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' Monitor Well Destruction and Installation Report City of Manteca wastewater Quality Control Facility ' Page 3 5.4 GEOLOGIC LOGGING ' A geologic log was obtained by logging 18-inch core samples collected at 5-foot intervals and from recording drilling conditions as reported by the driller. The subsurface materials consisted of silty-clay, silty-sands and medium to coarse sand. Groundwater was first encountered at approximately i 1-feet ' below grade, in a zone of well sorted sands. Detailed geologic and completion logs of the well boring are included in Attachment A. ' 5.5 MONITOR WELL CONSTRUCTION The monitor well was constructed with 15 feet of 2-inch OD, Schedule 40, flush-threaded, machine- slotted PVC screen (slot size 0.020) extending about 13 feet into the uppermost unconfined aquifer. A PVC bottom cap was placed at the bottom of the screen section and blank PVC casing was installed above the screen to the ground surface. A filter pack of No. 3 Monterey sand was placed in the annular space opposite the screened section and extended to 2 feet above the screen. The depth of the sand in the ' well annulus was monitored with a weighted tape measure while the sand was being placed.A 2-foot seal consisting of bentonite chips was placed above the sand as a protective seal. The bentonite was hydrated using potable water. A surface seal of neat cement grout was pumped into the annulus extending from the ' bentonite seal to the ground surface. The background monitor well was completed with a monument-type protective.structure set in a 2-foot square concrete pad. Four crash posts were installed at the comers of the pad. Table I summarizes the well completion for the monitor well. A well construction graphic is included on the well log presented in Attachment A.Photos of the completion are included in Attachment D. ' Table 1 Well Completion Data—Monitor Well MW-11 t Total Depth of Well(feet bgs) 25 Depth to Water(below Measuring Point) 14.56(02/05/07) Boring Diameter(inches OD) 8 ' Casing Diameter(inches OD) 2 Blank Casing Interval(feet bgs) 10 Screen Opening(inches) 0.020 ' Screen Interval (feet bgs) 10-25 Filter Pack Material #3 Monterey sand Filter Pack Interval (feet bgs) 8-25 ' Bentonite Seal Interval (feet bgs) 6-8 Cement Grout Seal Interval (feet bgs) 0-6 Dedicated Pump type Proactive Mini-Typhoon 12V Depth of Pump Intake(feet bgs) 24 ' 6.0 WELL DEVELOPMENT AND INSTALLATION OF A DEDICATED PUMP ' Well development was conducted February 5 and 6, 2007. The well was developed by surging and pumping until the discharge water was relatively free of sediment (clear of particles visible to the unaided eye). During development, Condor measured groundwater temperature, pH, conductivity, and t dissolved oxygen. Development water was discharged to the surface. Groundwater parameter logs are included in Attachment C. 1 0� ' CONDOR