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Soil Suitability I Nitrate Loading Study Addendum Letter 1rerracon Nostra Vita Winery Lodi, California May 20, 2019 Terracon Project No. NA197023 no nitrate impacted wells identified on the site or surrounding properties. A public water supply well is located approximately 65 feet south of the existing wine tasting building. An agricultural supply is located near the southeastern corner of the site. A groundwater sample was not included as part of the SSNLS update. Refer to NOA SSNLS discussion above for information regarding the groundwater analysis in 2008. Based on a review of the boring logs contained in our Geotechnical Engineering Report for Nostra Vita Family Winery dated May 10, 2019 (Terracon Project No. NA195045), four borings B1 through B4 were advanced on the site to depths of 16.5 feet bgs. Based on a review of boring B2 site soils nearest the proposed leach field consisted of fine to medium grained loose silty sand (0 to 4 feet), fine to medium grained hard silt with sand (4 to 6 feet),fine to medium grained dense silty sand (6 and 13 feet),fine to medium grained very stiff silt with sand (13 to 16.5 feet). Similar soils were encountered in the shallow percolation test borings. Groundwater was not encountered in the soil borings. Two shallow (3.5 feet bgs) percolation test borings (P2 and P3) were excavated in the proposed leach field area at the northeastern comer of the site using a 4 inch diameter handauger. The borings were placed in the center of the proposed leach field approximately 115 feet south of the public supply well. Boring P2 was excavated on May 15, 2019 and was found to be fully saturated on May 16, 2019 following an overnight rain event, therefore, an additional boring P3 was excavated on May 16, 2019 as a percolation test control. Approximately two inches of "pea gravel" was placed in the bottom of the open borings. A 2.0-inch diameter PVC pipe with perforations towards the bottom was installed on top of the gravel and the annular space was backfilled with "pea gravel'. Presaturation of boring P3 occurred approximately 24 hours prior to the day of testing. Approximately 1.0 foot of clear water was added above the top of the gravel. Boring P2 was fully saturated with approximately 3.0 feet of water above the top of gravel from the overnight rain event therefore no additional water. Both borings were found to be dry and intact after the 24-hour pre-soak period. The percolation tests were conducted in accordance with the requirements of the San Joaquin County EHD on May 17, 2019 per Procedure #2. Terracon added clear water approximately 0.5 feet above the top of the gravel and recorded the drop in water level at thirty minute intervals over a four hour period. Measurement of the water level during the percolation test was from a fixed reference point on the PVC casing using a calibrated Solinst electric water level detector with a depth accuracy of 0.01 feet. All tabulated values on the field data sheet are in decimal feet. Responsive ■ Resourceful ■ Reliable 5