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Nitrate Loading Study- Update 2 1��rracon <br /> Macchia Winery Acampo, CA <br /> February 6, 2017 Terracon Project No. NA177004 <br /> Nitrate Loading Study - Update letter dated October 29, 2007 (Project Number E07146A): The <br /> update letter was issued at the request of the SJCEHD to clarify clerical errors regarding <br /> contribution of rainfall calculation and deep percolation of rain. Based on the rapid percolation <br /> rate, an estimated 80 percent of rainfall was anticipated to enter the groundwater as recharge <br /> with a 20 percent reduction estimated for ETo and plant transpiration. Deep percolation of rain <br /> was estimated to be 14.06 inches per year with a nitrate concentration of rainfall estimated to be <br /> 1.0 mg/L N. <br /> Interviews Regarding Current and Proposed Site Uses <br /> In an effort to determine current system usage, Terracon submitted a SSNLS questionnaire to the <br /> client for completion. According to Ms. Tanya McMahan, General Manager, the site currently <br /> utilizes two septic systems comprised of the following: <br /> Location Number of Number of Number of Number of Washing <br /> Sinks Toilets Showers Machines <br /> Tasting Room 4 4 --- 1 <br /> Warehouse 2 2 --- --- <br /> The site is used for commercial purposes five days per week from 11 am to 5 pm with a maximum <br /> of eight employees working between six and eight hours per day. Mr. Jonathan McMahan <br /> indicated the facility receives approximately 50 visitors weekly at the winery tasting room which <br /> stay at the establishment for one hour on average. In addition, the winery will be participating in 2 <br /> up to twelve (12) 2-day marketing events per year with a maximum of 75 people attending each <br /> per day. <br /> At the time of the 2007 SSNLS, the site consisted of one single family residence and one septic <br /> system located on a 1.5 acre property; however, Mr. McMahan indicated a single family residence <br /> is not being used as such and is understood to be used as a tasting room. <br /> Average Daily Flow <br /> The following table is an Average Daily Flow estimate for the existing and proposed site uses: <br /> Table 1. <br /> Updated Typical Quantity of Effluent <br /> Estimated Average Days Gallons <br /> Use #of people Quantity of use Average Daily Flow Per Day <br /> per day per person per <br /> (gal) year (9Pd) <br /> Employee 8 13 260 (8 person x 13 gal x 260 days)/ 74.08 <br /> 365 days <br /> Visitor 10 15 260 (10 person x 15 gal x 260 days)/ 106.85 <br /> 365 days <br /> Marketing 75 15 Y4 (75 person x 15 gal x 24 days)/ 73.97 <br /> Events 1 1 365 days <br /> Total Average Daily Flow(gallons per day) 254.90 <br /> Bold=additional projected effluent increase <br /> Resourceful ■ Reliable a Responsive 2 <br />