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r Nitrate Loading Study <br /> Flag City#4 ■ Lodi, California Irerracon <br /> September 20, 2018 s Terracon Project No. NA187043 <br /> contribute to additional reduction of nitrate-nitrogen concentrations in groundwater to the extent <br /> that the nitrate-nitrogen concentration of groundwater flow from up-gradient areas is lower." <br /> The Hantzsche and Finnemore approach is "...a conservative (worst case) first approximation of <br /> groundwater nitrate-nitrogen concentration resulting from the combined effect of on-site sewage <br /> disposal systems and precipitation. This (the equation and approach) is for estimation of long- <br /> term effect (i.e., over years) on groundwater quality, and is not intended for prediction of seasonal <br /> changes" (Hantzsche and Finnemore, 1992). <br /> The method takes into account the development area, soil denitrification factor, rainfall volume, <br /> rainfall nitrate concentration, waste effluent quantity, and waste effluent nitrate concentration. The <br /> formula, assumptions and calculations used for the analysis are shown in Appendix B. The units <br /> of nitrate used in the mass balance equation are nitrate as N. The United States Environmental <br /> Protection Agency (EPA) maximum contaminant level (MCL) for nitrate as N in drinking water is <br /> 10 milligrams per liter (mg/L). <br /> 1.0 CHEMICAL AND PHYSICAL SOIL PROPERTIES <br /> 1.1 Chemical and Physical Soil Properties <br /> Terracon reviewed the United States Department of Agriculture (USDA) Natural Resources <br /> Conversation Service (NRCS) Web Soil Survey and USDA Soil Survey of San Joaquin County <br /> (1992) for information regarding soil properties. Based on information obtained from the USDA <br /> sources, site soils consist of two soil types including Acampo sandy loam and Devries sandy <br /> loam. Selected physical and chemical properties for the soil types are listed in the following table. <br /> Table 1. <br /> Physical and Chemical Properties* <br /> Soil Soil Salinity Septic <br /> Name/ Depth USDA Unified Soil Clay Permeability tank <br /> Map (in) Texture Classification (%) (in/hour) reaction (mmho absorption <br /> Symbol (pH) s/cm) fields <br /> 0-19 sandy loam SM 7-18 2.0-6.0 6.1-7.8 <2 <br /> - -._....._. _ ..... ....... <br /> sandy <br /> Acampo 19-47 loam,fine SM 7-15 2.0-6.0 6.1-8.4 <2 Moderate; <br /> / 101 to coarse cemented <br /> sandyloam.............._ .......----................._..__............._._..------ ......_ .....— --- <br /> 47-49 cemented --- -- --- -- -- <br /> ........................................._...._....................................__.._..._...................................................................................._......_..----..._....-—-- ...._....._..._........_.......-- ......._._._............_.......... <br /> 49-60 cemented --- -- --- --- --- <br /> 0-13 sandy loam SM 7-18 2.0-6.0 6.6-8.4 <2 <br /> .................. .................._..............._...._..._ ........_ ..----....._.._._ ............_.........._..............__..._ _ ....._........................................._._.... --...._........ <br /> .......... <br /> Devries/ sandy Severe; <br /> 149 13-28 loam,fine SM 7-18 2.0-6.0 6.6-8.4 <2 cemented <br /> sandyloam pan <br /> . ---——. _............—_.... —.._....._._ . ........ <br /> 28-80 indurated -- -- - - -- -- <br /> *Selected USDA physical and chemical properties <br /> Responsive ■ Resourceful ■ Reliable 3 <br />