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Soil Suitability /Nitrate Loading Study 1rerracon <br />Ehlers Property Lodi, California <br />May 13, 2021 Terracon Project No. NA217019 <br />approximately 0.5 feet (6 inches) of water above the bottom level of the percolation test holes. <br />The readings were taken every 30 minutes for a period of four (4) hours. <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 6. <br />Summary of Percolation Test. <br />Test No. <br />Date Tested <br />Percolation Test <br />Depth feet <br />Percolation Rate <br />min/in <br />Test Duration <br />hours <br />Comments <br />see note <br />131 <br />Satisfactory <br />3.00 <br />8.92 <br />4 <br />Percolation Rate <br />04/20/2021 <br />B3 <br />Satisfactory <br />2.3 <br />25 <br />4 <br />Percolation Rate <br />04/20/2021 <br />Note: A Satistactory percolation rate IS IOU minutes per Incn or IesS Tor snaiio leacn Ines aria )u minuies per ❑tun ur iess rur sepuc <br />pits per San Joaquin County Onsite Wastewater Treatment Systems Standards (EHD 42-014), January 2017. <br />Based on the percolation tests results, the two shallow borings achieved a passing percolation <br />rate of 60 minutes per inch or less for standard leach lines. <br />1.6.7 Discussion of Percolation Test Results <br />Based on the percolation tests results, Boring B1 and B3 achieved satisfactory percolation rates <br />of 8.92 and 25 minutes per inch, respectively, suitable for standard leach fields. Table 1.10.2 of <br />the OWTS manual indicates a minimum 8 -foot soil depth is needed from the bottom of the <br />leachfield to groundwater. Groundwater was encountered at approximately 5.5 feet bgs in our <br />soil profile boring B3. <br />1.6.8 Discussion of Septic System Sizing <br />In general, septic system construction should follow the San Joaquin County On -Site Wastewater <br />Disposal Standards (OWTS) where applicable. Based on the information provided by the EHD, <br />the facility is currently equipped with a 1,200 -gallon septic tank and one 100 foot long leach line <br />(Section 1.3.2) which appears adequate based on the proposed maximum usage rate (Section <br />1.3.7). <br />Responsive ■ Resourceful ■ Reliable 11 <br />