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F, February 28, 2007 NOA Project Number: E07023A ! 3.4 Future On-Site Sources of Nitrate 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 construction for the nitrate loading analysis and should not be used for septic system design purposes. Typically,use estimates for the sizing of septic systems include a peak use factor, whereas the numbers discussed here are based on long-term averages. The maximum expected septic tank usage for the site will be from various buildings. An office building will have five to six people working with no customers. Six to eight.employees and no F1 customers will work at a repair shop on site.A dispatch building will have fou#people working, and there will be four people working at a washing facility. Forty to fifty truckers will be coming and going throughout the day. The facility will be open normal business hours, five days a week in the approximately eight winter months of November through June, and will be open six days a week ui _ the summer months,July though October. Several septic systems are being proposed for construction. 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 C"1 (2003), Crites and Tchobanoglous (1998), and EPA (1980). The references indicate that 13 gallons for each employee is typical for an office worker and 5 gallons for each truck driver. (Crites and rchobanogious, 1998). A shower is proposed in the repair shop which will serve a maximum of ten to fifteen people a day. The following table presents the septic waste water uses associated with the Site. 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 flow rate estimate. The flow rates selected for the uses associated with this project are presented = next. 4 Table 1. Typical Quantity of Effluent Total People per Average Quantity per Average Daily Flow Category Day Person Per Parcel Shower 15 3 5gal/day/employee (15 employees*35 gpd) = 525 gpd Truckers 50 5 gal/day/trucker (50 truckers*5 gpd) = 250 gpd Employees 22 13 gal/day/employee (22 employees* 13 gpd) =286 gpd Total 1,061 gpd Note —gpd is gallons per day. P5