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Soil Suitability / Nitrate Loading Study <br />Cherokee Memorial Park Vineyard Chapel Addition Ŷ Lodi, California <br />March 5, 2021 Ŷ Terracon Project No. NA207102 <br />Responsive Ŷ Resourceful Ŷ Reliable 19 <br />2.3.4.1 Quantity and Quality of Wastewater from Project <br />Small and Decentralized Wastewater Management Systems Tables 4-2 and 4-3 (Crites and <br />Tchobanoglous, 1998) recommends the following typical commercial wastewater use rates: <br />13 gallons/person for offices <br />3 gallons/customer <br />Refer to Section 1.1 and 1.3.7 for further discussion regarding usage rates quantities selected. <br />The maximum daily flow rate for the existing facility operations is approximately 1,316 gpd. The <br />proposed Vineyard Chapel addition is anticipated to add approximately 525 gallons of effluent per <br />day for a combined maximum daily flow rate of approximately 1,841 gpd for the facility (Section <br />1.3.7). <br />The average total nitrogen concentration of domestic wastewater is normally considered to be 20 <br />to 85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is estimated <br />that commercial use will have higher concentrations of total nitrogen when compared to residential <br />use. For the purposes of the nitrate loading estimate, it is estimated that the average <br />concentration for total nitrogen in wastewater for the project is approximately 85 mg/L-N over the <br />long term. <br />2.3.4.2 Denitrification Estimate <br />Denitrification is an important process which occurs within the leach field whereby certain bacteria <br />utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) to the atmosphere. <br />Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 <br />percent. Soils with higher clay content, moist soil conditions, high pH, and organic material <br />denitrify by about 35 percent, and soils with high sand content and fast percolation rates are <br />estimated to denitrify at a lower rate, about 10 to 15 percent. <br />Based on the results of the shallow soil borings, the proposed leach field is expected to be located <br />within silty sand. Based on the prior 2015 SSS (Section 1.1), a denitrification estimate of 20 <br />percent was selected. <br />2.3.5 Nitrate Loading Scenario <br />A nitrate loading scenario was performed to determine the impact from the proposed project. The <br />scenario utilizes the variables discussed previously which represent the estimated conditions and <br />uses associated with this project. The following table presents a summary of the nitrate loading <br />calculation for the site. A copy of the nitrate loading calculation is included in Appendix F.