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Mr.Jadi Singh <br /> January 24, 2003 <br /> Job Number:LE02481 <br /> Page 8 <br /> 1..E <br /> the various soil layers with a representative of San Joaquin County Environmental Health <br /> Department. The percolation rate of the soils between the depths of 0 to 3 feet was of interest to <br /> `E our office as explained below. <br /> With the exception of P-2 which was set at a depth of 3 feet, the percolation tests were set at non- <br /> typical depths for a standard type of septic system. Many of the tests were set at depths to <br /> determine the extent of the slower percolating surface soil layer, not the standard 3 foot depth for <br /> a standard leach field. Table 3 presents a summary of the six percolation tests. <br /> Table 3, <br /> " Summary of falling bead percolation tests. <br /> Test No., Duration Percolation Percolation Rate Soil Type,Comments <br /> �.. Date Tested of test Test Depth(ft) (minutes/inch) <br /> P-1, 4 hours 1.28 62.4 min/inch Lt.brn.silty Pm sand,loose(SW),slow <br /> 11/26/02 percolation rate. <br /> P-2, 1 hour 3.00 0.98 min/inch Brn f-m sand,dense(w/some silt)(SP), <br /> 11/26/02 rapid percolation rate. <br /> " P-3, 4 hours 1.09 25 min/inch Lt.brn. silty f-m sand,loose(SW), <br /> 11/25/02 moderate percolation rate. <br /> P4, 1 hour 2.00 0.34 min/inch Brn f m sand,dense(w/some silt)(SP), <br /> 11/25/02 Rapid percolation rate.Open hole 6-inch <br /> diameter test pit. <br /> •• P-5, — 2.08 Very rapid Brn f-m sand,dense(w/some silt)(SP),too <br /> 11/25/02 rapid to measure,added 10 gallons,hole <br /> ran dry immediately. <br /> P-6, 1 hour 3.07 1.11 min/inch Bm f-m sand,dense(w/some silt)(SP), <br /> 11/26/02 1 rapid percolation rate. <br /> A satisfactory percolation rate is generally considered to be less than 60 minutes per inch for <br /> standard septic system leach field trenches. The falling head percolation tests were conducted on <br /> the site helped to characterize the soil layers between 1 and 3 feet. The double ring infiltrometer <br /> tests were performed to measure the surface soil and the soil located less than 2 feet in depth with <br /> a higher degree of accuracy than falling head percolation tests. <br /> Y <br /> 4i <br /> rpE[SO <br /> r 4 <br /> • x <br /> o � <br /> i.. <br />