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L L �/ <br /> 6. Job <br /> 20,2003 <br /> Job Number:LE03-421 <br /> Page 9 <br /> 6.2 Boring Preparation and Specifications <br /> In Parcel 2,the shallow boring was advanced to 3.25 feet and the deep boring to 21.81 feet. In <br /> Parcel 3,the shallow boring was advanced to 3.56 feet. All three borings were drilled using a <br /> truck-mounted Deep Rock auger rig on November 13, 2003. <br /> A 2-inch diameter PVC pipe with perforations on the bottom was used to measure the drop of <br /> water in the percolation test boring. Approximately 2 inches of"pea gravel'were placed in the <br /> bottom of the boring,then the PVC pipe was installed on top of the gravel. Several feet of"pea <br /> ` gravel'were backfilled in the annular space. <br /> ` 6.3 Presaturation of Borings <br /> Presaturation of the percolation test holes occurred on November 13, 2003. The depth of water <br /> L used to presoak was 12 inches above the bottom of the borings. After the 24-hour soak period, <br /> the presaturated holes were found to be intact and dry on November 14, 2003. <br /> L 6.4 Percolation Test Procedure and Results <br /> Three 4-hour percolation tests were conducted on November 14, 2003 in accordance with the <br /> requirements of San Joaquin County EHD. The last half hour of the three 4-hour percolation <br /> tests was observed by Robin Trindade, Environmental Health Inspector, of that office. <br /> 6' Measurement of the water level during the percolation test was from a fixed reference point on <br /> the PVC casing using an electric well sounder with an depth accuracy of 1/100th foot. All values <br /> on the field data sheet (appendix) are in decimal feet unless otherwise noted. After water drop <br /> was observed, the holes were checked for refill. The refill level is 6 inches of water above the <br /> bottom level of the percolation test hole. The readings were taken approximately every 30- <br /> minutes for the 4 hour duration tests. <br /> A satisfactory percolation rate for a deep (greater than 3.5-foot deep)test is 30 min/in or less, and <br /> ` a satisfactory rate for a shallow(3-3.5 foot deep)test is 60 min/in or less. <br /> At P-2 (Parcel 2),the shallow percolation test failed due to no movement of the water,but the <br /> deep percolation test achieved a satisfactory percolation rate of 28 min/in. At P-3 (Parcel 3), the <br /> shallow percolation test achieved a satisfactory percolation rate of 23 min/in. A summary of the <br /> percolation tests is presented in Table 5. <br /> 6. <br /> 'pFI1J 4 <br /> V Q'J®A <br />