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November 23, 2004 NOA Project Number: E040140A 3.4.1 Quantity and Quality ofDomestic Wastewater From Proposed Project The following discussion is for determining the long-term waste water flow generated from the proposed residence and business for the nitrate loading analysis. These estimates may not be appropriate for septic system design purposes since they do not contain any peak factors. The number discussed here are based on long-term averages. The on-site usage on the parcel is a combined use from the existing residence and the winery tasting room guests and staff. As mentioned previously,it is possible that a legal second dwelling unit of up to 1,500 square feet may someday be constructed on the property. For purposes of the nitrate loading study,we will assume that this dwelling will be two bedrooms and occupied by up to three people. ` Twelve (12) special marketing events may occur on site each year between April and October. These events will utilize portable restrooms. The waste water generated by the special events will not disposed on the property and will be removed off-site by a service company_(12ersonal communication,November 22-23. 2004). The winery staff is five (5) full time workers and one (1) part time worker. The expected days of operation are Friday thru Sunday, 11:00 AM to 4:00 PM. The average visitor attendance is 120 people per week. This is equivalent to 40 guests per day;three days per week. We understand the existing septic system was designed for winery tasting room use (personal communication, November 22-23, 2004). The estimated sewage flow rates for use categories are available from a number of references. The uses presented below were guided by the San Joaquin County On-Site Wastewater Disposal Standards (2003), Crites and Tchobanoglous (1998), and EPA (1980). The San Joaquin County On-Site Wastewater Disposal Standards does not provide a flow rates for residential use and was written primarily for septic system design. The text from Crites and Tchobanoglous (1998) (Table 4-2) indicates that the typical residential use rate is 70 gallons per day for a resident. The EPA (1980) Design Manual (Table 4-6) indicates the typical use rate is 45 gallons per day for a resident. Crites and Tchobanoglous (1998) mentioned that a bar customer is an average of 3 gpd/person and bar employees is an average of 13 gpd/person. Since the bar category is similar to winery,we will use the bar category estimates for the winery guests and staff. Since the Crites and Tchobanoglous (1998) information is the most current available, our office believes it provides the best estimate of both the residential and commercial category. The following table presents the septic waste water uses associated with the project. The rates presented from the references provide general guidance but do not always reflect a match in usage. Careful examination,professional judgement, and experience are necessary to select a reasonable 5