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.�,R SOIL PItQFIlER�CHARACPElSTICS iANDA; TI�YTI�A�` ' - € a } e¢ y g Asir. g€,& 3 j}1 ¢€'i{s yRR �,.a%ke? 3 8"..f.�f;x9 .m. �4f. . e Y. ` TES'.Il .j`,:L�a.•1 A.J.��=-J a11.1�! . 7(y ,y- � .;,� sis3?.144s�.��ia,}T+,+``s SOIL DESCRIPTIONS SAND,SILT AND CLAY SOIL NITRATE-NITROGEN PERCENTAGES CONTENT 42 In.Depth Loam 47%, 33%, 21% Ju I 10 ppm NO3-N 7.2 Ft Depth Silt Loam 22%, 53%, 26% f n 1 15 ppm NO3-N 16 Ft.Depth Sandy Clay Loam 47%, 23%, 31% to� 5 ppm NO3-N In correlating permeability and particle size analysis, the sand, silt and clay percentages suggest the soils to be somewhat similar between the shallow and deep perc test borings, particularly with regard to sand content. It would have been expected for the shallow, 42-inch perc test to have a relatively equal, if not faster perc rate than the deeper perc test boring due to the higher silt content, but this was not the case. Since the deep perc test had a greater head of water, percolation was 5.4 times faster in this boring in comparison to the shallow boring, thus demonstrating and proving the function head pressure has on soil permeability. f An analytical assessment of the subsurface soils was done on the three samples referenced above, with the test results noted on the SOIL ANALYSIS REPORT. Chemistry was done on the three soil samples to analyze several constituents that influence nitrate loading. The important soil parameters for nitrate loading assessment are the organic matter, pH, cation exchange capacity (CEC), and indigenous nitrate-nitrogen content. As noted from the test results, the organic matter in the soil profile is low. The nitrate-nitrogen contents reveal the shallow depth has a low concentration of nitrate-nitrogen at 10 ppm, however, the 7 foot depth increases to 15 ppm. The concentration decreases to 5 ppm at the 16-foot depth. There is a walnut tree near the test borings which suggests there may have been other trees at some time in the past. This may explain the observed differences in subsurface nitrate-nitrogen concentrations. Since septic effluent is composed predominately of ammonium (NH4), the pH, along with the ' Cation Exchange Capacity (CEC), have an influence on ammonium molecules. The pH of the shallow soils is acidic,while the deeper soils are neutral. This pH profile may not have a significant effect on inhibiting ammonium formation and stability, and therefore nitrification potential may not be decreased. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. Cation Exchange Capacity test results for all three soil samples is low, especially considering the clay content in the 16 foot boring. Consequently, there is a low potential for the retention of ammonium molecules for microbial uptake. However, since the nitrate-nitrogen concentration was quite low at the 16-foot depth, contrary to the lack of riitrification inhibiting factors discussed above, there may be a denitrification or immobilization influence on the nitrate- nitrogen concentration at the deeper depths. Nevertheless, the factors discussed make it important to reduce the depth of seepage pits to 16 feet instead of the typical 25 feet. 4 Chesney Consulting