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Soil Suitability Nitrate Loading Study 1��rracon <br /> Recreation Vehicle Service Facility■ Lockeford, CA <br /> April 12, 2017 ■ Terraoon Project No. NA177006 <br /> Table 5. <br /> Summary of Percolation Tests. <br /> Percolation Percolation <br /> Test No. Comments <br /> Test Rate Test Duration <br /> Date Tested (see notes) <br /> Depth (feet) (minutes/inch) <br /> March 9, 2017 3.5 0 30 minutes Unsatisfactory <br /> percolation rate <br /> March 23, 2017 25 13.88 60 minutes Satisfactory percolation <br /> rate <br /> Note: A satisfactory percolation rate is 60 minutes par 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 /> 1.6.7 Discussion of Percolation Test Results <br /> The sitly clay soils within the 0 to 3.5 foot range of the proposed septic disposal area at the site <br /> demonstrate an un-satisfactory percolation rate for a standard septic system per EHD / �\ <br /> requirements; however, the sandy soils within the 20 to 25 foot range of the proposed septic �O / <br /> disposal area at the site demonstrate a satisfactory percolation rate for a standard septic system <br /> per EHD requirements. <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 where applicable. The foregoing investigation and percolation test results <br /> indicate the site consists of surface silty clay soils where leach lines may be utilized, however as <br /> indicated, the area is known for subsurface clay statum and hardpan. For this reason, we are <br /> recommending seepage pits be used with leach lines, similar for sandy clay loam soils. <br /> (e 2� <br /> Based on a review of the permits and interviews with the site owner, the site is equipped with an <br /> existing 3,200-gallon septic tank, four 50 foot long leach lines, and four 25 foot deep seepage <br /> pits. The County may require inspection of the system, but tank, lines, and pits should be <br /> adequate to support the proposed use, provided the septic system is in good condition. <br /> 2.0 NITRATE LOADING STUDY <br /> Because of concern regarding nitrate leaching into groundwater from septic systems, a nitrate <br /> loading analysis is required by the EHD for the proposed development to determine the potential <br /> concentration of percolating effluent and rain fall over the long term. Where percolating effluent <br /> leaches into the ground, groundwater quality may be impacted to some degree should the effluent <br /> reach groundwater. <br /> Responsive ■ Resourceful ■ Reliable 11 <br />