Laserfiche WebLink
Soil Suitability / Nitrate Loading Study <br /> Ernst Property ■ Tracy, CA Irerracon <br /> February 21, 2019 revised April 9, 2019 ■ Terracon Project No. NA197000 <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 F. The units <br /> of nitrate used in the mass balance equation are nitrate-N, whose maximum drinking water <br /> contaminant level (MCL) is 10 mg/L. <br /> 2.1 Chemical and Physical Properties of Soil <br /> 2.1.1 Chemical and Physical Soil Properties <br /> Terracon reviewed the USDA NRCS Web Soil Survey and USDA Soil Survey of San Joaquin <br /> County (1992) for information regarding Capay clay soils (Section 1.5). Selected physical and <br /> chemical properties for the soil types are listed in the following table. <br /> Table 1. <br /> Physical and Chemical Properties* <br /> Soil Soil Septic <br /> Name/ Depth USDA Unified Soil Clay Permeability reaction Salinity tank <br /> Map (in) Texture Classification (%) (in/hour) (pH) (mmhos/cm) absorption <br /> Sym bol fields <br /> Capay 0-20 Clay CL 40-60 0.06-0.2 6.6-8.4 <2 Severe: <br /> clay/ 20-60 Clay, CL, CH 40-60 0.06-0 2 6.6-8.4 <2 peres <br /> 118 silty clay slowly <br /> `Selected USDA physical and chemical properties <br /> 2.1.2 Mass Transport Soil Properties <br /> The percolation test has revealed that site clay soils will allow for slow infiltration at shallow depths <br /> between 3.0 feet bgs. The longer the effluent remains near the surface, the more treatment is <br /> enhanced due to natural processes within the soil. Based on the slow permeability and high water <br /> absorption capacity of the clay soils, effluent is anticipated to remain within the clay soil column <br /> much longer when compared to more permeable sands, silts, and loamy soils. <br /> 2.2 Groundwater Analysis <br /> 2.2.1 Regional Groundwater <br /> A discussion of regional groundwater, including depth to groundwater and flow gradient is <br /> included in Section 1.4.1. No significant seasonal trends were evident from the sources <br /> consulted. <br /> 2.2.2 Potential Ground Water Contamination Issues <br /> A discussion of issues related to potential groundwater contamination is included in Section 1.4.2. <br /> Responsive■ Resourceful ■ Reliable 12 <br />