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` Monitoring Well Installation and Destruction Report <br /> City of Stockton RWCF <br /> Page 4 <br /> 6" To form a protective seal, a two-to four-foot-thick layer of bentonite pellets was installed above the sand <br /> as the augers were retracted. The depth of the bentonite in the well annulus was monitored with a <br /> weighted tape measure while the pellets were being placed, and the auger was gradually retracted to <br /> 6 minimize bridging. The bentonite was hydrated using potable water. A surface seal of neat cement was <br /> poured into the annulus and extended from the bentonite to the ground surface. The augers were removed <br /> before emplacement of the grout. Each well was equipped with a watertight expansion cap to protect <br /> 6. against flooding. The monitoring wells were completed with a flush mounted, traffic-rated vault box. The <br /> placement of the bentonite sanitary seals and cement surface seals was observed by Mr. Frank Girardi of <br /> SJCEHD. <br /> 6. TABLE 1 -MONITORING WELL CONSTRUCTION DETAILS <br /> Total Well Well Filter Bentonite Grout <br /> 6. Monitoring Date Well Casing BoreholeScreenScreen Pack Seal Seal <br /> Well ID Installed Depth Diameter Interval Interval Interval Interval <br /> ft in. (in.) ft ft ft ft <br /> L MW-IS 4/22/2010 9.1 4 10 4-9 3-9.1 1 -3 0- 1 <br /> MW-2S 4/23/2010 9.0 4 10 4-9 3-9.0 1 -3 0- 1 <br /> MW-19 4/22/2010 27 4 10 17-27 15-27 11 - 15 0- 11 <br /> v <br /> MW-198 4/22/2010 9.0 4 10 4-9 3-9.0 1 -3 0- 1 <br /> All measurements are in feet below ground surface(bgs)unless otherwise noted. ft=feet in.=inches <br /> V <br /> The hollow-stem auger and other down-hole equipment were decontaminated by steam cleaning prior to <br /> each monitoring well installation. Decontamination water and soil cuttings derived from the well <br /> installations were disposed of on Site proximal to each well. <br /> 3.5 WELL CASING SURVEY <br /> L In compliance with AB2886 (Water Code Sections 13195-13198), Kjeldsen, Sinnock and Neudeck of <br /> Stockton, California surveyed the locations of the four newly installed monitoring wells and adjacent <br /> wells MW-1 and MW-2 on May 20, 2010. The horizontal positions of the wells as surveyed are <br /> ` referenced to California Coordinate System Zone 3,NAD83. The vertical positions of the well collars are <br /> referenced to NAVD88 vertical datum. Survey coordinates and well collar elevations of the four newly <br /> installed are shown in Table 2, below, along with the resurveyed coordinates of two existing monitoring <br /> wells MW-1 and MW-2. <br /> TABLE 2-MONITORING WELL SURVEY DETAILS (MAY 20,2010) <br /> Monitoring Well Survey .Longitude X(Easting) Latitude Y(Northing) Z(Elevation)* <br /> ID Date <br /> MW-1 5/20/2010 -121.3289288 6322593.023 37.93046361 2162324.189 10.46 <br /> MW-1S 5/20/2010 -121.3289148 6322597.3332 37.93046617 2162325.2644 11.06 <br /> MW-2 5/20/2010 -121.3294999 6322438.152 37.93351161 2163435.482 9.71 <br /> LMW-2S 5/20/2010 -121.3294888 6322441.2542 37.93348795 2163427.1806 10.49 <br /> MW-19 5/20/2010 -121.341264 6319040.5863 37.93201228 2162919.4083 10.83 <br /> ` MW-19S 5/20/2010 -121.3412634 6319040.5045 37.93198683 2162910.3053 10.91 <br /> •Z(Elevation)=Topof-Casing Elevation <br /> 1. lkkt_i� <br /> A <br /> Ir ILA CONDOR <br />