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The attached A&L Laboratory Soil Analysis Report (Appendix B) illustrates the chemical analytical results and the textural analysis (sand, silt and clay percentages) of the soil samples which quantifying several constituents that influence nitrate loading from this project. The primary parameters for nitrate loading assessment are the organic matter, clay content, pH, cation exchange capacity (CEC), and the nitrate-nitrogen fractions of the soil. The organic matter in the two samples is low, which is typical for San Joaquin Valley soils. The 20-24" depth soils are a clay loam with 38.1% clay content, but decreases to 25.6% clay at the 42-48" soils. The sand content increases from 33.8% to 55.0%. This increase in sand content can create anaerobic conditions in the sandier stratum, thus leading to denitrification of the ammonium that has nitrified. The CEC concentration is relatively high for both samples due to the clay content. The pH of the soil is acidic at the shallower depth but dramatically becomes alkaline at the deeper depth. Alkalinity can cause a decrease in Nitrobacter activity, thus inhibiting the second step of the nitrification process although alkalinity generally increases the rate of nitrification. In addition, the observed alkalinity is sufficient to influence ammonium stability. Ammonia may be preferentially created, thus impeding nitrification of ammonium to nitrate. It has been observed on other projects that significant denitrification occurs directly above a hardpan strata composed of a sandier material, potentially due to anaerobic conditions, thus promoting denitrification. The nitrate nitrogen concentration from the two samples is very low at 1 ppm, signifying a high degree of denitrification potential. Section B: A filter bed effluent disposal structure is the only structure that can be installed for this project due to replacement area and well setback requirements. In addition, a 2,000 gallon septic tank has been specified instead of a required 1,200 gallon tank. Effluent from this tank will gravity to the distribution box (D-box). From the D-box, effluent will equally transfer under gravity through three laser-leveled perforated leachlines, with the leachlines connected together with perforated pipe at the ends to force equal effluent distribution. A sump structure at the east end of the filter bed will provide additional infiltrative area. A 12"-18" soil cover over the filter bed will allow oxygen intrusion and root structures from grass vegetation over the filter bed to manage nitrate loading through nitrification/denitrification and evapotranspiration. Section C: The rainfall recharge factor used in the Hantzsche-Finnemore equation for the AdvancedGeo report was specified by CIMIS data. Water balance documentation from Norman Hantzsche (one of the authors of the nitrate loading equation) found in Appendix C, illustrates his water balance analysis of Net Rainfall Recharge (NRR). The data presented indicates an NRR of 8.82" for the Stockton area, and is therefore applicable for this project. Page -2- Chesney Consulting