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Soil Suitability/ Nitrate Loading Study Irerracon <br /> Shipherd Property■ Ripon, California <br /> August 25, 2020 a Terracon Project No. NA207060 <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 10. <br /> Summary of Nitrate Mass Balance Equation. <br /> Result Average Effluent Leachfield Net Rainfall <br /> Land Use (Nc)' Acres Daily Flow Concentration Denitrification Charge(R) <br /> (mg/L-N) (A) (Q)(gpd) ( (mg/L)N) (d) (in/year) <br /> Existing 6.9 1.04 100 40 10% 6.38 <br /> Existing&Proposed 12.8 1.04 250 40 10% 6.38 <br /> Residence <br /> Total 12.8 <br /> Maximum contaminant level(MCL)for nitrate in drinking water is 10.0 mg/L-N. <br /> Based on the nitrate loading balance, nitrate levels for the existing residence is 6.9 milligrams per <br /> liter nitrogen (mg/L-N) below the MCL of 10.0 mg/L-N. The proposed two bedroom residence is <br /> anticipated to increase nitrate levels for the existing residence and proposed residence to 12.8, <br /> slightly above the MCL of 10.0 mg/L-N. <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 located 200 feet north of the site. Based on distance and gradient, the canal is not <br /> anticipated to be affected by percolating effluent. <br /> 2.4 Discussion of Nitrate Loading Results <br /> 2.4.1 Total Nitrate Impact <br /> Based on the method and assumptions described, the result of the nitrate loading balance (12.8 <br /> mg/L N for both residences) indicates that the development on the parcel may cause a buildup of <br /> nitrates in the aquifer slightly above the MCL of 10.0 mg/L-N. <br /> 2.4.2 Methods of Mitigation <br /> Based on the nitrate loading results, nitrate impacts to groundwater are anticipated; therefore, <br /> mitigation measures may be required for the project. <br /> 3.0 CONCLUSIONS AND RECOMMENDATIONS <br /> Based on the results of the field work, site soils consist primarily of silty sand in the upper 5.2 feet. <br /> A visual inspection of the soils from the percolation test and soil profile borings point to favorable <br /> Responsive ■ Resourceful ■ Reliable 16 <br />