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Soil Suitability / Nitrate Loading Study <br />Ehlers Property Lodi, California <br />May 13, 2021 Terracon Project No. NA217019 <br />2.3.4.2 Denitrification Estimate <br />Irerracon <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; therefore, a denitrification estimate of 15 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. <br />Table 9. <br />Summary of Nitrate Mass Balance Equation. <br />. Maximum contaminant level (MUL) for nitrate in onnKing water is -I u mg/L-N <br />Based on the nitrate loading balance, nitrate levels for the existing grain facility land use is 2.4 <br />milligrams per liter nitrogen (mg/L-N) below the MCL of 10.0 mg/L-N. The proposed hemp facility <br />is anticipated to increase nitrate levels to 4.2 mg/L-N, also below the MCL. <br />2.3.6 Impact of Nitrate Loading to Nearby Water Sources <br />Based on the aerial photographs and topographic maps (Section 1.1), the nearest surface water <br />source is a canal located on the northern adjoining property. Based on distance and gradient, the <br />canal is not anticipated to be affected by percolating effluent. <br />Responsive Resourceful F Reliable 15 <br />Average <br />Effluent <br />Leachfield <br />Deep <br />Septic System No. <br />Result (Nc)' <br />Acres <br />Daily Flow <br />Concentration <br />Denitrification <br />Percolation of <br />(mg/L-N) <br />(A) <br />(Q) (gpd) <br />(Nw) <br />(d) <br />Rainfall (R) <br />(mg/L-N) <br />(in) <br />Existing Land Grain <br />2.4 <br />5.43 <br />94 <br />85 <br />o <br />15% <br />11.55 <br />Facility <br />Existing Grain <br />Facility + Proposed <br />4.2 <br />5.43 <br />221 <br />85 <br />15% <br />11.55 <br />Hemp Facility <br />. Maximum contaminant level (MUL) for nitrate in onnKing water is -I u mg/L-N <br />Based on the nitrate loading balance, nitrate levels for the existing grain facility land use is 2.4 <br />milligrams per liter nitrogen (mg/L-N) below the MCL of 10.0 mg/L-N. The proposed hemp facility <br />is anticipated to increase nitrate levels to 4.2 mg/L-N, also below the MCL. <br />2.3.6 Impact of Nitrate Loading to Nearby Water Sources <br />Based on the aerial photographs and topographic maps (Section 1.1), the nearest surface water <br />source is a canal located on the northern adjoining property. Based on distance and gradient, the <br />canal is not anticipated to be affected by percolating effluent. <br />Responsive Resourceful F Reliable 15 <br />