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TABLE 2 PERCOLATION TEST RESULTS WITH CORRESPONDING APPLICATION RATES IN GALLONS /FT'/DAY 40 INCH DEEP PERC TEST BORING 83.3 min/inch / 0.123 gallons/ftZ/day PERCOLATION RATE/APPLICATION RATE OFFICIAL PERC TEST Application Rates adapted from Waste Quality Control for Siting,Design,Operation and Maintenance of On-site Wastewater Treatment Systems,based on the Pere Rate D. GROUNDWATER INFORMATION . l 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 Fall 2016 Lines of Equal Depth Map indicate the groundwater under the property to be approximately 40 feet below grade and may fluctuate between 30 ft and 50 ft below grade. The Fall 2016 Lines of Equal Elevation Map illustrates the groundwater directional flow to be in a northeasterly direction. NLS§ 2.2,3.1, SSS§ 2.1, 4.2. Since the surrounding properties have been farmed for a number of decades, in addition to high density housing within the town of French Camp which are on septic systems(upgradient to the project),the potential for nitrate contamination to the underlying groundwater aquifers can be considered significant. NLS§2.3, SSS§4.3,4.4,4.5, 4.6. There are no domestic or irrigation wells on the subject Parcel. The City of Stockton water is closely monitored for adverse constituents. Calculation of Alkalinity Requirement for Nitrification The nitrate-nitrogen loading to the underlying groundwater is 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 City supplied 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 on Page 6, would require: 62 mg/L NH4-N x 7.1 mg CaCO3 =440 mg/L alkalinity. The alkalinity concentration in the City water was tested at an average of 158 ppm, as reported in the City of Stockton Drinking Water Report dated May 2018. Therefore,there is an insufficient alkalinity in the domestic water for complete nitrification to readily proceed without the introduction of wastes along with the alkalinity in the soil environment. E. SURFACE WATER INFORMATION Storm water drainage management will be by on-site retention located a the south end of the property. Percolating rainwater and water from the adjacent Little o reek and stilling basin will most probably provide an indeterminable water table dilution effect to percolating wastewater effluent. (� Page -4- Chesney Consulting