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Soil Suitability/ Nitrate Loading Study Addendum Letter Irerracon <br /> Nostra Vita Winery Lodi, California <br /> May 20, 2019 Terracon Project No. NA197023 <br /> Nitrate Loading <br /> A nitrate loading scenario was performed for each building with a septic tank to determine the <br /> impact of the existing facility and proposed development. The scenario utilizes the variables <br /> discussed previously which represent the estimated conditions and uses associated with this <br /> project. The following table presents a summary of the nitrate loading calculation for the site <br /> based on the highest average daily flows for each the facility buildings with septic tanks. Nitrate <br /> loading scenarios were additionally calculated for the special events. A copy of the nitrate loading <br /> calculation is included in the Attachments. <br /> Table 4. <br /> Summary of Nitrate Mass Balance Equation. <br /> Septic Result Effluent Leachfield Deep <br /> Tank Land Use (Nc)* Acres *Average Daily Concentration DenitrificationPercolation <br /> (mg/L- (A) Flow(Q)(gpd) (Nw) of Rainfall <br /> No. N) (mg/L-N) ( ) (R)(in) <br /> Existing <br /> Tasting <br /> 1 Building + 4.3 45.5 847.26 85 25% 4.49 <br /> Special <br /> Events <br /> Wine <br /> 2 Production 1.2 45.5 45 85 25% 4.49 <br /> Building <br /> 'Maximum contaminant level(MCL)for nitrate in drinking water is 10 mg/L-N. <br /> 'Highest average daily flow rate calculated per septic tank/building. <br /> Based on the nitrate loading balance calculation, nitrate as N levels for the existing wine tasting <br /> room plus special events is 4.3 mg/L-N. The proposed wine production building is anticipated to <br /> add 1.2 mg/L-N which increases nitrate as N levels for the facility to 5.5 mg/L-N below the MCL <br /> of 10 mg/L-N. <br /> Conclusions and Recommendations <br /> In general, the parcel appears suitable for the proposed wine production building. The soils <br /> encountered on the site generally consisted of silty sand soils. A shallow percolation test <br /> demonstrated a satisfactory percolation rate of 8.62 minutes per inch at 3.5 feet bgs for shallow <br /> leach lines. <br /> Depth to groundwater is approximately 30-40 feet bgs. A groundwater sample was not collected <br /> from the public supply well. <br /> The max daily wastewater flow for the existing wine tasting building is 650 gallons of effluent per <br /> day. On special event days, the max flow is anticipated to add up to 2,400 gallons of effluent per <br /> Responsive ■ Resourceful ■ Reliabic: 7 <br />