface grade (bsg). <br /> Deeper well MW-18 D will be screened from approximately 75 to 85 feet bsg. The screens will <br /> be constructed of 0.020-inch slotted casing. The annular space of the wells will be backfilled <br /> with Lonestar No. 3 sand to approximately two feet above the screened section. Following <br /> installation of the filter pack, each monitoring well will be surged with a surge block to set the <br /> filter pack material and additional sand will be added to the annulus if required to maintain the <br /> filter pack over the top of the well screen. A 2-foot thick bentonite seal will be emplaced above <br /> the filter pack. The remaining annulus will be filled with cement/bentonite slurry(grout), mixed <br /> in accordance with San Joaquin County Environmental Health Department (SCEHD) <br /> specifications, to within six inches of surface grade. The surface will be completed with an <br /> 8-inch traffic rated well box set in concrete. Proposed well construction details are included in <br /> Enclosure B. <br />