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Re-Revised Groundwater Monitoring Well Construction <br /> Workplan <br /> August 2023 <br /> Drilling, Well Construction, and Monitoring <br /> The following describes the methods and approaches to the monitoring well drilling, <br /> construction, development, surveying, collecting baseline water quality, and documenting these <br /> activities. <br /> Permitting <br /> Eaton will obtain monitoring well drilling permits from the San Joaquin County Environmental <br /> Health Department (SJCEHD)prior to the start of work. <br /> Drilling and Logging <br /> All drilling activities will be overseen by a DWR geologist. Drilling and well construction <br /> activities for the new groundwater monitoring wells include the following: <br /> • All drill equipment will be high-pressure washed prior to arriving on site. <br /> • Drill an 8-inch diameter exploration to a maximum depth of 1,450 feet bgs using the mud- <br /> rotary drilling method. <br /> • Ream the borehole to a 12-inch-diameter boring, at the location to accommodate 2 well <br /> casings and to 16-inch-diameter boring to accommodate 2 or more well casings. The <br /> deepest well casing will be set into an 8-inch diameter boring. <br /> • Collect drilling cuttings every 10 feet or change in materials, classify materials according <br /> to the Unified Soil Classification System, and prepare a lithologic log during drilling. The <br /> materials will be classified by a Geologist or Geotechnical Engineer and reviewed by a <br /> licensed California Professional Geologist. <br /> • Perform geophysical logging suite including (electric, spontaneous potential, and gamma <br /> ray) and a caliper survey of the reamed borehole to estimate the volume of the filter pack <br /> or clay seals to be placed during well construction. <br /> Drill cuttings will be stock piled onsite adjacent to the monitoring wells for later reuse by BCID. <br /> No contaminated soils are expected to be encountered. Drilling fluids, thin-down water, <br /> development and purge water will be placed into the adjacent former canal and will either <br /> evaporate or percolate into the soils. <br /> Monitoring Well Construction <br /> DWR geologists will be present during the construction of the monitoring wells including <br /> placement of the well casing and screens, filter pack and seals. <br /> Figure 8 provides the typical well construction details. Final well construction details will be <br /> designed after the geophysical logging suite and lithologic logs are reviewed. The screen <br /> GEI Consultants, Inc. 18 <br />