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00� The field test results are found in Appendix E and the Table below summarize the test results: ;I j TABLE 2 PERCOLATION TEST RESULTS WITH CORRESPONDING APPLICATION RATES IN GALLONS/FT'/DAY DEEP 25 FT TEST BORING (9/1/22) 125.0 min/inch / 0.100 gallons/ftZ/day MODERATE DEPTH 12 FT TEST BORING (9/1/22) 35.7 min/inch / 0.467 gallons/ft2/day SHALLOW WEST TEST BORING (9/2/22) 10.9 min/inch / 0.786 gallons/ft/day SHALLOW EAST TEST BORING(9/2/22) 50.0 min/inch / 0.311 gallons/ft/day AVERAGE OF THE TWO SHALLOW TEST BORINGS 30.5 min/inch / 0.552 gallons/ft/day Application Rates adapted from Waste Quality Control for Siting,Design,Operation and Maintenance of On-site Wastewater Treatment Systems,based on the Perc Rate. D. GROUNDWATER INFORMATION NLS§2.1, SSS§4.1. Groundwater depths and elevations throughout San Joaquin County are illustrated on maps published by the County Flood Control and Water Conservation District. The 1983 and 1999 Lines of Equal Depth Maps indicate the depth to water at approximately 75 ft. These two years are considered the approximate heaviest rainfalls on record. The Fall'2019 Lines of Equal Depth Map illustrate an approximate 100 ft depth to groundwater,thus revealing a 25 ft drop in water table elevation due to excessive pumping and limited recharge during serious drought periods. From the Lines of Equal Elevation Maps, groundwater directional flow appears to be in an easterly direction. NLS§2.2,3.1, SSS§2.1,4.2. Properties to the north, south, and east are currently on septic systems. Considering this area was farmed for decades and the density of residential units,there is potential for nitrate contamination to the underlying groundwater in this locale. NLS§2.3, SSS§ 4.3,4.4, 4.5,4.6. There is one well on the property located near the NEC or the Aspire School Building. This well is used for landscape irrigation of the property exclusively. Calculation of the Alkalinity Requirements for Nitrification The nitrate-nitrogen loading calculations are contingent upon the environmental factors required for nitrification to occur. These conditions include soil pore-space oxygen content, soil temperature, pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the water source, in addition to the introduction of wastes and soil alkalinity. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen(NH4 N) oxidized. Nitrification of the Total Kjeldahl Nitrogen(TKN) concentration of 131 mg/L, as determined below,would require: 131 mg/L NH4-N x 7.1 mg CaCO3=930 mg/L alkalinity. The alkalinity in well water is unknown but probably around 150 mg/L. The alkalinity determined from the septic tank effluent sample was 727 mg/L. 150+ 727 = 877 mg/L alkalinity. Therefore, there may be sufficient alkalinity for nitrification of the effluent ammonium fraction to occur. Page -4- Chesney Consulting