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lrerracon Nitrate Loading Study <br />Nielsen Property Ripon, California <br />January 15, 2019 Terracon Project No. NA187066 <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 /> <br />1.0 CHEMICAL AND PHYSICAL SOIL PROPERTIES <br /> <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 Delhi loamy sand. Selected physical and chemical properties are <br />listed in the following table. <br />Table 1. <br />Physical and Chemical Properties* <br />Soil <br />Name! <br />Map <br />Symbol <br />Depth <br />(in) <br />USDA <br />Texture <br />Unified Soil <br />Classification <br />Clay <br />(%) <br />Permeability <br />(in/hour) <br />Soil <br />reaction <br />(pH) <br />Salinity <br />(mmho <br />s/cm) <br />Septic <br />tank <br />absorption <br />fields <br />Delhi / <br />142 <br />0-16 loamy sand SM 0-5 6.0-20 6.1-7.8 <2 Severe; <br />poor filter 16-26 loamy sand SM 0-5 6.0-20 6.1-7.8 <2 <br />26-60 sand SP-SM 0-5 6.0-20 6.1-7.8 <2 <br />*Selected USDA physical and chemical properties <br />1.2 Mass Transport Soil Properties <br />The below additional information pertaining to mass transport for was obtained from the USDA <br />sources listed in Section 1.1. <br />Delhi loamy sandy soils are located across the site and consist of somewhat excessively drained <br />soils. Delhi loamy sandy soils have rapid permeability and slow runoff. The rate of water in-take <br />in irrigated areas is anticipated at 3.0 inches per hour. For homesite development with septic tank <br />absorption fields, the main limitations are rapid permeability and poor filtration. A tillage pan may <br />form if soil is tilled when wet; however, the pan may be broken up by chiseling or ripping. <br />The longer effluent remains near the surface, the more treatment is enhanced due to natural <br />processes within the soil. Based on the loamy sandy soils and rapid permeability anticipated for <br />Responsive • Resourceful • Reliable 3