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Soil Suitability/ Nitrate Loading Study Irerracon <br /> Ernst Property Tracy, CA <br /> February 21, 2019 Terracon Project No. NA197000 <br /> 1.6.5 Percolation Test Procedure <br /> The percolation test (131 at 3.0 feet bgs) was conducted in accordance with the requirements of <br /> the San Joaquin County EHD on February 6, 2019. As there was no water remaining in the test <br /> hole overnight, Terracon conducted the percolation test by following Procedure #2. Terracon <br /> added clear water approximately 0.5 feet above the top of the gravel and recorded the drop in <br /> water level at thirty minute intervals over a four hour period. Measurement of the water level during <br /> the percolation test was from a fixed reference point on the PVC casing using a calibrated Solinst <br /> electric water level detector with a depth accuracy of 0.01 feet. All tabulated values on the field <br /> data sheet are in decimal feet. The percolation test was observed by Mr. Naseem Ahmed, EHD <br /> representative. A copy of the field data is included in Appendix E. <br /> 1.6.6 Percolation Test Forms and Results <br /> A shallow percolation test is defined by the EHD as being between 36 and 42 inches in depth. <br /> While a deep percolation test is defined by the EHD as being between 42 inches and 25 feet in <br /> depth. The shallow percolation test must demonstrate a satisfactory percolation rate of less than <br /> or equal to 60 minutes per inch drop in water level within the existing septic system disposal field <br /> of a parcel to utilize a standard septic system and 30 minutes per inch or less for septic pits. <br /> Details of the percolation tests are summarized in the table below. <br /> Table 5. <br /> Summary of Percolation Tests. <br /> Test No. Percolation Percolation Comments <br /> Date Tested I Test Rate Test Duration ( ) <br /> see notes <br /> Depth (inch) (minutes/inch) t <br /> B1 Satisfactory Percolation <br /> 02/06/2019 36 35.71 4 hours Rate <br /> Note: A satisfactory percolation rate is 60 minutes per inch or less for shallow leach lines and 30 minutes per inch or less for septic <br /> pits per SJEHD,Onsite Wastewater Disposal Standards,October 2003. <br /> The completed percolation test form with Mr. Ahmed's verification signature is included in <br /> Appendix E of this report. <br /> 1.6.7 Discussion of Percolation Test Results <br /> The silty sandy soils with clay encountered in the shallow boring demonstrated a satisfactory <br /> percolation rate for shallow leach lines. <br /> Responsive ■ Resourceful ■ Reliable 10 <br />