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II. SOIL SUITABILITY STUDY FINDINGS A. SUBJECT PROPERTY AND SURROUNDING STUDY AREA INFORMATION SSS§ I.J. As referenced, surrounding land use consists of residential, commercial, and some indu' tfial. Those properties within the County have on-site domestic well water and septic systems. SSS§ 3.1,'3 2, 3.3,3.4,3.5,3.6,3.7 Application files at EHD for repairs/replacements/ ad if ns are not available at this tintefor review of existing systems within a one-half mile radius study area. Therefore, septic system lifespan in this locale cannot be ascertained. However, it canbe � determined that due to the indigenous underlying permeable soils,the proposed system will have a considerable lifespan if properly operated. The project is not located within the flood plain. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS The United States Department of Agriculture - Soil Conservation Service (USDA-SCS) indicates the property soil consists predominately of Jacktone clay#180 with the extreme eastern end of the property as Jacktone clay urban complex (181). SSS§5.2. The surface and subsurface soil investigation began on August 17, 2016 with the drilling of a 36-inc deep perc test boring. The perc test boring was drilled adjacent to the proposed location of the disposal area so that no disturbance of the effluent accepting soil profile would occur. NL 1.1 2. Composite soil samples from the test boring were retrieved for chemical and particle sizom the 0-2 ft depth and the 2-3 ft depth. As the noted on the attached A&L Laboratory Soil Analysis Report, chemical analyses of the retrieved soil sample quantify several constituents that influence nitrate loading for this project. The important parameters for nitrate loading assessment are the organic matter, clay content, pH, cation exchange capacity(CEC), and the nitrate-nitrogen content of the soil. As noted, the organic matter in the 3 ft surface soils is low, at 2.0%, and 1.8% down to the 3 ft depth. These O.M. concentrations suggest that there is a small potential for future nitrate forming from organic matter and an equally small potential for denitrification of nitrate molecules that may form through nitrification. However, as nitrate molecules that may form percolate downward, these molecules encounter a higher density, fine sandy silty soil. This soil type can be anaerobic,thus promoting denitrification and inhibiting nitrification. Because septic effluent is composed predominately of ammonium(NH4),the pH, along with the CEC, are significant influences on ammonium molecules. The pH of the soil is alkaline which may have a positive effect in promoting ammonia formation and not ammonium formation,which is the precursor to nitrate formation. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. Cation Exchange Capacities of the soil samples illustrate a CEC of 29.6 and 25.7 meq/100 g, respectively,which was expected given the clay content of the top soils,but not necessarily of the 2-3 ft deep soils. This suggests that the lower soils (2-3 ft depth)have a high potential for the retention of ammonium molecules for microbial assimilation within these soils. The nitrate-nitrogen concentration is very low at both depths. 2