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29 August 2017 AdvancedGeo AGE Project No. 95-0121 Environmental Page 4 of 5 3.1. BORING ADVANCEMENT AND SOIL SAMPLING Utilizing a truck-mounted, hollow-stem auger drill rig (CME-75 High Torque Drill Rig) equipped with 8.25-inch diameter hollow-stem augers, two soil borings will be advanced to depths of approximately 55 feet bsg for the purpose of logging lithology. Beginning at a depth of 15 feet bsg, relatively undisturbed soil samples will be collected from all soil boring locations at 5-foot intervals using a California modified split-spoon sampler fitted with 2-inch diameter, 6-inch long steel sleeves. Soils sampled in the borings will be visually classified by an AGE geologist in accordance with the Unified Soil Classification System (USCS). Additionally, soil samples will be field screened for the presence of volatile organic compounds using an organic vapor meter (OVM), equipped with a photo-ionization detector (PID). Soil sample descriptions and OVM readings will be recorded on a log for each boring. 3.2. WELL COMPLETION AND ELEVATION SURVEY Upon reaching a total depth of approximately 55 feet bsg, each soil boring will be single- completed as a groundwater monitoring well utilizing a 2-inch diameter, Schedule 40 PVC blank well casing and 0.020-inch slotted well screen installed from 35 feet to 55 feet bsg. A diagram of the proposed monitoring well construction is depicted in Figure 3. After installing the well casing in each soil boring, a filter pack material consisting of pre- washed #3 Lonestar sand will be added through the augers from total depth to approximately 2 feet above the screened interval. Following placement of the filter pack, the well will be surged to assist in settling the filter pack. Additional sand will be added if settling occurs. A three-foot bentonite seal will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the wells. The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack. The bentonite pellets will be allowed to hydrate for the duration of time specified by the manufacture (i.e. 30 minutes), prior to grouting. The remaining annular space will be filled to within one foot of the ground surface with a cement grout. The grout mixture will consist of Type 1/II portland neat cement and not more than 3 gallons of water per 50-pound sack of cement. The grout will be placed by pouring or pumping through a tremie pipe or auger. A grouting inspection will be scheduled with San Joaquin County EHD personnel prior to any application of grout. Following completion of the monitoring wells, each well location will be surveyed at the top of each well casing by a California-licensed surveyor relative to a City of Stockton benchmark and the North American Vertical Datum 88.