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Soil Suitability/ Nitrate Loading Study <br />Lease Property ■ Acampo, California <br />December 17, 2021 Terracon Project No. NA217090 <br />Table 8. <br />Net Rainfall Recharge <br />Ircerr on <br />Based on this method, the average net rainfall recharge for the site is estimated to be 8.09 <br />inches/year. <br />The nitrate concentration of rainfall is estimated to be 1 mg/L-N (Hantzsche and Finnemore, <br />1992). <br />2.3.3 Current On -Site Sources of Nitrate <br />The current on-site sources of nitrate include the existing septic system and natural processes. <br />2.3.4 Future On -Site Sources of Nitrate <br />Future on-site sources of nitrate include the existing septic system, proposed septic system and <br />natural processes. <br />2.3.4.1 Quantity and Quality of Wastewater from Project <br />The following discussion is for determining the long-term wastewater flow generated from the <br />proposed development for the nitrate loading analysis and should not be used for septic system <br />design purposes. Typically, use estimates for the sizing of septic systems include a peak use <br />factor, whereas the numbers discussed here are based on long-term averages. <br />The estimated sewage flow rates for use categories are available from a number of references. <br />The uses presented below were guided by the San Joaquin County On -Site Wastewater <br />Treatment Standards (OWTS) dated 2017, Crites and Tchobanoglous (1998), and EPA (1980). <br />Table 4-2 of the text from Crites and Tchobanoglous indicates that the typical residential use rate <br />is 70 -gallons per day per bedroom. The EPA Design Manual (Table 4-6) indicates the typical use <br />rate is 45 -gallons per day per resident. Based on a review of the United States Geological Survey <br />(USGS) California Water Science Center California Water Use 2010 Data, average daily domestic <br />use per capita was estimated at 69 -gallons per day. <br />In February 2020, the EHD approved a revised calculation method for long term average <br />discharge of waste water and recommended 100 gallons for the first bedroom and 50 gallons for <br />each additional bedroom. <br />The following table presents the proposed septic wastewater use for the site. The rates presented <br />from the references provide general guidance but do not always reflect a match in usage. Should <br />Responsive ■ Resourceful ■ Reliable 15 <br />ET <br />Net Rainfall <br />CIM IS Station <br />Average Precipitation <br />Potential ETO <br />Actual ET <br />Adjustment <br />Recharge <br />Number /Location <br />(in/year) <br />(in/year) <br />(in/month) <br />Factor <br />(in/year) <br />042/Lod i <br />15.46 <br />50.50 <br />0.445 <br />22.47 <br />8.09 <br />166 Lodi West <br />Based on this method, the average net rainfall recharge for the site is estimated to be 8.09 <br />inches/year. <br />The nitrate concentration of rainfall is estimated to be 1 mg/L-N (Hantzsche and Finnemore, <br />1992). <br />2.3.3 Current On -Site Sources of Nitrate <br />The current on-site sources of nitrate include the existing septic system and natural processes. <br />2.3.4 Future On -Site Sources of Nitrate <br />Future on-site sources of nitrate include the existing septic system, proposed septic system and <br />natural processes. <br />2.3.4.1 Quantity and Quality of Wastewater from Project <br />The following discussion is for determining the long-term wastewater flow generated from the <br />proposed development for the nitrate loading analysis and should not be used for septic system <br />design purposes. Typically, use estimates for the sizing of septic systems include a peak use <br />factor, whereas the numbers discussed here are based on long-term averages. <br />The estimated sewage flow rates for use categories are available from a number of references. <br />The uses presented below were guided by the San Joaquin County On -Site Wastewater <br />Treatment Standards (OWTS) dated 2017, Crites and Tchobanoglous (1998), and EPA (1980). <br />Table 4-2 of the text from Crites and Tchobanoglous indicates that the typical residential use rate <br />is 70 -gallons per day per bedroom. The EPA Design Manual (Table 4-6) indicates the typical use <br />rate is 45 -gallons per day per resident. Based on a review of the United States Geological Survey <br />(USGS) California Water Science Center California Water Use 2010 Data, average daily domestic <br />use per capita was estimated at 69 -gallons per day. <br />In February 2020, the EHD approved a revised calculation method for long term average <br />discharge of waste water and recommended 100 gallons for the first bedroom and 50 gallons for <br />each additional bedroom. <br />The following table presents the proposed septic wastewater use for the site. The rates presented <br />from the references provide general guidance but do not always reflect a match in usage. Should <br />Responsive ■ Resourceful ■ Reliable 15 <br />