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Soil Suitability 1 Nitrate Evading Study Irerracon <br /> Whitlow Property ■ Stockton, CA <br /> November 20, 2019 a Terracon Project No. NA197078 <br /> Table 11. <br /> Summary of Nitrate Mass Balance Equation. <br /> Result Average Effluent Leachfield deep <br /> Acres Concentration Percolation <br /> Land Use (Nc]' Daily Flow Denitrificatfon <br /> (mgiL-N) (A) (a)igid1 (Nw) (d) of Rainfall <br /> (mglL-N) (R)(in) <br /> Residence 15.9 1.50 560 45 35% 4.49 <br /> Nitrate as N Total 15.9 <br /> Maximum ccntamrnant level(MCL)Tar nitrale in drinking water is 10 mg/L-N. <br /> Based on the nitrate loading balance, nitrate Ievets for the proposed residence is 15.9 mgfL-N <br /> above the MCL of 10.0 mglL-N. <br /> 2.3_6 Impact of Nitrate Loading to Nearby Water Sources <br /> Based on a review of the topographic map (Section I3 1), there are no surface water sources near <br /> the site. As the subject property is relatively flat, we do not foresee percolating effluent affecting <br /> surface water resources. <br /> 2.4 Discussion of Nitrate Loading Results <br /> 2.4.1 Total Nitrate Impact <br /> Based on the nitrate loading calculations, nitrate levels as N levels for the proposed four bedroom <br /> residence is 15.9 mg1L-N above the MCL of 10 mg/L-N when two people are calculated per <br /> bedroom. <br /> 2.4.2 Methods of Mitigation <br /> If the EHD requires mitigation for the project, mitigation may consist of the utilization of an <br /> advanced water treatment product, which are specifically designed t4 lower nitrates at point of <br /> discharge or other nitrate mitigation option. <br /> 3.0 CONCLUSIONS AND RECOMMENDATIONS <br /> The site was formerly developed with a residence and septic system which were removed due to <br /> a house fire in 2019. The site is proposed to be developed with a new four bedroom residence <br /> and new septic system. The soils encountered on the site generally ranged between clay, silty <br /> clay, silty sand, and lean clay. A satisfactory percolation rate of 27.7 minlinch was achieved at <br /> boring B3 and accepted by Mr. Michael Kith of the EHD. The former onsite septic system and <br /> adjoining property septic systems utilize one 25 foot deep seepage pit per leachline. <br /> Depth to groundwater is anticipated to be greater than 90 feet bgs. Two groundwater samples <br /> collected from the onsite domestic well reported levels of nitrate as N (15 mglL) above the MCL <br /> Responsive ■ Resourceful ■ Reliable 18 <br />