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Soil Suitability/ Nitrate Loading Study Addendum Letter Irerracon Nostra Vita Winery Lodi, California May 20, 2019 Terracon Project No. NA197023 Table 3. Summary of Percolation Tests. Test No. Percolation Test Percolation Rate Comments Date Tested Depth(inch) (minutes/inch) Test Duration (see notes) P3 42 8.62 4 hours Satisfactory Percolation 05/17/2019 Rate P2 42 8.33 4 hours Satisfactory Percolation 05/17/2019 Rate A satisfactory percolation rate is 60 minutes per inch or less for shallow leach lines and 30 minutes per inch or less for septic pits per SJEHD, Onsite Wastewater Treatment Standards, January 2017. As the site was permitted for one percolation test, Terracon selected the control boring P3 to be observed by Ms. Sukhreet Kaur, EHD representative on May 17, 2019. Although boring P2 was not observed by the EHD, both borings demonstrated satisfactory percolation rates. A copy of the field data for boring P3 is included in the Attachments. In accordance with the San Joaquin County Onsite Wastewater Treatment System Standards (OWTS)dated January 2017, Table 6.6-Water Use Computation table,the following average daily flow rates have been selected to calculate the wastewater flows for the facility: e) Bars or cocktail lounges 20 gallons per person (similar to a wine tasting customer) o) Day workers at schools or offices 30 gallons per shift (similar to an office employee) r) Industrial building with no food cafeteria 15 gallons per person (similar to a warehouse employee) Average Daily Flow Rates (Max Flow x# Days used per year/ 365 days per year For the purpose of the nitrate loading analysis, a long term average daily flow rate of 197.26 gpd was calculated for the special events which are held 30 days per year (2,400 gpd x 30 days per year/365 days per year). The remaining buildings will remain in use year round; therefore, a long term daily flow rate was not calculated. The average total nitrogen concentration of domestic wastewater is normally considered to be 20 to 85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is estimated that commercial use will have higher concentrations of total nitrogen when compared to residential use. The NOA reported the average total nitrogen concentration of wastewater to be 85 mg/L-N for the winery facility with 25% denitrification factor. Terracon concurs with the NOA SSNLS 85 mg/L-N nitrogen concentration of wastewater and 25% denitrification factor and recommends a deep percolation of rainfall rate of 4.49 inches per year. Responsive ® Resourceful Reliable 6