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"a r II. SOIL SUITABILITY STUDY FINDINGS A. SUBJECT PROPERTY AND SURROUNDING STUDY AREA INFORMATION SSS§ 1.1. Land use to the immediate west and south is agricultural production land. To the east is the City of Tracy Wastewater Treatment facility and to the north is a commercial recycling facility. SSS§ 3.1,3.2,3.3,3.4,3.5,3.6,3.7, 6.8. Applications on EHD microfiche files were not available for review to determine the number of permits issued for repairs/replacements/additions to existing systems within the one-half mile radius study area. The septic systems in this locale are extremely sparse so data is-limited. Given the clay content of the on-site and surrounding soils, septic system longevity is most likely limited and septic system failures will eventually occur. The project site has level terrain; consequently,there is no need to incorporate design considerations for slopes within the effluent disposal area. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS SSS§ 5.2. The United States Department of Agriculture-Natural Resource Conservation Service (USDA-NRCS) indicates the property soils are Capay clay(#118). The surface and subsurface soil investigation began on June 13,2016 with the drilling of one 36-inch deep perc test boring. In addition to the perc test boring, an excavator was used to explore the underlying soils and to remove a concrete structure. An excavation down to 12 ft was conducted with the soils a consistent clay. No water(water table/groundwater)was encountered. NLS§ 1.1, 1.2. Auger cuttings were sampled from the bottom of the 3-ft test boring for chemical analysis. As noted on the A&L Laboratory Soil Report in Appendix C, analyses of the soil sample quantifies a number of constituents that influence nitrate loading for this project. The important parameters for nitrate loading assessment are the organic matter,pH, cation exchange capacity } (CEC), and the nitrate-nitrogen content of the soil. As noted,the organic matter is 1%which translates to an Estimated Nitrogen Release(ENR) of 54 lbs. of N/acre. This is an insignificant concentration of nitrogen over a one acre area. The soil nitrate-nitrogen concentration is high at 73 ppm. It is unknown why this high concentration exists, s but this is only a slight concern given the clay soil will promote denitrification. s Because septic effluent is composed predominately of ammonium(NH4),the pH, along with the CEC, qJ are significant influences on the ammonium molecules. The pH of the soil is alkaline at the proposed soil-effluent interface which has a positive effect in promoting ammonia and not the nitrate substrate ammonium within the alkaline soil environment. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. The CEC illustrates a high potential for the clay soil for retention of ammonium molecules that remain as ammonium and are not converted to ammonia in the soil environment. Nitrification is also hindered due to the alkaline pH and from the anaerobic micro-sites within the clay soil. Page-2- Chesney Consulting