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Soil Suitability/ Nitrate Loading Study Addendum Letter Lange Twins Winery P„ Acampo, California Irerracon May 21, 2019 Terracon Project No. NA197005 Document Review Based on a review of the Soil Suitability& Nitrate Loading Study for Lange Twins Winery, Inc.dated August 5, 2005 prepared by Neil O. Anderson & Associates, Inc. (NOA), Project No. E05098A, the site formerly consisted of a 79 acre tract of pasture land with riparian habitat former Assessor Parcel Number (APN) 003-150-08. Jahant Slough divided the northern half of the site from the southern half. The site was improved with on agricultural well and no septic systems. Depth to groundwater was reported at 49 feet below grade surface (bgs) and groundwater was not encountered. In 2005, a groundwater sample collected from a former onsite agricultural well was analyzed for Nitrate and dibromochloropropane (DBCP). Nitrate was reported at 13.8 milligrams per liter (mg/L). below the United State Environmental Protection Agency (EPA) maximum contaminant level (MCL)of 45 mg/L. DBCP was not identified in the groundwater sample. Surface soils indicated the site consisted of Bruella sandy loam and San Joaquin loam. Four soil borings (P-1 through P-4)advanced at 3.5 feet bgs and 25 feet bgs. Soils consisted of sandy silt (0-3 feet bgs) and ranged from clayey sand (3-5 feet bgs), hardpan (5-8 feet bgs), silt with clay (8-14 feet bgs), sandy silty with clay(8-20 feet bgs)to clayey sand (25 feet bgs). Two shallow and two deep percolation tests were conducted in August 2005. Percolation rates were reported as follows:P- 1 deep at 125 minutes/inch, P-1 shallow at 25 min/inch, P-2 deep at 5 min/inch, and P-2 shallow 16.6 min/inch. With the exception of P-1 deep, NOA reported the percolation tests had satisfactory percolation rates. NOA calculated the average daily flow for the septic wastewater to be 446 gallons per day (gpd) (40 employees x 13 gallons per person per day, six days per week). The average total nitrogen concentration of wastewater was reported at 60 milligrams per liter nitrogen (mg/L-N). A 25% denitrification factor was selected due to the presence of fine-grained soils. Deep percolation of rainfall was estimated to be 5.76 inches per year. The nitrate mass balance was calculated to be 1.6 mg/L-N below the MCL of 10 mg/L-N. The 2005 NOA report did not include visitors or special events in the calculations. Terracon was provided with a copy of the following additional documents. Phase I Site Plan dated February 4, 2019 prepared by WMB Architects Based on a review of the Phase I Site Plan a 400 SF tasting stand-alone restroom building will be developed north of Building 1 located on the eastern portion of the facility. Based on information provided by Mr. Lange, the restroom building will include 4 toilets, 1 handicap, and a common trough sink and will service the existing tasting room. Phase 2 Site Plan dated November 2, 2018 prepared by WMB Architects Based on a review of the Phase 2 Site Plan the office 11,775 SF office building will be developed northeast of the existing bottling building, between the existing eastern and western ponds. Based on information provided by Mr. Lange, the building will serve as an office with breakroom. Responsive ■ Resourceful ■ Reliable 2