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Soil Suitability/ Nitrate Loading Study Irerracon Jeremy Winery Lodi, CA May 7, 2019 .. Terracon Project No. NA197008 groundwater, distance from the river, and topographic gradient to the west, we do not foresee percolating effluent affecting nearby water resources. 2.4 Discussion of Nitrate Loading Results 2.4.1 Total Nitrate Impact Based on the method and assumptions described, the result of the nitrate loading balance (6.0 mg/L N) indicates that the development on the parcel is not expected to cause a buildup of nitrates in the aquifer above the MCL of 10 mg/L-N. 2.4.2 Methods of Mitigation Because of the favorable result of the nitrate loading calculation, mitigation measures are not warranted. 3.0 CONCLUSIONS AND RECOMMENDATIONS The soils encountered on the site generally consisted of cemented silty sand and stiff silt with sand. The two shallow percolation tests (125 min/inch and 250 min/inch) and deep percolation test (125 min/inch)failed to achieve an acceptable percolation rate for standard leachfields and/or seepage pits. The result of the nitrate loading balance (6.0 mg/L N) indicates that the proposed winery is not expected to cause a buildup of nitrates in the aquifer above the MCL of 10 mg/L-N; therefore, nitrate mitigation measures are not warranted. There are no functioning groundwater wells on the site; therefore, a groundwater sample was not collected. Groundwater was not encountered in any of the borings drilled on the site to a maximum depth of 25 feet bgs. Depth to groundwater is anticipated to be greater than 90 feet bgs. In summary, the parcel appears suitable for the proposed winery development; however, based on the slow percolation rates, Terracon recommends an engineered septic system design for the project. Additionally, the septic system design should accommodate the peak flows of the planned special events and follow the San Joaquin County OWTS standards where applicable. Responsive ■ Resourceful ■ Reliable 18