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Soil Suitability 1 Nitrate Loading Study Irerracon Betschart Property Lodi, CA July 19, 2019 Terracon Project No. NA197044 convenient and simplified method to estimate long-term groundwater nitrate impacts on an area- wide basis. Hantzsche and Finnemore found that over a long period of time, water quality in the upper saturated groundwater zone closely approximates the quality of percolating recharge waters. They believe that their method is a good planning tool and provides useful information to planners and local officials but with some real limitations. In their article published in Ground Water, Hantzsche and Finnemore mention that "...the equation ignores dispersion, lateral flow, and mixing with groundwater flow from up-gradient areas. These processes would generally contribute to additional reduction of nitrate-nitrogen concentrations in groundwater to the extent that the nitrate-nitrogen concentration of groundwater flow from up-gradient areas is lower." The Hantzsche and Finnemore approach is "...a conservative (worst case) first approximation of groundwater nitrate-nitrogen concentration resulting from the combined effect of on-site sewage disposal systems and precipitation. This (the equation and approach) is for estimation of long- term effect (i.e., over years)on groundwater quality, and is not intended for prediction of seasonal changes" (Hantzsche and Finnemore, 1992). The method takes into account the development area, soil denitrification factor, rainfall volume, rainfall nitrate concentration, waste effluent quantity, and waste effluent nitrate concentration. The formula, assumptions and calculations used for the analysis are shown in Appendix F. The units of nitrate used in the mass balance equation are nitrate-N, whose maximum drinking water contaminant level (MCL) is 10 mg/L. 2.1 Chemical and Physical Properties of Soil 2.1.1 Chemical and Physical Soil Properties Terracon reviewed the USDA NRCS Web Soil Survey and USDA Soil Survey of San Joaquin County (1992)for information regarding San Joaquin loam soils (Section 1.5). Selected physical and chemical properties for the soil types are listed in the following table. Table B. Physical and Chemical Properties* Soil Name/ Depth USDA Unified Soil Clay Permeability Soil Salinity Septic tank M Map (in) Texture Classification (/o) (in/hour) absorption (PH)reaction (mmhos/cm) fields Symbol Fine 0-5 sandy SM 10-14 2.0-6.0 5.6-7.3 <2 Kingdon loam fine Fine 5-14 sandy SM 10-14 2.0-6.0 6.1-7.3 <2 Moderate, sandy loam wetness, loam/ peres slowly 189 Sandy 14-28 loam,fine SM 10-14 2.0-6.0 6.1-7.3 <2 sandy loam Responsive a Resourceful s Reliable 12