Laserfiche WebLink
Soil Suitability/Nitrate Loading Study <br /> Schuler Property - Tracy, California Irerracon <br /> May 30, 2019 2 Terracon Project No. NA197026 <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 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 6. <br /> Physical and Chemical Properties* <br /> Soil Soil Septic <br /> Name/ Depth USDA Unified Soil Clay Permeability Salinity tank <br /> Ma in Texture Classification % in/hour reaction mmhos/cm absorption <br /> P (� ) � ) l� ) (pH) � ) rp <br /> Symbol fields <br /> 0-17 Clay loam CL 27-35 0.2-0.6 6.6-7.3 <2 <br /> Stomar Clay <br /> clay 17-47 loam, CL, CH 35-60 0.06-0.2 6.6-8.4 <2 Severe: <br /> loam/ clay peres <br /> 253 Clay slowly <br /> 47-60 loam, SC, CL 27-40 0.2-0.6 7.7-8.4 <2 <br /> silty clay <br /> loam <br /> *Selected USDA physical and chemical properties <br /> 2.1.2 Mass Transport Soil Properties <br /> Silty sandy soils were encountered at 42 inches at percolation test boring B1. The percolation test <br /> has revealed that site soils will allow for sufficient infiltration at shallow depths <3.5 feet bgs. <br /> Clayey soils were encountered in the soil profile boring B2 between 6.5 and 10 feet bgs. The <br /> longer the effluent remains near the surface, the more treatment is enhanced due to natural <br /> Responsive ■ Resourceful ■ Reliable 12 <br />