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1 <br /> 4350 E.Acampo Road Project No.2018-0043 P a g e 16 <br /> immediate vicinity of the site.This is a moderately high amount of septic systems,with the majority t <br /> of these systems located in the three separate subdivisions within a mile of the site. ' <br /> There is currently a domestic well onsite. <br /> The onsite water well was tested for nitrate. Total nitrogen was reported at 3.8 mg/L. The lab results ' <br /> are included in Appendix B. <br /> 4.2 Contribution of Rainfall <br /> An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The <br /> estimate of deep percolation of rain is based on the average monthly precipitation of rain fall for Lodi, ' <br /> California, based on the nearest weather station to the site available. The estimate first determines <br /> whether the average monthly precipitation exceeds average monthly potential evapotranspiration. <br /> If so, then the difference is potential deep percolation. This method does not consider runoff. See ' <br /> Plate 7 for the data and calculation. <br /> Average potential evapotranspiration was obtained from the California Irrigation Management <br /> Information System (CIMIS).The site is located within evapotranspiration zone number 12,as well ' <br /> as the Lodi station used in the analysis. The average rainfall for the area was also obtained from <br /> CIMIS where the average rain fall for the Lodi area was obtained from the Western Regional Climate <br /> Center(www.wrcc.dri.edu)and was found to be 17.27 inches per year for years 1893 to 2015. ' <br /> Based on this method, the average deep percolation of rain for the Acampo area is estimated to be <br /> 5.29 inches. The nitrate concentration of rain fall was estimated to be 1 mg/L-N (Hantzsche and ' <br /> Finnemore, 1992). <br /> 4.3 Current On-Site Sources of Nitrate ' <br /> There is currently one home on-site where the existing septic system, along with <br /> groundwater and rainfall,are recognized as potential current on-site sources of nitrate. ' <br /> 4.4 Future On-Site Sources of Nitrate <br /> 4.4.1 Quantity and Quality of Domestic Wastewater from Proposed Project ' <br /> The following discussion is for determining the long-term wastewater flow anticipated from <br /> the current and planned residential houses for the site, to be incorporated into the nitrate ' <br /> loading analysis.The anticipated wastewater flow determined is not intended to be used for <br /> septic system design, because septic system sizing includes a peak use factor, whereas the <br /> numbers discussed herein are based on a long-term conservative measure of estimated <br /> effluent volume. <br /> There is currently a 3-bathroom, 2 bath residence with associated septic system onsite. In <br /> addition, a proposed 3-bedroom, 2-bathroom residence with a separate septic system is <br /> planned for the site. Per San Joaquin County Environmental Health requested guidelines <br /> based on previous nitrate loading studies,an average daily flow of 140 gallons per bedroom ' <br /> per day is estimated for the site. The following table presents the nitrate contributing septic <br /> Petralogix Engineering,Inc <br /> 26675 Bwella Road,Galt,Ca 95632 ' <br /> (209)400-5729 <br /> w .petmlogkcom <br /> 1 <br />