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Civil, <br /> Environmental <br /> ft Water <br /> Resources <br /> IVIh;NtORA�l1�JM "._ <br /> ENGINEERING CORP. <br /> TO: Kasey Foley,REHS <br /> Interim Director, San Joaquin Environmental Health Department <br /> FROM: Norman Hantzsehe,PE,Questa Engineering Corporati91 <br /> DATE: February 19,2019 <br /> SUBJECT: OWTS Design Review for 7151 E Peltier Road,Acampo <br /> .PROJECT OVERVIEW <br /> The project is for the expansion of an existing winery with the addition of up to approximately <br /> 13,000 square feet of building,constricted in two phases. The new building will be used for <br /> storage,fermentation processes,laboratory,break zoom and bathroom. A maximum of six <br /> employees are expected to use the facilities.The property also has an existing single fy <br /> residence and wine tasting facility,with capacity for up to 40 visitors per day. amil <br /> Plans and supporting documentation for the OWTS are contained in the"Nitrate Loading Study" <br /> and"Soil Suitability Study"by Dillon&Murphy Engineering,November 2019. Surface soils in <br /> the area are mapped as Brxella sandy loam with good permeability. Percolation testing showed a <br /> rate of 27.8 minutes per inch at 42-inches depth. Groundwater in the project area is estimated <br /> from regional groundwater maps to be about 100 feet below ground sxuface. A standard septic <br /> tank leachfield system is proposed for the project. <br /> The nitrate loading study by Dillon&Murphy utilized a water-nitrogen mass balance analysis <br /> following the Hantzsche/Finnemore methodology. The analysis considered the wastewater flow <br /> and nitrogen loading from the new employees,existing residence and up to 40 wine tasting <br /> visitors per•day. The resultant nitrate-nitrogen concentration impacting the groundwater from <br /> the new OWTS was estimated to be less than 10 mg-N/L,based on calculations for a flow of up <br /> to 2,480 gallons per day, which is double the projected wastewater flow. <br /> COMMENTS <br /> My review comments pertain specifically to the Nitrate Loading Study, i agree with the overall <br /> approach,methodology and most of the information provided in the Dillon&Murphy study. <br /> IIowever, I have questions about some of the assumptions used in the analysis and I have <br /> reconunendations to improve fixture analyses of this type. <br /> 1 <br /> Box 70356, 1220 Brickyard Cove Rd.Suite 206 Pt.Richmond,CA 94807 T.•510/236.6114 F.•510/236.2423 E:Ouesta@GuestaEC.com <br />