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F1 June 27, 2005 NOA Project Number: E050" 4.3 Current On-Site Sources of Nitrate Current on-site sources of nitrate include the application of fertilizer for the vineyard (no wine production is done on-site) and a cherry orchard.Vineyards are relatively low consumers of nitrogen r (N) and require up to 25 to 30 lbs. per acre. Cherry orchards require slightly more nitrogen requiring approximately 95 to 125 lbs. per acre annually. For the purposes of the nitrate estimate,we will assume that any fertilizers and irrigation are applied at agronomic rates so that any fertilizer leaching to ground water is minimal and appropriate management practices are used. The nitrate loading study will not consider any vineyard fertilizers for the nitrate balance equation. rd 4.4 Future On-Site Sources of Nitrate F14.4.1 Quantity and Quality of Domestic Wastewater From Proposed Project f The following discussion is for determining the long-term waste water flow enerated from the F1pro osed residences 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. Plate 10 is the nitrate loading calculation for the new development. With the building of the Trucking/Construction Company a septic system is to be installed on the property. The company employs 10 drivers and 50 office workers. In the future, next 10 years,Mr.Lagorao estimates that P they will hire another 15 office workers. The office workers will be working 8 hour days, Monday through Friday. The typical office employee is estimated to generate 13 gallons of wastewater per day. The 10 drivers are only at the property for pick-up and drop-off of the trucks and are gone for most of the work day. Because the drivers are out of the office all day, they will be treated similar to a `customer use,' generating .five gallons er da . The trucking company also estimates that they will receive 20 customers per wi e" (average of 4 per day). In summary, the maximum expected level will �- � y F be 65 office em�l2yees�generating 13 gallons per day and 14 customers/truck drivers using five 1 I gallons of wastewater per day. 1aa 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 LlastewaterDisposal Standards o (2003), Crites and Tchobanoglous (1998), and EPA (1980). The text from Crites and Tchobanoglous f (1998) (Table 4-2) indicates that the typical residential use rate is 70 gallons per day. The EPA (1980) Design Manual (Table 4-6) indicates the typical use rate is 45 gallons per day for a resident. F1The higher estimate of Crites and Tchobanoglous will be used for residential use. Also, the estimates for Office Employee and Public Lavatory will be used from that book as well. The following tables 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 in 4 F