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TABLE 2 PERCOLATION TEST RESULTS FOR THE DISPOSAL AREA SYSTEM WITH CORRESPONDING APPLICATION RATES IN GALLONS/FT /DAY 36 INCH DEEP PERC TEST BORING 8.6 min/inch / 0.800 gallons/ft'/day PERCOLATION RATE/APPLICATION RATE Appheation Rates adapted from Water QualityControlleoinyfor Siting,Design,Opemnon,midMaintenance ofOnsite Wastewater Treatment Systems. D. GROUNDWATER INFORMATION NLS§2.1, SSS§ 4.1,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 Lines of Equal Depth place the groundwater depth at 30 ft below grade which corresponds with a geotechnical finding conducted for the project that found the water table depth at 28 ft. With regard to groundwater directional flows, it is generally regarded that groundwater flows either toward the Stanislaus River, or in northeasterly direction depending on the flow volumes of the River. / NLS§2.2 3 .1, SSS§ 2.I, 4.2 Since surrounding properties have been intensely farmed for several decades, the potential Jr nitrate contamination in the underlying groundwater is significant. This was c nfirme by ZLwater sample from the on-site domestic well revealing a nitrate concentration 0184 ppm'nitrate. Groundwater research in the scientific literature suggests there may be a large &Wg kation potential within aquifers or saturated zones. This may be occurring since it would be logical to assume a much higher nitrate concentration in the underlying aquifers. NLS§2.3, SSS§ 4.3 4.4, 4.5 As referenced,the domestic water from the well that serves the on-site residential structure was sampled for both nitrate and total alkalinity. Calculation of Alkalinity Requirement for Nitrification The estimated nitrate-nitrogen loading found on Page 9 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 is derived from the well water supply, from within the soil environment, and from the introduction of human waste constituents. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen (NH,N) oxidized. Nitrification of the average Total Nitrogen(TN)concentration of 60.1 mg/L, as explained on Page 7 would require: 60.1 mg/L NH4-N x 7.1 mg CaCO3 =426 mg/L alkalinity. The alkalinity in the domestic well water supply is presently 325 ppm. This concentration, coupled with soil alkalinity and waste alkalinity may be sufficient to promote nitrification. 4