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TABLE 2 PERCOLATION TEST RESULTS WITH CORRESPONDING SOIL TYPE, PERCOLATION RATE AND APPLICATION RATE IN GALLONS/FT2l DAY jj 38 INCH DEEP PERC TESD BORING 8.9 min/inch / 0.800 gallons/1'1'/day LOAM GROUNDWATER INFORMATION NLS§2.1. Groundwater depths and elevations throughout San Joaquin County are illustrated on maps published by the County Flood Control and Water Conservation District. The Fall 2016 Lines of Equal Depth Maps and the Lines of Equal Elevation Maps indicate groundwater depth and directional flow. Depth to groundwater is approximately 100 ft below grade and the groundwater directional flow appears to be in a northeasterly direction. NLS§ 2.2,3.1. Surrounding agricultural properties are currently farmed and have been for decades, and surrounding properties have been on septic systems so the potential for nitrate contamination of the underlying groundwater can be considered significant. NLS§2.3. The domestic well on the property was sampled and tested for total alkalinity and nitrate. The alkalinity is low at 138 mg/L and the nitrate concentration is 65 mg/L, 20 mg/L over the MCL of 45 mg/L. Discussion on the Alkalinity Requirement for Nitrification The nitrate-nitrogen loading calculation results 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 well water, in addition to the introduction of wastes. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia- nitrogen(NH4 N) oxidized. Nitrification of the average Total Nitrogen(TN) concentration of 62 mg/L, as determined below, would require: 62 mg/L NHa N x 7.1 mg CaCO3 =440 mg/L alkalinity. The alkalinity in groundwater was determined to be 138 mg/L. Therefore, soil alkalinity and alkalinity from wastes must provide a significant alkalinity concentration for nitrification to occur. SURFACE WATER INFORMATION Climatic Data: Rainfall versus Evapotranspiration NLS§3.2. It is generally and scientifically accepted that when precipitation exceeds evapotranspiration(Eto), deep percolation of surface rainwater may occur. Evapotranspiration refers to water evaporation that takes place both at the soil surface and transpiration by plants. Page 3 of 12 Chesney Consulting