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1 <br /> December 14, 2005 <br /> NOA Project Number: E05079B <br /> Page 2 <br /> San Joaquin County Community Development application and tentative parcel map for more <br /> information. <br /> Percolation Testing <br /> A site map indicating the locations of the percolation test holes is attached to this letter. Two <br /> O5. The soils were found to be <br /> brown silty <br /> drilled on August 3 20 <br /> shallow percolation tests were d g , <br /> sand mixed with clay. A 1.5-inch diameter PVC pipe with perforations on the bottom was used <br /> to measure the drop of water in the percolation test boring. Approximately 2 inches of"pea <br /> gravel" were placed in the bottom of the open soil boring, then the PVC pipe was installed on top <br /> of the gravel. "Pea gravel' was then used to backfill in the annular space. <br /> Presaturation of the percolation test holes occurred on August 3 and 4, 2005. The depth of water <br /> used to pre-soak was 12 inches above the bottom of the borings. <br /> After the 24-hour soak period, the presaturated holes were found to be intact on the day of <br /> testing. All the deep and the shallow holes on the subject property were found to be dry on the <br /> day of testing except for the shallow boring on lot four which contained approximately 1 inch of <br /> water remaining. <br /> Percolation tests were conducted for the borings on the site on August 5, 2005 in accordance with <br /> the requirements of the EHD. A percolation test with a duration of four hours was performed for <br /> each hole. The last half-hour of test was observed by Mr. David Van Dyne, Registered <br /> Environmental Health Inspector, EHD. <br /> 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 11100th foot. All <br /> tabulated values on the field data sheet(appendix) are in decimal feet. After water drop was <br /> observed, the holes were checked for refill. The refill level was approximately 0.5 ft(6 inches) <br /> of water above the bottom level of the percolation test hole. The readings were taken every 30 <br /> minutes for a period of four hours. <br /> The completed percolation test forms are attached to this letter. Details of the percolation tests <br /> are summarized in Table 1. <br />